C63 wont start, wiring issue?
#1
Junior Member
Thread Starter
C63 wont start, wiring issue?
Okay so i've checked and couldn't find anyone with similar issues.
Here is the long and detailed story of my problem.
The first time my car would't start, I went through my whole car and checked every damn fuse in it. Threw code P0628 "Fuel pump A control Circuit Low". I found 1 blown fuse in the small fuse box located to the left of the steering column. Replaced the 20A fuse and my car started right up.
about 3 days later she died again. No warning signs at all just simply wouldnt start.
I rechecked all of my fuses and relays. All good.
I stated to suspect that maybe the fuel pumps (both fuel pumps and sending unit) shorted out so I bought used fuel pump... I know don't judge me lol
Didn't fix the cars still.
Then I replaced the fuel pump module located under the right hand side of the rear seat. And it started right up!!
That lasted about a month until it just didnt start again.
It turns over, it tries to start but the fuel pumps arent turning on at all and ive already replaced the module and still nothing
Here is the long and detailed story of my problem.
The first time my car would't start, I went through my whole car and checked every damn fuse in it. Threw code P0628 "Fuel pump A control Circuit Low". I found 1 blown fuse in the small fuse box located to the left of the steering column. Replaced the 20A fuse and my car started right up.
about 3 days later she died again. No warning signs at all just simply wouldnt start.
I rechecked all of my fuses and relays. All good.
I stated to suspect that maybe the fuel pumps (both fuel pumps and sending unit) shorted out so I bought used fuel pump... I know don't judge me lol
Didn't fix the cars still.
Then I replaced the fuel pump module located under the right hand side of the rear seat. And it started right up!!
That lasted about a month until it just didnt start again.
It turns over, it tries to start but the fuel pumps arent turning on at all and ive already replaced the module and still nothing
#3
Super Member
since you know where the fuel pump control module is you need to feed power to the output side of the module(to the pumps) and see if the car starts and runs. if it does start and run then the pumps are good, wiring from the module to the pumps is good. then test to see that the input side of the module is getting power....being as you said you had a blown fuse i would assume one of two things, either your module/pumps went bad OR you have a short in the wiring(when the cat work was done there may have been some wire damage or the weld in parts may be too close to the body and caused the insulation to burn off a section of the harness)....keep us posted
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masonpardo (04-18-2017)
#5
Junior Member
Thread Starter
Here is a little update.
I replaced the module with a used module from ebay.
I also replaced my battery and then BOOM it started right up!
Ran like it was meant to run!
then a couple hours later I tried to start it and it started but bogged down untill it died. So, not sure if the module is dead again and maybe its only starting because of fuel already in the lines.
I have an appointment this weekend to get it checked out. Hopefully all goes well.
I replaced the module with a used module from ebay.
I also replaced my battery and then BOOM it started right up!
Ran like it was meant to run!
then a couple hours later I tried to start it and it started but bogged down untill it died. So, not sure if the module is dead again and maybe its only starting because of fuel already in the lines.
I have an appointment this weekend to get it checked out. Hopefully all goes well.
#6
Junior Member
Thread Starter
Okay so just in case someone is following this thread or has a problem in the future here is the culprit!!
Just to the right of the battery there are two fuses one of which is a 40 amp
this is the wire coming from the back of that fuse it somehow got loose and started to overheat which caused a loose connection and there for throwing out my fuel pumps.
The burnt wire goes to the fuel pump module under the right side of the rear seat.
Fixing it tomorrow. Let's hope it's the only problem The single wore on the right feeds power to the fuel pump module.
Closer look of the burnt wire. Loose connection.
Just to the right of the battery there are two fuses one of which is a 40 amp
this is the wire coming from the back of that fuse it somehow got loose and started to overheat which caused a loose connection and there for throwing out my fuel pumps.
The burnt wire goes to the fuel pump module under the right side of the rear seat.
Fixing it tomorrow. Let's hope it's the only problem The single wore on the right feeds power to the fuel pump module.
Closer look of the burnt wire. Loose connection.
#7
Junior Member
Thread Starter
Okay so just in case someone is following this thread or has a problem in the future here is the culprit!!
