Hi!
I recently bought a 90 Bronco with I thought a 351W. According to the VIN at least that is what it should have. The oil pan was leaking and oil pressure was iffy so I change the oil pump..too pull the pan I took off the intake plenum to raise the engine enough to get the pan out. After all this I discover I have a 302!

The engine was running ok before hand, but the EGR valve was bad and after checking the PCV valve that needed replacing too. here it gets interesting. The EGR valve according to the parts store was from a 6 cylinder so they did not give me a direct replacement they gave me the valve listed for an 8. I put that on with the new PCV and put the whole damn thing back together.
(also the oxygen sensor I replaced about 2,000 miles ago)

We still do not know what year the 302 is as it is definitely a replacement engine and I am still looking for the code. It does have a serpentine belt.

After putting it back together and checking and rechecking all electrical connections and vacuum hoses it won't idle. When started it goes to about 1000 RPMs for about 4-6 seconds then just CUTS. I am completely out of ideas...any help would be greatly appreciated!!!!!!

Thanks!

 

My first thought would be to check the connection at the IAC valve. If it's unplugged, plug it in. If it is plugged in, unplug it and try starting the motor without it.

 

Seems your iac valve might be the culprit, have u replaced that,Aand or checked the connection? TR

 

I have checked to ensure it is getting voltage when the key is on. and it is but I have not replaced the valve itself. If I pull it is there anyway to easily determine if it is gone or do I need to spen the 90.00 on a new one? Thanks!

 

Does it sputter for a moment?

What happenes if you catch it and give it gas?

 

First thank you for all your help and suggestions...

Second...
It does not sputter at all it flat out cuts...but If I keep my foot on the pedal I can keep it running at about 800 RPMS or so and higher...

 

Colad try unplugging it and see what that does , same thing?Try that before u spend the $$ for one, theres a way to check the iac valve and clean it . Voltage for it with (key on )( not running) should be 10.5 volts resistance should be between 7-13 ohms.U can clean this solenoid with carb cleaner.TR

 

Ok guys, rookie here. I've got a similar stalling prob that I'm running out of ideas on.

What is an IAC Valve?

Edited to say: Never mind, I found it. Idle Air Control valve.

 

for anyone that dosnt know

IAC is the idle air control valve is is located just over and a littel right of the air intake tubes on the throttle body its about 5 inch long and is a cylender . it has a small black box at the and wich is the motor that contolls the valve very easy to change not too expensive and is one of the number one parts that go on fords. i have noticed that after market iac's last about 2 years just what i have noticed with 5 broncos 3 my own and one 92 f250. who knows could just be my luck.

 

Black Ford and others, I would suggested that use TB cleaner not Carb cleaner as this (carb cleaner) can foul up your TPS!

 

Correct chlay, throttle body cleaner, what i use, i was quoting the haynes manual,my bad TR

 

Shot in the dark - but a cheap shot. Check out my post at https://www.ford-trucks.com/forums/s...readid=190998.

You never know.

 

when you get it started and try to keep it running does it run smooth or is it really lousy?if you have checked for vacumn leaks and have found nonei would put the old egr valve back on and see if this fixes your problem. can you unplug the pcv valve and plug the hose? try these things first before spending any money . seems like you may have an egr valve that may be sticking open. at any time after the repairs did it run properly.
seems to me that you are overlooking something very simple, but if it ran fine before than it has to be something that you just did like the egr. a vacumn leak or some other thing that you may have touched and not realized.
remember it is usually the simple things that trick us into thinking that it is serious. just backtrac your steps and im sure you will locate the problem.

 

Put an old type EGR valve on it. Sounds like the engine was replaced at some time. Do you know what model 302 you have? Ford EGR valves operate differently. Could be the replacement is causing the problem.