Idle issue... Starts at about 1500, then up to around 2500.

[MacinTek]

Okay... new wire harness in, new plugs, wires, cap and rotor in, new fuel lines in, vacuum hoses connected correctly, car finally starts and runs... boy does it run! It starts at around 1500 rpm, the after a few seconds, it climbs to 2300 -2500 rpm. and stays there.

Somewhere during reassembly, I seem to have lost the plug thingy that goes over the fuel mixture adjuster in front of the fuel distributor. Is that a major deal? I covered it with a piece of duct tape until I can replace the rubber plug.

[Jonathan]

That adjustment hole won't cause that high idle. Not 2,000+ RPM anyway. Duct tape is fine for now.

That high of a number can be related to a loose or poor connection on the back of the ECU (the black one) in the tray behind the driver's seat. Specifically look for the connector on the passenger side (if it is laying flat in its designed position). That connector will have four wires in it and two of them (diagonally) will go to the little gadget under the valley referred to as the thermistor. If that little bugger is not plugged in well or some other reason why it isn't getting continuity, it can cause that sort of high idle to get stuck there.

You could also have a number of things a little out of whack on the idle speed microswitches and what not near the throttle spool. If you press it back to the rest position from standing behind the car at the engine bay, OR if snapping the gas gets the idle to come back down, then that first thing I described is NOT your problem. If snapping the gas never helps, then it's likely an electrical connection gone bad and not so much a sticky idle system component.

[DMC5180]

The plug being will cause an unmetered air leak of which you will see a slight rise in rpm, but not 800-1000. A golf tee works good for a temporary plug. Make sure the idle micro switch is being engaged with the throttle closed. Also verify you didn't knock one of the wires off the switch when you were mucking around with things.


Dennis

[MacinTek]

That adjustment hole won't cause that high idle. Not 2,000+ RPM anyway. Duct tape is fine for now.

That high of a number can be related to a loose or poor connection on the back of the ECU (the black one) in the tray behind the driver's seat. Specifically look for the connector on the passenger side (if it is laying flat in its designed position). That connector will have four wires in it and two of them (diagonally) will go to the little gadget under the valley referred to as the thermistor. If that little bugger is not plugged in well or some other reason why it isn't getting continuity, it can cause that sort of high idle to get stuck there.

You could also have a number of things a little out of whack on the idle speed microswitches and what not near the throttle spool. If you press it back to the rest position from standing behind the car at the engine bay, OR if snapping the gas gets the idle to come back down, then that first thing I described is NOT your problem. If snapping the gas never helps, then it's likely an electrical connection gone bad and not so much a sticky idle system component.

Hmm... I did notice that the microswitch wasn't pressed when idle, so I adjusted the upper screw so that is did press the switch when the throttle is closed. Is there a balancing act between the upper and lower adjusting screws?

[DMC5180]

Hmm... I did notice that the microswitch wasn't pressed when idle, so I adjusted the upper screw so that is did press the switch when the throttle is closed. Is there a balancing act between the upper and lower adjusting screws?

Yeah there can be. But for your purposes start with the lower screw backed off the stop. The adjust the upper to trip (click) the switch plus a couple turns. That should get you to a normal 775 ish idle. You can make tweaks to the lower screw once you are warmed up to help iron out idle hunt.


Dennis

[PJ Grady Inc.]

Okay... new wire harness in, new plugs, wires, cap and rotor in, new fuel lines in, vacuum hoses connected correctly, car finally starts and runs... boy does it run! It starts at around 1500 rpm, the after a few seconds, it climbs to 2300 -2500 rpm. and stays there.

Somewhere during reassembly, I seem to have lost the plug thingy that goes over the fuel mixture adjuster in front of the fuel distributor. Is that a major deal? I covered it with a piece of duct tape until I can replace the rubber plug.

If you changed the engine harness it's almost certainly a bad/open connection at the idle thermoswitch under the intake manifold known as the infamous VOD. I've never seen a bad connection directly at the ICU but a bad ICU will cause the same symptoms. Sounds like the connection is suspect or the ICU is bad or both (worst case scenario). Use a circuit tester (Ohm scale) to check for an open circuit at the blk/ylw and blk/slate wires at the ECU plug-in to see if it's the switch connection before doing anything else.
Rob

[Ron]

I noticed you have a thread on the alternator light being on but the battery seems to stay up. That could be a symptom of a shorted rectifier diode (or trio) in the alternator, which would allow AC to get into the system and muck everything up...probably a good idea to resolve that first.

[MacinTek]

:thankyou:
As it turns out, the culprit was the turnbuckle between the microswitch (butterfly valves) and the throttle mechanism was either too short or too long (I can't remember that far back (20 minutes) due to rampant drug use in my misspent youth), keeping the butterflies slightly open at idle. Idle is now steady at what appears to 750 to 775.

Now, about that alternator... gawd only knows what's in there. It's an '83 so it probably shipped with a motorola but, I think it got replaced a while back. My father kept terrible records of things as mundane as his car. I'll probably replace it soon since I'm sure it suffered some ill effects when the starter kept shorting out.

Symptoms when it shorted out while I was driving were... tachometer goes nuts, I smelled smoke... stopped car and it wouldn't start... and I was at the smog test station when this went down. 11 months later, I can get it smog'd just in time to pay next year's registration.
:smokelot:

[DMC5180]

A photo of the alternator showing the wire connections would help.

[MacinTek]

A photo of the alternator showing the wire connections would help.

http://dmctalk.org/attachment.php?attachmentid=36994&stc=1http://dmctalk.org/attachment.php?attachmentid=36995&stc=1

[DMC5180]

Motorola and from the looks of it it's been on there for years. When you changed the harness did you make sure the brown/yellow small wire is connected at the alternator?


