2.3-16 HIGH idle, slow rpm drop
 

It's my 87 16V. I was having an intermittent high (1500) or normal idle. No dependancy on temp. The kicker is that the RPMs would fall extremely slow, making shifting... interesting. Well now I have a constant idle of 2500. No idea why. So far...

-New water temp sensor for the injection system
-IACV cleaned and bench tested, operates with 12 volt.
-EHA seals replaced
-OVP tested fine
-Throttle Micro Switch tested fine
-Fuel pump/ cut-off relay re-soldered.

Anybody?

Hi,
Do a search on '190e high idle'. There are several posts on this issue and the causes could vary. After you browse thru the results I am positive you will have some idea on how to fix it.

smk_texas
98 s420
93 190e

I have done so. This is a fairly common problem but I have already tried the common solutions. Hence the list in my first post.

for the car to be idling that high you have to have a vacuum leak and a big one.have you smoke tested the intake? have you checked the rubber boot on the underside of the fuel injection plenum?

I've checked all areas for leaks. There are none that I can detect. It also appears that when I warm the fuel pump relay behind the battery, the idle drops some.

why don't you check the pins on that relay for corrosion both sides.

The idle drops some, but not to where it should be. I re-soldered all the contracts inside the relay, cleaned the contacts and used dielectric grease on the pins on reassembly.

On the 190revolution forums one member had the same problem and replacing the Kilma fixed it. Sound probable?

yes it does.the td signal goes through the klima relay before it gets to the ecu which runs the idle.i have seen the klima short out the td signal before.unplugging the klima relay should tell you if it's at fault.

I unplugged it with no effect. After that I carefully played with the mixture, now it will start and run at 1200, but after revving it a few times it stays at 2500.

well either you are sucking in unmetered air or there is a problem with the throttle body not closing off.i assume that the 2500 rpm is still maintained if you unplug the idle valve?

After about 6 hours today of research on the KE-Jetronic system, here are my findings. The KE system is an electronic hybrid version of the K system. The EHA valve is the primary "output" control of the ECM to the injection system. The coolant temp, ambient temp, throttle position, air meter position sensors are all inputs that basically control the EHA.

I found a test procedure for the EHA. With the ignition on, I should have a 20mA at the EHA, I am currently getting 49mA. This signifies a wrong, or bad ECM. The internal resistance reading of the EHA should be 19.5 +-1 ohm. I am reading 19.

At this point it's looking like I need a 16V ECM.

Anyone know what ECM's will work with a 16V? Will a 2.3, or 2.6 8V version work?

Any luck here?
To answer your questino I just read this thread http://www.peachparts.com/shopforum/tech-help/185817-16v-will-not-rev-past-3000-rpm.html?highlight=16v+eha which said the 16V EHA and 8v EHA are the same....

Did you find a solution for the high idle slow rpm drop on your 2.3-16?
 

Did you find a solution for the high idle slow rpm drop on your 2.3-16? Did you fix the problem by replacing your ECM?

I'm having the same issue with my 86. It certainly makes shifting and stoplights exciting.

NOTE: I've found that if you quickly turn the key back (off) one position to shut off the engine and then quickly turn it back (on) to the run position the idle comes back to 800-900rpm .....but this is only a temporary fix until the throttle position changes and it's back up to 2500 rpm.