[dreadnought1666]

Hi everyone

I've got a problem with my 1994 Mercedes E320 (might be a 1993 since thats what it says on the throttle body)
the problem being that when in park or neutral the idle jumps between 600 rpm and 1100 rpm.

I have rebuilt the entire wire harness for the engine, rebuilt the wire harness for the throttle body, new gasket for throttle body, checked for vacuum leaks everywhere without any success, changed some vacuum hoses and fittings anyway and still the problem doesn't go away

error codes are on pin 8 :
4 : MAF (yes i have three of them and all of them a shot)
13: air-fuel mixture too rich or too lean

no error codes on pin 14

the thing is that when i put it in Drive or Reverse, everything is fine, idle is where it's supposed to be and everything
so I'm suspecting that the CC/ISC module is faulty, or can the MAF make such a difference in idle speed ?

one final note is that the Cruise Control doesn't work at all

 

[Jayare]

Not having cruise is a serious indicator that the ETA is faulty. Remember, the bio junk wiring is also the wiring inside the unit.

Do you have any history on the OVP relay?

Sent from my XT1080 using Tapatalk

 

[dreadnought1666]

Not having cruise is a serious indicator that the ETA is faulty. Remember, the bio junk wiring is also the wiring inside the unit.

Do you have any history on the OVP relay?

Sent from my XT1080 using Tapatalk

There is no traction control on it (which i think that ETA means) it doesn't even have the ASR throttle body, and the OVP relay is swapped out from my spare parts/donor E320 (same year different options on it) it was the first thing that was swapped out (also changed the fuse in it)

 

[dreadnought1666]

and sorry for double posting but i need to correct myself regarding your reply Jayare, the ETA is completely rewired with brand new wires, and the car runs fine otherwise, it's just the idle at park and neutral that is jumping around, and I was actually a bit afraid to test the cruise control after i rewired the ETA

 

[mercron]

Normally you will get error code number 2 from pin 14 if your non-ASR CC/ISC module is faulty. But, your CC doesn't work too. This could be a faulty CC stalk.

Idle fluctuations in P and N without CC/ISC code could be the MAF, MAF wiring, intake air leaks, or your ECM. It does come up as an error from pin 8.

Also, error 13 from pin 8 indicates faulty fuel injectors or fuel pressure regulator. Have you checked those?

http://manual.startekinfo.com/manual/JSP/e2/1_1/m11.jsp


Sent from my iPhone using Tapatalk

 

[dreadnought1666]

Normally you will get error code number 2 from pin 14 if your non-ASR CC/ISC module is faulty. But, your CC doesn't work too. This could be a faulty CC stalk.

Idle fluctuations in P and N without CC/ISC code could be the MAF, MAF wiring, intake air leaks, or your ECM. It does come up as an error from pin 8.

Also, error 13 from pin 8 indicates faulty fuel injectors or fuel pressure regulator. Have you checked those?

STAR TekInfo


Sent from my iPhone using Tapatalk

I do know that the MAF is bad, it give out WAY too high voltage, but it is still the same problem if i remove the cable from the MAF (which should make everything go to standard pre programmed values right ?)

MAF wires are new point to point

ECM has been replaced from donor car

intake has been checked all over (also replaced from donor car)

fuel injectors would make the car misfire (which it doesn't do)

fuel pressure regulator has actually not been checked
but i would suspect that it throws this 13 code due to the MAF giving WAY too high values, thus resulting in a way too rich or way to lean burn or am i wrong in suspecting that ?

 

[mercron]

MAF is a possible candidate. It controls your fuel trim. Check FPR if leaking through the vacuum tube to the intake.

Easy way to check MAF is to unplug connector with engine running. If no change in idle fluctuation issue then that's the problem.


Sent from my iPhone using Tapatalk

 

[mercron]

I do know that the MAF is bad, it give out WAY too high voltage, but it is still the same problem if i remove the cable from the MAF (which should make everything go to standard pre programmed value

It looks like you pulled the connector already and no change - it still idles badly. No, pulling this connector will not reset your ECM programming. It will take 10-19 trips for the ECM to adapt to a new MAF.

My E320 is running fine and when I pull the MAF connector my idle hunts between the ranges you are saying. Looks like a bad MAF in your case, or leaking FPR.



Sent from my iPhone using Tapatalk

 

[autocomman]

You cant fix an idle control issue with a fuel mixture that it outa wack becuase that will cause the engine to idle outa wack. No getting around this issue, the MAF has to be fixed or what ever is causing your AFR issues. Then if you still have an issue with the idle go back to the idle control. But the idle control cant control an engine that is too rich or lean, that alone will cause surging.

 

[dreadnought1666]

It looks like you pulled the connector already and no change - it still idles badly. No, pulling this connector will not reset your ECM programming. It will take 10-19 trips for the ECM to adapt to a new MAF.

My E320 is running fine and when I pull the MAF connector my idle hunts between the ranges you are saying. Looks like a bad MAF in your case, or leaking FPR.



