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-   -   I'm stumped.... no fuel pressure. (https://www.gtcarz.com/chevy-gmc-70/im-stumped-no-fuel-pressure-106862/)

MeenZ28 08-06-2007 12:30 AM

I'm stumped.... no fuel pressure.
 
To start, I JUST replaced the fuel pump a little over a month ago....

The car cranks fine but wont fire. Battery is holding a charge and everything electrical is good. Tapped a pressure gauge tester to the schader valve on the back of the fuel rail and got NO reading. The needle didnt even want to move. So I traced the fuel lines. Disconnected them from the rails, nothing. Took them from the filter... fuel was there. And the fuel pump sounds like it's working (that hum comes on when the key is turned but she wont fire and I'm readin no fuel pressure at all.

Could the fuel pump be dead? Or what else could it be? I'm stuck....

blue89vert 08-06-2007 12:34 AM

somethin clogged? i have no idea

toofazt 08-06-2007 12:43 AM

Have you tried replacing the fuel filter?

MeenZ28 08-06-2007 12:55 AM

Yes sir, I had that thought. I did that this morning. Didnt make a differance. In fact I thought it a bit strange, I know the tank is full, but when I disconnected the line from the filter it kept spilling into the catch can I had. I figured it'd stop after a few minutes seeing as how i had no pressure but it kept coming. I HAD to change the filter just to stop lossing the fuel...

ITSA6 08-06-2007 12:58 AM

your car is emo trying to kill itself. my guess would be maybe when you replaced the pump(i think you did) that you got a defect one? like how you can get a bad alternator or something? that's my guess

MeenZ28 08-06-2007 01:08 AM

Thats what i was thinking but again - when I turn the key I can hear it power up.... that means it works.... right?

Yes I know Epic is tempremental - always has been. I just think it's funny that she's running great for a month and the second A great crusie comes up..... dead. She would do this to me....

ITSA6 08-06-2007 01:10 AM

i dunno cause when our alt was bad we could still start the car but a dash light would stay on. I don't know a ton about the LT-1 so i can't make an honset guess there

MeenZ28 08-06-2007 01:19 AM

Well I apreciate the try but does anyone have a guess as to what this is? I was ready to chalk it up to an ignition problem like the Opti dieing but when I saw there was no fuel pressure.... I'm f-in lost. Someone clue me in here.

A-RoN'sZ 08-06-2007 01:55 AM

Sorry man...I would've thought fuel filter myself considering I changed mine the other day, and the old one was terrible, but since you already checked that...hope you figure it out and get everything fixed.

mpe331lx 08-06-2007 05:18 PM

Sometimes replacement pumps come with crap rubber fuel hose. I have a 95 4V swapped mustang that I recently put a Cobra in tank pump and tank set up in. When I replaced the lines I used 30R9 fuel injection hose. The gas ate it up and the pressure blew a hole in it in about a month.

I hate to say it, but it sounds like you need to drop the tank again.
If you hear the pump running, and dont have any fuel pressure before the filter, you either have a faulty pump (unlikely) or a blown hose from the pump to the outlet in the fuel hat (bracket that retains the pump).

Make sure that you use gates submersible fuel hose that meets SAE 30R10 specs.

5/16" Gates# is 27093
3/8" gates# is 27097

Napa packages gates hose under thier own part number, they should be able to cross it. I got mine from bumper to bumper (Parts depot)

MeenZ28 08-06-2007 08:24 PM

Well it sounds liek the next step is looking at the pump assembly either way. Luckly I did it the access door method last time so it should be too tough. I hope you're right bro, because if you are i will take your advise and hopfully that will fix it. Otherwise I can't figure out why there'd be no pressure...
Thank you, I'll keep yall posted.

Bernotas05 08-07-2007 02:00 AM

Yea that does sound like a good reason, I have heard quite a few stories of that happening when I used to work at advance auto. A lot of people came in to get the fuel injection hose because the gas ate thier rubber lines up. The gas hardens the rubber up almost making it into plastic and a good bump will make it crack hence why you would loose pressure. The fuel injection hose is quite a bit more expensive a foot compared to the standard rubber fuel line but its well worth it.

Hopefully that is you problem.

iceman2k 08-07-2007 12:50 PM

My advice is try to analyze part by part the problem. If u hear the pump kicking on, the problem should be from the tank to the injection. I understand that the starter and everything around is working so it isn't the problem.
When i change some part and days later i hear o feel something wrong with the car the first thing i think is that i did something wrong while changing it, but most of the time it has nothing to do with it, so dont just assume that the pump is faulty or the installation was wrong (even when it's possible), check other things. The thing everybody says sound like a good option. Finally wanted to tell u that i had a bike that did the same thing and resulted to be the computer, just in case it helps. Good luck!.

JooneJune 10-17-2007 01:49 AM

Start from scratch.
(USE THE TRAP DOOR METHOD, ONLY TAKES 15MINUTES!) I've done both now I have a sweet trap door that I can access my fuel pump from.

-You said you replaced the fuel pump, with what a OEM replacement or a 255lph? Check to see the unit functions properly and was installed correctly (which includes fill your fuel tank lol.)
-Check to see the quick disconnects outside the fuel tank are connected properly.
-Check the fuel filter
-Check for kinks between the fuel filter and disconnects by the fuel rail.
- Connect the fuel fittings to the fuel rail
- ***Check the Fuel Pressure Regulator.***
-With a fuel guage check for fuel pressure @ the shrader. (if you don't have it's a good $30 investment otherwise depress the schrader for fuel)
-With proper FP check the injectors

That would check your fuel system in a nutshell.

In reference to electrical problems, there is a relay under the driverside kick pannel. Normally has a black (G) pink (12v) grey (12v) and Drk grn/whi (Pulse 12v) they go bad... resulting in the drk grn/whi to fail.


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