I swapped engines in my 1989 F-150 5.0L with a salvage engine that the salvage yard told me was an '88 engine. Haven't checked any engine codes on it yet and not exactly sure where to look up codes. Anyway, the engine has good compression and purrs like a kitten at idle. The problem lies in the fact that there is no power when you get on it. Under no load or loaded conditions, it won't rev above 3500 rpm and is a dog when you want to accelerate. If you just putz around town it seems fine, but falls on its face when you get on it. Can't seem to find any vacuum lines that may be leaking. The other kicker is that it starts really hard when it's warmed up. It's triggering a check engine light, but haven't been able to pull a code due to what appears to be a missing wire....possibly a ground. Also, it is not registering any coolant temp at the gauge even though the the harness wire is connected to the temp sensor. I am unbelievably frustrated with this problem right now. Any help would be much appreciated if anyone else has experienced this.

 

check your thermostat and make sure its not stuck open.

also you should be getting a reading if your gauge and gauge harness is working, make sure the gauge is working

 

Thermostat is definitely cycling. Anything else?

 

Might be a simple electrical problem. Make certain that the engine is grounded well. Also check your plug wiring and order. If you got an HO motor some how it would have the 351 firing order, but I dont see how it would idle.

Do you have a dialback timing light? You could check your ignition advance to make certain that it was working correctly.

I really think that it is something simple.

 

I tend to agree with you that it seems like a simple electrical problem, but I am not sure where to troubleshoot at?? Does anyone have an electrical schematic for this year of vehicle?

When you said engine grounded well, I'm assuming you mean the ground strap from the block to the chassis?

 

It sounds to me like the ignition timing is way too retarded! Which harmonic balancer did you use? Using the wrong one can misplace the timing marks. That would account for both the smooth idle and lack of power, with the idle setting cranked up to compensate. Did you have the timing chain off? One tooth either way will make a BIG difference in performance.

 

Has anyone lost an injector or two and heard of this type of problem? I left the same harmonic balancer that was on the engine that was put in.