I've been unsucessful in locating the fuel pump check valve on my '95 C280. It has a single pump and filter, but I cannot find a check valve in the line or on the pump. Is it built into the pump on these models? Or is it located elsewhere? Thanks.

Why are you looking for this on the C?

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Benzmac:
Donnie Drummonds
1991 GMC Syclone
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

It's hard to start when the engine is warm and has been sitting for a while. It starts fine if you don't let it sit for very long. It starts fine when cold. I posted this problem a while back and got several responses that indicated a possible fuel pressure leak down. Since there is not an accumulator on this model, I thought I would try the check valve and the pressure regulator to eliminate them as a possiblity. Any other suggestions?

On the C, I have not seen a check valve problem yet. I would check the small green fuel pump relay in the trunk. Also, I have seen the fuel pumps fail and over-voltage relays.

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Benzmac:
Donnie Drummonds
1991 GMC Syclone
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

Thanks, Donnie. I may have located the problem. The pressure regulator leaks fuel from the vacuum hose connection when the system is under pressure. While it is running, if you remove the vacuum hose, fuel will constantly drip out. If the engine is stopped, it will drip until the pressure is low. This raw fuel dripping into the intake path when the engine is off may be "flooding" the engine and the reduced pressure in the fuel rail may cause some prblems. By the way, where is the check valve located?

Replaced the fuel pressure regulator today. Problem is solved. Thanks to everyone for the help. I still would like to know where the fuel pump check valve is located on this model.

[This message has been edited by ARJAY (edited 07-20-2000).]

[This message has been edited by ARJAY (edited 07-20-2000).]