1986 Other Ford Models Engine Stalls/bucks at high RPM

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.

3 Replies

2CARPRO JACK

MECHANIC
11,533 POSTS

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?