m103 2.6 Engine Trouble
 

Evening everyone,

So I usually don't drive my 190E 2.6 on the weekends, I like to get the other cars some time on the road but I had to move the 2.6 today and I started it up and It was NOT happy at all. The idle was just a hair above 500 on tach. It made a real low kind of "misfire" noise. I just gassed it up Friday night and drove it around town (some stores I had to run to) and everything was fine.

I am including this video to see if you guys can tell if anything is amiss. I know you wont be able to see anything but the audio should be pretty smooth.

Last week I had some idle problems too, I took it to the shop and the darn thing wouldn't even cough. Everything ran as smooth as it has in the past. They pulled the OVP relay and found some corrosion at the pins, but that was it. It had rained pretty good that week too just as it did this past weekend. So perhaps some water got into the OVP and corroded some parts of it, i'm not sure. I would like to pull it and take it a part see if theres any internal problems...

I checked all the fluids, everything looked good. The oil needs changed (I'm 50 miles over 3k) but coolant was clean no oil or anything.
Here's the Video:
http://i98.photobucket.com/albums/l2.../th_m103-1.jpg

Hope you guys can help! Thanks for reading,

Kris

Update:

I removed the OVP, there was corrosion around Pin 87E and 30. So after reading how other members took theirs apart and found more corrosion I decided to do the same:

Link to Large Image of OVP PCB Pic #1:
http://i98.photobucket.com/albums/l250/MafiaNicky/190e%20projects/IMG_7678.jpg

Link to Large Image of OVP PCB Pic #2
http://s98.photobucket.com/albums/l250/MafiaNicky/190e%20projects/?action=view&current=IMG_7680.jpg

The images arent the greatest but in the bottom portion of the device there lots of corrosion around these two solder point on the far right side and a trace broken in two spots that connects to pin 30 and the internal relay. I repaired the traces and re-soldered all the points.

I put it back in the car. Started up ok, sounded like it was fixed then the idle went to ***** again and I turned it off. I tried to start it back up but now it wont budge, I tried 3-4 times cranking for various periods of time to no avail.

I'll probably end up replacing the "fixed" OVP not to far down the road even though I dont think thats the problem.

CIS sender in the head acting up? Maybe the cold start injector is leaking? Injector leaking? MAS relay? Fuel pump pulling too many amps? Vac leaks?

Time to start testing stuff. :(

so I just tested the IACV for voltage and current..

2.5 V car running and 0 mA all the time. I pulled up the FSM which said resistance across the device should be 19.5+/-1.5....I got 8.5

Update #3

I came across a thread that referred to checking the voltage at the throttle microswitch as a viable test to see if the OVP was functional. I tore apart the OVP yesterday resoldering a broken trace and removing corrosion and testing the overall circuitry. I got 11.7 Volts at the microswitch which is the same value that was measured at the battery. So according to this the OVP is working.

Im still attempting to understand/track down why i'm only getting 1-2 Volts at the IACV.

Upon gazing in the FSM the procedure for testing the IACV is:

"Connect test cable to actuator, set measurement to mA, switch on ignition, read"
"Without Lambda = 10mA, With = 20mA"

"If not ok--> Test Adjustment Plug"
"Designation Without Lambda - ECE, Designation with lambda KAT"
"If OK check wiring for continuity. Also check Resistance of the actuator ~19.5 +/- 1.5 Ohms"
"If Ok End of Test" "If not ok--replace Actuator"

I dont know what this KAT thing or where it would be located.
What governs the IACV voltage and current regulation?

After examining the pdfs:

the IACV pin 1 is hooked up to pin 3 on the CIS-E module
the IACV pin 2 is hooked up to pin 6 on the OVP relay.
in the PDF the IACV is refered to as Y6 "Idle Speed Adjuster (Air Valve)"

Update #4

After some seaching I managed to find a thread here:
(http://www.peachparts.com/shopforum/tech-help/157525-w126-low-icv-voltage.html?highlight=CIS-E+diagram)

Referencing a low voltage (2.5v, which is exactly my reading too) measured across the IACV. The thread seems to believe just straight replacing the OVP, however the original poster never reported back whether or not it solved his problem. A link within the thread points to a suggestion of simply replacing the OVP. I am not sure this is the solution as I've dismantled the OVP and everything inside it checks out.