Dwell reading and CO adjustment

[madstudios]

Hi everyone!
Today I've tried to make my first dwell reading, I've just replaced my 02 sensor with a new one (it was disconneted before that) and now I need to make mixture adjustment.
I've followed the procedures from other topics, but I'm not sure what's going on.
Here is a picture of my dwell meter.
48458
And here is the video of my today's dwell reading.
https://vimeo.com/200097075
Car was warm, fans on.
But reading was about 75 on 4 cylinder scale.

But, after 10 minutes of reading, I've heard a buzzing sound, and I noticed that interfered on dwell reading, here is the video when started the buzz.
https://vimeo.com/200098640
When buzzing, the read drops to 42...

My car was running ok without the 02 sensor, but smelling gas a lot.
With the sensor connected, the engine oscilates a little bit, but runs ok, also smelly.

I don't have a clue if the readings I'm getting are right.
Too lean or too rich?
Any ideas?
Thanks!






Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

[Michael]

The O2 sensor is not working, if the sensor is new and installed correctly, and dwell hooked up and the diag. port functional, then maybe a bad computer?

[madstudios]

The O2 sensor is not working, if the sensor is new and installed correctly, and dwell hooked up and the diag. port functional, then maybe a bad computer?
Dwell was hooked up in the orange wire of missing port diagnose. O2 Sensor is new and properly installed.
When I disconnect and reconnect the 02 sensor with the engine running, It's noticeable that it has some sort of effect, but I don't know if the lambda system is working properly, I bought the car only 3 months ago, and the car was running with sensor disconnected for a long time I suppose.


Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

[Michael]

Well before you go looking at the mixture setting you have to make sure absolutely everything is in proper working order. All vacuum leaks corrected, throttle plates set right, make sure the microswitch is working, and about a dozen other things. The mixture is the very last thing to set.

[dmcnc]

The buzzing sounds like the Frequency Valve, which is good. 75 is high. Once at operating temperature and in Neutral (or P for auto) - your dwell gate should swing between 35-55 on 4 cyl scale if your mixture is right and everything else is working correctly. Also, in order to make sure you're getting the right dwell readings open the throttle (3-5 seconds on about 2-3k RPMs) and drop the throttle. You should be able to check your dwell readings at this point.

As for your fuel adjustments, stick to very small increments, repeat the throttle crank described above and check your readings.

[dmcnc]

The buzzing sounds like the Frequency Valve, which is good. 75 is high. Once at operating temperature and in Neutral (or P for auto) - your dwell gate should swing between 35-55 on 4 cyl scale if your mixture is right and everything else is working correctly. Also, in order to make sure you're getting the right dwell readings open the throttle (3-5 seconds on about 2-3k RPMs) and drop the throttle. You should be able to check your dwell readings at this point.

As for your fuel adjustments, stick to very small increments, repeat the throttle crank described above and check your readings.

Correction - your pulse ratios should be 35-45 degrees during normal operations (sensor connected and CO properly adjusted).

[madstudios]

Look what I've discovered today.
https://uploads.tapatalk-cdn.com/20170120/e1f99969fd1c28a4757f00eea0f73c49.jpg
Somebody cutted the hose between the valve and oil filler.
I'll buy a new hose and a new oring to the oil filler (it's pretty loose, is it normal?)
Does this interfere on dwell reading?




Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

[DMCMW Dave]

Look what I've discovered today.
Somebody cutted the hose between the valve and oil filler.
I'll buy a new hose and a new oring to the oil filler (it's pretty loose, is it normal?)
Does this interfere on dwell reading?

Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

No it would not interfere with the reading. But it would make your oil get dirty much faster than normal. That's PCV suction.

[Jonathan]

Is the CPR on this engine not mounted in the spot one would normally find it?

To me it looks like the CPR is between the end of the A/C compressor and the oil filler / CSV. Is that even possible?

The earlier video to me sounded like there was air leaking somewhere. Either as unmetered air or vacuum or both. I was trying to see if something looked out of place and thought his delay valve seemed to be stretched a bit farther forward than mine is. Or might be plumbed in backwards.

And on another note as I was looking at your video closer... what/where exactly is your thermotime switch plugged into?

