Fuel pressure problem ?
Thread Starter
Instructor
Joined: Sep 2015
Posts: 143
Likes: 25
Fuel pressure problem ?
Hello,
Another c 4 gremlin. 92 lt1 46,000 miles. Car starts good , drives pretty good with , what only can be explained as a very very small miss at Idle only. Seems to stumble just a few seconds when started, until you get rolling about 50 feet, then it's ok. Changed fuel filter, can smell fuel at what I think is a relief air tube drivers side rear facing down. Use to have fuel pressure when removing fuel cap, but blew out canister lines, no pressure anymore ? Check valve inside rear fender, lines appear ok. Can hear hissing sound like fuel rail drivers side being pressurized with key to run. will do it 4 to 6 times before stopping. No fuel leaking at fpr vaccum hose and no pressure test has been done yet.
Another c 4 gremlin. 92 lt1 46,000 miles. Car starts good , drives pretty good with , what only can be explained as a very very small miss at Idle only. Seems to stumble just a few seconds when started, until you get rolling about 50 feet, then it's ok. Changed fuel filter, can smell fuel at what I think is a relief air tube drivers side rear facing down. Use to have fuel pressure when removing fuel cap, but blew out canister lines, no pressure anymore ? Check valve inside rear fender, lines appear ok. Can hear hissing sound like fuel rail drivers side being pressurized with key to run. will do it 4 to 6 times before stopping. No fuel leaking at fpr vaccum hose and no pressure test has been done yet.
Instructor
Joined: Sep 2011
Posts: 140
Likes: 7
From: Fort Ripley Minnesota
It would be nice to actually have a pressure gauge on the fuel system to see what is actually happening, if your fuel pump is working proper you would turn the ignition on and the fuel rails will be charged with fuel pressure at 46-50 PSI, only a one time charge until you start the vehicle and apply vacume which will lower the PSI. (Check valve issue)
The stumble at initial take-off almost sounds like a TPS fault or adjustment.
The stumble at initial take-off almost sounds like a TPS fault or adjustment.
Instructor
Joined: Sep 2011
Posts: 140
Likes: 7
From: Fort Ripley Minnesota
"Can hear hissing sound like fuel rail drivers side being pressurized with key to run. will do it 4 to 6 times before stopping."
I think Skidball's statement is the first issue that needs to be addressed, my fuel system charges only one time during initial ignition ON.
I think Skidball's statement is the first issue that needs to be addressed, my fuel system charges only one time during initial ignition ON.
