Brand new fuel pump issues
09-21-2022, 09:42 PM
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2008 r350 4matic
Brand new fuel pump issues
Been diagnosing my no start, but cranks issue for a couple days now. New pump install, because I had no pressure on the fuel rail. Check relays and fuse with multimeter...relays click and have continuity when closed. No voltage, at the 4 pin pump plug...seems like a possible bad wiring harness. Vehicle just wouldn't start one morning. No codes pulled up, and no warning, like irregular sounds. Just wondering if I should purchase a new wiring harness. looks like this plugs direct into the engine harness...not sure. or possibly connect to another harness, leading to the back, where the fuses and relays are located. Vehicle is a 2008 R350 4matic
09-22-2022, 06:03 PM
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2006 R500
Do you have voltage at the relay? If so, check for continuity between the fuse box and the plug. Also make sure the other power pin in the plug has continuity to ground.
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ChrsBowman (09-22-2022)
09-22-2022, 09:21 PM
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2008 r350 4matic
Appreciate it...ill be checking that tomorrow. Didnt think about continuity from the plug to the fuse box. Als, might be the SAM fuel pump relay or control module...i never checked that
