How does the Auto decelerat?

[Bitsyncmaster]

I've been working on an idle ECU update and just wondering what the difference there is between an auto or 5 speed.

I know with the 5 speed some owners may keep the engine engaged right down to idle RPM. I'm not one of those, I press the clutch when I'm ready to change gears to downshift. Even press the clutch coming to a stop way before nearing idle RPM.

So with an auto, I would think the dropping RPM would be much slower because the car movement is still helping the engine RPM to drop slower. Is that a correct assumption? I was wondering if I should have a user switch that changes some software timing for an auto.

My new software uses the idle switch input signal so running without the idle switch is not an option. That signal lets my software know when the user has let off the throttle.

Still don't know why an auto with stage 2 would cause problems other than it could fake out the lambda with high duration cams.

[81dmc]

I've been working on an idle ECU update and just wondering what the difference there is between an auto or 5 speed.

I know with the 5 speed some owners may keep the engine engaged right down to idle RPM. I'm not one of those, I press the clutch when I'm ready to change gears to downshift. Even press the clutch coming to a stop way before nearing idle RPM.

So with an auto, I would think the dropping RPM would be much slower because the car movement is still helping the engine RPM to drop slower. Is that a correct assumption? I was wondering if I should have a user switch that changes some software timing for an auto.

My new software uses the idle switch input signal so running without the idle switch is not an option. That signal lets my software know when the user has let off the throttle.

Still don't know why an auto with stage 2 would cause problems other than it could fake out the lambda with high duration cams.
Not really. The rpm immediately drops off a few hundred RPM and bleeds down like a manual from there. It hits idle though much earlier than the manuals.

I can take a couple driving vids next week if you want.

[Bitsyncmaster]

Not really. The rpm immediately drops off a few hundred RPM and bleeds down like a manual from there. It hits idle though much earlier than the manuals.

I can take a couple driving vids next week if you want.

That would be helpful to see the RPM gauge when coming to a slow and a faster stop. Thanks.

[Timeless]

Stage 2 auto: I can attempt a video tomorrow if I take the car out.

[Bitsyncmaster]

Stage 2 auto: I can attempt a video tomorrow if I take the car out.

That would also be great.

[Timeless]

Just recorded this. To a stop from ~55mph - no A/C on. Let me know if there is anything specific you need recorded.
https://youtube.com/shorts/a_b0zoAzKXg?feature=share

[Bitsyncmaster]

Just recorded this. To a stop from ~55mph - no A/C on. Let me know if there is anything specific you need recorded.
https://youtube.com/shorts/a_b0zoAzKXg?feature=share

Thanks that helps a lot. Really slow RPM dropping. I think I know what to add to my software for a user switch if auto or standard.

[Bitsyncmaster]

Well working on my idle ECU update has stopped. Looks like my FD has a problem. Acts like it sticks and then jumps on the mixture. I have been having issues for many years since I stopped driving it enough. It started with poor cold running on the road but idle is OK. Now I get the dwell reading holding at the minimum value but I work the adjustment I can get about 30 degrees but it wont hold.

So looks like I need to rebuild the FD:mad1::mad1::mad1:

[Ron]

You might check the roller bearing for the plunger, while you are in there...

[Bitsyncmaster]

You might check the roller bearing for the plunger, while you are in there...

I will but it feels like the air plate has pressure building up even with no rest pressure.

[Bitsyncmaster]

Well I pulled the FD and as soon as I pulled the double return lines that pressure on the rest plate went away. The center piston is very free moving. When I pulled the PPR the larger O-ring (not the small sealing o-ring) was disintegrated and junk from it was in the piston side. I pulled the PPR piston and it and the small o-ring look good.

I don't know if that caused my problem but I'm thinking since I have the FD out on the bench, I will split it just make sure the inside is clean. That will let me blow out the screens on the injector hose side anyway. So I plan to use the old parts and just clean it up.

[Bitsyncmaster]

Well I split the FD. Looked clean inside so hoping the disintegrated O-ring was the cause of my problem. Have to get the hoses back connected but will probably be tomorrow to get that done.

[Bitsyncmaster]

Well I mess up something. Injectors are spraying all the time. I assume the center "piston" the turned down side points out. That side was dirty so I assumed that is the way it pointed.

[Bitsyncmaster]

You might check the roller bearing for the plunger, while you are in there...