Normally it is the one that comes out from underneath the valley and connects to the blue wired cable and white connector right at the firewall below the ballast resistor and then goes in behind to the ECU area behind the driver's seat. It gets easily confused with the connector for the O2 sensor, but the O2 sensor actually comes in below where you can see from the engine bay side and the thermotime switch connector is the higher up one looking from the ECU side. Yours looks like there isn't anything connected to that white connector. What's the deal?

48483

[Michael]

Is the CPR on this engine not mounted in the spot one would normally find it?

To me it looks like the CPR is between the end of the A/C compressor and the oil filler / CSV. Is that even possible?

The earlier video to me sounded like there was air leaking somewhere. Either as unmetered air or vacuum or both. I was trying to see if something looked out of place and thought his delay valve seemed to be stretched a bit farther forward than mine is. Or might be plumbed in backwards.

And on another note as I was looking at your video closer... what/where exactly is your thermotime switch plugged into?

Normally it is the one that comes out from underneath the valley and connects to the blue wired cable and white connector right at the firewall below the ballast resistor and then goes in behind to the ECU area behind the driver's seat. It gets easily confused with the connector for the O2 sensor, but the O2 sensor actually comes in below where you can see from the engine bay side and the thermotime switch connector is the higher up one looking from the ECU side. Yours looks like there isn't anything connected to that white connector. What's the deal?

48483
Good catch, OK where is the CPR?? Because it sure is not where it's supposed to be. I bet there are a lot of lines blocked off on that one, in fact I have a feeling that car has been hacked to run and a lot of Kjet essentials(incl. Lambda) have been cut out of the loop.

[madstudios]

Is the CPR on this engine not mounted in the spot one would normally find it?

To me it looks like the CPR is between the end of the A/C compressor and the oil filler / CSV. Is that even possible?

The earlier video to me sounded like there was air leaking somewhere. Either as unmetered air or vacuum or both. I was trying to see if something looked out of place and thought his delay valve seemed to be stretched a bit farther forward than mine is. Or might be plumbed in backwards.

And on another note as I was looking at your video closer... what/where exactly is your thermotime switch plugged into?

Normally it is the one that comes out from underneath the valley and connects to the blue wired cable and white connector right at the firewall below the ballast resistor and then goes in behind to the ECU area behind the driver's seat. It gets easily confused with the connector for the O2 sensor, but the O2 sensor actually comes in below where you can see from the engine bay side and the thermotime switch connector is the higher up one looking from the ECU side. Yours looks like there isn't anything connected to that white connector. What's the deal?

48483

Hi Michael!
Yes, the CPR is between the Oil Filler and AC compressor (don't ask me why).
https://uploads.tapatalk-cdn.com/20170120/50d7f466d2b970da2568194062730560.jpg
The white connector is connected on the wire that comes from the valley.
https://uploads.tapatalk-cdn.com/20170120/aaa2db45674debd51c47e24c38cf7027.jpg
If you see anything else weird, please let me know. I only have the car for 3 months.
Thanks


Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

[Jonathan]

If you see anything else weird, please let me know. I only have the car for 3 months.

Here is the vacuum routing label. The engine should match what you see on this diagram.

48484

I don't know why your CPR would have been moved or what problems, if any, that would create. As long as the fuel lines, vacuum hoses and electrical connections are still where they need to be, it likely shouldn't be a problem. A little cramped for space maybe though. I can see the spot where the CPR normally is and there is a ground termination there. Perhaps check and make sure that is all tight and clean any corrosion you see.

One thing that is not correct is the short, fat hose coming off the CPR and which is normally not connected to anything (it is a vent and left open and hanging there). Yours appears to be connected to the hose going into the charcoal canister and which should be connected at that little white plastic adapter to another slim hose connected to what is labelled as the "throttle edge tapping" on the routing diagram.

48485

I don't have a picture handy showing this throttle edge tapping with everything still installed on the car, so here is a picture with that port labelled on a picture when I had my intake removed.

48486

I can't see this area on your car so not sure what is connected to that port. Normally you can reach it with your fingertips without removing the intake, but it is tight.

You/we might benefit if you take a few more still photographs of other areas of the engine bay to see if other connections or things are out of place.

Speaking of which, please confirm your ballast resistor is hooked up correctly, as it looks like you are missing the double connection on the upper right side in your photos. I can't see the wire colours from the photos, but if it is hooked up the same incorrect way mine was when I first got my car, it can cause the little connector on the wires to get hot and melt itself off.

