1986 Other Ford Models Engine Stalls/bucks at high RPM

Tiny
JERRY GMAN
  • MEMBER
  • 1986 FORD
  • 6 CYL
  • 4WD
  • MANUAL
  • 10,000 MILES
I have a 1986 Ford Bronco II. 2.9L. It stalls at high rpm. Changed fuel fliter, checked fuel pumps, 40 psi on fuel rail KOEO, drops to 32psi KOER. Changed fuel pressure regulatore, and EGR valve and EGR valve position sensor, and Exhaust gas Oxygen sensor. Fuel pumps are working good. I cleaned all carbon out of the EGR ports and tubes. Timing is at 10 degrees btc. It will start and idels good, but when I apply the throutell it stalls even with no load (in neutral). I checked all vacume hoses, no leaks. The Actron tester gives me a 33 (EGR valve opening not detected), but as stated I changed the EGR valve and position sensor.

I get 16 to20 PSI on the fuel rack whin I try to thriughtel up. I get 5 volts on the ornge lead. On volts on the BLK or Green. But I also get a ground indication on all three leads with the key off.
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Saturday, May 3rd, 2008 AT 4:27 PM

3 Replies

Tiny
JACK42
  • MEMBER
EGR only should open at a light throtle cruise down the road anyway, not on a rev or at low speed. Have you tested the TPS? (Throttle position sensor) Might not be working, so the comp doesnt know the engine is off idle. Should be 3 wires, 1 is a 5 volt reference from the comp, 1 is a ground and the other is signal voltage back to the comp to tell it where the throttle is. When you try to rev, does the fuel pressure stay the same?
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Sunday, May 4th, 2008 AT 8:02 AM
Tiny
JERRY GMAN
  • MEMBER
The fuel pressure is 16 to 20 psi when I revup the engine.
I have 5 volts on the oreng/white circuit, but I also get 0 olms on all circuits Org/white, Blk, and green.
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Sunday, May 4th, 2008 AT 5:27 PM
Tiny
JACK42
  • MEMBER
When you move the throttle one of the other wires should increase in voltage, this is the signal wire to the PCM. If you dont have this, the Throttle Position Sensor could be bad
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Monday, May 5th, 2008 AT 7:27 AM

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