I recently traded my f150 for an 89 Bronco xlt. the original 351 windsor is still in. The previous owner was a "mechanic" and so far ive had to replace the waterpump, timing cover, timing chain and harmonic balancer because of him, as well as extract studs from the block that he broke off. I got everything back together and was going to give it a start. The previous owner left the bronco sitting for 6 months, and put seafoam in the gas tank. It started up, but was running rough. The exhaust smelled really rich, and the motor kept advancing, and eventually cutting out if I tried to apply the throttle. I put some B12 additive in the tank to help clear things out. I also got the motor timed. It kept advancing and cutting out. The IAC sensor tested bad. I have another IAC off of a 2000 expedition. The quick connections are different, but if I got rid of those and wired in the IAC from the expedition using solderless connections, would it work for the Bronco given that the sensor is off a triton 5.4? I havent been able to pull the codes yet, and I understand that I should do that soon, but is there anything else I should test that could be the cause of the issue?

 

Lemme get this straight... you properly fixed all the things PO hacked and the first thing you're going to do with your name on it is hack in some non standard sensor?

There could be lots of things causing the current problems including dirty injectors, low fuel pressure, vacuum leaks, and a whole bunch of things not directly related to the EFI system. Don't start guessing.. check fuel pressure, pull the codes, check all the vacuum lines, change air and fuel filters, and go from there.

 

Im sorry, I forgot to list some more things that ive done. I put a new fuel filter on and I have an inline pump to put on it if the pump is bad. The B12 additive I used should help with cleaning out the injectors, but I was still going to go through those when I get the time. The air filters are still in really good condition. There was some build up in the intake on the throttle body, that got cleaned out. Im also going to check the spark plucks. My dad looked at it and he restabbed the distributor and re timed it, and it idles better, but still has the same problem. I was just wondering, that if the IAC sensor is the problem, will the sensor I have off of a 5.4 work on the 351?

 

If the motor won't take any throttle the IAC isn't your problem it is more likely to be low fuel pressure or really dirty injectors.. especially on a truck that has sat for a while. If the IAC is gummed up the idle may be unstable but I rarely see these things fail so give it a good cleaning and put it back on.