48487

[madstudios]

Here is the vacuum routing label. The engine should match what you see on this diagram.

48484

I don't know why your CPR would have been moved or what problems, if any, that would create. As long as the fuel lines, vacuum hoses and electrical connections are still where they need to be, it likely shouldn't be a problem. A little cramped for space maybe though. I can see the spot where the CPR normally is and there is a ground termination there. Perhaps check and make sure that is all tight and clean any corrosion you see.

One thing that is not correct is the short, fat hose coming off the CPR and which is normally not connected to anything (it is a vent and left open and hanging there). Yours appears to be connected to the hose going into the charcoal canister and which should be connected at that little white plastic adapter to another slim hose connected to what is labelled as the "throttle edge tapping" on the routing diagram.

48485

I don't have a picture handy showing this throttle edge tapping with everything still installed on the car, so here is a picture with that port labelled on a picture when I had my intake removed.

48486

I can't see this area on your car so not sure what is connected to that port. Normally you can reach it with your fingertips without removing the intake, but it is tight.

You/we might benefit if you take a few more still photographs of other areas of the engine bay to see if other connections or things are out of place.

Speaking of which, please confirm your ballast resistor is hooked up correctly, as it looks like you are missing the double connection on the upper right side in your photos. I can't see the wire colours from the photos, but if it is hooked up the same incorrect way mine was when I first got my car, it can cause the little connector on the wires to get hot and melt itself off.

48487

Thank you so much for your help, Jonathan!
I'll take more pictures, and post here later.



Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

[PJ Grady Inc.]

I see a lot of misrouted wiring aand hoses besides the vent hose that Jonathon pointed out. You should fix all the issues before driving the car. Somebody was doing some real experimentation here and the result is not pretty nor safe. They didn't know what they were doing it would seem!
Another real point of concern is the distributor lead to the ICU. The 2nd picture clearly shows the molded plastic housing around the EC connectors is broken and could easily cause loss of spark if it degrdes any further. This part is NLA but I could probably dig one up for you in a pinch.
Rob

[madstudios]

Here is the vacuum routing label. The engine should match what you see on this diagram.

48484

I don't know why your CPR would have been moved or what problems, if any, that would create. As long as the fuel lines, vacuum hoses and electrical connections are still where they need to be, it likely shouldn't be a problem. A little cramped for space maybe though. I can see the spot where the CPR normally is and there is a ground termination there. Perhaps check and make sure that is all tight and clean any corrosion you see.

One thing that is not correct is the short, fat hose coming off the CPR and which is normally not connected to anything (it is a vent and left open and hanging there). Yours appears to be connected to the hose going into the charcoal canister and which should be connected at that little white plastic adapter to another slim hose connected to what is labelled as the "throttle edge tapping" on the routing diagram.

48485

I don't have a picture handy showing this throttle edge tapping with everything still installed on the car, so here is a picture with that port labelled on a picture when I had my intake removed.

48486

I can't see this area on your car so not sure what is connected to that port. Normally you can reach it with your fingertips without removing the intake, but it is tight.

You/we might benefit if you take a few more still photographs of other areas of the engine bay to see if other connections or things are out of place.

Speaking of which, please confirm your ballast resistor is hooked up correctly, as it looks like you are missing the double connection on the upper right side in your photos. I can't see the wire colours from the photos, but if it is hooked up the same incorrect way mine was when I first got my car, it can cause the little connector on the wires to get hot and melt itself off.

48487

https://uploads.tapatalk-cdn.com/20170123/e9b37db7922ff839329a9c847aa1f67d.jpg
https://uploads.tapatalk-cdn.com/20170123/cead2ada1815660c7d32d402ae402b26.jpg
https://uploads.tapatalk-cdn.com/20170123/7c6e0aeb0571530adcb0ec907976d513.jpghttps://uploads.tapatalk-cdn.com/20170123/58d2aaa162b1ac0f91352af05383ec97.jpg



Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

[Jonathan]

Hi Fernando,

Good pictures. That helps.

At this point in time, I would say you should do as Rob suggested, and get your car back in the original configuration it was meant to be in. Vacuum hoses, electrical connections, fuel system component mounting locations, etc.

