1995 Trans Sport 3.8L stalls out while driving...


MKRyder
01-19-2009, 10:46 PM
Once the van warms up it just shuts down. Driving or parked doesn't make any difference. Here is the funny part about this issue...90% of the time if I release the fuel pressure through the fuel pressure release valve, it will restart again or if I wait for 1 -2 hours it will start again on its own.

Checked for spark immediately after it fails and it has it.

I'm thinking it is posibly the oil pressure sender that is at fault because it cuts out the fuel pump if a fault is detected. I would like to know if anyone has had this same/similar problem and what steps they took to check/rectify it because the oil pressure unit is very hard to get at and I don't want to start replacing parts if its not neccessary. I also tried a GM code reader but my pin configuration is not the same as the reader (the dealer said it was the right code reader.) If you have knowledge of what pins to jump on this vehicle, I would also appreciate it. (Book says A-B but I have no B)

Thanks in advance.

Jeffrv
01-20-2009, 09:00 PM
I presume the code reader you got was the reader that uses LED lights, costs about $25? No, they can't be used for this year because, as you point out, the B pin is not present.
As far as the stalling, that has been a common complaint with the cam and/or crank sensor failure, and may or may not set a trouble code or light. I have replaced both on my 95 and it has been running OK for about 5 years now. I have no explanation for the fuel pressure problems you indicate, unless the fuel pressure regulator has failed and the fuel rail is overpressurizing. Check the vaccuum line to it for cracks or broken fittings, or check the fuel pressure if you can.
Jeff

LMP
01-21-2009, 09:11 AM
Crank sensor is a common culprit indeed ...somewhat awkward to change...will provide instructions if needed....but fuel failure on mine (no fuel, but spark was there) was caused by ignition module going awry. It handles the twin pickup from the crank sensor (3x and 24x) and one is used for fuel synchronizing. One of the "buffers" was dead. IN my case though, this was permanent...the car would not start at all....
At least, it is very easy to change it and frankly, at that age, I consider this normal maintenance as it has proven a culprit in many instances on this forum and I'd try this easy swap first http://www.avigex.ca/xport/d1977a.jpg
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=370039504827&ru=http%3A%2F%2Fmotors.shop.ebay.com%3A80%2F__%3F_ from%3DR40%26_trksid%3Dm38%26_nkw%3D370039504827%2 6_nd1%3D%26_fvi%3D1

Serious "technical" test can be done with an oscilloscope to see exactly if both signals from the crank sensors come up...and if they make it through the ignition module...but this requires the equipment and serious electronics knowledge.
MOre photos for my crank sensor swap can be browsed through at www.avigex.ca/xport
...and by the way, no codes were showing when the problem occured...same for others on this forum.

...and ..there is a red wire going nowhere near the EGR valve: http://www.avigex.ca/xport/MAFArea.jpg

see diagram www.avigex.ca/xport/fuelcontrol_iac.jpg (fuel pump prime connector) this one can be used to feed the fuel pump directly with 12v just for testing.
the fuel pump would not work by itself if the computer does not see the synchronizing pulses ..but the injectors would not pulse either...so running the fuel pump would be to no avail.

as for releasing thr fuel rail pressure and trhis causing to restart...I've no idea...there is no fuel pressure pickup so I do not know how the computer would make the difference...bizarre....Of course, there is a "possibility" that the fuel pump is tired and stops at times under load....and could restart once rail pressure is released...mmm... but I doubt...but well, all is possible...

and no, the oil pressure switch will not cut the fuel pump; on the contrary, it keeps the fuel pump running once engine is started in case of fuel pump relay failure (like loss of activation from computer)....so I do think you really loose the injector pulses...

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