2000 Pontiac Grand Am 3.4 engine woes

[Supreme Cutlass 1994]

Okay here's the poop.

I'm helping a friend with his car tonight and it has some issues with the engine.
Low power, he says that it takes forever to get up to speed and he has replaced the spark plugs, wire , o2 sensors and cut the cat off.

I'm thinking that it's fuel related and I will test the fuel pressure tonight and scan for whatever codes I can find. I'm guessing the fuel filter is the original and might be plugged up and caused the fuel pump to pump less.


The car has 150,000 mile on it and was taken to a couple of different mechanics for some leaks that developed after a trip to uncles Eds oil change.

I'm hoping one of the mechanics didnt sabotage their car. ( hey you never know )

Or her car could just be getting old. Any advice would be greatly appreciated !!

[siKKa]

is she hot? lol yeah id start with checking fuel pressure first. a bad filter or pump may be to blame. cutting the cat off wiill trigger a CEL. but thats no big deal.

[pocket-rocket]

is she hot?

I'm helping a friend with his car tonight and it has some issues with the engine.

I think you guys started in a good direction. I probably would have checked fuel pressure first because I have a gauge and it's free to do since the gauge has been paid for a while back. I agree with your thinking. First thing I would do if the pump sounds normal when it primes (before engine start) and pressure is low is change the filter. If it still reads low after that, change the pump. The plus side to doing it this way is 1) if it's the filter, problem solved. 2) if it's the pump, they always want the filter changed for warranty purposes anyways, so that is out of the way. Before the pump change, I would check the compression though, just in case.

[mfuller]

Have you checked the oil to see if it's overfull?
The car can act like a dog if the crankcase has been over-filled.

[bob442]

MAF meter. that will cause that exact problem. did he put in a reusable air filter? oils from those will cause all of this.

[Supreme Cutlass 1994]

Okay heres and update.

The fuel pressure is @ 55 psi and the engine had nasty flat spot so I tested the throttle postion sensor and we go some weird readings. It was if it had a flat spot , so we replaced it and the one that came out was pretty loose. With the scanner hooked up and the engine idling we had a random miss fire that would bounce around from one plug to the next. So the next step will be to check the crank postion sensor and clean the surfaces really good ( grease caked in there might be confusing the sensor) Then taken the ignition modual in to be tested after that.

Thanks for all of the advice

[60dgrzbelow0]

The presence of ample fuel pressure eliminates the fuel pump as one of the usual suspects, but it is only one half of the equation. If you smell any hint of fresh gasoline under the hood ...pull the vacuum line off of the Fuel Injector Pressure Regulator...if any liquid gas is present... then replacing it might relieve that flat spot you mentioned. RockAuto carries replacements: Ac-Delco P/N 11713622

[siKKa]

Or her car could just be getting old. Any advice would be greatly appreciated !!

^ ^ ^ ^ ^

[Supreme Cutlass 1994]

^ ^ ^ ^ ^

Yes it is getting old and some what neglected BUT...if we can figure this out before any more damage is done this engine /transmission combo should go well over 200,000 miles.

I suspect a leaking crank seal has been weeping for a while and the oil collecting on the cam sensor and cam sensor trigger on the back of the harmonic balencer. Causing the engine spark module to be (blind ) and get erratic readings.

[Supreme Cutlass 1994]

The presence of ample fuel pressure eliminates the fuel pump as one of the usual suspects, but it is only one half of the equation. If you smell any hint of fresh gasoline under the hood ...pull the vacuum line off of the Fuel Injector Pressure Regulator...if any liquid gas is present... then replacing it might relieve that flat spot you mentioned. RockAuto carries replacements: Ac-Delco P/N 11713622

Yes that is a cheap and easy way to trouble shoot the fuel pressure regulator. I will call my friend and pass your advice on.
Thanks for your help

[pocket-rocket]

Yes it is getting old and some what neglected BUT...if we can figure this out before any more damage is done this engine /transmission combo should go well over 200,000 miles.

I suspect a leaking crank seal has been weeping for a while and the oil collecting on the cam sensor and cam sensor trigger on the back of the harmonic balencer. Causing the engine spark module to be (blind ) and get erratic readings.

The ICM is run by the crank sensor in the back of the block, the one behind the crank pulley is just for the Sequential portion of the fuel injection (which is only engaged from idle to around 2500 RPM, IIRC). Those usually either work or they don't. Also, I've got no doubts the car can hit 200k miles. I still wouldn't rule out the fuel filter yet. You might be getting correct fuel pressure, but it might not have enough volume flowing. I say this because you have no idea when the last one was changed, so really it needs changed anyways. Also I do agree with bob442. MAF sensors are picky. Don't use brake clean on it. There is a special cleaner made for MAF sensors that is sold at the parts store. It's pricey, but not when you compare it to the price of a new MAF. On the can it claims to "give 4-10 hp gain", but what they don't mention is it's not that it pulls it magically from the air, it's what you lost from a dirty MAF.

[Supreme Cutlass 1994]

Update

So we took the ignition control modual in to be tested and it's okay. We also pulled the vacuum line off the fuel pressure regulator and there is fule leaking out . So you guys were right !! thanks for all of the advice and I will update this again after we take a road test.

[60dgrzbelow0]

I love the "WE" part of the happy ending to this story... "WE" in this case on a Test Drive is....... Good...

[Supreme Cutlass 1994]

Okay..here's my thoughts on the we..that I use as much as possible.
My friend and is trying to fix his daughters car. Thats makes us a team, and reserching here as muchas possible for your input makes us all team mates by proxy .

After changing the fuel pressure regulator and replaced the crank sensor but there is a still a problem with the power as the rpm increases . I still think that the fuel filter is a plugged up and the engine is starving for fuel.

The fitting for the filter is rusted and seized on the fuel line butI the holding the fuel line and spinning the fuel filter should take care of that.

Once again another update with some results after the fuel filter gets changed

[60dgrzbelow0]

is she hot? lol yeah id start with checking fuel pressure first. a bad filter or pump may be to blame. cutting the cat off wiill trigger a CEL. but thats no big deal.

Actually... The "WE" I was referring to would be YOU and The Lady on that Test Drive.... But we are indeed Brothers in the idea of the fact that the "Group Think" we engage in here on the forum, more often than not, will eventually sort things out...