Vacuum hoses are easy to remove and then reinstall correctly. So too are electrical connections. You may or may not need to disconnected some of your fuel lines to get things back in order.

I think I see your frequency valve laying behind the fuel distributor. I can't tell what, if anything, it is physically mounted to, but if it is not secured down, I don't like the idea of that fuel system component having the freedom to move around, and especially not fall down low enough to come into contact with the exhaust crossover piping. That's dangerous, not just sloppy.

It does appear as though your ballast resistor isn't wired correctly. The upper right hand connection is meant to have two wires terminated on it and the lower left hand connection is not supposed to have any on it. I don't know enough about the current going through the resistor to explain why this happens, but with it left the way yours is, you can find yourself having a car that won't start and a plastic connector that got melted off. That might be why the one in your picture is a white replacement connector as it's already been damaged in the past like this.

I would also suggest relocating the CPR back to where it is meant to be. You might be able to accomplish this without opening up the fuel lines as it looks like it is just an exterior screw securing it to the block (in the current location as well as the proper location). Much like the frequency valve has an external screw (and clamp) holding it in place over on the other side of the engine block.

You may or may not be able to get the engine running well leaving it the way it is and it may or may not be safe to do so. What will get tricky is when you have problems with an engine set-up that's not as per the design, the trouble shooting and advice will be a lot of guess work thanks to not knowing what your starting point was.

So, I suggest:

1.) unclip the electrical connections that are accessible from atop the engine (label them beforehand if you like).
2.) disconnect vacuum hoses that have been identified as being incorrect.
3.) with the electrical and vacuum lines out of the way, see if you can relocate the CPR where it should be without disconnecting the fuel lines. Mount the frequency valve where it should be in a similar way.
4.) correct the connections on the ballast resistor.
5.) Post photos or questions once you have this completed or get stumped.

[madstudios]

Hi Fernando,

Good pictures. That helps.

At this point in time, I would say you should do as Rob suggested, and get your car back in the original configuration it was meant to be in. Vacuum hoses, electrical connections, fuel system component mounting locations, etc.

Vacuum hoses are easy to remove and then reinstall correctly. So too are electrical connections. You may or may not need to disconnected some of your fuel lines to get things back in order.

I think I see your frequency valve laying behind the fuel distributor. I can't tell what, if anything, it is physically mounted to, but if it is not secured down, I don't like the idea of that fuel system component having the freedom to move around, and especially not fall down low enough to come into contact with the exhaust crossover piping. That's dangerous, not just sloppy.

It does appear as though your ballast resistor isn't wired correctly. The upper right hand connection is meant to have two wires terminated on it and the lower left hand connection is not supposed to have any on it. I don't know enough about the current going through the resistor to explain why this happens, but with it left the way yours is, you can find yourself having a car that won't start and a plastic connector that got melted off. That might be why the one in your picture is a white replacement connector as it's already been damaged in the past like this.

I would also suggest relocating the CPR back to where it is meant to be. You might be able to accomplish this without opening up the fuel lines as it looks like it is just an exterior screw securing it to the block (in the current location as well as the proper location). Much like the frequency valve has an external screw (and clamp) holding it in place over on the other side of the engine block.

You may or may not be able to get the engine running well leaving it the way it is and it may or may not be safe to do so. What will get tricky is when you have problems with an engine set-up that's not as per the design, the trouble shooting and advice will be a lot of guess work thanks to not knowing what your starting point was.

So, I suggest:

1.) unclip the electrical connections that are accessible from atop the engine (label them beforehand if you like).
2.) disconnect vacuum hoses that have been identified as being incorrect.
3.) with the electrical and vacuum lines out of the way, see if you can relocate the CPR where it should be without disconnecting the fuel lines. Mount the frequency valve where it should be in a similar way.
4.) correct the connections on the ballast resistor.
5.) Post photos or questions once you have this completed or get stumped.

