Hi I’m new to this forum and need some help.


I have an E320 1994. I have had it for over 2 years now and have had a few problems on it that I have been able to fix. But this problem goes a little above my knowledge.
This week I replaced my regulator for my motor Blower, this morning I drove my car to work and on the last leg of my drive, the car started to surge at stoplights.
My car will surge between 500-1000RPM in all gears; when I am at cruising speed I am alright. This surge will happen about every second. I looked for loose vacuum hoses but found none. I am not getting any indicator faults on my dashboard, either.

Any insight would be greatly appreciated.

Get the codes from pins 8 and 14..
...and pull the vac line off the Fuel pressure regulator while at idle and see if any petro comes out the vac port of reg.

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A Dalton

I had same symptoms on E 220, local MB dealer replaced MAS sensor based on error code and problem continued. After checking everything it turned out that power to MAS sensor was open circuit due to broken wire that powered MAS sensor.

And error code @ 8 pin actually said MAS sensor is open circuit

Thank you Arthur Dalton and Phantom Lord. I was at work and without access so had my family post now back at work. Will check this post later thanks so much to any that can help. This is frustrating.

E320 1994 W124 body frame.



If the Fuel pressure regulator is on the front of the engine just off the right side of the center of the motor then yes I checked it and it is not shooting any petro out of it.



I plan to visit Radio Shack tonight after work and see what I can do about putting together your code reader.





Note: no matter what speed I drive I can still feel the surges. They are tiny at higher speeds. I am going through twice as much gas, I was getting 27 MPG now it has to be half of that. Also, when I come to a stoplight the car will sputter while surging. One time when I slowed down the car started coasting on me. If I turn the car off then restart I loose the sputtering, but still have the surge. Again the surge revs at Idle between 500 and 1,200 RPM. Right now I have no indicator lights on and I know all bulbs are working. I feel that it might be a vacuum leak because I believe I hear something behind the black pipes on the right side of the motor. I believe that would be the Manifold.

Thanks again for any insight.

Okay I put together the Code box and here are the following codes

Pin 8
4-Hot film mass air flow sensor
5-CTP switch
9-O2S 1 before WC -voltage too high, circuit open or voltage implausible
13-O2S (Lambda) control system operating at rich or lean limit
21-Ignition output 3 or ignition coil for cylinder 1 and 6
23-Ignition output 2 or ignition coil for 3 and 4


Pin 14
5-Stop lamp switch (S9/1)
11-Closed throttle recognition signal to engine control module

Thanks for any insight or input that you may be able to give me.

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Gary

E320 1994
ML320 1998

Clear them all and then see what comes back.

I would look for a vac leak for starters. Check the whilte plastic line under the front engne cover.

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A Dalton

I had the stop lamp code on my '94 and an in-op cruise control, ... replaced the US bulbs with the nickle-plated 21w bulbs and the cruise now works.

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Gone to the dark side

- Jeff

I cleared the faults and all came back except fault 5 from pin 14.

Yesterday I did find one of the vacuum lines, under the front cover, that leads to the left and goes under the engine to a sensor off.

When I listen to the engine, I swear that I can hear a leak under what I believe to be the manifold on the right side of the engine. I didn't get a chance to jack up the car and look under it for faulty vacuum lines. I see two vacuum lines going under the back part of my engine.


Again thank-you for all the help you have given me. I have just started working on our Mercedes and am lost on some of these topics.

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Gary

E320 1994
ML320 1998

"babymog: I had the stop lamp code on my '94 and an in-op cruise control, ... replaced the US bulbs with the nickle-plated 21w bulbs and the cruise now works."

I do have this problem with my cruise control when I am going under 45 MPH and have it on, it will surge on me sometimes.

What is the US bulbs where are they located??


Thank-you

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Gary

E320 1994
ML320 1998

The engine management limit and trim codes can be all related to vac leaks. The ECU and 02 sensor can not correct for that lean condition.
Check every line. After ypu fix any leaks , you want to clear codes and then get a single F;ash..that will allow you to reset the memory to mean so the old codes do not re-appear without drive cycles. [ adaptation]
The coil codes are most likely the Blue Labeled coils..common faut on those coils .
The CTP code can be a sticking throttle cable ..look for at least 1/4" play at the cable end..it is adjustable. That code also will appear if you attempt to work the throttle from under the hood by hand. It must be actuated by the pedal only.
I would also get some MAF spray cleaner and give the MAF a cleaning, along with checking the air filter for flow....and also check the clamp on the air cross-over pipe at the intake...any unmetered air will cause MAF code.

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A Dalton

"Arthur Dalton-and also check the clamp on the air cross-over pipe at the intake..."

Is this the pipe that goes straight down in the middle of the air intake manifold on the top right of the engine??

And I did throttle the engine from the outside of the car.

Arthur is there any repair manuals on here for the E320 1994. I do not have a manual. And need just about as much help as I can get.

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Gary

E320 1994
ML320 1998

I have went through all of my vacuum hoses and two were off, some were brittle and I changed them out. But I still have the surging problem. I cleared out the code on 8 and 14. After letting the car sit in idle it will surge between 500 and 1200 rpm. I then checked the codes again and am getting a code 5 off of pin 8. Does anybody know were the CTP is and how to check it??

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Gary

E320 1994
ML320 1998

how's the condition of your wiring harness?

I know my wiring harness is an original. I see some on Ebay but how can you know if they are not in the same condition that I currently have???

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Gary

E320 1994
ML320 1998

Email the ebay poster and ask for the date code on the harness........

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A Dalton