By the way, that roller bearing is not spinning freely. Maybe that was causing the problem. Anyway, I pulled the FD apart and it looks like an O-split when I assembled it. I guess I need to put a little grease onto the o-rings so they can slide in.

[Bitsyncmaster]

My new O-rings are about .007" thinner than the old ones. Hope they work OK.

Roller bearing spins freely now. Just a little solvent on Q-tip cleaned it up. Added a little 3 in 1 oil also.

[Bitsyncmaster]

Got it back on the car and so far looking better. I get my 75 PSI primary pressure and it drops to 35 PSI when I shut off the pump.
Injectors are not spraying. I will need to do the base setting since I backed the adjustment way out.

I do have a very slight leak on one spot where the FD halfs meet but I will address that later.

[Bitsyncmaster]

Well no luck getting it fire. I adjusted the mixture just so one injector started to drip. Also that's the point you start hearing the screech from a few injectors. I would think I would get a pop anyway from the CSV but there has been nothing as far as any fire.

[Timeless]

If you need injectors I'll have some available in 2 weeks or so.

[Ron]

Well no luck getting it fire. I adjusted the mixture just so one injector started to drip. Also that's the point you start hearing the screech from a few injectors. I would think I would get a pop anyway from the CSV but there has been nothing as far as any fire.
Plugs fuel fouled??

Did you inspect the roller bearing for a flat spot? (Thinking about you saying it acts like it sticks and then jumps on the mixture earlier.)

[Bitsyncmaster]

Plugs fuel fouled??

Did you inspect the roller bearing for a flat spot? (Thinking about you saying it acts like it sticks and then jumps on the mixture earlier.)

I did not feel any flat spots when I was cleaning it. I check one plug and it is dry. I still think something is wrong with the FD. It holds rest pressure but when I press the air plate it does not cause any injection and the rest pressure stays.

I think my next step is to pull all injectors, put in jars and power up the fuel pump and press the air plate to see if they are working.

[81dmc]

Here's a video for you Dave. Shows Automatic trans behavior.


https://www.youtube.com/watch?v=IvKFGKqct_o

[Bitsyncmaster]

Here's a video for you Dave. Shows Automatic trans behavior.


https://www.youtube.com/watch?v=IvKFGKqct_o

Thanks. Right now my ECU software does not do anything above 1300 RPM (it just holds the idle motor at normal idle RPM position). All my work is when it drops below 1300 RPM. The software has to not drop that idle motor setting until it gets to normal idle RPM. What I found works good was try to hold 1100 RPM which was working good until my Kjet was doing random things.

[Bitsyncmaster]

Well I tested with all 6 injectors in jars and the fuel pump running and all looks good. With no air plate pushed I just get a few drops from each injector. Pressing the air plate all injectors spray nicely. I even put the CSV in a jar and powered it and it sprays great.

So now I'm going to start checking ignition. I see the tach bounce 0 to 500 RPM when cranking but not sure if that is normal because my engine always starts fast. From past experience I would see a more consistent 700 RPM when cranking.

[David T]

Well I tested with all 6 injectors in jars and the fuel pump running and all looks good. With no air plate pushed I just get a few drops from each injector. Pressing the air plate all injectors spray nicely. I even put the CSV in a jar and powered it and it sprays great.

So now I'm going to start checking ignition. I see the tach bounce 0 to 500 RPM when cranking but not sure if that is normal because my engine always starts fast. From past experience I would see a more consistent 700 RPM when cranking.

From this experience you can see that you must engineer this so that it will work in spite of the condition of the motor and it's systems. What I mean is many of the cars I see do not run perfectly. Between vacuum leaks, bad spray patterns, etc, they do not idle well. No amount of software is going to compensate for the mechanical defects that usually exist in the fleet. Some will buy your device hoping it can compensate or correct for all of the other problems they have and will be disappointed when it doesn't and can't.

[Bitsyncmaster]

Well it's getting spark. I put the timing light on a couple plug wires and it fires when cranking. I can't think of what could cause it to never fire. I tried some starter fluid and still not even the hint of a fire. I'm wondering if an intake valve is stuck open. I guess I could put a vacuum gauge on the intake and see if it pulls any vacuum. I've never tried checking vacuum when cranking.

[81dmc]

Try ether.


