Fuel Problem.. Starving at higher RPM's - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


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Old 03-31-2006, 09:49 AM   #1
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Default Fuel Problem.. Starving at higher RPM'*

Hey guys. My 97 is starving for fuel in the higher RPM'*... The injectors are all good (removed them and inspected them) The fuel pressure is good through the entire range.. And the only code i am getting is a general misfire code... The car seems to be limiting/governing itself when its hits 4000/4500 RPM... Also it seems to running somewhat rich when your just cruising along. When i need to get on it though the power is not there.. Kinda a PITA because i cant figure out whats wrong.. Any ideas?? I do have a printout from ALLDATA on the diagnosis steps but its 10 pages long. Just wondering if anyone has eperienced this before.

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-Fred
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Old 03-31-2006, 09:58 AM   #2
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How old are your plugs and wires?

Faulty plugs and wires would contribute to your misfire code.
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Old 03-31-2006, 10:01 AM   #3
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You mention the fuel pressure is good through the entire range. Did you test this while driving or only sitting still in park. If you are starving for fuel I would expect to see a drop off around the 4-4500 rpm where you have power issues.

You also mention you think the car is running rich. A fuel starvation issue shouldn't be happening when the car is rich.

I have seen cars test fine for fuel pressure per the book test, idling within specs and even recover fine if the throttle is cracked a few times. However fail miserably when consistant demand is put on them. (visible watching fuel pressure while driving.)

Does the problem appear to be any better or worse when the car is warmed up or cold?
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Old 04-01-2006, 09:42 AM   #4
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plugs and wires are not too old at all..

BillBoost: I did test the fuel pressure while driving the car. There was no drop off when the power dropped. It feels that the car is running rich at lower RPM'*. It feels like there is more tourqe then usual and it accelorates much quicker with little pressure on the pedel... Im stuck with this one...

Ive gone through about 16 steps on the ALLDATA diagnostics and all of them have shown up negative.


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-Fred
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Old 04-01-2006, 08:43 PM   #5
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Fuel pump filter sock might be plugged/restricted. Fuel pressure is one thing, but having enough fuel flow at higher rpms is important.
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Old 04-02-2006, 12:09 AM   #6
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I actually just called about one, and for less then 10 bucks what the heck its worth a shot!

-Fred
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Old 04-03-2006, 08:11 AM   #7
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Fred...I wouldn't change the sock.

Bobc, how can you build pressure w/o volume when the car is using fuel? Far as I know if the demand is larger than the supply...pressure won't build. Think of running a hose with running water into a sewer grate. Once in the sewer there is no pressure because you no longer have any restriction.

Pressure could be there during idle, but not driving. If this was a fuel pressure situation there should be a drop off when running WOT for any amount of time.

Fuel strainer sock is functioning fine, fuel filter could be a slight restriction, that'* a cheap part and you don't need to drop the gas tank for this regular maintenance item. But again...I doubt it'* the filter.

Please check the air cleaner to ensure it'* not dirty and clogged. How old and what brand is the O2 sensor? If sitting still for a while do you get a rotten egg smell from the car?
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Old 04-03-2006, 09:54 AM   #8
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Quote:
Originally Posted by BillBoost37
Fred...I wouldn't change the sock.

Bobc, how can you build pressure w/o volume when the car is using fuel? Far as I know if the demand is larger than the supply...pressure won't build. Think of running a hose with running water into a sewer grate. Once in the sewer there is no pressure because you no longer have any restriction.

Pressure could be there during idle, but not driving. If this was a fuel pressure situation there should be a drop off when running WOT for any amount of time.

Fuel strainer sock is functioning fine, fuel filter could be a slight restriction, that'* a cheap part and you don't need to drop the gas tank for this regular maintenance item. But again...I doubt it'* the filter.

Please check the air cleaner to ensure it'* not dirty and clogged. How old and what brand is the O2 sensor? If sitting still for a while do you get a rotten egg smell from the car?
Thanks BillBoost I will check my Air Cleaner today when i get home. The O2 sesor is probably long overdue to be changed and i dont notice a rotton egg smell.

-Fred
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Old 04-04-2006, 09:12 AM   #9
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Not the air cleaner and I hooked the car up to the computer and the o2 is working good....
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Old 04-04-2006, 09:28 AM   #10
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Hmmm.. let'* run through the basics then...

Plugs and wires are fairly new, What brands?
When was the last time you checked the pcv or replaced it?
Are there other symptoms that go with this issue?
How long has this been happening?
Could this be a bad tank of gas or low octane?
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