Thanks for all the information!
I've started to put everything in the right place.
CPR now is where it should be, also the vacuum hoses.
https://uploads.tapatalk-cdn.com/20170124/df58f50cf5c376149b2b171fc6ac1150.jpg

But I couldn't move the Frequency Valve to the right place, because the hoses are too short, I'll leave it where it is for now and buy longer hoses, at least it's not moving around.
https://uploads.tapatalk-cdn.com/20170124/c9ca2eb69994744dfcb7ea9e55525d3e.jpg

I also noticed that the vacuum solenoid is missing, I've found this cable unplugged that I assume it would be connected to the solenoid, am I right? (Sorry about my dirt hands [emoji6])
https://uploads.tapatalk-cdn.com/20170124/22c1e0186407a039fef178868fd9453a.jpg

It's very hard to see if the the vacuum hoses are properly connected to the thermal control valve. Which is the best way to reach this area?

Thanks!



Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

[Bitsyncmaster]

Yes that connector is to plug into the solenoid for the ignition advance.

By the way, that metal ring that you are using to hold one fuel line is what you pull up to access the mixture adjustment screw. So you probably don't want to use it to hold your fuel line.

[Michael]

Whatever that contraption is holding the fuel line on the distributer is replace it! Looks like someone used nylon thread to secure a fuel line on a CIS car?? Could just be they are keeping the rubber cover in place, just make sure the plastic line is intact and not depending on that thread.

[Jonathan]

No vacuum advance solenoid. That's interesting. That clamp you see around the waist of the frequency valve is what normally holds it in place against the block. It isn't moving, like you said, because that clamp is holding it in place approximately where the vacuum advance solenoid would be.

Are you familiar with what the vacuum advance solenoid looks like? Maybe it is mounted somewhere else (although you have to wonder why on earth someone would just start relocating stuff willy-nilly like this?). The vacuum advance solenoid has... wait for it... vacuum lines normally connected to it, so that's another way to try and find it.

Look here: http://dmctalk.org/showthread.php?10336-Assorted-helpful-technical-photos&p=165043&viewfull=1#post165043

The little flat disc looking contraption might still be there, just beyond the electrical distributor. Sort of hard to see, but you should be able to get a look. Tell us if that piece is on the car and if there are any vacuum hoses connected to it and where they go.

... also, from your recent pictures, can you tell us what that gigantic (red) ground wire/cable is that seems to be secured to a bolt in the frame kind of right beside the spot where the otterstat is? Viewed from above, you can see the large gauge red wire bolted to the frame but not where the other end goes. Never seen one quite like that so that's why I ask.

You also asked how to get to the connections on the thermotime switch, and those are very difficult, if not impossible, to get to without removing the intake. Don't do that right yet, but be prepared in that you may need to before you get everything sorted out right.

EDIT:

Ok, just saw a couple more things. In the photo in your last post of the frequency valve, that clear looking tubing that is just beyond and below it doesn't look factory, or like it belongs. I would guess that one or more of our missing pieces are connected to that little guy.

Oh, and in your picture where you showed that little yellow plug on the vacuum tapping, I thought your full throttle microswitch wiring connections looked like they were out of place. On a different picture I can see why... you don't have the full throttle microswitch mounted on the throttle spool. Not sure if it anywhere to be found. I don't see an auto trans fluid dipstick in your pics, so assuming your car is a manual trans, you only need the microswitch with the flap that goes on the bottom, and not the second microswitch without the flap that is only for the auto trans cars. Those aren't terribly important except that if the previous experimenter owner of your car jumpered those wires for some reason, you'll be running in a too-rich mode when you don't want to be.

Fun fun. I feel like your car was the guinea pig at the local high school auto shop or something? Just joking, no harm meant by that. I kind of like helping to figure this kind of stuff out. Compared to dealing with rusty bolts that is, this is a piece of cake. :)

[madstudios]

No vacuum advance solenoid. That's interesting. That clamp you see around the waist of the frequency valve is what normally holds it in place against the block. It isn't moving, like you said, because that clamp is holding it in place approximately where the vacuum advance solenoid would be.

Are you familiar with what the vacuum advance solenoid looks like? Maybe it is mounted somewhere else (although you have to wonder why on earth someone would just start relocating stuff willy-nilly like this?). The vacuum advance solenoid has... wait for it... vacuum lines normally connected to it, so that's another way to try and find it.

Look here: http://dmctalk.org/showthread.php?10336-Assorted-helpful-technical-photos&p=165043&viewfull=1#post165043

The little flat disc looking contraption might still be there, just beyond the electrical distributor. Sort of hard to see, but you should be able to get a look. Tell us if that piece is on the car and if there are any vacuum hoses connected to it and where they go.

