servohead

Simple question on my 1999 FRC M6 car. (65k miles): Where is the check valve for the fuel pressure located? Is that integrated into the fuel pump? Reason I ask is, after the car sits for about 9 hours during the day (not night strangely) and I go to start it it cranks over for 2 seconds or so before it fires up. I usually let the fuel pump prime itself with the key in Pos. 2, and let the gauges do the sweep - then start it, and lately it's been slow to fire up. Am I on the right track?

Fuel: Mobil 1 93 currently w/techron in tank.
Miles: 65k
Sp plugs 20k miles ago, new wires, No PCM codes, fuel filter 5k ago.

Jorge

The valve is on the front of the drivers side fuel rail
just remove the dust cap and you will see it

CTSV OWNER

Jorge is referring to the schrader port to check the pressure. I think he's asking about the fuel rail not holding pressure. There are a couple possibilitys.

1) fuel pump leaking internally back into the tank.
2) pressure regulator leaking past the diaphram into the vacuum port
3) fuel leaking thru a injector into the engine
4) external leak, of course you would smell this.


Dave

noahdr

if it only happens when its hot outside I think it might be one of your temperature sensors. The car will add more fuel to the mixture when it senses its cold (kind of like a choke but it adds more fuel instead of cutting of the air). If the car always starts right up first thing in the morning but wont start after she's been driven you might be looking at a temp sensor. but thats just a guess I would check the fuel pressure to see if it is bleeding off first, maybe you do have a leak somewhere.

servohead

Thanks for your responses guys, So it sounds like I really most likely have a fuel pump issue, because the check valve is in the pump assy?

CTSV OWNER

I see your a Volvo mechanic. Take the fuel lines off the rail under the hood attach shut off valves. Install your pressure gage. Then prime the lines and quickly shut off the valves. See if it holds or looses pressure. If it looses pressure check your injectors or regulator. If it holds open the return valve. Then if it still holds you can open the feed line and watch it drop. That way you will know for sure it's the pump.


Dave

rich_r31

I took it to Chevy, and they told me that the check valve (part # 10299145) and the vent/ hose (part # 10298121) is bad and the pressure leaks down back into the tank. They told me that the valve/ vent is above the gas tank and they need to drop the tank at a charge of $500... cha ching... I told them to get... well you know...

FRCTony

Can't be check valve if you are priming before cranking. Also, if it were the check valve, it would do it in the morning as well.

Easy enough to check by attaching a gauge to the test port...

LoneStarFRC

He has a '99 and the pressure regulator is in the fuel filter, not upfront.
The check valve is made into the discharge line coming out of the driver's side fuel tank. It's called the "rear fuel feed pipe" and if the check valve is bad/flaky, the line has to be replaced.
Fuel pressure check at the fuel rail is the starting point here. If the pressure bleeds off after turning the key (engine not running), then the rear fuel feed pipe is the most likely culprit.
GM part# 10448899
If the pressure is low with the engine running, then that's a different story.

Been there, done that.

HTH,
Robert

BTW, I have a '99 too.