Fuel Pump/Crankshaft Sendor or Ignition Module?

[Mnc01]

Hi...

I have searched but no one has the answer to my "specific" problem.

The wife has a 2000 Grand Am. The other day she was driving and it cuts off. After she sits from anywhere from 10 mins to 45 mins, the car will start. She can maybe get 1 or 2 blocks and it cuts off again. No spuddering or jerking. It's like someone just turned off the engine using the key. You can feel it loose power. The lights does not blink or go off. As you feel it die, you step on the gas and nothing happens...but the dash lights are still on. After we sit for a while it will start for a few minutes...then off again. If you try and crank right away, you do not hear the noise from the fuel pump but after you sit for a while..you hear the fuel pump and it cranks.

Question is... is it the fuel pump or ignition module. I would think if it was the fuel pump it should not start at all. But on the other hand, are we letting the module kind of cool down then when we crank it get's hot again and cut the fuel pump off?

Lastly..if I have to change the pump..how do I get to it? I hear there may be an access door in the trunk without me having to drop the tank. Can someone tell me for sure?

Thanks

BTW- I already tried the relay. I bought a new onw and it did the same thing.

[gt00]

Lastly..if I have to change the pump..how do I get to it? I hear there may be an access door in the trunk without me having to drop the tank. Can someone tell me for sure?I think your fuel pump is going , after it gets warm it has an issue and fails . The pump is in the fuel tank and it must be dropped to gain access ..... ;)

[tenspeed]

Changing out a fuel pump is not cheap or easy.

Next time it quits, squirt a shot of starter fluid in the intake. That will tell you if it's a spark or a gas problem.

[Mnc01]

Crap! I figured that. I know a guy that will drop the tank and install a new one for about $350. I will see...thanks guys.

[Mnc01]

Changing out a fuel pump is not cheap or easy.

Next time it quits, squirt a shot of starter fluid in the intake. That will tell you if it's a spark or a gas problem.

BTW Tenspeed...when you say spark, what are you refering to? Plugs? if so..I changed those too. Please let me know..

Thanks

[rixGAphx]

’00 2.4 4-cyl, 8-yrs old, about 100k miles?
Manual or auto tranny?
New spark plugs (hopefully ACDelco platinum).
New fuel pump relay.
The SES light isn’t ‘on’, or you would have said so, right?
A major service should be done to the engine and car at about this milage, and we know you’ve changed the plugs; what other service has been done?
Your profile doesn’t indicate what part of the country you’re in, so we don’t know what climate you’re actually experiencing.
GM has a proving grounds here in Phoenix where they tested GA’s (not enough, IMO), and if you’re not seeing 110*F like us or Vegas or Bakersfield, then temp-related problems are kinda far down the list.

The other day she was driving and it cut off.
After she sits from anywhere from 10 mins to 45 mins, the car will start.
She can maybe get 1 or 2 blocks and it cuts off again.
No spuddering or jerking. It's like someone just turned off the engine using the key. You can feel it loose power.
The lights does not blink or go off. As you feel it die, you step on the gas and nothing happens...but the dash lights are still on.
After we sit for a while it will start for a few minutes...then off again.
If you try and crank right away, you do not hear the noise from the fuel pump but after you sit for a while, you hear the fuel pump and it cranks.
Could be many things, fuel pump, ignition (the entire system that provides electrical energy to the spark plugs), sensors, the PCM itself.

The problem *might be with the FP heating-up as gt00 stated, but that doesn’t seem right to me.
IMO, this is NOT the behavior of a weak fuel pump that ’gets hot’ and stops working until it cools.
The FP is in the bottom of the fuel tank, and it is very well-designed such that it is constantly cooled by the gasoline flowing through it.
Even if that gasoline were in my tank here in Phoenix, sitting in a parking lot all afternoon and broiling at 114*F, it WILL cool the FP’s internal workings.

