I'm helping out one of my employees who has a 1995 Ford F-150 with a 5.0. originally the problem was that it would run okay for a while and then stall out and want to run really lousy. Pulled the codes and got a TPS problem, so I replaced it. (it's possible I got it in backwards, I was hurrying home only to see my beloved Lady Boilermakers get beat by the evil UConn Huskies...cheaters! ) Anyway, what problems can that cause if the TPS is either misaligned or turned completely around? I'm sure I put it in like the old one came out, but I can't be sure. Would the truck still run? Also, what is that sensor to the left (facing the engine) with the vaccum hose the runs directly into the intake? I broke it and was hoping to glue the fitting back on.
Now, however, I've about got it whittled down to a fuel delivery problem. The last codes I got of note were 116 (coolant temp out of range, but it's cold here) 636 (Transmission temp out of range, see previous) and 542 (fuel pump open, bad ground, or always on) so I'm hoping that it's the relay. Problem is there is no owners manual that goes with this truck available. I need to know which of the 4 or 5 black relays in the fuse box under the hood on the drivers side wheel well is the fuel pump relay. I don't hear any noise when I turn the key on.
The answer to the earlier question is: if you are standing next to the drivers side fender looking down at the row of relays, the fuel pump relay in the 1995 Ford F-150 is the second one from the fender. I went to the Autozone library and looked it up in the Haynes Manual.
Also, near as I can tell, a Throttle Position Sensor (TPS) won't make your engine NOT run, but if you put the sensor contact point on the wrong side of the throttle plate extension shaft, it will force the throttle plates open a little causing the "high idle speed" warned of in tech manuals. It may also not allow the TPS to move properly and cause damage to the new TPS if forced.
I'm still stuck with the distinct aroma of gas when the engine is cranking and a 542 code. Where could the fuel pump be shorting out? Has anyone else out there had this problem?
Just wanted to update anyone suffering with the similar problem I am on my progress.
Following up on some info I gleaned from a couple of posts here, I tried replacing my Ignition Control Module to see if that would make my 542 code disappear and the truck run like a dream. No such luck.... First of all, be forewarned, there are two ICM's that with fit the 302 and only one of them is for your application. I purchased (at the cost of $45) the wrong one..... SUCK
So I went in search of the "right one". Advance Auto Parts tested the old ICM for me and said my old part wasn't broke (adding to my foul mood, "be glad you didn't spend that money!" the guy said). So tomorrow, I will use my brand new, one-use-only, Ford ignition control module tool to put the old ICM back in and begin the hunt for 542 code anew..... I suspect wiring might be my next candidate. Seems that a LOT of people are having this problem. Just exactly how many grounds are there on one of these 302's?
Does anyone want to buy a slightly used ICM (grey in color)? I got one I'll sell you, cheap. (go here :