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Discussion Starter · #1 ·
The car is a 1992 c900 lpt (lucas) automatic.

That's about it, after I start the car, it idles fine, but when i go to step on the accelerator, the enqine quits. I had to idle home just now to get to my house (if it pressed the accelerator VERY VERY gently i could get it to rev up little by little, but if i pressed harder, engine quits).

This happened yesterday when i was getting my car fixed at Saab, first cleaned the injection rail, then swapped air masses to check, then swapped distributor to check, then all seemed fine. But on my way home, happened again.

The one thing that did work was unplugging the throttle body switch plug (in the picture, I'm not sure if that's the right terminology), and plugging it back in. That worked fine til about a kilometer from my house then it quit on me. So I unplugged the plug again and it worked for about 10 seconds, then quit.

First I thought some contact spray would help, but it doesn't seem to be a bad contact. So what's broken? Ideas?



 

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sounds like a fuel pump on the way out, or a clogged fuel filter.
 

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teej said:
The one thing that did work was unplugging the throttle body switch plug (in the picture, I'm not sure if that's the right terminology), and plugging it back in. That worked fine til about a kilometer from my house then it quit on me. So I unplugged the plug again and it worked for about 10 seconds, then quit.



http://allyoucanupload.webshots.com/v/2003730688266550196
http://allyoucanupload.webshots.com/v/2003760101553915645
http://allyoucanupload.webshots.com/v/2003779326295994648
It's called a throttle position sensor. Never had to battle one myself, but I imagine that if it was failing it could confuse your ECU and cause the problem.
 

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Discussion Starter · #5 ·
thanks 4 the eplies guys.

i swapped the throttle position sensor today and it worked fine til about the same distance to my house. engine quit again.

unplugged the throttle position sensor and then it worked as normal til i got really confused because the throttle position sensor is mechanical (correct) but the unplugging/replugging behavior seems like re-setting something un-mechanical (ECU?).

why would unplugging the TPS and re-plugging it back in make the car work again (if only temporarily)? Could it be the ECU (the other end of the plug)?

my mechanic is confused, suggested we try and change the plug, but if it was the plug, why would it work in the first place, and every time i reset it thereafter?

Gotta get this resolved, tonight i caused the single biggest traffic jam in bangkok cuz of this... for a second i even considered a toyota :( ....
 

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Discussion Starter · #6 ·
p.s. we went over the fuel side trouble-shooting... doesn't seem to be the problem, and doesn't explain why unplugging/replugging the throttle position sensor solves the problem (at least temporarily).
 

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Try loosening the gas cap, to eliminate the possibility that the tank vent isn't working, although a fuel pressure test should have revealed that. The throttle position sensor can't cause the problem you describe.
 
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