Let’s back up a bit, to identify when and under what circumstances the ‘engine shut-off’ condition occurs.
Does it happen:
* During the first 5 mins of driving in the morning, when the car is warming-up?
* During the day while running errands, and the car is already ‘warmed-up’?
* Or both?
Are there times when you/she can drive along just fine for 1/2 hour+ without problems, or does this happen EVERY TRIP, like every 10-mins or so?
Is the fuel tank kept nearly-full, or about half-full, or like most of us, is the tank usually only about 1/4 full?

You state, “The lights does not blink or go off. As you feel it die, you step on the gas and nothing happens...but the dash lights are still on. “
What “lights doses not blink”??
What “dash lights are still on”?? When your driving in the daytime, there should be no dash lights on; at night, the backlighting of the gages should of course be on; is this what you mean?

Finally, is there anything ELSE going on with the car, seemingly un-related, that you haven’t mentioned?
Are any other idiot lights (ABS, Oil Pressure) ever ‘on’?

Standing by,
-Rick

[tenspeed]

When I say spark, I mean the entire ignition system.

The starter fluid will ignite if there is a spark at the plugs. It's a quick way to determine if the problem is with the fuel system or the ignition system.

It could be something like low oil pressure shutting the fuel off. That would cut power to the pump. There is a two second over ride when starting the engine. You should hear the pump run every time you turn the key to "On".

I would suspect that if you had a bad pump, the engine wouldn't die suddenly. I would think that it would sputter a few times first. I don't know for sure. I've never had a pump fail.

It sounds like power is be removed from the ignition system for some reason. If it was a bad coil, the other coil(s) would continue to fire and the engine would run poorly.

[Mnc01]

’00 2.4 4-cyl, 8-yrs old, about 100k miles?
Manual or auto tranny?
New spark plugs (hopefully ACDelco platinum).
New fuel pump relay.
The SES light isn’t ‘on’, or you would have said so, right?
A major service should be done to the engine and car at about this milage, and we know you’ve changed the plugs; what other service has been done?
Your profile doesn’t indicate what part of the country you’re in, so we don’t know what climate you’re actually experiencing.
GM has a proving grounds here in Phoenix where they tested GA’s (not enough, IMO), and if you’re not seeing 110*F like us or Vegas or Bakersfield, then temp-related problems are kinda far down the list.

Could be many things, fuel pump, ignition (the entire system that provides electrical energy to the spark plugs), sensors, the PCM itself.

The problem *might be with the FP heating-up as gt00 stated, but that doesn’t seem right to me.
IMO, this is NOT the behavior of a weak fuel pump that ’gets hot’ and stops working until it cools.
The FP is in the bottom of the fuel tank, and it is very well-designed such that it is constantly cooled by the gasoline flowing through it.
Even if that gasoline were in my tank here in Phoenix, sitting in a parking lot all afternoon and broiling at 114*F, it WILL cool the FP’s internal workings.

Let’s back up a bit, to identify when and under what circumstances the ‘engine shut-off’ condition occurs.
Does it happen:
* During the first 5 mins of driving in the morning, when the car is warming-up?
* During the day while running errands, and the car is already ‘warmed-up’?
* Or both?
Are there times when you/she can drive along just fine for 1/2 hour+ without problems, or does this happen EVERY TRIP, like every 10-mins or so?
Is the fuel tank kept nearly-full, or about half-full, or like most of us, is the tank usually only about 1/4 full?

You state, “The lights does not blink or go off. As you feel it die, you step on the gas and nothing happens...but the dash lights are still on. “
What “lights doses not blink”??
What “dash lights are still on”?? When your driving in the daytime, there should be no dash lights on; at night, the backlighting of the gages should of course be on; is this what you mean?

Finally, is there anything ELSE going on with the car, seemingly un-related, that you haven’t mentioned?
Are any other idiot lights (ABS, Oil Pressure) ever ‘on’?

Standing by,
-Rick




Hey Rick...thanks for responding..I will try and answer everything..

It automatic tranny and I live in Atlanta. I did use AC Delco. I installed them when this started happening. No idiot lights are on under normal driving. I have changed plugs and air filter every few months. I have not changed the fuel filter yet though...

