HELP! 2010 S63 Blowing Fuel Pump Fuses, Starter wont power on
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MBWorld Fanatic!
Joined: Jan 2003
Posts: 6,278
Likes: 14
From: Windermere, Sunny FLA
CLK55, CL500, Q45
HELP! 2010 S63 Blowing Fuel Pump Fuses, Starter wont power on
Hey guys, 2010 S63 having a few issues, long story short...
Took the vehicle in to my independent to have the infamous head bolts upgraded as preventative maintenance.
Install went fine, however afterwards car was throwing a CEL for running too lean. Smoke test determined one
of the valve cover gaskets was not seated correctly. My indy went ahead and replaced the gasket. Tested the
car on the lift and all seemed well.
An hour later went to pull the car up front for me to pick up and the car would not start. Dash lights up and everything
seems normal, however when you turn the key the starter does not engage. Ordered new Bosch starter and installed,
still nothing. If you ground out with a screwdriver, the starter engages. Obviously engine does not start because car
does not recognize we are jumping the starter.
Chasing wires/fuses/relays and we found when the key is turned, the starter is not getting power to turn on. We also
found one of the fuses in the Front SAM box (engine bay driver side) keeps blowing as soon as the car has power or
"wakes up." It is F21 (20amp) Circuit 87 - Fuel Pump Relay.
We have checked all other fuses and relays related to the fuel pump are in good working order, as well as checked for
burns on the fuse boxes. Also checked wiring on fuel pump as that was an issue for another member.
Anybody have any idea on where to go next as we cant seem to figure out this problem?
Why does F21 keep blowing fuses instantly? We tried 15/20/25/30A and they all blew as soon as installed.
Any and all help would be much appreciated!
Took the vehicle in to my independent to have the infamous head bolts upgraded as preventative maintenance.
Install went fine, however afterwards car was throwing a CEL for running too lean. Smoke test determined one
of the valve cover gaskets was not seated correctly. My indy went ahead and replaced the gasket. Tested the
car on the lift and all seemed well.
An hour later went to pull the car up front for me to pick up and the car would not start. Dash lights up and everything
seems normal, however when you turn the key the starter does not engage. Ordered new Bosch starter and installed,
still nothing. If you ground out with a screwdriver, the starter engages. Obviously engine does not start because car
does not recognize we are jumping the starter.
Chasing wires/fuses/relays and we found when the key is turned, the starter is not getting power to turn on. We also
found one of the fuses in the Front SAM box (engine bay driver side) keeps blowing as soon as the car has power or
"wakes up." It is F21 (20amp) Circuit 87 - Fuel Pump Relay.
We have checked all other fuses and relays related to the fuel pump are in good working order, as well as checked for
burns on the fuse boxes. Also checked wiring on fuel pump as that was an issue for another member.
Anybody have any idea on where to go next as we cant seem to figure out this problem?
Why does F21 keep blowing fuses instantly? We tried 15/20/25/30A and they all blew as soon as installed.
Any and all help would be much appreciated!
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Thread Starter
MBWorld Fanatic!
Joined: Jan 2003
Posts: 6,278
Likes: 14
From: Windermere, Sunny FLA
CLK55, CL500, Q45
So follow up, as still have not got this car on the road yet. Fixed the pinched wire harness...
Now I am having misfire issues on one bank. Cylinders 5,6, & 8 randomly misfire. Turning off engine and starting again fixes issue for a few minutes.
Tried switching spark plugs and coil packs around to isolate those issues. No change. Any ideas on where to go now?
Now I am having misfire issues on one bank. Cylinders 5,6, & 8 randomly misfire. Turning off engine and starting again fixes issue for a few minutes.
Tried switching spark plugs and coil packs around to isolate those issues. No change. Any ideas on where to go now?
MBWorld Fanatic!
Joined: Feb 2012
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From: Phoenix
222 S-65
OP power supply to injectors and coils to that bank of cylinders. Grounds. Another damned good look at harnesses. Everything got disturbed with repairs. We've already seen one issue due to oopsie at the shop... It happens!
Thread Starter
MBWorld Fanatic!
Joined: Jan 2003
Posts: 6,278
Likes: 14
From: Windermere, Sunny FLA
CLK55, CL500, Q45
Alright guys, I bit the bullet and bought a new engine wire harness, however my mechanic has been dragging his feet and not
installed it yet. Does anyone have any diagrams on how to replace the harness, thinking of doing it myself. Pretty handy with
repairs under the hood, but some instructions will always help, as I just follow the old wire loom with the new one.
Thanks!
installed it yet. Does anyone have any diagrams on how to replace the harness, thinking of doing it myself. Pretty handy with
repairs under the hood, but some instructions will always help, as I just follow the old wire loom with the new one.
Thanks!
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Thread Starter
MBWorld Fanatic!
Joined: Jan 2003
Posts: 6,278
Likes: 14
From: Windermere, Sunny FLA
CLK55, CL500, Q45
As an update, in case anyone in the future has this problem, I installed a new engine harness on the car. Resolved the issues,
however still a slight idle vibration, will be looking into that this weekend.
As for replacing the engine harness.... the engine had to come out. 16 shop hours later, it has been replaced.
however still a slight idle vibration, will be looking into that this weekend.
As for replacing the engine harness.... the engine had to come out. 16 shop hours later, it has been replaced.
