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Help! What looks like a bad fuel pump but isn't a bad fuel pump?

TQP

New Member
Joined
Aug 20, 2018
Messages
2
Location
Texas
My XLR/V(s)
2006 Blue XLR
A few months ago I began to have periodic starting problems on my 2006 XLR. It frequently wouldn't start although the starter would crank. Once it started, it would run fine until the next time I stopped. I had a few mechanics look at it and they couldn't figure out what was wrong. I finally broke down and took it to a dealer who had a mechanic who has experience with these cars. He ultimately diagnosed it as a bad fuel pump. For a couple thousand bucks, he replaced the pumps and sensors in both tanks (all with OEM parts).

When I got the car back it seemed to run fine for a couple of days, then it began doing the same thing... cranking but not starting. However, EVERY time it would not start, I could connect a jump box to the battery and it would start first time and run rock solid until the next time I stopped. Then about half the time it wouldn't start again until I put a jump box on it when it would start right up again.

I recently got frustrated and took it to a different Cadillac Dealership. They are diagnosing it as a bad fuel pump again, but I don't believe it. The probability that they are serially installing one bad fuel pump after another seems slim. Plus it doesn't explain why it will always start with a bit more power from a jump box or how it will fun perfectly and indefinitely once you do get it started.

One more thing... I've put a couple of different batteries in it thinking maybe a dead cell or bad battery. It currently has a nice Odyssey battery that tests perfectly. so that doesn't seem to be the problem.

So, my question is "What looks like a bad fuel pump, but isn't a bad fuel pump? Hopefully somebody here has seen this before.
 

Fireduck69

Seasoned Member
Joined
Mar 21, 2015
Messages
334
Location
NorthEast PA
My XLR/V(s)
2007 Black XLR-V
I haven’t experienced this but sounds like a corroded connection some where. This is the same fuel system as the C5 so maybe do some search on the vette forums for similar problems.
 

mickeytee

Seasoned Member
Joined
Apr 5, 2017
Messages
803
Location
North Atlanta
yep. check out those 2 ground wires on the frame at the rear behind the tire. Almoste everyone I have looked at is corroded . take them off clean the m and install a serated electrical lock washer.
 
Joined
Jul 26, 2013
Messages
561
Location
Central Ohio
My XLR/V(s)
2004 Black Raven, Ebony
You should search the site, but I believe there is a similar post and indicated the ground directly from the starter to the chassis was the culprit. Please post your results so we can all learn from this one.


Sent from my iPhone using Tapatalk
 

David_B

Seasoned Member
Joined
Aug 31, 2014
Messages
446
Location
SE Michigan
My XLR/V(s)
N/Z
Behind the tire? or between the door and the tire? There was another thread here about one there I thought..

yep. check out those 2 ground wires on the frame at the rear behind the tire. Almoste everyone I have looked at is corroded . take them off clean the m and install a serated electrical lock washer.
 

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