The first time it happened was after my wife was driving for about 15 mins. It crank right up. Then it happened again about 10 mins later. Cranked up..then again about 1/2 later..cranked up. By then I had met her. I had someone at advance test the alternator and batt...all is well. So I changed out the relay. The car went for about 20 miles then just when I thought it was fixed it did it again. But this time it would only go about a block at a time before cutting off. Temp that day was about 90 outside. I towed it home and have not drove it since. It's been about 4 days..since we had another car to car pool in. I went out yesterday listened to the FP when I cranked and it started right up. I idled the engine at about 2k to simulate driving and hled it for a while to see if it would cut off...it didn't. In that time I would have drove about a block or two. But it did not cut off. Gas is at 3/4 tank. Dash lights do not come on until I actually pull off and come to a complete stop. But none are on when driving. I hope I gave you enough info for you to help! :O

[Mnc01]

Thanks Tenspeed...this thing is a thorn to me...just trying to get the wife back on the road. Not sure what to do next..

BTW...when this was happening I did NOT hear the pump start EVERY time I turned the key. Last night I turned it once and heard the pump. I turned it two more times (without starting) and did not hear it. Then I tried to start it and it started. Does it build up pressure or whatever it needs the first time and do not make the noise if you happned not to start the engine?

[rixGAphx]

How many miles on the car?

While we ponder the additional info, change the FF. Shoulda been changed about every 30k miles.

$13 and 1/2 hour of necessary maintenance that will prevent future problems.
Might solve this one (a crudded-up filter could flow a little gas, then some crud could shift and just STOP the flow; after the fuel-pressure eases, the crud drops out of the filter media, again allowing some flow).

[Mnc01]

How many miles on the car?

While we ponder the additional info, change the FF. Shoulda been changed about every 30k miles.

$13 and 1/2 hour of necessary maintenance that will prevent future problems.
Might solve this one (a crudded-up filter could flow a little gas, then some crud could shift and just STOP the flow; after the fuel-pressure eases, the crud drops out of the filter media, again allowing some flow).



Hey Rick..thanks..Ok will do on the FF. The miles is about 120k. Where is it at..by the fuel tank or in the engine compartment?

Thanks again..

[rixGAphx]

FF is behind the tank under the center of the car, best accessed by jacking and supporting the passenger side and creeping under from that side.

Disconnect battery NEG/ground cable first.
GENTLY relieve the fuel pressure at the hex-headed outlet of the FF, with a rag wrapped around it and a basin to catch the 1/2 cup or so of gasoline that will dribble.

Good luck,
-Rick

[Mnc01]

Hey Everyone

I changed the FF and drove it up and down the street. After about 10 mins, it cut off again. I was at a quiet part of the street. When I turned the key to "on" I heard a humming sound each time. I felt the the FP was working, but it still would not crank. It was turning over and trying to crank but I am almost certain it's a fuel issue. The wife came down the street with my SUV and we towed it home. After a while I tried to crank again. I turned the engine to "on" but this time I heard something different. I actually heard it spitting gas. It sort of sounded like someone with diarrhea (sorry to be so graphic) but then it started. So in a nutshell..when it wont start it just hum's...but when it will start you can hear it spit gas.

I am fairly confident it is the pump. But my father in law is insisting I check/change the crankshaft sensor.

What would be the symtoms if the CPS was going or gone bad?

I am thinking of getting the fuel pump changed tomorrow.

[b0ogeyman]

ive got that problem before , and the CAM position sensor fixed my problem!!!
but i did get the code for it too , bad cam postion sensor , or crank postion , could do that if you feel that the PCM is telling the car not to start!!

but as i said i did have the code for them but my car was doing same exact thing at 1st start its fine no problem drive for 5 min and it shuts off .



Hey Everyone

I changed the FF and drove it up and down the street. After about 10 mins, it cut off again. I was at a quiet part of the street. When I turned the key to "on" I heard a humming sound each time. I felt the the FP was working, but it still would not crank. It was turning over and trying to crank but I am almost certain it's a fuel issue. The wife came down the street with my SUV and we towed it home. After a while I tried to crank again. I turned the engine to "on" but this time I heard something different. I actually heard it spitting gas. It sort of sounded like someone with diarrhea (sorry to be so graphic) but then it started. So in a nutshell..when it wont start it just hum's...but when it will start you can hear it spit gas.

