Fuel Delivery Issues
Thread Starter
Junior Member
Joined: Nov 2009
Posts: 39
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1999 Mercedes-Benz C43 AMG
Fuel Delivery Issues
So Ive been having problems with my car not starting. It will turn over but not start. I immediately felt that there was something wrong with my fuel system so I rented a fuel pressure gauge and tried to diagnose it. Upon connecting the gauge, I got no pressure reading with just the ignition on (not started). Once I got it started (repeated cranking) the pressure went up to the appropriate range. I then turned it back off and the pressure dropped to zero immediately. After asking around and looking around on the forums I concluded it was my fuel pump. After replacing the pump, and fuel pump relay..its still not fixed. However I did find the problem. I connected a 12V source directly to the new pump and bingo...the pressure gauge rose to the appropriate reading with just the ignition on and the car started on the first crank. So that tells me that is has to be something with the wiring harness the runs to the pump right? If someone could provide me with some insight on what else it could possibly be I would greatly appreciate it.
Also, could it be a bad fuse or something? Is there even a fuse for it and if so where the hell is it...lol?
Also, could it be a bad fuse or something? Is there even a fuse for it and if so where the hell is it...lol?
MBWorld Fanatic!
Joined: Apr 2010
Posts: 4,437
Likes: 43
From: PDX
1999 C43, 2008 P30 E63, 2014 SQ5, 2024 Model Y Performance
Found this in another thread (the search function is a wonderful thing)
"yeah its in the trunk. thats where my mechanic uplugged the fuse for mine when he ran the bg fuel cleaning system, unplugged a fuse on the right side of the trunk under the spare cover"
Here is the thread I copied from:
https://mbworld.org/forums/c36-amg-c...-location.html
If replacing the fuse doesn't work get a DMM (Digital multi meter) and check the voltage/ohms coming through the power/ground wires to the fuel pump, this should tell you if it is your power or ground that is bad.
"yeah its in the trunk. thats where my mechanic uplugged the fuse for mine when he ran the bg fuel cleaning system, unplugged a fuse on the right side of the trunk under the spare cover"
Here is the thread I copied from:
https://mbworld.org/forums/c36-amg-c...-location.html
If replacing the fuse doesn't work get a DMM (Digital multi meter) and check the voltage/ohms coming through the power/ground wires to the fuel pump, this should tell you if it is your power or ground that is bad.
Thread Starter
Junior Member
Joined: Nov 2009
Posts: 39
Likes: 0
1999 Mercedes-Benz C43 AMG
So I found my fuel pump fuse. Its the very top left fuse in fuse box in the trunk. Anyways I pulled the fuse, which was fine by the way, and put a multi meter on housing and I it had no voltage what so ever. Just to check myself, I did the same on the fuse below it and I got a 12V reading.
So, based on this is most likely the problem and there is an electrical issue going on? Also, is there a fuel pump safety switch on this car that may be triggered which is causing my problem?
So, based on this is most likely the problem and there is an electrical issue going on? Also, is there a fuel pump safety switch on this car that may be triggered which is causing my problem?
MBWorld Fanatic!
Joined: Apr 2010
Posts: 4,437
Likes: 43
From: PDX
1999 C43, 2008 P30 E63, 2014 SQ5, 2024 Model Y Performance
So I found my fuel pump fuse. Its the very top left fuse in fuse box in the trunk. Anyways I pulled the fuse, which was fine by the way, and put a multi meter on housing and I it had no voltage what so ever. Just to check myself, I did the same on the fuse below it and I got a 12V reading.
So, based on this is most likely the problem and there is an electrical issue going on? Also, is there a fuel pump safety switch on this car that may be triggered which is causing my problem?
So, based on this is most likely the problem and there is an electrical issue going on? Also, is there a fuel pump safety switch on this car that may be triggered which is causing my problem?
