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· My Own "Carbon Fiber Guy"
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2,671 Posts
Discussion Starter · #1 ·
OK, my Supra is officially down!!!! It looks to be a fuel issue but I thought that I would ping the members of SF to see if anyone has any ideas.

Set up:

VPC / GCC
Two Denso Fuel Pumps (primary stock and the second is on a relay)
Aeromotive Fuel Pressure Reg.
T70
Blitz 850cc injectors
Stock ignition

Symptoms:

Car will start for a few seconds then it starts to have an erratic idle and stalls out. When this happens the fuel pressure goes up to about 30PSI and starts to slowly dive to 0PSI and that is when the idle starts to go. It isn't always constant though. Some times I will try to start the car and I will not get any fuel pressure. It sounds like a fuel problem but where? Could a failed VPC cause the problem? Maybe a dying fuel pump? The fuses look good so the obvious is out. Any ideas???

Oh, and a side note, we took about an hour to figure out how to load the car on a wrecker. It took a lot of wood and we had to load the car backwards!!!ohnoes:
This was a laugh but we got it to my garage with NO damage:





That was the worst / hardest towing experience I have ever had. Breaking down on a Sunday when the wrecker services with REALLY low ramps are closed is not good. Had to make due:biggrin:
 

· Registered
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544 Posts
sounds like its out of gas...
Exactly...I had this SAME exact problem today. My car was running funny, it would shut off.. the whole 9. Turns out my gas gauge was stuck and there was no gas in the tank and whatever was in there lost all its octane. The car was misfiring and all. I drained it out and put a fresh tank in and its never been happier.
 

· Premium Member
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14 Posts
First make sure the pumps are coming on(if you are getting 30psi sounds like they are). Then check the filter(if there are two filters in your system I would guess this isnt the issue, but its a free check so give it a go) Then remove the pumps from the tank and look for an issue there(split fuel line, popped off line, etc..). If all of that is good, I would suspect the regulator next.
Honestly, I would guess the problem lies in the tank(split hose, or whatever)
 

· My Own "Carbon Fiber Guy"
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2,671 Posts
Discussion Starter · #15 ·
First make sure the pumps are coming on(if you are getting 30psi sounds like they are). Then check the filter(if there are two filters in your system I would guess this isnt the issue, but its a free check so give it a go) Then remove the pumps from the tank and look for an issue there(split fuel line, popped off line, etc..). If all of that is good, I would suspect the regulator next.
Honestly, I would guess the problem lies in the tank(split hose, or whatever)
Well, the pressure goes up and then dies off. If it is a failed fuel pump then couldn't it come on line then die off?? Is there any way to check the pump without digging into the tank? Maybe put my ear to the tank to listen for it:)

I think that you may be right though and I have to go after the fuel tank.
 

· Working OT
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9,049 Posts
Well, the pressure goes up and then dies off. If it is a failed fuel pump then couldn't it come on line then die off?? Is there any way to check the pump without digging into the tank? Maybe put my ear to the tank to listen for it:)

I think that you may be right though and I have to go after the fuel tank.
You should be able to hear the pumps come on when you turn the key to the on position. I wouldn't think it's a clogged filter if it has new pumps on the car but that would be a cheap place to start.
 

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3,086 Posts
You should be able to hear the pumps come on when you turn the key to the on position. I wouldn't think it's a clogged filter if it has new pumps on the car but that would be a cheap place to start.
Yup you should be able to hear it come on that way but you have to take it out anyway to look for any problems like a bad fuel line or tear or something.
 

· My Own "Carbon Fiber Guy"
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2,671 Posts
Discussion Starter · #20 ·
I had the same problem. I used aeroquip fuel line inside the tank from my fuel pumps to the bulkhead fitting. The lines aren't made to be submerged in fuel. They ruptured and did this exact thing.
This would make sense. Once the pressure goes up the fuel would just pour out of the hole in the line and then the pressure drop off slowly as fuel leaks out. It would also explain why it has gotten progressively worse. Because the tear has gotten bigger.... It looks like I need to pull the bulk head off of the tank.
 
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