I am fairly confident it is the pump. But my father in law is insisting I check/change the crankshaft sensor.

What would be the symtoms if the CPS was going or gone bad?

I am thinking of getting the fuel pump changed tomorrow.

[rixGAphx]

I am fairly confident it is the pump.
But my father in law is insisting I check/change the crankshaft sensor.

What would be the symtoms if the CPS was going or gone bad?

I am thinking of getting the fuel pump changed tomorrow.The CKS (CranKshaft position Sensor, as opposed to CMS CaMshaft position Sensor) on GA's are pretty solid. GM did alright by us on these things.
Just 'search' this site, VERRRRRYY few complaints of CKS (or CMS).

Your FIL is prolly a Jeep/Dodge man.
Those things eat CKS for breakfast, lunch, and dinner.

Tell him you checked the CKS: The GM system is VERY good at diagnosing this problem, and there are no codes for the CKS.
* * *

The second 'poopy sound' is an interesting twist.
Might indeed be further indication of a Fuel Pressure problem, though I've never known the fuel lines, rail, or FRP to make noise audible in the cabin.

The fuel pump is a 'vane-type' that spins around and forces gasoline out kinda tubine-like.
The vanes have rubber edge seals, and these seals wear-out over time; they wear MUCH more quickly if they are spinning 'dry', that is, if the tank runs dry.
Worn vanes don't allow the pump to develop as much pressure as it should (about 65 psi for a new one; reduced at the fuel rail to 36 psi for low rpm and 45 psi for acceleration/higher rpm).
Continuing to spin the fuel pump while trying to start an out-of-gas car will shorten the vane seal life immensely.
Did wifey do this?
When the seals are bad, the engine may run, run spottily, or only run at lower-rpm (when less pressure is required).

Would running the engine for 10 minutes heat-up the rubber seals, so they are a *little* more flexible and therefore less-capable of maintining pressure?
I dunno.
* * *

Another scenario:
The gas tank is a sealed system, so vapors don't pollute the environment.
As fuel is sucked-out by the fuel pump (about 2 gallons/hour for a 25mpg GA driving at 50mph; or 2 qts(s) per 15 minutes of driving), air must replace the lost volume in the tank.
The 'air' comes from the Evap Emissions Recovery System (consisting of underhood tubes and devices, plus the charcoal canister) going through the line back to the tank.
If this system is faulty, it almost ALWAYS sets a 'code' since it's so important to emissions.
But if that return tube to the tank were crimped or smashed, then it might not set a code and might not allow air to fill the void as gas is sucked-out.
If the tank is nearly-full, there's very little air in the top, and the loss of 1-1/2 quarts (10 mins) creates quite a suction.
The fuel pump would then be scucking against a suction, and the net fuel pressure would be low, or non-existent.

This used to happen a lot with carb'd engines, where the fuel pump only operted at about 6 psi and the gas caps were 'vented'; if the vent got plugged, your gas-guzzling V8 could soon stall.

After a few minutes rest, air leaked back-into the tank, the 'suction' disappeared, and the engine would start.
Still happens to lawnmowers, which have 'vented caps'; solution is to twist the cap open, hear the 'whoosh' of air into the tank, seal it, and mow for another 10 minutes. Good excuse for a beer break :D
Rare in modern OBD-II FI engines, since the entire emissions/vapors is so well-controlled and monitored, but it does seem to exactly parallel your experience.
Mebbe the 'poopy sound' was actually the 'whoosh'?

Good luck,
-Rick

[Mnc01]

Thanks Rick and B0ogyman..

One additional thing I forgot to mention...when it started doing this last week..we had a guy at advance auto look at it. He came out to the car with a tester that he plugged in under the dash. He tested and got no error codes. Would any of those sensors register if there was a problem...I would think so...but I am not a expert :)

So Rick...in your opinion would the FP be the next thing to look at?

