C55 cranks but won't start
Thread Starter
Junior Member
Joined: Feb 2007
Posts: 53
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From: Chicago, IL
2005 Silver C55, 2008 Ducati 1098
C55 cranks but won't start
I know that this topic has been discussed in some depth, just want to run my situation by some of you to see your thoughts.
Recently picked up a 2005 C55 with 33k on the odometer, my second C55, so ecstatic about that!
Had it for about a week, twice it would crank but would not start. Took the key out, tried it again and it would start, check engine light came on, but restarted and went away.
Today same problem, but no matter how many times I took the key out and cranked it, it would not start. Had it towed home, fun $150 bill, but the guy said the car starts and was confused why I had it towed.
The part where I am kinda at a loss of where to start is that it seems that the car being tilted forward may have gotten some gas to the engine to start it.
So I am thinking maybe it was the Fuel Pump and sending unit, I assume they come together when purchasing from the dealer. The tow truck driver thought maybe the fuel filters, because it being leaned forward got it starting. Some of the stuff I have been reading says CPS sensor. Half tempted to replace all three to not have to worry about this ever again, but would rather not if it can be avoided. I kinda rule out CPS sensor cause if it was bad it wouldn't have started after being dragged for 10 miles, tilted forward.
On a side note, anyone have the MBH headers, really thinking bout picking up a set of those.
Recently picked up a 2005 C55 with 33k on the odometer, my second C55, so ecstatic about that!
Had it for about a week, twice it would crank but would not start. Took the key out, tried it again and it would start, check engine light came on, but restarted and went away.
Today same problem, but no matter how many times I took the key out and cranked it, it would not start. Had it towed home, fun $150 bill, but the guy said the car starts and was confused why I had it towed.
The part where I am kinda at a loss of where to start is that it seems that the car being tilted forward may have gotten some gas to the engine to start it.
So I am thinking maybe it was the Fuel Pump and sending unit, I assume they come together when purchasing from the dealer. The tow truck driver thought maybe the fuel filters, because it being leaned forward got it starting. Some of the stuff I have been reading says CPS sensor. Half tempted to replace all three to not have to worry about this ever again, but would rather not if it can be avoided. I kinda rule out CPS sensor cause if it was bad it wouldn't have started after being dragged for 10 miles, tilted forward.
On a side note, anyone have the MBH headers, really thinking bout picking up a set of those.
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Joined: Sep 2010
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From: Washington DC
1999 E320 4matic Wagon, 2005 C55 AMG - sold, 1998 VW Jetta TDI - sold, 2006 C230 Sport - Totaled :(
It's the CPS, I guarantee it. If the CPS goes bad, it will sometimes start and sometimes not, like you are describing. When I first noticed mine, it would have an issue where it would crank about 10-15 times before starting, then other times would start immediately. Ordered the CPS. By the day it came in, it was a really really cold morning and I went to start, it cranked several times and did not start. But then I took the key out, tried again and then it worked, only this time the CEL came on. Replaced the CPS that afternoon, CEL went away, car started without issue. Had my friend run the STAR computer on it and verified that there was a stored code for the CPS that was the problem.
My friend is an MB Tech at the dealership and he told me he's never seen a fuel sending unit go bad on these cars. I'm not saying it's not possible, but most likely that isn't the problem. On this car, the fuel filter and fuel sending unit are one and the same, you can't just replace fuel filters like other models. Most likely it's CPS. If anything, the CPS is $45 and you will have to replace it anyway at some point so might as well. Not too difficult of a job either.
My friend is an MB Tech at the dealership and he told me he's never seen a fuel sending unit go bad on these cars. I'm not saying it's not possible, but most likely that isn't the problem. On this car, the fuel filter and fuel sending unit are one and the same, you can't just replace fuel filters like other models. Most likely it's CPS. If anything, the CPS is $45 and you will have to replace it anyway at some point so might as well. Not too difficult of a job either.
