1994 Pontiac Grand Am car stops and will not restart

Tiny
GRANDAMGUY
  • MEMBER
  • 1994 PONTIAC GRAND AM
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 136,000 MILES
I am an mechanic and have replaced the coil packs/plugs/housing/ignition module/boots/fuelpump/fuelfilter and still. When the car is cold it starts right up and idles perfectly, it will drive fine but after about 10mins of running it shuts off, no sputtering/coughing, just like you turned off the key. It will crank all day long but not restart, the fuel pump does run for a few secs on each key turn. If you wait 20mins or so it will start again but only for a minute or so. This sounds thermal reltated but I am at a loss as what to look at/for. The Passlock alarm system was bypassed years ago so dont see that as an issue. Any ideas please !
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Wednesday, May 6th, 2009 AT 6:20 PM

10 Replies

Tiny
RASMATAZ
  • MEMBER
Recheck the fuel pressure and monitor it if its within specs if okay you practically replaced the ignition system-Check the crankshaft position sensor on left side of engine near oil filter
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Wednesday, May 6th, 2009 AT 6:40 PM
Tiny
GRANDAMGUY
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I looked for the 'shcrader valve' which is usually on the fuel rail of most cars and was unable to locate it, so how to test the fuel pressure? I take it you are looking for fuel pressure at the rail not in the tank ! Also the crank sensor is checked how? Seeing most of this car is original i'm inclined to replace the sensor if it's not $$$, and how would the crank sensor get heat related defects? Just wondering. MANY thanx for the quick reply !
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Wednesday, May 6th, 2009 AT 8:35 PM
Tiny
RASMATAZ
  • MEMBER
I take it you are looking for fuel pressure at the rail not in the tank !

Yes sir its a must that you check it I need this data to complete the fuel system prior to swinging over to the ignition system.

Are you getting spark? If not investigate the CPS

Check the CPS resistances and its voltages. This sensor tells the computer the engine speed and pistons position and to fire the coil/s
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Wednesday, May 6th, 2009 AT 11:41 PM
Tiny
GRANDAMGUY
  • MEMBER
I installed an fuel pressure gauge directly after the fuel filter, and get just about 30-32 lbs and it stays long after the car is turned off and very slowly drops over a long period of time, so beleive the pressure is ok. Now the good question is Where is the crank sensor located at, does it go inside the block and pick directly from the crank or is it an external piece?
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Friday, May 8th, 2009 AT 11:53 AM
Tiny
RASMATAZ
  • MEMBER
The fuel pressure is low it should be 41-47psi


http://www.2carpros.com/forum/automotive_pictures/12900_fp_10.jpg



Check the crankshaft position sensor on left side of engine near oil filter. Sorry I couldn't come up with a pic for the exact location-See testing of CPS below


http://www.2carpros.com/forum/automotive_pictures/12900_cps_28.jpg




http://www.2carpros.com/forum/automotive_pictures/12900_cps2_6.jpg

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Friday, May 8th, 2009 AT 4:11 PM
Tiny
GRANDAMGUY
  • MEMBER
Well I have no idea how to increase the pressure as its a brnad new Bosh fuel pump assembly(not just new pump) and it came with new filter(sock) and fuel filter is brand new, so with key on and getting pressure of over 32labs is about the max it will get. As for the CPS location I concur that it is on the front side by the filter but impossible to locate, even tried using my alldata set to show a nimage with no luck, I see you use the mitchell set and it doesnt show either. What a pain :) once found I plan on replacing it just to end any issues with that and hoping it will play nice after. Thanx for quick reply ! !
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Friday, May 8th, 2009 AT 4:52 PM
Tiny
RASMATAZ
  • MEMBER
Check the fuel pressure regulator might not be maintaining the pressure-

When you plug the vacuum hose to it the pressure should increase
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Friday, May 8th, 2009 AT 5:58 PM
Tiny
GRANDAMGUY
  • MEMBER
Well I found the CPS, its right next to the stater, you can just see it looking thru the intake runners, when I removed the screw and tried to wiggle it out, it was broken, so themagnet section with the O-Ring is flush inside the block.. Attached is a lousy picture, the center is the magnet, to the left is the mounting hole, to the right is the starter. Unless I can figure a way to either drill out the center of the magnet and use a screw extractor, I might be forced to remove th intake and that will be quite a job along with all the dirt after years of driving. Though of tacking a long welding rod to the end of the magnet and try to remove it that way, but concerned about pushing anything any further in the block, just making it that much harder. Any ideas ?


http://www.2carpros.com/forum/automotive_pictures/352877_CPS_1.jpg

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Friday, May 8th, 2009 AT 6:37 PM
Tiny
RASMATAZ
  • MEMBER
Drilling and screw extractor sounds good while a vacuum cleaner sucking the debris at the same time.
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Friday, May 8th, 2009 AT 9:25 PM
Tiny
GRANDAMGUY
  • MEMBER
I used a drill bit to basically route out the plastic around the magnet untill the magnet showed a litle movment, then used custom made 90' vise grips grabbed onto the magnet and wiggled and pulled and slowly POP it came out and seemed to leave no residue in the hole. Installed the new CPS and fired it up, BTW when running the fuel pressure is around 40lbs so that is within limits. Let it idle for 20mins and drove it around block before heading out to get gas. All "seems" fine now. Many thanx for your help ! ! ! ! ! ! Hmmm just tried to PM ya but it says I need 10 posts first?
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Saturday, May 9th, 2009 AT 8:01 PM

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