1986 Ford Bronco II 2.9l 4WD 160k miles

YERBOY

MEMBER
1986 FORD BRONCO

This bronco sat for about 2 years. I have drained old fuel, replaced the fuel pump in the tank, the high pressure fuel pump, fuel pressure regulator, fuel injectors, spark plugs, air charge sensor, MAP sensor, and clean EGR valve and entry in to the intake manifold, put clean fuel into the tank after cleaning the tank also. The vehicle now starts, I am able to rev the engine after a cold start, but when the engine warms up and I press the gas pedal it kills the engine, almost as if it is getting flooded. I believe it is temperature related because after it dies I have to wait for it to cool off before attempting to start it again. I

1 Reply

RUDPRO

MECHANIC
224 POSTS

You cleaned th EGR valve but are you sure it's working right. With the engine cold, start it, let it warm up a minute or so, touch the valve, it should not be hot. You can also test it with a hand operated vacuum pump.

Disconnect the wiring harness to the air bypass valve on the throttle body. Disconnect the vacuum hose to the EGR valve and plug it. Connect a hand operated vacuum pump to the EGR valve. With the engine idling at normal idle RPM, it's on the sticker under the hood, you may have to open the throttle slightly with the air bypass disconnected, apply 5-10 inches of vacuum to the EGR valve. The idle should drop more than 100rpm and may even stall. When you remove the vacuum, the idle should return to normal. That means the EGR is OK. If not replace.

Are your spark plugs fouling? Are you getting sufficent spark to them? Is your timing correct?

Also check the O2 sensor. Connect a digital voltmeter black lead to a good ground and back probe the O2 sensor wire connector with a paper clip and connect the voltmeter positive lead to it. With the engine warmed up and running, the voltmeter should swing rapidly between.01 and 1.1 volts dc. That would mean the O2 sensor is most likely OK.

Is the check engine light coming on. If it is you should get the codes read. You can buy a fairly cheap code reader for about $30 for your vehicle.