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From: A.D., U.A.E
2000 (W202 C200) & 2000 (W202 C55)
It's the CPS, I guarantee it. If the CPS goes bad, it will sometimes start and sometimes not, like you are describing. When I first noticed mine, it would have an issue where it would crank about 10-15 times before starting, then other times would start immediately. Ordered the CPS. By the day it came in, it was a really really cold morning and I went to start, it cranked several times and did not start. But then I took the key out, tried again and then it worked, only this time the CEL came on. Replaced the CPS that afternoon, CEL went away, car started without issue. Had my friend run the STAR computer on it and verified that there was a stored code for the CPS that was the problem.
My friend is an MB Tech at the dealership and he told me he's never seen a fuel sending unit go bad on these cars. I'm not saying it's not possible, but most likely that isn't the problem. On this car, the fuel filter and fuel sending unit are one and the same, you can't just replace fuel filters like other models. Most likely it's CPS. If anything, the CPS is $45 and you will have to replace it anyway at some point so might as well. Not too difficult of a job either.
My friend is an MB Tech at the dealership and he told me he's never seen a fuel sending unit go bad on these cars. I'm not saying it's not possible, but most likely that isn't the problem. On this car, the fuel filter and fuel sending unit are one and the same, you can't just replace fuel filters like other models. Most likely it's CPS. If anything, the CPS is $45 and you will have to replace it anyway at some point so might as well. Not too difficult of a job either.
ZAYED,,
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From: Washington DC
1999 E320 4matic Wagon, 2005 C55 AMG - sold, 1998 VW Jetta TDI - sold, 2006 C230 Sport - Totaled :(
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MBWorld Fanatic!
Joined: Sep 2010
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From: Washington DC
1999 E320 4matic Wagon, 2005 C55 AMG - sold, 1998 VW Jetta TDI - sold, 2006 C230 Sport - Totaled :(
That's what I've heard as well from most others on the forum; maybe that eventually would have happened to me if I didn't address it early? Mine just seemed to be a hit or miss, sometimes would start no problem and other times would struggle. Only fully failed to start once, but I'm sure it would have gotten worse if I didn't act as quickly.
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LET C32 2002
It's the CPS, I guarantee it. If the CPS goes bad, it will sometimes start and sometimes not, like you are describing. When I first noticed mine, it would have an issue where it would crank about 10-15 times before starting, then other times would start immediately. Ordered the CPS. By the day it came in, it was a really really cold morning and I went to start, it cranked several times and did not start. But then I took the key out, tried again and then it worked, only this time the CEL came on. Replaced the CPS that afternoon, CEL went away, car started without issue. Had my friend run the STAR computer on it and verified that there was a stored code for the CPS that was the problem.
My friend is an MB Tech at the dealership and he told me he's never seen a fuel sending unit go bad on these cars. I'm not saying it's not possible, but most likely that isn't the problem. On this car, the fuel filter and fuel sending unit are one and the same, you can't just replace fuel filters like other models. Most likely it's CPS. If anything, the CPS is $45 and you will have to replace it anyway at some point so might as well. Not too difficult of a job either.
My friend is an MB Tech at the dealership and he told me he's never seen a fuel sending unit go bad on these cars. I'm not saying it's not possible, but most likely that isn't the problem. On this car, the fuel filter and fuel sending unit are one and the same, you can't just replace fuel filters like other models. Most likely it's CPS. If anything, the CPS is $45 and you will have to replace it anyway at some point so might as well. Not too difficult of a job either.
Thread Starter
Junior Member
Joined: Feb 2007
Posts: 53
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From: Chicago, IL
2005 Silver C55, 2008 Ducati 1098
Replaced the CPS sensor a couple of weeks ago and seems to have solved the problem. Just a little concerned now about purchasing the aftermarket version as opposed to the OEM or Bosch part number.
Followed this video which was pretty good and made it somewhat easy. Took about 1.5 hrs.
Anyone had any bad experiences with using an aftermarket CPS sensor?
Followed this video which was pretty good and made it somewhat easy. Took about 1.5 hrs.
Anyone had any bad experiences with using an aftermarket CPS sensor?
MBWorld Fanatic!
Joined: Sep 2010
Posts: 1,545
Likes: 6
From: Washington DC
1999 E320 4matic Wagon, 2005 C55 AMG - sold, 1998 VW Jetta TDI - sold, 2006 C230 Sport - Totaled :(
