Hello!

I realize there's a whole lot of talk about idle issues with K-Jet as it is, but I'm not sure I follow the logic of my specific problem.

The symptoms are:

- high idle (over 2k, sometimes with 500rpm blips, sometimes not) with everything connected
- high idle (~1.2-1.5k, no blips) with the ICV connector off
- revs fine, drives fine aside from the high idle

I have the older three-pin ICV. Rubber and hoses are in good condition as far as I can tell. I've gone through electrical testing of wiring to the computer, here are my findings:

- ICV: the voltage between outer pins and the center pin is around 13.21. With ignition on, the ICV acts erratically from what I can tell
- TPS/Potentiometer: I haven't yet tested it with voltage applied, but the resistance between pins doesn't change when the plate is pushed down. Neither is the resistance at the levels prescribed in the service manual when at rest.
- Full throttle sensor: shows erratic readings between 2 and 40ohms when throttle is at full.

My questions are:

1. Should the voltage supplied to the ICV be the same on both outer pins? My understanding was that one pin rotates the ICV one way, the other pin - another way. Does this mean my problem is the controller behind the battery?
2. Since the car drives fine, I assume the potentiometer has to be fine, but my readings say otherwise. Is my testing procedure wrong?
3. Is there further testing I should've done?

replace the overvoltage relay and cross your fingers. i've fixed alot of funny idle problems on those and 124s doing that. get oe, had trouble with others out of the box. good luck, chuck.

I've seen that suggestion before. My OVP fuse has actually blown before, I replaced the whole OVP with a cheaper one (https://www.ebay.com/itm/111278114965). Right now, I've swapped back to the original with a new fuse and saw no changes in behaviour.

What's the OE brand of the OVP relay?

Clean the AFM plate with carb cleaner.

Make sure the micro switch is working and the throttle cable is adjusted properly. The roller needs to be depressed at idle.

You may have unmetered air entering the intake. The only way to be sure is to have a smoke test done. Or - The ICV is stuck open. Take it off and clean it with carb cleaner.

Leaky injectors, CSV, Fuel distributor plunger stuck or leaking fuel distributor.

These are just good guesses and things that you need to eliminate before further testing

I've done that

A few months ago, before major idle issues started, I noticed the spring was missing there. I've replaced it since then, and the microswitch does activate at idle.

Gotcha. I did bench test the ICV: at rest, about a third is open. When voltage is applied, it opens up and closes as I believe is intended. I don't, however, understand why the fuel injection computer is providing voltage across both outer pins (as I mentioned above): is this intentional?

Oh, you presume it's running rich then? Is there any overall topical test (beside testing exhaust for gases) to see if that's the case? I don't seem to be heating up too much, nor is the exhaust smelling too rich.

Thanks for the input, I'll focus on these.

If it were me, I would do a smoke test. The hoses can look good but still leak. How about the other seals? Brake booster? Injector seals? Intake seals? Big rubber boot under the AFM? How about the u shaped hose under there too?You can make a DIY smoke machine for about $20. or take it to a shop that has a smoke machine, if should only be an hour of labor.

No I don't think it is running rich. After the engine is at operating temperature, pull the connector to the O2 sensor. Put the red positive lead of your DMM to the o2 sensor signal wire and ground the negative lead black to ground. Set the meter to dc volts. the signal should cycle from .1 volt to .9 volt. with the middle .45 volts which is lambda. If it doesn't read that, then adjust the 3 mm allen screw until it does. lean is .1 volts or lower rich is .9 volts or higher. No need for a exhaust gas tester. Now the ECU can do its job. This is the way that Steve Brotherton sets the mixture.

Again, I think you have an air leak and you can't detect it until you do a smoke test.

I have two 190e's- a 1992 2.3 and a 1993 2.6. The 1984 190e is a different KE jetronic system, similar but different.