Dennis

[Ron]

I don't see the brown/yellow light wire...

See post in alternator thread (http://dmctalk.org/showthread.php?12519-Alternator-charging-but-Battery-light-is-on&p=180993&viewfull=1#post180993).

[MacinTek]

I don't see the brown/yellow light wire...

See post in alternator thread (http://dmctalk.org/showthread.php?12519-Alternator-charging-but-Battery-light-is-on&p=180993&viewfull=1#post180993).
It's mounted to a post on the top side of the alternator. Is there another post I haven't seen?

[DMC5180]

It should be attached to the small stud next to the large wire connection.

http://images.tapatalk-cdn.com/15/09/26/d465e5ba1edbfc4b2c7e77e00c52101f.jpg

[PJ Grady Inc.]

http://dmctalk.org/attachment.php?attachmentid=36994&stc=1http://dmctalk.org/attachment.php?attachmentid=36995&stc=1
1983 Deloreans that were delivered through the east coast prep center in Sommerville N.J. came undercoated with the same smooth finish as this alternator. It is probably the original alternator on the car if the chassis is undercoated too so it may be time for a new one.
Rob

[Jonathan]

1983 Deloreans that were delivered through the east coast prep center in Sommerville N.J. came undercoated with the same smooth finish as this alternator. It is probably the original alternator on the car if the chassis is undercoated too so it may be time for a new one.
Rob

I have that same finish on parts of my frame, mostly at the engine area. Anything else you can tell me about that from a history perspective? What it is or why it was put on or whether removing it is good bad or in between?

[David T]

I have that same finish on parts of my frame, mostly at the engine area. Anything else you can tell me about that from a history perspective? What it is or why it was put on or whether removing it is good bad or in between?

Many of the '83's were undercoated. Probably to hide cosmetic damage to the frames. Some may have been done by dealers as an up-charge, dealers make a lot of money (at least they did) doing an undercoating. Costs about $5 in materiel and $25-30 in labor and they would charge $100 or more. Usually done by an inexperienced guy and he would splatter it all over. It is also done to help sound deaden the car but it adds a lot of weight. Really should not get the stuff on the mechanicals like an alternator but it is hard to control where it goes, it isn't as precise as a paint spray gun. More like a large nozzle spitting it out in chunks. Really was not necessary on a Delorean, the epoxy protected the frame better than the undercoating ever could. IMHO you should remove it but it is a TON of work. A really nasty, dirty job. Eastwood makes a spray that will soften it up and make it easier (not easy) to remove.

[Bitsyncmaster]

My 81 has undercoating on the frame. From what I have seen, it is a pretty good job but it did get on everything under the car. I like the black color you see from the rear of the car so I painted my new muffler heat shield black.

[Jonathan]

Mine is an 81 too, and it also came in through NJ (a dealership there at least). They did an ok job, it's applied well and not all over everything in a sloppy way. It's really just on the rear half so not consistent from front to back over the whole car. I don't think my car had ever been very well cleaned underneath until recently, and when I got under there, I got back to the gray epoxy on a number of areas. Hard to tell if I was cleaning off grime or undercoating!! Some of it looked like that rust protection slop we used to see here in Canada when you would get the bottom of your car oiled for reasons I don't know. Messy is all I can think of.

[PJ Grady Inc.]

I have that same finish on parts of my frame, mostly at the engine area. Anything else you can tell me about that from a history perspective? What it is or why it was put on or whether removing it is good bad or in between?

Being an 81 yours was likely done by a dealer. The 83's received a very smooth finish undercoating that seemed to help with controlling rust better then the bare epoxy so there is no reason to remove it IMHO. It doesn't look as clean and they tended to spray electrical components which is not advisable.
Appling body wax to the interior cavities after scraping out any loose epoxy is the method I've been using to stop/control rust for many years and it's proven quite effective over time. For external rust I use a zinc rich primer followed by a two part polyurethane to keep a stock appearance. That is more effective at controlling rust than the original epoxy.
Rob

[MacinTek]

1983 Deloreans that were delivered through the east coast prep center in Sommerville N.J. came undercoated with the same smooth finish as this alternator. It is probably the original alternator on the car if the chassis is undercoated too so it may be time for a new one.
Rob

Well... I'm a big believer in "if it works, don't fix it"...and, apparently, my geriatric alternator still works; I just had the gauge lead on the wrong post (the one opposite the correct one).

Started her up just now, after correcting that and she started right up and the battery light is off. :)

Now, if I could only get the cassette player repaired so I can use my bluetooth cassette device to connect my iPhone to the stock (not Craig) radio.
:shhh:

[DMC5180]

I'm glad you got it straightened out and working.

[PJ Grady Inc.]

Well... I'm a big believer in "if it works, don't fix it"...and, apparently, my geriatric alternator still works; I just had the gauge lead on the wrong post (the one opposite the correct one).

Started her up just now, after correcting that and she started right up and the battery light is off. :)

Now, if I could only get the cassette player repaired so I can use my bluetooth cassette device to connect my iPhone to the stock (not Craig) radio.
:shhh:

Yes that would do it for sure. As long as a Motorola is working there is no reason to change it. They are pretty good alternator's especially when comparing them to "The Ducellier".
Your last request is a tough one. I just asked my electrical engineer buddy to casually check on an external interface option as the internal technology just doesn't exist to do it.
Rob

[DMC5180]

There is someone on here that has successfully added an auxiliary audio input jack to the Craig unit. There might even be a how-to right up on it. I also seem to recall him offering to do the modification to your unit for a nominal charge.


Dennis

[DMC5180]

Dennis. Unintended post that I can't seem to delete via tapatalk.