94 F250 5.8L, high idle and won't start problems
Greetings all. I'm looking for some trouble shooting suggestions. I search the forum but did not really find an answer. Here's the situation. Vehicle: 1994 Ford F250 with 5.8L, auto. I just purchased the truck at an auction a week ago so I don't know much history about the truck other than what I found under the bench seat (a lot of dirt and some french fries ;') Anyway, it was owned by a concrete/construction company and has been well used with 260,000+ miles shown on the odometer. I drove the truck home ~200 miles, every time I'd have to stop you could feel the engine fighting the brakes. In park or neutral the truck would idle rather high making for a good clunk when you would shift into drive or reverse. I asked a friend for some ideas and he told me to check the Idle Air Control Valve (IACV). Sure enough, if I unplug the connector to the IACV, the truck drops down to a nice low idle. If the engine is cold you might have to feather the gas pedal a little to keep it running, but when it warms up it seems to run fine with the IACV unplugged, (well, just sitting there in park, no A/C on or turning the wheel putting a load on the P/S pump.) I tried cleaning the IACV but it did not seem to make any difference. If I plug the IACV in, high idle. If I unplug the IACV, nice low idle. So I would assume that means that the IACV is junk, not just dirty, and I need to replace it.
When the IACV fails, do they typically fail open or closed?
Can you take a measurment on the pins of the IACV to test if it is good or bad?
If you were to take a measurment at the wiring harness, what kind of a meter do you need? DMV or a Oscilliscope. What kind of reading should you be getting?
Second problem: Won't start without giving it a shot of starting fluid now. After I figured out that I could get the idle down by unplugging the IACV, I decided to degrease/clean the engine compartment. I sprayed a couple cans of GUNK Engine Cleaner under the hood, let it soak, then started it up and hosed it off. (NOTE: Did not need to use starting fluid any time before cleaning the engine.) I took the truck for a spin around the block to heat up the engine compartment and dry things out. During my spin I noticed that the truck was running like crap, I figured that there was some moisture in the distributor cap. I got home, opened the cap and confirmed my hunch. I blew the cap out with compressed air and strated the truck back up, (NOTE: No starter fluid needed.) I then proceeded to remove some of the misc. wiring that was left in the truck from the previous owners. I took my time doing this traceing the wires back to figure out the circuits. I removed the switch for a beacon light, another switch that went to some accessory that had already been removed, the power/antenna to what I assume was a two way radio, old car phone, and lastly a car alarm system. Again, I was very careful removing all the wiring, traceing the circuits making sure that I was not removeing any factory wiring. I then went to start the truck and it would crank but would not fire. I started to think that maybe something with the security system was preventing the engine from starting so I check for spark and confired that I had good spark. Then I thought maybe power to the fuel pump was being cut off so I sprayed a little starting fluid in the TB. I figured the truck would start and die as soon as the starting fluid was consumed, but to my surprise the truck keep running. I started to think that maybe the problem was due to the IACV being unplugged so I plugged it back it but it would still not start unless I gave it a shot of starting fluid.
So why do I need to use starting fluid to get the truck started now? Once started it seems to run fine.
Point me in the right direction guys, PLEASE!!!