You won't get a lot of vacuum when cranking. The only way to check valve sealing is differential compression. Though if it was a stuck valve, it would fire on other cylinders.

[Ron]

I agree, a stuck valve would probably make it back fire on its cylinder and the rest should still hit.

(Still sounds like fuel fouled plugs... ;-)

[Bitsyncmaster]

Try ether.


You won't get a lot of vacuum when cranking. The only way to check valve sealing is differential compression. Though if it was a stuck valve, it would fire on other cylinders.

I was thinking an intake valve stuck open would not let it pull any vacuum (fuel and air). Well I checked vacuum and it just makes the gauge oscillate between 0 and 1 inch when cranking.

Spark and fuel should fire if it pull into the cylinder. I need to get a compression gauge. That would show any bad cylinder.

[81dmc]

I was thinking an intake valve stuck open would not let it pull any vacuum (fuel and air). Well I checked vacuum and it just makes the gauge oscillate between 0 and 1 inch when cranking.

Spark and fuel should fire if it pull into the cylinder. I need to get a compression gauge. That would show any bad cylinder.

I recommend OTC 5609
https://www.amazon.com/dp/B0030EVL60

It has PSI on both sides. I use that on aircraft.


If a valve is leaking bad, pulling valve cover and hitting it with a hammer under pressure will likely unstick it.



Anyways, I highly doubt that?s your issue.

[Bitsyncmaster]

I recommend OTC 5609
https://www.amazon.com/dp/B0030EVL60

It has PSI on both sides. I use that on aircraft.


If a valve is leaking bad, pulling valve cover and hitting it with a hammer under pressure will likely unstick it.



Anyways, I highly doubt that?s your issue.

Thanks. Yes, why would something act up so suddenly. But I'm open to any other suggestions. Google says 3 to 5 inches during cranking but is that for K-jet.

[81dmc]

Thanks. Yes, why would something act up so suddenly. But I'm open to any other suggestions.
Did you disconnect CSV? It could be stuck and flooding it

It's better to turn off fuel pump (via inertia switch), and try to start car with ether to verify integrity of ignition system and the engine itself.

[Ron]

I was thinking an intake valve stuck open would not let it pull any vacuum (fuel and air)...
It would only loose vacuum for the one cylinder.
...normally only a few inches when while cranking.

[Bitsyncmaster]

Well I ordered a compression gauge. Can't hurt to check it anyway. Never had checked it.

[Bitsyncmaster]

Did you disconnect CSV? It could be stuck and flooding it

It's better to turn off fuel pump (via inertia switch), and try to start car with ether to verify integrity of ignition system and the engine itself.

Mine only engages the CSV after one second or cranking. But I have also tried it with the hot start jumpered so it engages instantly.

[Bitsyncmaster]

I though of another possible cause. Timing chain broken. I would think I would hear a problem when cranking but I don't.

[DMC-Ron]

Dave,
Maybe you have already checked this. After cranking pull a couple of plugs and see if they are wet or dry. Knowing if it's flooding, or starved ,helps focus the troubleshooting.

Ron

[Bitsyncmaster]

Dave,
Maybe you have already checked this. After cranking pull a couple of plugs and see if they are wet or dry. Knowing if it's flooding, or starved ,helps focus the troubleshooting.

Ron

Will try that today. Second thought on timing chain. Can't be that since I tested two plug wire for spark and distributor turns from the cam shaft.

[Bitsyncmaster]

Plug is dry after cranking. Tried a lot of starter fluid again and still no hint of any fire. All I can think off is it's not drawing any fuel into the cylinders. Don't really know what would make fuel condense on a plug. I'm going to try another ignition coil. I remember with my lawn tractor, I got spark on my timing light but that turned out to have a bad ignition coil.

Tried another coil. No change.

[81dmc]

If timing chain broke, the engine would be locked up.


Try pulling plugs and ground on head and see spark color with helper cranking. Also make sure your plug wires are right.

[Bitsyncmaster]

If timing chain broke, the engine would be locked up.


Try pulling plugs and ground on head and see spark color with helper cranking. Also make sure your plug wires are right.

All I did was pull the FD first time. Then second time I pulled the top half of the mixture unit to clean that roller bearing. Plugs and ignition distributor have not been touched. I did try stock ignition ECU, Stock Idle ECU and stock RPM relay just because those units use the ignition signal.

