Fuel pump problem?
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Fuel pump problem?
I have an 06 vert, supercharged (maggie mp112). My check engine light (CEL) came on the other day so I took it to the gm dealer today. They said its a fuel issue, banks 1 and 2 are running lean, hence the CEL. An FYI the pod fuel gauge says 44 psi (it should be 58-60). Further, the GM tech said its a tune issue, and that a speciality shop tuner should be able to tune for the boost a pump (BAP) to increase fuel pressure? Later in the day I took the car to a speciality shop and the tech their said its not a tune issue, rather its a fuel pump problem (needs replacing). He never even tested the BAP? Question I have do I replace the fuel pump, the BAP, or get a tune?? How do I hone in on this problem to determine what the culprit is?
Last edited by msd127; Apr 12, 2016 at 08:38 AM.
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If it were my vette, I would get the technical info for my specific BAP electronics, and I would hook up wires so that I could monitor it under full load with a voltmeter.
I believe some raise the voltage as high as 18V, but your documentation should tell you the voltage level you should see.
IF you are getting the specified higher voltage to your fuel pump, and it is not keeping fuel pressure up, I would suspect the pump is starting to fail (which is a problem sometimes with boost a pump setups).
A failing pump usually gets worse the more you drive it too. Meaning, you may see good fuel pressure if you get on it the first few minutes of driving, but see it drop after you drive an hour or so.
Now if your voltage is low during your testing, it could be bad/loose wiring, a failing BAP, etc.
Others may chime in with more info too.
I believe some raise the voltage as high as 18V, but your documentation should tell you the voltage level you should see.
IF you are getting the specified higher voltage to your fuel pump, and it is not keeping fuel pressure up, I would suspect the pump is starting to fail (which is a problem sometimes with boost a pump setups).
A failing pump usually gets worse the more you drive it too. Meaning, you may see good fuel pressure if you get on it the first few minutes of driving, but see it drop after you drive an hour or so.
Now if your voltage is low during your testing, it could be bad/loose wiring, a failing BAP, etc.
Others may chime in with more info too.
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Thanks Seadawg that is helpful. Interestingly the fuel pump pressure stays constant at 44 psi through an entire drive, i.e., 1hour, 2hours etc. Would this indicate that the pump is working but at a reduced output with the BAP trying to offset the weakness? Also the car cold starts ok as well. However, I definitely need to test the BAP.
Last edited by msd127; Apr 12, 2016 at 09:10 AM.
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Sorry, until you get some voltage data, it's hard to tell too much more.
You may want to look at doing something like this too, for warnings in the future.
https://www.corvetteforum.com/forums...onitoring.html
You may want to look at doing something like this too, for warnings in the future.
https://www.corvetteforum.com/forums...onitoring.html
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Joined: Nov 2007
Posts: 4,427
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From: Bay Area CA
I have an 06 vert, supercharged (maggie mp112). My check engine light (CEL) came on the other day so I took it to the gm dealer today. They said its a fuel issue, banks 1 and 2 are running lean, hence the CEL. An FYI the pod fuel gauge says 44 psi (it should be 58-60). Further, the GM tech said its a tune issue, and that a speciality shop tuner should be able to tune for the boost a pump (BAP) to increase fuel pressure? Later in the day I took the car to a speciality shop and the tech their said its not a tune issue, rather its a fuel pump problem (needs replacing). He never even tested the BAP? Question I have do I replace the fuel pump, the BAP, or get a tune?? How do I hone in on this problem to determine what the culprit is?
Test the voltage at the BAP's hot, it should be around 12-13 volts. Jump the hobb switch with a wire and test the voltage at the BAP's hot. If the hobb switch is working, voltage should be around 17 and the BAP is doing it's job. If the voltage remains 12-13, then I would start by replacing the hobb switch. If no voltage, the car will not start.
The hobb switch is hooked up to a vacuum source so once boost reaches 3 psi. it kicks in raising voltage to the fuel pump. Some BAP's have an adjustment ****, if yours does make sure it is adjusted to installers spec.
Last edited by Mike's LS3; Apr 12, 2016 at 11:29 AM.
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Joined: Nov 2007
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From: Bay Area CA
To access the BAP hot, I removed the drivers rear tire and inner fender and the BAP was behind the inner fender.
This is how my BAP was installed, your installer might have the location of the hobb switch and BAP elsewhere. Ask them to save time.
Look up Kenne Bell BAP for diagrams and info.
Last edited by Mike's LS3; Apr 12, 2016 at 11:47 AM.
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