Can anybody help me here?
I have a 86 300 E 158K. Very clean and I have been doing all the repairs on it. I have all the factory shop manuals. But my ongoing problem is this: Hot or Cold, I have an intermittend starting problem. I have changed fuel pump, fuel pump relay, accumulator, filter, cold start valve, Co2 values are correct, new battery, all sensors check ok. New plugs, wires, distributor, rotor,cap. All rubbers on vacuun lines are replaced. CIS/EZL Temp. sensor is new. Car apperars to have a very slight valve seal leak. Air Flow Sensor plate is adjusted correctly. Have NOT looked at Fuel Distributor Contol Piston yet. Could be getting stuck. Fuel pressure OK

The crancking duration is very long during this problem. And I also hear some sort of crackling/gurgeling noise from the gas tank. I checked the evap system, seems to be ok. It seems to run very rich at that time, when it starts. Acts like loosing fuel pressure, but yet sometimes tries to run backwards, acting like no ignition. The dealer doesnt seem to know, although they can hear the noise when you open the gas filler cap.

Please advise.

Mino

I have seem an air flow sensor go bad will cause running problem like your.



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MB STARS Master Guild Technician,12 years MB tech
5 years independent shop owner

The girgling sound is weird. I have not seen this yet. The one thing I have seen related though is a crimped fuel line under the chasis of the car. Someone set a lift on it at one point and caused a crimp in the fuel line. That was a hard one...
The overvoltage relay can cause weird things as well.

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Benzmac:
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

Hi guys I'm back again.
I have replaced numerous different items now. Including injectors, brand new cold start relay, to no avail.
But I have made some big improvement when I disassembled the mixture control unit and the fuel distributor and cleaned everything real good. The car runs and starts much better. The A/F ratio is set as well and holding.
On other CIS systems there is an initial throttle plate opening specification. At least the manuals tell you what the gap needs to be and one adjusts that by the set screw at the throttle stop. I know that the 300 E has a setscrew as well but the shop manuals do not mention what the setting is.
I guess I could go to the dealer and measure one but I find more intellect about MB's at this forum than anywhere else.

Does anybody know what the gap needs to be? Thanks for all.

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Regards

Mino Erhan Dallas, TX
'86 300E
'67 Peugeot 404 Conv.
'85 Peugeot 505 STI
'99 Suzuki GSF 600 Bandit

The proper way to set this is with a small pin that is barely visible unless you are looking for it. It is located to the left of the adjustment tower in front of the fuel distributor. To lessen the gap you need to drive this pin in GENTLY. If you go too far, you will be taking it all back apart. Set it up to no less than 1.5mm.

Have you replaced the overvoltage relay.????



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Benzmac:
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

Yes sir, brand new Overvoltageprotection Relay.
Sorry about the misunderstanding with the throttle plate. I do know how to set the airflow sensor plate (luckily the manual shows that). What I seem to have trouble finding is, the initial opening angle or gap of the throttle plate, thats the one that has the set screw with a counter nut. The one that the throttle linkage attaches.

Thanks for your help

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Regards

Mino Erhan Dallas, TX
'86 300E
'67 Peugeot 404 Conv.
'85 Peugeot 505 STI
'99 Suzuki GSF 600 Bandit