... also, from your recent pictures, can you tell us what that gigantic (red) ground wire/cable is that seems to be secured to a bolt in the frame kind of right beside the spot where the otterstat is? Viewed from above, you can see the large gauge red wire bolted to the frame but not where the other end goes. Never seen one quite like that so that's why I ask.

You also asked how to get to the connections on the thermotime switch, and those are very difficult, if not impossible, to get to without removing the intake. Don't do that right yet, but be prepared in that you may need to before you get everything sorted out right.

EDIT:

Ok, just saw a couple more things. In the photo in your last post of the frequency valve, that clear looking tubing that is just beyond and below it doesn't look factory, or like it belongs. I would guess that one or more of our missing pieces are connected to that little guy.

Oh, and in your picture where you showed that little yellow plug on the vacuum tapping, I thought your full throttle microswitch wiring connections looked like they were out of place. On a different picture I can see why... you don't have the full throttle microswitch mounted on the throttle spool. Not sure if it anywhere to be found. I don't see an auto trans fluid dipstick in your pics, so assuming your car is a manual trans, you only need the microswitch with the flap that goes on the bottom, and not the second microswitch without the flap that is only for the auto trans cars. Those aren't terribly important except that if the previous experimenter owner of your car jumpered those wires for some reason, you'll be running in a too-rich mode when you don't want to be.

Fun fun. I feel like your car was the guinea pig at the local high school auto shop or something? Just joking, no harm meant by that. I kind of like helping to figure this kind of stuff out. Compared to dealing with rusty bolts that is, this is a piece of cake. :)

Yes, the little flat disc is there, and the vacuum hose is going to the valley, so as the other one from CPR, and manifold tapping, are going the same way, but I can't see exactly where they're connected.
https://uploads.tapatalk-cdn.com/20170125/9603a94326829b565c0c4c0a2ab34dee.jpg
The vacuum advance solenoid definitely is missing, I'll have to buy a new one.
I'll take a look into the other things you've mentioned, and I'll let you know.
Thanks again!


Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

[David T]

Somebody obviously did some work on this car and did not put things back quite as they should be. I am sure the more you look the more you will find out of place. Instead of pointing out each thing one-by-one, you need to get pictures, a LOT of pictures, and try to get it all sorted out.

[madstudios]

Somebody obviously did some work on this car and did not put things back quite as they should be. I am sure the more you look the more you will find out of place. Instead of pointing out each thing one-by-one, you need to get pictures, a LOT of pictures, and try to get it all sorted out.

Thanks, David.
You're right, I'm trying to do this, but the pictures I found on the web it also have some inconsistencies and it's difficult for me to know what's right or wrong.
I'm really glad that all of you had the patience to help me understand a little bit more about my car and about D's.
If anybody knows where can I get some detailed pictures for reference, of a nice stock D, please let me know.
Thanks


Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

[madstudios]

Today I guess I've adjusted the mixture properly. I had to lean about 2/4 on the mixture screw (it was very rich), but my idle it is a little bit high.
https://vimeo.com/201351206
I drove around some blocks, and the car runs so much better!
But I noticed that my hot start problem got worse. :/




Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

[Bitsyncmaster]

Today I guess I've adjusted the mixture properly. I had to lean about 2/4 on the mixture screw (it was very rich), but my idle it is a little bit high.

Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

Now back off your idle screw (lower one first). If your idle system is working you should get 775 RPM. My car had bad deceleration springs and would idle at 1000 RPM even with the idle screw backed all the way out.

[madstudios]

Now back off your idle screw (lower one first). If your idle system is working you should get 775 RPM. My car had bad deceleration springs and would idle at 1000 RPM even with the idle screw backed all the way out.

I guess my idle is not working, if I lower it, the engine does not idle at 775. But I think microswitch is working, if I accelerate and press the microswitch with a screwdriver, the rpm lower a bit. What else I need to check?


Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

[Bitsyncmaster]

I guess my idle is not working, if I lower it, the engine does not idle at 775. But I think microswitch is working, if I accelerate and press the microswitch with a screwdriver, the rpm lower a bit. What else I need to check?


Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

You should be able to hear and feel the idle motor buzz when you turn the key to on (don't start the engine). If you don't get a buzz, you will need to trace the idle circuit.

The idle motor center pin should have 12 volts and each side pin will be switching on and off at 100 Hz. A voltmeter would show less DC voltage than the center pin on those outside pins.

[madstudios]

You should be able to hear and feel the idle motor buzz when you turn the key to on (don't start the engine). If you don't get a buzz, you will need to trace the idle circuit.

The idle motor center pin should have 12 volts and each side pin will be switching on and off at 100 Hz. A voltmeter would show less DC voltage than the center pin on those outside pins.

This is the buzz you're talking about?
https://vimeo.com/201365855
If so, yes, it's buzzing.


Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

[David T]

To get it to idle low and smooth you must get everything working exactly as it should. No vacuum leaks, all of the hoses routed correctly, etc. With all of the stuff out of place and cobbled together I suggest you try to get it all sorted out before trying to tune it. Make sure the 3 large brass screws are LIGHTLY seated closed. Make sure the throttle arm is returning ALL the way to the idle stop and tripping the micro switch. Make sure the throttle plates are closed all the way and the decel springs are not damaged allowing air to bypass the throttle plates. My guess is you will wind up undoing all of the work that was previously done and then try to put it back together correctly. That will be difficult since you don't know what correctly is and there are no other Deloreans nearby. The best we can do is help you with pictures.

[Bitsyncmaster]

This is the buzz you're talking about?
https://vimeo.com/201365855
If so, yes, it's buzzing.


Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

Yes that sounds like the idle motor buzzing. You can also put your hand on it and feel the vibration. That verified your idle ECU drivers are working and connected to the idle motor. As David T stated, everything needs to be checked and set correctly.

On my car, it took months to determine the deceleration springs were the cause of my 1000 RPM idle. My 1000 RPM only happened when the engine was fully warmed up. I did get a solid 775 RPM with the engine cold. When the engine is cold, you need more throttle to hold that 775 RPM so the leaking at the deceleration springs was small enough the idle system could overcome that leak.

Also verify you do not get vacuum at the ignition distributor when the engine is at idle. If you get advance at idle that will increase the idle speed more than the idle system can handle.

[madstudios]

Yes that sounds like the idle motor buzzing. You can also put your hand on it and feel the vibration. That verified your idle ECU drivers are working and connected to the idle motor. As David T stated, everything needs to be checked and set correctly.

On my car, it took months to determine the deceleration springs were the cause of my 1000 RPM idle. My 1000 RPM only happened when the engine was fully warmed up. I did get a solid 775 RPM with the engine cold. When the engine is cold, you need more throttle to hold that 775 RPM so the leaking at the deceleration springs was small enough the idle system could overcome that leak.

Also verify you do not get vacuum at the ignition distributor when the engine is at idle. If you get advance at idle that will increase the idle speed more than the idle system can handle.

After the mixture adjust with the dwell meter, my car runs great only with hot engine, but oscillates when the engine is cold, and it was very difficult to start hot or warm.
I decided to enrich a little bit, and the hot start issue apparently is solved.
But everytime I start the car hot or warm, the rpm rises to 3000 for a few seconds, then idle normally.

Any thoughts?

https://vimeo.com/201576826



Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

[Jonathan]

After the mixture adjust with the dwell meter, my car runs great only with hot engine, but oscillates when the engine is cold, and it was very difficult to start hot or warm.
I decided to enrich a little bit, and the hot start issue apparently is solved.
But everytime I start the car hot or warm, the rpm rises to 3000 for a few seconds, then idle normally.

Any thoughts?

https://vimeo.com/201576826



Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

When you start the car and it goes to about 3,000 RPM, are you doing anything to help it come back down? And I mean specifically are you touching the gas pedal with your foot at all during this time?

[madstudios]

When you start the car and it goes to about 3,000 RPM, are you doing anything to help it come back down? And I mean specifically are you touching the gas pedal with your foot at all during this time?

No, did not touch the pedal at anytime in this video.
Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

[Bitsyncmaster]

I am guessing that high idle start may be a problem with the idle ECU. Are there any other owners near you that you could borrow their idle ECU just to test?

[madstudios]

I am guessing that high idle start may be a problem with the idle ECU. Are there any other owners near you that you could borrow their idle ECU just to test?

