Possible fuel pump going bad?
honestly man it sounds more like an opti failure. my car is doing the same thing. it turns off on me when idle, while driving, when coming to a stop, hessitates, stutters, spits, backfires. the symtomes are wores when the car gets warm or hot too. all these are symptoms of opti falure. From what i was told is the sensor in the opti that keeps track of the cam gets weak loses the position and the car shuts off as a safety.
Oh joy lol
But when I hooked the fuel gauge up and gave it gas, the pressure dropped as the rpms climbed. That supposed to happen?
But when I hooked the fuel gauge up and gave it gas, the pressure dropped as the rpms climbed. That supposed to happen?
Last edited by whytryz28; Sep 29, 2009 at 07:15 AM.
I just went back out to recheck everything and the only thing that changed were
Key on engine off - 36psi (previous was 38psi) Supposed to be around 41-43psi
Idle- The needle keeps jumping between 36-38psi still, Not sure what idle PSI is supposed to be.
Im gonna change the filter and see what it reads. I think its the pump and not the opti, I can hold the rpms and it wont stutter with decent fuel.
Key on engine off - 36psi (previous was 38psi) Supposed to be around 41-43psi
Idle- The needle keeps jumping between 36-38psi still, Not sure what idle PSI is supposed to be.
Im gonna change the filter and see what it reads. I think its the pump and not the opti, I can hold the rpms and it wont stutter with decent fuel.
Ok, so I figured id throw some real world driving at it this time.
Brought the engine to running temp. fuel psi still at a low 36. Around 2-3k it started to break up and pop and the fuel pressure would drop to around 34psi before the stuttering stopped.
Does this sound like a pump issue still or Opti? Or is it bothe because the fuel drop and poping?
Brought the engine to running temp. fuel psi still at a low 36. Around 2-3k it started to break up and pop and the fuel pressure would drop to around 34psi before the stuttering stopped.
Does this sound like a pump issue still or Opti? Or is it bothe because the fuel drop and poping?
Last edited by whytryz28; Sep 29, 2009 at 08:46 AM.
Launching!
Joined: Feb 2009
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From: bodymore
i still say its the pump. when you give it gas the pressure should rise. that pressure is a bit low for idle, too. did you do any wot readings? did it shoot up when you did, if you did them? if not, then the pump is probably on its way out. if it can't deliver the adequate fuel pressure, you aren't going to get enough fuel, and its gonna stumble from the weaker combustion. ever run out of gas, esp in these cars? notice how when there is hardly any fuel left, the shifter and engine stumbles and moves around irregularly right before being shut off? same thing..
i still think its fuel related. you can run it because you have close to adequate fp but you don't have enough to drive it around reliably and you don't wanna do that anyway since the pump is on its way out
get the racetronix pump / harness, cut a hole above the gas tank and change the pump. if thats not it, well, you have a leak somewheres. but that should be easy enough to find if you do and then you'll have a brand new racetronix kit
i still think its fuel related. you can run it because you have close to adequate fp but you don't have enough to drive it around reliably and you don't wanna do that anyway since the pump is on its way out
get the racetronix pump / harness, cut a hole above the gas tank and change the pump. if thats not it, well, you have a leak somewheres. but that should be easy enough to find if you do and then you'll have a brand new racetronix kit
I brought it as high as 4k rpm and the fuel pressure did not increase one bit.
I have the racetronix wire kit on the way and about to buy a walbro from the sponsor here who is selling them to ls1tech members for $99 shipped.
I have the racetronix wire kit on the way and about to buy a walbro from the sponsor here who is selling them to ls1tech members for $99 shipped.
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Joined: Feb 2009
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From: bodymore
wish that was going on when i needed a fuel pump. good luck man, it does sound like its on the way out. i doubt extra voltage through a new wiring harness will help that out but with a new pump too it'll be stronger than the day the dealer sold the car haha good luck
Launching!
Joined: Feb 2009
Posts: 280
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From: bodymore
ls1 cars have a different pressure spec, i'm not sure on the numbers though don't have my book here with me at school so don't use the 41-47 3-10 less for idle and steadily rise up to 41-47 as throttle is opened.
i think the pressure is a little bit higher don't quote me on that though
i think the pressure is a little bit higher don't quote me on that though
well i agree fuel should not be droping whille rpms are rising. this should be #1 consern at this time. tell me this. when you smash the gas can you still reach your readline before the car shifts or dose it shift early? if your car shifts early and acts like its hitting the rev limiter at like lets just say 4500 then its definatly ur fuel pump. if your still able to reach your redline then I would assume that your fuel pump is working fine as it has enouph fuel pressure to get up there in the rpm's. however if you are absolutly positive that the fuel pressure is droping far enouph to give you trouble then go ahead and throw money at it and see if it fixes the problem. who knows u might get lucky.
well i agree fuel should not be droping whille rpms are rising. this should be #1 consern at this time. tell me this. when you smash the gas can you still reach your readline before the car shifts or dose it shift early? if your car shifts early and acts like its hitting the rev limiter at like lets just say 4500 then its definatly ur fuel pump. if your still able to reach your redline then I would assume that your fuel pump is working fine as it has enouph fuel pressure to get up there in the rpm's. however if you are absolutly positive that the fuel pressure is droping far enouph to give you trouble then go ahead and throw money at it and see if it fixes the problem. who knows u might get lucky.
Not the pump.
When my pump went out mine wouldnt even hold pressure key on engine off. When it would FINALLY start after like 3-4 priming attempts, the idle was about 43psi. I taped the guage to the windshield and took it for a rip, it would drop to 25psi and the car still ran fine. Pulled alot stronger once i changed the pump, but it still ran fine.
Something else is going on with your car buddy.
When my pump went out mine wouldnt even hold pressure key on engine off. When it would FINALLY start after like 3-4 priming attempts, the idle was about 43psi. I taped the guage to the windshield and took it for a rip, it would drop to 25psi and the car still ran fine. Pulled alot stronger once i changed the pump, but it still ran fine.
Something else is going on with your car buddy.
Not the pump.
When my pump went out mine wouldnt even hold pressure key on engine off. When it would FINALLY start after like 3-4 priming attempts, the idle was about 43psi. I taped the guage to the windshield and took it for a rip, it would drop to 25psi and the car still ran fine. Pulled alot stronger once i changed the pump, but it still ran fine.
Something else is going on with your car buddy.
When my pump went out mine wouldnt even hold pressure key on engine off. When it would FINALLY start after like 3-4 priming attempts, the idle was about 43psi. I taped the guage to the windshield and took it for a rip, it would drop to 25psi and the car still ran fine. Pulled alot stronger once i changed the pump, but it still ran fine.
Something else is going on with your car buddy.
I should rephrase my previous statement, i HIGHLY doubt its the pump.
No idea man, but i severly doubt its the pump. Only way to know for sure is to tape the guage to the windshield and drive it around till it starts doing it and see.
When its a cold start the motor idles ok, when it warms up and i mess with the throttle is when it stumbles. But it idles fine.