Starting Hot Engine

[KAMAL]

HI,

I HAVE E420-1995, IT STARTS PRETTY GOOD IN MORNING OR COLD ENGINE. BUT DURING THE DAY WHEN I DRIVE THE CAR AND RESTART HOT ENGINE. IT TAKE TWO-THREE TIMES BEFORE THE ENGINE STARTS. I DONT PRESS THE GAS PEDAL DURING THIS PROCESS. I WAS WONDERING IF THIS IS SERIOUS OR JUST A MAINTENANACE ISSUE. IF SO IS THE SPARK PLUG GAPING CAUSING THIS PROBLEM.

PLEASE ADVICE.

THANKS

KAMAL

[Ashman]

I had/have same issue on a 1992 300CE m104 engine. I changed spark plugs and gap, and it didn't make much difference.

I plan on looking into it more, but for me its not a big deal. I think mine is caused by the injectors leaking down.

If I turn off the car, it will retsart on first try if I start it within a few minutes, let it sit for 10-20 minutes or more and I have to crank it twice.

Cold starting starts fine.

I talked to my mech about it and he thinks it might be the injectors leaking down as well, since the car runs smooth as silk when its on.

Alon

[Benzmac]

Kamal,
This engine should crank the first time, every time. The EFI is designed that way. If you are cranking more than 1 time, you have a problem.

I would have diagnosis done to see what the problem is.

We have replaced many distributor caps and rotors on this engine.

BTW> Alon, Your car uses CIS fuel injection. This one uses EFI...
Different fuel injection system and injectors altogether.

[vinamg]

You might want to check your fuel pressure regulator. Remove air cleaner. It's on the driver's side toward the back. First check if the vacuum line has any fuel around it. Hook up a vacuum gauge to the regulator. If you don't have one, run the car for a while to build up pressure. Disconnect vacuum line from nipple and check if any fuel comes out.

Vin

[loubapache]

My 1990 300E (now sold) had this problem for over three years and 40kmi. It finally disappeared.

I think it was dues to the following two reasons:

1. Vapor lock in the fuel system.

2. Slightly leaky injector(s) due to deposits.

I did not replace anything for the problem and it just disappeared. I think the regular use of Techron eventually cleaned the injectors.

Sounds like classic Vapor Lock...Service EFI.

[Ashman]

AHA there ya go. Thanks for the correction donnie.

I was just trying to be helpful, sometimes more than one head can help figure out an issue.

On my car its probablyt he injectors, cold start is perfect, ovp and all other related items fine. car only has issues after its been warmed up and shut down for a short period.

After talkign to my mech we think the injectors would be leaking down if thats the case. for me.

I'm looking into it, just don't want to spend on repairs right now if I don't have to. x-mas season is the worst on the checkbook.. hehe

Alon