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Stalling Problem


krushmoto
07-18-2005, 12:22 PM
I have a 2000 Malibu LS w/ 113K miles. On 7/16 while driving with the a/c on all of a sudden the car stopped accelerating so when I pulled over the engine stalled, like it ran out of gas. I cranked it & it started no problem and ran for the rest of the day w/ the a/c on no problem.
But on 7/17 w/ the a/c on again the same stalling problem. But this time it wouldn't start. I waited about 5 minutes and cranked it again it started. Turned the a/c back on and drove for about 5 mi when it stalled again. Took about 5 min again. and it started again so I drove home but w/o the a/c on this time and it drove fine except for slight "hiccups" while driving.
I got home and did a fuel pressure test and it read at 54 psi w/ the old fuel filter. Changed fuel filter and redid the test and it went up the 60 psi but backed back down to 54 psi after a few seconds. Started it up and the pressure read at about 50 w/ everything off.
Is this normal and also any ideas on why the car stalled when the a/c was running?
Also the car has been having some problems, it "hiccups" while driving (while driving it feels like I took my foot off the accelerator for a second and gave it gas again), and on hills under normal acceleration the rpms pulsate but when I give it more gas and the tranny downshifts and the pulsating stops, most times.
Any ideas what's wrong with the car and please don't say it's the fuel pump. Thanks.

BeatnikTermite
07-18-2005, 03:36 PM
It sounds like it could be the crank sensor, especially if youare not getting any computer code readouts to lead you to the fuel system.

Did you recently notice the coolant leaking issue as is discussed so frequently. The coolant pools down on top of the lower intake where the sensor is, and eats away at the wires. It is pretty standard practice to replace the sensor when doing the rebuild for the Manifold gaskests.

krushmoto
07-19-2005, 01:09 AM
Not sure if it's the crank sensor. I haven't seen any coolant pooling by the intake manifold but I have seen coolant pooling on top of the tranny but that's due to coolant slowly leaking out of the coolant temp sensor.
But here's what happened today, I was driving with the a/c on again when it started happening again so I dropped gears slowly until I goto 2nd but the rpm's jumped to around 2500 so I put it back in 3rd and the engine caught on so I was able to continue driving. Hope I can replicate this on my way to work tomorrow so I'm not delayed by having to wait for the engine to "reset".
But what does the crank sensor do anyway?

BeatnikTermite
07-19-2005, 07:10 AM
I believe it is called the Camshaft position sensor on this car, as I think you have already figured out. Sorry, it was called the crank sensor on the older 3.8 L GM engines.

It determines the cam rotation and position to set the fuel ratio. If it goes bad, the computer thinks the engine has stopped spinning, and it cuts the fuel. This is why I think it usually shows up as a fuel issue, but you don't get any error codes.

BeatnikTermite
07-19-2005, 07:15 AM
Also, are you sure the gaskets are not blown?

The two areas where the coolant pools when the do go are: 1) On the block near the Cam Position Sensor; and 2) On top of the transmission.

You may want to make sure by monitoring the coolant level.

krushmoto
07-21-2005, 12:32 AM
Also, are you sure the gaskets are not blown?

The two areas where the coolant pools when the do go are: 1) On the block near the Cam Position Sensor; and 2) On top of the transmission.

You may want to make sure by monitoring the coolant level.

100% sure the gaskets aren't blown. Coolant leaks from the threads of the coolant temp sensor. Watched it leak when the engine is running at normal temp. And this is when I started smelling coolant, after I changed the coolant sensor.
Well anyway I replaced the cam sensor and the car still stalled. But this time I was able to confirm it's the fuel pump. When the car wouldn't start I used my remote starter to listen for the injectors energizing but there was nothing so I'm 100% sure it's the fuel pump. So I'm getting the fuel pump changed tomorrow. Hopefully it'll only cost me an arm and not an arm and a leg.
I'll keep you all updated.

krushmoto
07-30-2005, 01:01 AM
Replaced the fuel pump and car runs ok. It still feels like the gas is cutting off for a second while driving but hopefully it's not the multi coil packs or someething else.
Any ideas why it's doing that?
Also rpms fluctuate when I'm driving up hills.

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