PDA

View Full Version : Gtm hard start, loosing prime. (Long)



GTMKris
04-22-2011, 06:37 PM
For a while now the car doesn't want to start. It spits and sputters to life, once running it runs great without a hitch. I put a fuel pressure gauge on the fuel rail. You cycle the ignition and the pump runs. Pressure builds to around 60lbs. As soon as the pump stops running the pressure drops to 0lbs. First thing that comes to my mind is the fuel pressure regulator. Guess what, the pressure regulator is part of the fuel pump which is $400 for the cheap one.

Since the engine is loosing its prime(fuel pressure) its causing the hard start condition. So this is what I'm thinking. If I can find a generic fuel pressure regulator somewhere I can put it inline from the tank to the filter. At that point it would work like any other return style fuel system. Pump comes on,builds pressure,pump stops, regulator holds prime. Since my donor was a 02 vette the fuel filter has two ports on one side a 1 on the other. The one is the outlet from filter to the motor. On the other side one is a inlet and the other is a return back to the tank, I assume that this just bleeds excess pressure back to the tank.

My donor is a 02 vette. On the fuel rail there is a little silver piece on the fuel rail that I thought was the fuel pressure regulator, turns out its just a plug that fills the hole where I think that there was a regulator on a previous model car that the fuel lines are used for. Not really for sure on this but in the ffr manual it shows my style and the previous style where there is a little nipple sticking out.

Will this work. Am I correct in my thinking?

I hooked all the fuel lines the original way from the manual using the jet pump. It wasn't until today that I realized that people don do that anymore.

The Stig
04-22-2011, 08:21 PM
Hi Kris.

This is something that I was worried about as well. I was told that the use of a "one way valve" would solve the issue, and keep the prime in the fuel lines. With the one-way, the fuel can't run back down the lines.

VD2021
04-22-2011, 09:03 PM
Kris,
This may not be your problem, but the "Y" fuel line that you had to modify has a check valve. Its diameter is just larger than the line so it would be easy to miss. It has and arrow pointing in the direction of the fuel flow.

http://i814.photobucket.com/albums/zz61/vd2021/100_2244.jpg

http://i814.photobucket.com/albums/zz61/vd2021/100_2243.jpg

GTMKris
04-22-2011, 09:50 PM
I did not install this part. I have the "Y" in there but no check valve. Looks like it was a corvette part. How did I miss that. Did I just read over it or was it not in the manual. Thanks Guys, bet that solves my problem.

VD2021
04-22-2011, 11:21 PM
Kris,
The manual didn't mention it. Maybe because if you install it per the manual you it should be there by default??? I only noticed it because I didn't like the bend that was in the portion feeding into the filter and decided to rebuild it. Any fuel capable check valve of the correct line size should work as I'm sure the OEM one will be outrageous.