Unfortunately no, there only 6 or 7 D's in Brazil, I only know one guy who have an automatic D, but he's in other state, 600 miles from here.
I'll clean the connections and try to see if anything changes. Thanks!


Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

[Jonathan]

You still need to correct your ballast resistor wiring.

[madstudios]

You still need to correct your ballast resistor wiring.

I've already corrected the ballast resistor wiring.
The only thing is not there yet is the vaccum solenoid, I already bought but it will take 20 days to get here.


Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

[sdg3205]

That's a weird issue - to consistently run up to 3000 rpm then fall back down. I agree with Dave - sounds like an ECU or idle speed motor issue.

Is there any chance your throttle linkages are keeping the butterfly valves open at start up? Try disconnecting the linkage arm at the butterfly valves so there is no possible pre load or interference and start the engine again.

[Bitsyncmaster]

That's a weird issue - to consistently run up to 3000 rpm then fall back down. I agree with Dave - sounds like an ECU or idle speed motor issue.

Is there any chance your throttle linkages are keeping the butterfly valves open at start up? Try disconnecting the linkage arm at the butterfly valves so there is no possible pre load or interference and start the engine again.

+1
I was thinking the same thing with the linkage.

[madstudios]

+1
I was thinking the same thing with the linkage.

I've disconnected the linkage, still the same...
About the ECU, I read somewhere that a way to check if it's working, you have to disconnect the ecu plug with engine running to see if the rpm increases. I don't know if this is the best way to test it, but looks like it's working. Funny that the rpm increases the same amount as when I start it hot.
https://vimeo.com/201743820


Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

[Bitsyncmaster]

If you disconnect the connector with 4 wires, then the RPM should run about 2500 RPM because pulling that connector opens the thermistor circuit. Your idle ECU seems to be working but that consistent 3000 RPM on startup makes me think you have a flaky circuit in the ECU. I've never seen your startup problem before so it's just a guess the ECU may be causing that.

[dmcnc]

I've disconnected the linkage, still the same...
About the ECU, I read somewhere that a way to check if it's working, you have to disconnect the ecu plug with engine running to see if the rpm increases. I don't know if this is the best way to test it, but looks like it's working. Funny that the rpm increases the same amount as when I start it hot.
https://vimeo.com/201743820


Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

That would mean your idle motor is working! ECU issue then?



Sent from my iPhone using Tapatalk

[madstudios]

That would mean your idle motor is working! ECU issue then?



Sent from my iPhone using Tapatalk

I was thinking to open the ECU and test the components, I friend of mine worked whole life with electronics, I think he can help, he asked me for the schematics, I couldn't find anywhere... But to open the box it's not easy, I'm afraid to brake the plastic case. Any recommendations?



Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

[Bitsyncmaster]

I was thinking to open the ECU and test the components, I friend of mine worked whole life with electronics, I think he can help, he asked me for the schematics, I couldn't find anywhere... But to open the box it's not easy, I'm afraid to brake the plastic case. Any recommendations?



Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

It's tricky to open the idle ECU without breaking the plastic. I've had a lot of practice so I can do it. The problem is the short sides also have the case fitting.

My guess is you have a bad capacitor or weak IC. Don't think your electronics guy will find that problem without a schematic and test set up.

[madstudios]

It's tricky to open the idle ECU without breaking the plastic. I've had a lot of practice so I can do it. The problem is the short sides also have the case fitting.

My guess is you have a bad capacitor or weak IC. Don't think your electronics guy will find that problem without a schematic and test set up.

I understand, but I want to try something before buy a new ECU, I'm afraid that problem could be something else.
Is this ECU repairable, or the only way is buying a new one?


Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

[Bitsyncmaster]

I understand, but I want to try something before buy a new ECU, I'm afraid that problem could be something else.
Is this ECU repairable, or the only way is buying a new one?


Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772

I sell an idle ECU of my own design. I require your old one back since I use the case and connector. If you damage the case, I would require your old one back first to update.

[madstudios]

I sell an idle ECU of my own design. I require your old one back since I use the case and connector. If you damage the case, I would require your old one back first to update.

Thank you Dave!
You're idle ECU is awesome and solved my high rpm problem!




Fernando Silotto. Sao Paulo - Brazil
Delorean Vin 3772