[Bitsyncmaster]

I should get my compression gauge today. I've removed all 6 plugs, disconnected the ignition ECU and pulled the RPM relay. Not sure if I will be able to use the hose with gauge since our plugs are deep in the cylinder. I would think you would need a very deep socket to go over the hose. So either I make a socket like that or set up a foot switch to crank the engine.

[Bitsyncmaster]

Got my compression tester. Turns out using the hose you just screw it into the plug hole with the force twisting the hose. A large O-ring makes the seal without needing to use any more force.

1) 135 PSI
2) 115 PSI
3) 100 PSI
4) 145 PSI
5) 140 PSI
6) 105 PSI

Not very good as far as matching. I may do it again with a few drops of oil into each cylinder. But this is a cold engine and it should be done on a hot engine. Anyway, I need to find another cause of it not firing at all.

[Bitsyncmaster]

Well I found out I did not crank the engine over long enough on my dry compression test. So those values were probably not a good evaluation.

Looking on Google it said to use about a tablespoon of oil in each cylinder. I used my scale to measure out about 12 to 15 grams of oil. It's really quite a lot more then I thought. Readings went way up.

1) 205 PSI
2) 200 PSI
3) 210 PSI
4) 243 PSI
5) 237 PSI
6) 235 PSI

When your cranking with only one plug (the gauge), crank for about 5 or more pulses (that's what you hear). That may be 3 or 4 seconds.

Anyway, my valves are good. When it fires, I expect a lot of smoke from all that oil.

[81dmc]

You have confirmed air and fuel so far.


You have a spark issue.

[Bitsyncmaster]

You have confirmed air and fuel so far.


You have a spark issue.

That is what I'm thinking but my timing light does flash on two of the plug wires I checked. And I did look at the primary with my O-scope and that was normal with the 400 volt spikes that tells me it's putting current on and off into the coil.

[81dmc]

Like said before, pull spark plug and connect it, ground on block, and crank to see spark color and timing.

[Bitsyncmaster]

Well it fired up very instantly after that oil compression test. But now I'm in the shit house with wife for smoking out the house. The smoke did white out the garage for a long time. I let it run till it got to normal temp but the dwell is stuck at minimum. The oil probably killed my O2 sensor. Which way do I turn the mixture screw to get it off minimum dwell? I did try adjusting it but it never moved the dwell.

All I can think of causing my starting problem was I mush have flooded the cylinders with fuel when I had that o-ring split in my first FD rebuild. So it could not draw the fuel air mixture into the cylinders. I want to check that manifold vacuum when cranking after I get the engine back to normal again.

[David T]

Or you have a bad connection on the ballast resistor. The connections are steel and can rust. If you adjust the valves you may be able to get all of the cylinders more even. The closer they all are to each other the more evenly they will fire, the smoother the idle.

[Bitsyncmaster]

Or you have a bad connection on the ballast resistor. The connections are steel and can rust. If you adjust the valves you may be able to get all of the cylinders more even. The closer they all are to each other the more evenly they will fire, the smoother the idle.

I don't have any ballast resistors. I run the GM module and a 1.5 ohm primary coil.

[Bitsyncmaster]

Second restart was no smoke. I let it warm up again and was able to dial in the dwell. So looks like my O2 sensor is still working. I may replace it anyway.

If your dwell is holding at the minimum then your mixture is to rich and you turn the mixture screw CCW.

Now I have to fix that very minor leak between the halfs of the FD.

[Bitsyncmaster]

I fixed the FD leak but now it does not like to hold a good dwell. I'm going to replace the O2 sensor to see if that helps. It also takes a lot of cranking to start the engine cold but that may be the mixture setting. It does idle good. I checked the AFR and it is also not holding at idle. High RPM seems OK.

[David T]

I fixed the FD leak but now it does not like to hold a good dwell. I'm going to replace the O2 sensor to see if that helps. It also takes a lot of cranking to start the engine cold but that may be the mixture setting. It does idle good. I checked the AFR and it is also not holding at idle. High RPM seems OK.

The motor (when cold) starts on the CSV so the idle has nothing to do with starting at that point. Verify the CSV is squirting when cold. An O2 sensor going bad tends to have a smaller swing in the dwell readings. One way to rejuvenate an O2 sensor is to heat it up with a torch and try to burn out the contaminants. Can't hurt to replace it though.

