No fuel pressure

[Rachelreed]

Just wondering if anyone can help with a new fuel pressure problem? My brother and I are trying to get my late father is Buick going.

It has a brand new 450 pump with a new hanger. It also has a hot wire kit. I checked the fuses under the dash we check the fuse in the hot wire kit and we also swapped out the fuel pump relay. I double check the wiring at the factory connector it appeared that the wires from the hanger or backwards red to black and black to red so we can’ it also has a hot wire kit. I checked the fuses under the dash we checked the fuse in the hot wire kit and we also swapped out the fuel pump relay. I double checked the wiring at the factory connector it appeared that the wires from the hanger were backwards red to black and black to red so we fixed that. After I went back home to Texas my brother ran a ground from the factory fuel pump wiring to the battery and still no luck? Could this be the regulator it’s self?


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[Chuck Leeper]

Regulator does not control the pump operation.
Check the relay trigger power. Jump the relay, and see if the pump runs. If yes, then it could be the ecm not triggering the relay.
Check the low oil pressure sw and the plug, below the turbo.

 

[Rachelreed]

Regulator does not control the pump operation.
Check the relay trigger power. Jump the relay, and see if the pump runs. If yes, then it could be the ecm not triggering the relay.
Check the low oil pressure sw and the plug, below the turbo.

The car runs an aftermarket computer from a place in Florida my brother said. He also said it doesn’t run the stock oil sensor


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[Rachelreed]

Regulator does not control the pump operation.
Check the relay trigger power. Jump the relay, and see if the pump runs. If yes, then it could be the ecm not triggering the relay.
Check the low oil pressure sw and the plug, below the turbo.

Can you give me an idea of how to jump the relay?


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[michael evans]

Behind the alternator there is a two-white plug (not the single-white wire plug) that will power the fuel pump if you apply 12-volts to it.

 

[Chuck Leeper]

Can you give me an idea of how to jump the relay?


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Who knows... With the aftermkt ecm, what else is changed, is only a guess.
Suggest you find a shop that can troubleshoot the system.
Otherwise, all you'll get is ideas, like mine.
If you want to continue, post up the pertinent info, as to how the car is equipped.

 

[Pronto]

Check the hotwire kit to see if it has a fuse in it as well. It may have blown.

 

[GNRick]

Could be a broken wire at the bulkhead connector on top of the fuel pump hanger. Happened twice to me. Racetronix sells a heavy duty bulkhead.

 

[Jerryl]

Could be a broken wire at the bulkhead connector on top of the fuel pump hanger. Happened twice to me. Racetronix sells a heavy duty bulkhead.

This. ^^^
If the bulkhead wasn't upgraded with a 450 pump, most likely the contact are compromised. Even with a 340 it's borderline.

 

[Jerryl]

Behind the alternator there is a two-white plug (not the single-white wire plug) that will power the fuel pump if you apply 12-volts to it.

Not sure this info.is correctly stated as intended.
Do not add power to the 2 wire plug. The pump wire is a single wire plug.

 

[dynoman]

It has a brand new 450 pump with a new hanger.

The new hanger should have a new bulk head connector on it already , but how does the intermediate harness that connects to the bulk head connector look ?
Also you said the FP relay was changed , which one ?? The hotwire relay out back or the stock relay under the hood on the passenger side fender ?

 

[Rachelreed]

The new hanger should have a new bulk head connector on it already , but how does the intermediate harness that connects to the bulk head connector look ?
Also you said the FP relay was changed , which one ?? The hotwire relay out back or the stock relay under the hood on the passenger side fender ?

Yes, new relay at the fender. We then unplugged the Hotwire and plugged the pump harness back into the stock wiring.. same result.

Everything I’ve read says this is usually a ground issue? We ran a ground from the battery to the factory wiring under the car just before the factory plug coming out of the trunk area...


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[Rachelreed]

Who knows... With the aftermkt ecm, what else is changed, is only a guess.
Suggest you find a shop that can troubleshoot the system.
Otherwise, all you'll get is ideas, like mine.
If you want to continue, post up the pertinent info, as to how the car is equipped.

Per my bro- xfi, 60lb injectors, -8an and-6an lines, Walbro 450 pump, racetronix hangar, Hotwire, alky, brand new battery


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[Pronto]

You need to verify that pump is getting power.

 

[Rachelreed]

We got it guys!!! This was a combo problem! The harness from racetronix was incorrect to the Hotwire kit! Also, we ran ground direct to battery! Fired right up.. here is pics of the wiring as it was sent.

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[Pronto]

Well, your Dad burned up those drag radials for sure. Glad you found the issue.

 

[John Larkin]

If you want to tidy up that harness, I believe the relay bracket will fit right over one of the bumper mounting bolts. Then the hanger harness will go over the tank strap. It will not be seen from rear that way. Of course that fuel filter is mounted under the bumper which is odd. I would relocate that also.

 

[michael evans]

Not sure this info.is correctly stated as intended.
Do not add power to the 2 wire plug. The pump wire is a single wire plug.

Had it backwards then it is the single wire. The double wire is the tachometer.

 

[dynoman]

We got it guys!!! This was a combo problem! The harness from racetronix was incorrect to the Hotwire kit! Also, we ran ground direct to battery! Fired right up.. here is pics of the wiring as it was sent.

Good job , way to stay after it !!
Thanks for posting the fix .

 

[Rachelreed]

Good job , way to stay after it !!
Thanks for posting the fix .

Hey thanks for the help!!!


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