Still tinkering with my 93 300E 2.8. I have had a starting problem for a little over a month now, sometimes starting instantly, other times taking a couple minutes of trying and having to press the accelerator. But here is my question.

I put a new fuel filter on the car because when it blew the headgasket awhile back, it sat for 6-8 weeks before I had the time to conquer that quest. So I figured it would be wise to install a new fuel filter. After putting it on, the car started instantly, much to my surprise. I drove it off the ramps, turned it off, and cranked again. Back to the normal hard to start. But it got me thinking. That was about a week ago. It has been less and less often that it takes more than one try to start the car, so I pulled out the fuel rail gauge again(had checked it months ago and had 60psi). When key is turned on, it jumps to 75ish area for just a second and then drops to 55. Crank on the car and it stays between 62-64psi and stays there with car running, just shaky. Let it sit for 15 mins and the pressure would drop to around 35psi. Bled it off and repeated the test 4 times always with the same results and the car starting easily. Is it likely the culprit to be the pressure regulator has some "trash" messing with the valve or possibly warped it, and by releasing the pressure on the rail it seats back to where it is supposed to be? I'm hoping this seems logical to someone other than me, because a regulator isn't an expensive part.

Any thoughts and suggestions would be great as I am sure this will help others I've seen come through this forum with similar symptoms.

Forgot to add that when the car is running, it drives great, no loss of power, but has stalled on occasion sitting at a stop while in (D).

I was wondering what happened to you....

sounds like you found your problem...I know nothing about this, but the guys should be able to help with this....

good luck !!!

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1993 300E, 2.8 M104 .....

Thanks latief, still been keeping an eye on the forums, just been putting up with the starting issue. Figure the only real problem I may cause is having to get a new starter driving it like this for a long period of time, but would just go to a local parts store and grab one with a lifetime warranty if it were to go out. Just hoping one of the mechanics that participate here might have a minute to hop in and put in their 2 cents.

Suprised no one has any thoughts on this. Was hoping to hear from a mechanic to make sure I was headed the right direction. Going to order one I guess and I'll post the results once I get it in.

Check fuel pump wiring,tank screen,then fuel pressure reg.

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1999 w140, quit voting to old, and to old to fight, a god damned veteran

I'm not an expert, but try this: pull the vac line off the regulator, if there is any fuel present or if it smells of fuel you have a leaky diaphragm in the regulator and will nedd a new one.

J. M. van Swaay

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1994 E320 Wagon, 230,000 miles
1995 E320 Sedan, 106,000 miles
1994 E500 Sedan, 79,000 miles

I did pull the vacuum line on it before and nothing was coming out is why I hadn't given it more thought before, but the loss of pressure so quickly once ignition is turned back off leads me to believe there is a leak in the system. Hoping its the pres reg as it is easy to access, but not a guarantee. It may be down the line somewhere else. But I have it ordered, and will post the results, hopefully good ones.

Your fuel injectors are leaking and flooding the motor. They have to hold the residual pressure and arent'. Fix is new injectors.

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Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles

Ikchris, I have pulled the fuel rail and tested the injectors when cold. Then drove it for 15 mins and pulled the rail and tested them hot. No leaks. Had thought of that as I had one stick open before on a car, but acted very differently.