Help with a high idle....

[Jonathan]

thanks everyone!

attached is the image of the loose harness. I had to run the car to move it into position, so i'm gonna let the manifold and such cool off a bit before testing the backside of the idle microswitch; I'll report back soon.

edit: sorry, the photo flipped upside down when i uploaded it for some reason...

That piece you show not plugged into anything is fine. It is for automatic transmission cars (assuming you have a manual trans car). If you had an auto, you would have a second, similar switch stacked on top of the one you see there connected to the white connector. They both get activated by pressing the gas pedal all the way to the floor, and then when the throttle spool rotates all the way around, it presses up against that metal flap and engages the switches. That's called the wide open throttle or full throttle switch. The one you have enriches the fuel mixture and the additional one on the automatic kicks it down one gear.

Anyway, back to the idle microswitch we were wondering about... you see that bright red plastic splice connector that is on the single wire going to your idle switch? That's been added after the fact by someone and could be part of your problem. See if you can follow what else might be spliced into it and also if it seems loose.

[rjd2]

ok, more info:delorean microswitch 1.jpg

1) is this the microswitch? i don't want to lose anything in translation/assumption on my part. whatever this part is, if i manually depress it, the idle speed actually goes UP by about 300RPM or so.

2)as i have been hunting this problem, the standing idle speed has now risen to about 2300-2500.

3) with the engine off, i detached the cream harness that runs to the pictured switch here. if i run a DVM across the two pins, and manually depress the switch, at the 2Meg setting, switch depression throws the impedance to 0. I do not know if that is proper, but the switch is definitely not INactive entirely.

4)with the car running, detachment of the cream 2 pin harness has no effect on idle speed.

5) the two connections on the back of the plate that is depressed by the idle screw(is THAT what is considered the microswitch?), one a yellow wire and one a black/green wire, they seem snug-i checked them.

Elvis-I wanted to do your test, but I cannot find a 3 pin harness leading to the idle motor anywhere. The only detachable harness I'm finding is that cream colored 2 pin harness.

[rjd2]

ok! sorry for my ignorance, upon further research, the microswitch i previously posted an image of is the FULL THROTTLE switch. i now see that the idle speed microswitch is the larger one next to the air intake valve with two wires(black and black/green) leading to it.

attached is an image of a can-thing; the yellow wire that runs out of it, the joint is failing. i either need to take it apart and solder it, or replace it. what is that canister thing?

delorean can wire.jpg

lastly, the red junction point on the wires to the idle speed microswitch is just that-it's a non-solder junction; it basically taps into the green/black wire and provides a junction point for the yellow wire. it was on the car when i acquired it.

[opethmike]

The electrical connector to the idle speed motor is black. If you pull that off of the motor, there will be three pins.

[DMC-81]

ok! sorry for my ignorance, upon further research, the microswitch i previously posted an image of is the FULL THROTTLE switch. i now see that the idle speed microswitch is the larger one next to the air intake valve with two wires(black and black/green) leading to it.

attached is an image of a can-thing; the yellow wire that runs out of it, the joint is failing. i either need to take it apart and solder it, or replace it. what is that canister thing?

delorean can wire.jpg

lastly, the red junction point on the wires to the idle speed microswitch is just that-it's a non-solder junction; it basically taps into the green/black wire and provides a junction point for the yellow wire. it was on the car when i acquired it.

I believe the canister thing is the coil suppressor, 108561, http://store.delorean.com/p-6878-suppressor-coil.aspx
You can see it in the lower left of this picture:

image.jpg

[rjd2]

I believe the canister thing is the coil suppressor, 108561, http://store.delorean.com/p-6878-suppressor-coil.aspx
You can see it in the lower left of this picture:

image.jpg

thanks. the wire leading to the coil suppressor completely failed; i've ordered the part, and once in place, i'll continue tests and report back. thanks much all!

[Elvis]

That has nothing to do with your high idle.

[NckT]

As Elvis said ^^^^

That capacitor is an attempt to try and reduce arcing on the switch contacts to reduce wear etc.

You'd be better off trying to do continuity tests from the idke ecu to the various ends to prove the wiring (via the bulkhead connectors). You can't do the continuity to the microswitch though as this goes via the anti-back feed diode, but you could use the diode function on a multi meter and test this at the ecu and switch end wiring.

Diagnostics are best but to save time, typical causes of High idle are (in no particular order):

Vacuum leaks (idle motor brass pipe to venturi O ring not in place/ poor seal)

Upper throttle 'hammer' not making contact on the microswitch/ not adjusted correct

Bad connection/ open circuit thermister (check for resistance at the ecu multi plug disconnected from the ecu)

Stuck/ sticking idle control valve

Shorted winding in idle control valve that causes one of the ecu's switching transistor to fail (ecu can be fixed for £2 or so)

Run on Air admittance (Poppet) emission valves on the throttle disc spring failure

Poor adjustment of the accelerator cable

Sticking throttle spool/ bad link rod adjustment/ mechanical issue.

Good luck

[Elvis]

what means "^^^^" ?

[NckT]

what means "^^^^" ?

It's supposed to reference your post above, as in an upward arrow