86 2.9L engine issues

[jimmyfloyd]

1986 Ranger 2.9L 4x4 Manual

Ok, the truck has some issues that need attention. The PO threw parts at the problem, so many things have been replaced and some have not.

Issues:

Hard start after sitting 45 minutes.
rough idle
seemingly a misfire
Backfire that blew out the side of a fairly new muffler.

The first thing noticed was that there are a lot of wires that need attention. Some have missing insulation and some have horrible repairs. This will be sorted out as there is time.

The truck currently starts up and runs, but I wouldn't say well. The PO put on a bunch of new parts, but said that it still probably could use to be timed. Not sure if this would cause these issues.

Any suggestions on where to start, other than fix the wires and replace the muffler?

 

[adsm08]

Check fuel pressure. Put the gauge on it, get it running, kill it, and let it sit. Watch for the change in pressure from about 1 minute after it is shut off until the 45 min is up.

 

[jimmyfloyd]

I will check that soon.

We did find the fuel line by the regulator looks like it was pinched or bent and might be restricting flow.

 

[adsm08]

Doubtful. I have a spot in my one line where I have it almost folded over and mine runs fine.

That system flows about twice as much fuel as it actually uses. That's the beauty of a return-type system. Small things like that don't take them down.

 

[jimmyfloyd]

ok, bummer. I'll have to get a fuel pressure tester and get that on here.

 

[jimmyfloyd]

Ok, getting it sorted out a little bit.

Ended up replacing the resistor from the ignition module. This is apparently only used on a few 85-87 vehicles, and not available otherwise, so we had to find one in the junkyard. The original was frayed at the resistor and was grounding out to the chassis when you hit bump. Since it was close to the housing, we could not just re-use the original.

Now it seems like the fuel pump is running all the time, even with the key in and the engine off. Is this normal? Also, I have been reading, and it seems that some trucks has 1 fuel pump and some had 2. Not sure where this one falls though, as I have not personally crawled under it yet.

 

[adsm08]

Yours has two. They are wired together in parallel and should prime for 2-5 seconds at key on, then stay off until the engine RPM hits about 300 or so, and then run continuously until engine RPM drops too low or the key is shut off.

 

[jimmyfloyd]

ok, so if they are running constantly, then something is at issue with wiring, or possibly the computer. Does anyone have a wiring diagram for the 86 or what we should be testing on this?