Just to the right of the battery there are two fuses one of which is a 40 amp
this is the wire coming from the back of that fuse it somehow got loose and started to overheat which caused a loose connection and there for throwing out my fuel pumps.
The burnt wire goes to the fuel pump module under the right side of the rear seat.
Fixing it tomorrow. Let's hope it's the only problem The single wore on the right feeds power to the fuel pump module.
Closer look of the burnt wire. Loose connection.
Just to the right of the battery there are two fuses one of which is a 40 amp
this is the wire coming from the back of that fuse it somehow got loose and started to overheat which caused a loose connection and there for throwing out my fuel pumps.
The burnt wire goes to the fuel pump module under the right side of the rear seat.
Fixing it tomorrow. Let's hope it's the only problem The single wore on the right feeds power to the fuel pump module.
Closer look of the burnt wire. Loose connection.
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#8
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Join Date: Jun 2008
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2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
Nice catch dude. How did you track that down, smell?
#9
Junior Member
Thread Starter
I have a mechanic friend so we first tested every cable for voltage and we found the one cable that would get 12v then drop it randomly.
So we pulled the harness apart looking for any sort of knick in the wiring that would be shorting it and eventually traces it all the way back to the 40A fuse. The wire come directly from the back of the fuse and into the fuel pump module (there are two fuel pump modules)
anyway im off to mb to see if they have the part. I'll post a picture of the location of the fuse
So we pulled the harness apart looking for any sort of knick in the wiring that would be shorting it and eventually traces it all the way back to the 40A fuse. The wire come directly from the back of the fuse and into the fuel pump module (there are two fuel pump modules)
anyway im off to mb to see if they have the part. I'll post a picture of the location of the fuse
#10
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Join Date: Jun 2008
Location: Los Angeles
Posts: 8,067
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1,680 Posts
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
Wiring issues are the worst - testing can be so tedious. Glad you have it sorted.
#11
First off thank you for your post! Helped me find my problem immediately with the fuse next to the battery. I noticed the top red wire going to the fuel pump module was turning brown from shorting out/getting hot. I pressed it in and it fired right up. What did you end up doing to fix this? Did you get a new 40 amp fuse plate that sits by the battery or just a new wire from the fuel pump module to the 40 amp fuse plate?
Thanks in advance!
Thanks in advance!
#12
First off thank you for your post! Helped me find my problem immediately with the fuse next to the battery. I noticed the top red wire going to the fuel pump module was turning brown from shorting out/getting hot. I pressed it in and it fired right up. What did you end up doing to fix this? Did you get a new 40 amp fuse plate that sits by the battery or just a new wire from the fuel pump module to the 40 amp fuse plate?
Thanks in advance!
Thanks in advance!
anyone ?
#14
Can you shoot me a DM or email me at gixxermr2@yahoo.com
Had the same issue and wanted to know exactly what you did to remedy it.
Did you get a new fuse holder or did you wire in an aftermarket one?
Had the same issue and wanted to know exactly what you did to remedy it.
Did you get a new fuse holder or did you wire in an aftermarket one?
I have a mechanic friend so we first tested every cable for voltage and we found the one cable that would get 12v then drop it randomly.
So we pulled the harness apart looking for any sort of knick in the wiring that would be shorting it and eventually traces it all the way back to the 40A fuse. The wire come directly from the back of the fuse and into the fuel pump module (there are two fuel pump modules)
anyway im off to mb to see if they have the part. I'll post a picture of the location of the fuse
So we pulled the harness apart looking for any sort of knick in the wiring that would be shorting it and eventually traces it all the way back to the 40A fuse. The wire come directly from the back of the fuse and into the fuel pump module (there are two fuel pump modules)
anyway im off to mb to see if they have the part. I'll post a picture of the location of the fuse
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Sr Leem (03-15-2021)
#15
I ran into the same problem fuse is dark at the end as well
Can you shoot me a DM or email me at gixxermr2@yahoo.com
Had the same issue and wanted to know exactly what you did to remedy it.
Did you get a new fuse holder or did you wire in an aftermarket one?
Had the same issue and wanted to know exactly what you did to remedy it.
Did you get a new fuse holder or did you wire in an aftermarket one?
Any help please email too car cranks but does roll over at all. Nathaniel32thorpe@gmail.com