Sent from my iPhone using Tapatalk

thank you for the tip, will order a new MAF ASAP, will also check the FPR but I suspect it to be fine, since every single other rubber/plastic hose i've looked at has been just fine, this has actually been a year long project... wait even longer then that since I got that car in 2015, it's a VERY long story though, but the very short version of it is that i had to swap the engine cause it was cooked, and when that was done and i wanted to testfire the car well... lets just put it like this, that the ECM is not very happy when both terminals on the battery gives off positive energy, therefore i had to swap the ECM, later had to swap the ETA cause (in retrospect figured out that) an ASR ETA does not run on a non-ASR CC/ISC module, so basically i thought that maybe that's what fried the CC/ISC too however between the ETA & ECM & fresh battery swap and the start of the surging idle, it ran just peachy for about a week

Oh by the way.. have a look at this
http://www.w124performance.com/docs/mb/diagnostics/DTC_List_W124_M104.pdf
if you scroll down to pin #8 and look at the page labeled 1 first it talks about fuel mixture and reseting that
on page 3 it is described how you do it, the question is though, does it still take about 10 trips ?

You cant fix an idle control issue with a fuel mixture that it outa wack becuase that will cause the engine to idle outa wack. No getting around this issue, the MAF has to be fixed or what ever is causing your AFR issues. Then if you still have an issue with the idle go back to the idle control. But the idle control cant control an engine that is too rich or lean, that alone will cause surging.

that is very true, I will fix the MAF, but it's almost starting to feel like the car is cursed or something.

 

[mercron]

Yes, you can reset a new ECM with ignition ON by clearing all codes, holding button down on the diagnostic port for 6-8 sec, turn off engine min 2 sec, turn on min 10 sec, then start. That's the ECM.

To reset a new CC/ISC module, turn ignition On for 90 sec then start.

ECM adapts to other components like MAF, O2 sensor, crank position sensor, engine temp sensor, transmission shifts, error codes from diagnostic module much longer.


Sent from my iPhone using Tapatalk

 

[dreadnought1666]

just a little update, i ordered a new MAF about a week ago, and then went on a holiday just to find out that they delayed sending it *sighs* oh well hopefully it will be here this week, if not should be here by monday :smile

 

[dreadnought1666]

alright so here it is
i've installed the new MAF, and done a couple of runs with it, first run it went beautiful on idle, but there was just no power in it when i accelerated, it got up to 80 degrees C and still was perfect on idle

turned her off went and did a few things for a couple of minutes then wanted to go for another run, started her up (temp still being at 80 degrees or around there) and idle went back to going between 600 and 1100 arouund, but went out anyway and then there was power in the engine on that run

went back home power still rough, turned her off, took off air filter, started her up and went for another run, and she ran a bit weird but not out of the normal during driving conditions but when i came back idle was still jittering so i checked the MAF connectors and there was only around 8 volts going in, and 5.42 coming out to the ECM !!!!!!! holy shite

so i replaced the OVP again too and checked the connectors coming into the MAF and they were back to around 12 volts
as of writing this, has only had her idling up to around 40 degrees C and she idles nicely

going to do some more test runs later to see how she behaves, it smells on the exhousts like shes still running a bit rich though, so what do you guys think ? o2 sensor ?

 

[sbaert]

Are you absolutely sure the "rebuilt" wiring is not the culprit here?

Particularly, the throttle body wiring gauge needs to be exact and twisted in the right order.

FWIW, I have never seen good long term results with "rebuilt" especially DIY rebuilt wiring on these cars.

The big clue is that your cruise is not working.

 

[dreadnought1666]

actually not tested cruise after the wiring got rebuilt on the ETA, and yes it is spot on correct,went out to check the O2 sensor which was between 0,40 volts to 0,73 volts which seems to be accurate and correct, temp was around 50-60 degrees C and was having weird idle again with 8 volts coming into the MAF *sighs*

 

[mercron]

It still doesn't sound like a CC/ISC module issue. Normally you'd get code 2 for that from pin 14. Did you clear all codes and checked again?

Did you check your fuel pressure regulator for leaks? Unplug the vacuum hose and observe for 3 to 5 minutes if there are any fuel coming out of it.

If your MAF is now getting the right voltage and you're still having idling issues not showing any codes, you may have faulty coils, wires, and spark plugs. They can go bad without throwing any codes. I'd check those too.


Sent from my iPhone using Tapatalk

 

[dreadnought1666]

all codes cleared and still no codes on pin 14
still codes 4 and 13 on pin 4 though
no issue with the FPR or rather no leaks in the hose at least
spark plugs are brand spanking new
and coils i have changed from spare parts engine without any affect whatsoever

 

[dreadnought1666]

forgot to mention that the voltage has dropped to 8 volts again going in, thinking about direct connecting the positive side of the MAF to the battery to see if that changes anything ?

 

[dreadnought1666]

ok so ran the engine for about 10 minutes
cold start idles perfect
voltage in to MAF is at 12.05 volts
pulled the FPR vaccum hose, nothing came out of the FPR while running it

however MAF voltage drops to 8 volts in when starting engine a second time hot...
that is very weird in my opinion

 

[dreadnought1666]

also fault code 5 showed up