[rixGAphx]

He came out to the car with a tester that he plugged in under the dash. He tested and got no error codes.
Would any of those sensors register if there was a problem.Exactly.

The tester was an OBD-II scan tool (OnBaord Diagnostics, second generation) anad the connection port for GM's is in the center of the driverside underdash.

The car's PCM (powertrain Control Module, the engine-tranny 'puter) monitors the sensors, sets the spark timeing, fuel injection, and tranny shift points.
It stores data from the sensors, and sets DTC's (Diagnostic Trouble Codes) when it senses something amiss.
More-sophisticated benchtop scanners can actually monitor the PCM in 'real-time' while the engine runs.
The PCM will store codes for 30 on-off cycles of the ignition key, so a technician can look-back in history about a week to see if things happened earlier but have since corrected themselves or otherwise disappeared as problems.
So Rick...in your opinion would the FP be the next thing to look at?I don't think we've narrowed it down enough to say that's what's wrong.
Certainly if you were paying me to do the work, and I said that was the problem, you'ld be rightly pissed when I asked for $350 and said, "It still doesn't work properly."

Before throwing monely at the *probable* cause, I would do some cheap verification:
* Crawl under the car, and inspect for crimps/damage the three 'fuel' lines that run from the engine bay, alongside the driverside chassis rail, and into the tank (fuel supply, fuel return, and evaporative emissions).
* Buy a can of Winter Starting Fluid and carry it in the car; loosen the screws on the air filter box, so it can be quickly opened.
* Drive around, and wait until this 'stalling' next occurs, then:
* * Quickly remove the gas cap, and listen for the 'Whoosh'; then try to start the engine.
* * If the engine doesn't start, then have somebody else try cranking it whle I sprayed Starting Fluid into the air horn; if the engine starts,or even coughs like it wants to, then you know there's spark and the problem is fuel.

Good luck,
-Rick

[Mnc01]

Ok Rick..well we got it...It was the fuel pump. We swaped it out with another one and she is "on the road again"

Thanks you so much for your in sight...and thanks to everyone one else! I will continue to be a member! I will need this board more and more I assume!:lol:

[gt00]

It was the fuel pump. I believe someone mentioned that .... :)

[Mnc01]

Yes you did GT00 all the props!

But now ,,she just came home..new problem...although I hope it's small. Since the fuel pump was changed, her gas hand don't move. It was on half before all this and she has drove to work a couple of time about 60 miles round trip each day..her tank is still reading 1/2.... Is there something I can do to correct?

[tenspeed]

Zero the trip odo when she fills the tank.

[Mnc01]

Zero the trip odo when she fills the tank.

Hey Tenspeed ..thanks for your reply...but...uhhhhh..how are they connected? Please explain...I can't make the connection :)

[arthurgoboom]

Take it back to whoever changed the pump. Either the fuel level sensor arm is sticking or the wires are pinched or something and it's the shop's fault.

[rixGAphx]

Take it back to whoever changed the pump. Either the fuel level sensor arm is sticking or the wires are pinched or something and it's the shop's fault.X2.

Complain loudly NOW!!

If you don't get it fixed now, you will forever be dependent upon doing what tenspeed said:
Zeroing the trip odo at each fill-up so you know how many miles you've driven/fuel used, since the gage needle will forever be inaccurate.

Zeroing the odo doesn't have any affect on the fuel gage/sender.

[colby8100]

i had the same problem on an 86 modle truck i put a 383 vortec stroker in it well they cant us mechanicle fp so i put electric n it would some times crank so i change ff it ran a lil better but still same problem so i figured was cheep fp so i put a holley high volume fuel pump still same thing so we dropped the tank to check pick up it was fine but the lil rubber hose that hook the tank to the lines had busted i donno if this will help but it couldnt hurt to check it was making an awful sound like u talking about it runs fine now

[colby8100]

for the gage it has a float inside the tank it might be hung up but if not there 2 or either 3 wires that mount to the top of the tank ones a pos and one or two is a neg they might have forgotton to hook them back up or either pinched a wire or some thing