87 Bronco, starts good but stops 10 sec later.

Tiny
JEFF13ATKINSON
  • MEMBER
  • 1987 FORD BRONCO
87 Bronco start just fine, but then seems to run out of fuel. I have replaced the pump relay, the pumps both seem to work. Also if I push gas peddle it runs out quicker and usually backfires (lean fuel). Could the computer be cutting off the injectors from continuing to supply fuel? The car was in a fire, could the comptuer be bad? I did not think these things fail in just one area. (All or nothing) Help and or ideas would be appricaited. Jeff
Monday, November 19th, 2007 AT 3:13 PM

6 Replies

Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
First thing to do is test the fuel pressure, hookmup the gauge and make it stall, watch the gauge pressure and see what happens, if it drops off real fast and then dies, the pump is too weak.
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Monday, November 19th, 2007 AT 3:49 PM
Tiny
JEFF13ATKINSON
  • MEMBER
  • 5 POSTS
Thanks fro the idea. I finally got around to installing a pressure guage in fuel line. I am getting good fuel pressure even after the stall and it is maintained. I checked ignition and replaced spark plugs and replaced the engine computer, now what's next? Any suggestions would be appriciated. Could it be a bad EGR valve, that would let the car start but not continue to run. I tried unpluggin the snesor and it seems to make no difference.
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Tuesday, December 4th, 2007 AT 2:10 PM
Tiny
MERLIN2021
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See if after it stalls if the truck has any spark, the modules go bad all the time in old fords. The other thing to check is the pressure regulator, unplug the vacuum line, any fuel in it? If yes, replace it.
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Tuesday, December 4th, 2007 AT 2:14 PM
Tiny
JEFF13ATKINSON
  • MEMBER
  • 5 POSTS
How do I check if the truck has spark after it stalls. If the engine is not turring over there will be no spark. Right?

The truck starts right back up again after it stalls but only runs for 10 sec, then stalls again. If the truck starts, then there is spark, would the ign modular fail to spark 10 sec after starting?

If I pump the gas pedal (like we used to do on a carboerated engine) it back fires, then stalls.

The fuel pressure guage I installed nearest the engine after the regulator, shows at least 35 to 40 psi.

If the EGR valve is stuck, would it produce this kind of symptom?

Help! Jeff
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Tuesday, December 4th, 2007 AT 3:49 PM
Tiny
JEFF13ATKINSON
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Anyone know if I can just block off the EGR valve some how to see if this is my problem.

Will the engine still run properly? I don't need emission compliance. Is that all that would be effected?

How would you go about blocking it off?
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Thursday, December 6th, 2007 AT 11:33 AM
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
Unplug the vacuum line to it, but usually a stuck egr will not let the car run, take the two bolts off and see if the pintle moves free, use your vacuum pump.
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Thursday, December 6th, 2007 AT 12:18 PM

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