[Bitsyncmaster]

I did a flow test of the reassembled FD and all six jars filled the same amount. Just wanted to check it again while waiting for my new O2 sensor to arrive (think tomorrow).

[Bitsyncmaster]

I can't win. The new O2 sensor works for about 5 min then it open circuits. Seems to work fine looking at it on my o-scope and then suddenly goes dead.

[David T]

A few possibilities;
Running to rich
Wrong sensor/defective sensor
Bad electrical connection (could be the ground)
Sensor cools off too much.

[Bitsyncmaster]

A few possibilities;
Running to rich
Wrong sensor/defective sensor
Bad electrical connection (could be the ground)
Sensor cools off too much.

Well it's defiantly a bad sensor. It was new but who knows if someone used it and returned it. But my guess is a manufacture defect. That could have got through there test because it works for about 5 min and then the output goes to almost 0 volts instantly. It's not open circuit but it must have contamination that "shorts" the output.

Anyway, I've given up on my software update for my idle ECU. I could get it working good all the time in the garage but road testing after the engine warms up it will stall coming to a stop. I went back to the original software and that works great. I only started the update because users with an auto and stage II had problems. I may try again but I'm burned out with that software.

[Bitsyncmaster]

For my final test after replacing the O2 (again) and setting the dwell, I ran a cold start this morning. Had my fuel pressure gauge connected to measure control pressure and my tailpipe wideband (I don't run a CAT).

Cold start, CP =28 PSI, AFR =11.9
30 seconds, CP=35 PSI, AFR = 12.2
60 seconds, CP = 44 PSI, AFR = 13.1
90 seconds, CP = 50 PSI, AFR = 14.2

CP stays at 50 PSI

120 seconds, AFR = 14.3
180 seconds, AFR = 14.5

Then O2 goes closed loop at 3 minuets and AFR holds around 15.8. That is at 850 RPM idle. I bumped the idle up to 1000 RPM and AFR went down to 15.4. I thought I read setting dwell should be done at 1100 RPM but I could not find that document. It does look like the unheated narrow band sensor does need higher RPM to accurately hold 14.7 AFR. If anyone can find that document of using 1100 RPM please let me know. What I can do is add 1100 RPM to my idle ECU.

[David T]

For my final test after replacing the O2 (again) and setting the dwell, I ran a cold start this morning. Had my fuel pressure gauge connected to measure control pressure and my tailpipe wideband (I don't run a CAT).

Cold start, CP =28 PSI, AFR =11.9
30 seconds, CP=35 PSI, AFR = 12.2
60 seconds, CP = 44 PSI, AFR = 13.1
90 seconds, CP = 50 PSI, AFR = 14.2

CP stays at 50 PSI

120 seconds, AFR = 14.3
180 seconds, AFR = 14.5

Then O2 goes closed loop at 3 minuets and AFR holds around 15.8. That is at 850 RPM idle. I bumped the idle up to 1000 RPM and AFR went down to 15.4. I thought I read setting dwell should be done at 1100 RPM but I could not find that document. It does look like the unheated narrow band sensor does need higher RPM to accurately hold 14.7 AFR. If anyone can find that document of using 1100 RPM please let me know. What I can do is add 1100 RPM to my idle ECU.

What you are looking for is D:04:01 and :02 in the Workshop Manual. The speed is 950 RPM. It is the factory procedure to set the mixture screw by measuring CO and HC.

[Bitsyncmaster]

What you are looking for is D:04:01 and :02 in the Workshop Manual. The speed is 950 RPM. It is the factory procedure to set the mixture screw by measuring CO and HC.

Thanks. Guess I don't need to change the ECU software because it already can select 950 RPM.

[Bitsyncmaster]

Well wrapping this up (for now), running the old idle ECU software works so good on my car I'm aborting the software update. I would need to test with an auto stage 2 car to determine what to change.

Also the stock narrow band O2 sensor runs lean at idle speed (about 15.8 AFR) but with throttle above 2000 RPM (cruising speed) I get 14.8 AFR (no load, car still). Not sure how that lean idle would affect emissions testing but it would be interesting if a heated O2 sensor was tested.

[Timeless]

Well wrapping this up (for now), running the old idle ECU software works so good on my car I'm aborting the software update. I would need to test with an auto stage 2 car to determine what to change.
If you're looking to vacation in South FL, you're welcome to test on my stage 2 auto. :race: