Idle Surging ...codes 13 (pin 8), code 2 (pin 14) - PeachParts Mercedes-Benz Forum

latief · #1 06-14-2010, 03:30 PM

Suddenly, out of the blue, and after the car was parked 2 days in the heat (it is very hot over here)....I'm getting idle surge and even weird driving behavior...

Codes I pulled are 13 on (pin 8), and 2 on (Pin 14)....

Ideas? no other codes present....

Thanks...

mbdoc · #2 06-15-2010, 08:25 AM

Code 13 at pin #8 is suggesting that the computer has fully adjusted the mixture.
NO adjustment left.

Most likely issues, air mass sensor, vacuum leaks, and (or) fuel pressure issue.

Code #2 from pin 14 is much harder to diagnosis, however suggests a problem with the throttle actuator.

Better diagnostic tool with live data would help with diagnosis.

latief · #3 06-15-2010, 08:52 AM

will a bad throttle actuator cause a fluctuating idle? the issue comes and goes randomly, and idle goes up and down between 600-1000....cruise control is working.....

I do have corroded wiring in the ETA harness...but if not broken, i would not like to deal with it...

thanks,

mbdoc · #4 06-15-2010, 09:24 AM

Yes, the air mass sensor AND (or) the throttle actuator can cause that idle issue.

latief · #5 06-16-2010, 01:57 AM

So now I am not sure what to do with this...it seems i have two separate problems...

First, The rich condition has been plaguing this car ever since i got it......I have done the headgasket, changed all engine hoses, checked all vacuum lines....changed injector seals and pintle caps. I have two MAF sensors (both known to be working on other cars), have changed oxygen sensor twice...pulled the vac line off the fuel pressure regulator (no gasoline or gasoline smell)....changed OVP with the updated number....still, i am getting code 13 on HFM that will not go away, and the exhaust smells like a car with a bad mixture....what next? before the idle started jumping, i had a very slight pulsation in idle that i could not get rid off...the only thing i have not checked and just learned about was the purge valve...i will check that tomorrow, but after that not sure what to do....

for the more recent and noticeable Idle surging, I think it is my throttle actuator as the harness on that thing is corroded. cruise control works perfectly, so I am not sure if i should touch it or not.....

I will be selling the car within a month or so since i will be going overseas, so i want to sell it with minimal problems......

what are your thoughts on both problems?

input is highly appreciated...

thanks

George560sel · #6 06-16-2010, 06:25 AM

I have the same problem, car is 93 300e M104 3.2L w/ 170Kmi. I bought it w/ 150Kmi and no record and no problem except no start turn out it only need new OVP relay which I change to the new one. After that I change all 3 coils, spark plugs, and spark plugs wires (3). About 2000 mi ago, I got the surging idle problem, pulled the code got code 13 on pin 8. Mileage drop from 19 something to 14 mpg. Exhaust smell wierd, black carbon deposit at the tail pipe. Pull the spark plugs, all 6 look black (carbon deposit) seem like it running too rich, fuel not burn completely. Try to find any vacuum leak but found nothing. Took the AMS out and clean it with the AMS cleaner, seem to help a little bit. Change the new air intake temp sensor, nothing change. Recently I read about the ETA wiring, so I design to investigate that. Pull the ETA and splice the wires, bad news. All wires are disintegrated. New one cost $1,300, rebuild around $800 which I don't think I can spend on this old girl. Anyways, I'm in the middle of rewire this ETA now and will let you know if it cure the surging idle problem. BTW, you can check your ETA wire without pulling it out, just peel the shield of ETA. BTW, I did check the number of main engine wiring harness, the number suggested it had been replaced but the lower one is bad (my next project) but I don't think it caused the surging idle.

latief · #7 06-17-2010, 02:36 PM

So, after clearing the codes again, i checked today....

Code 9, 13 on the DM (pin 8). The code for the throttle actuator disappeared, but the car occasionally goes into a nasty idle surge that goes away soon. i will be rewiring the throttle tonight, i have had enough with it....hopefully i don't destroy it !!!!

another finding, my purge valve appears to be dead. there is no pulsation i could feel under any conditions. i took out the vacum line (the side going into the body) and there is continuous vacumm pulling at that side....so i took the valve out, and a large amount of coal-like particles came out of it....i was able to blow into it from either direction with no resistance (it is always open) .....

so i will be cleaning this valve with wd40 as suggested, but my feeling is that i need a new one.....will this be causing the lean/rich idle mixture codes i am getting?

thanks

rayhennig · #8 06-19-2010, 02:40 AM

Your symptoms sound similar to mine but your fuel system's very different. However, it might be worth checking ...

Have you got an air intake temperature sensor on your air filter housing?

If so, measure the resistance of it - mine was open circuit so it was telling the system that the incoming air was about -100 degrees C.

In my case, the specified values are:

>> 20C: 2500 ohms,

>> 80C: 300 ohms.

Bought a new sensor from MB for €12, reset the duty-cycle back to 50% (it had leapt to low 90s with new sensor) and now the car is 100% except for a tiny hesitation when first pulling away after leaving it hot for, say, 30 minutes. I all other respects it's fine and this was my cheapest and most dramatic repair EVER!!

RayH