Hurray, I have finally found…something... while trying to ohm out the injectors. Discovered that pulling the plugs off the injectors was still not too easy… until I got out a pair of hemostats! Got’em at the flea market and they are perfect for this kind of stuff! Anyway, I have found that the wires leading to the injector for the #5 cylinder are shorted! The insulation is just plain gone and the wires are/were touching! Looks like there is a common wire to all six of the injectors RED. I assume it is positive current. There are only two other wires running to 3 each and 3 each of the six total injectors. Red w/ brown stripe and green w/white stripe. This means two circuits with three injectors on each circuit.

If one group of three injectors is shorted what happens??? Do all three injectors that are shorted fire (stay open) constantly or do they not fire at all??? Will this short in the wires of this circuit damage the injectors, PCM, ect.??? If injectors are dumping fuel (firing/staying open all the time) will all this fuel take out the O-2 sensor???

HELP!

I completely removed the harness from the truck. Completely re-did the electrical tape job, inspecting each/every wire. Put the volt OHM METER on each of the wires. All ohmed out GOOD! There is one circuit that is some what weird. But other wise all are OK! Going to shrink tube the wires that are missing insulation and reinstall the harness. Just wondering what other damage this short could have done???

 

Probably not a lot. The Computer pretty much just turns grounds off and on and that is what it does here it runs these in batch mode three on three off etc etc. By turning on grounds they can protect the proceesor from electrical shorts.

 

Ohmed out the fuel injectors. Here are the results.

Cylinder #1 14.7

Cylinder #2 14.7

Cylinder #3 14.5

Cylinder #4 14.7

Cylinder #5 14.6

Cylinder #6 14.6

Electrically the injectors are OK. This doesn’t address any performance issues!

I read a post where all of the injectors ohmed out OK. But the flow in CC’s was off enough to warrant replacement of at least one of the injectors. Is there a way to clean/test these babies short of sending them off to a injector shop?

 

Well it is good news about he PCM. I am still curious as to what happens to a shorted fuel injector…how it performs. My flashing CE light tells me I have a intermittent problem. If this really is the problem (honestly don’t think so) perhaps the wires weren’t touching all the time.
Will reinstall the harness today and update.

 

Well it seems the injectors resistance readings look ok & are well matched.

How do they appear, deposit wise???? Do you think they really dirty enough to need a professional cleaning????

Maybe something like Fords pressurized fuel injector cleaning kit would do it, or if they're not to bad, & can of Chevron's "Techron Consentrate" in a full tank of Chevron or Texaco/Chevron gas would suffice.

I've never had a FI wiring problem, but seems to me, if the short was a "dead short" the injector would be inoperative & that cylinder would be fuel starved.

If the short were a intermittent thing, then it seems to me, the cylinder would be lean or dead, depending on how bad the short was & how well it weakened or killed the injectors "on" pulse.

How in the world did the injectors wiring harness leads insulation become so damaged. Did they show signs of being overheated??? Or had some critter been chewing on them???? lol

 

Re-installed the harness. Same miss fire only it seams to be getting worse. The truck starts to miss at about 25-30 MPH now, not just when I punch it (at higher RPMs). Has steadily gotten worse. Maybe something will finally completely break. This intermittent stuff is the worst.

Not sure how this wire got damaged. I have seen some squirrel tracks and fur. Also one of the rubber parts on the fuel evap. canister is chewed-on.

Cleaned and tested the IAC valve, just for the heck of it. Also checked the readings on the TP sensor. Both check out OK. I don’t see a MAF sensor??? Any body know where it is or if a ’88 2.9 has one?

I think I am done on the fuel side. Going to start on the ignition side. Probably will do the TFI troubleshooting guide today.

 

Not absolutely sure, but I think the earlier Rangers had the MAP sensor located on the passenger side firewall.

If i's vacuum line is leaking, it can send bad data to the computer that'll mess up the timing & fuel mixture, so check it out closely if you have one.

Maybe someone with that year & engine will chime in.

How did the injectors look for deposits????

 

Did the troubleshooting chart for the TFI ignition. Coil is new so I skipped to the first test for the other items. First test for TFI yeilded bad numbers indicating that TFI was bad. Replaced TFI. Truck now sets a code 14 and stalls. Can't re-time it because of the stalling.

Does any one have troubleshooting/pin point diagostics for a code 14?

 

I didn’t pull the injectors to look at them. I didn’t want to take a chance of hurting an o-ring without having already made the decision about whether or not to have them professionally cleaned. It really sounds like something I want to do. But right now I may need that money for something else…like the rent or some ignition parts. LOL
Located the MAP. It is right there on the firewall, passengers side, like you guys said. Pulled the hose from the Pentium. The engine stalled. It did not sound or act like the upper RPM misfire I am trying to troubleshoot.

 

Ok guys,
I guess I got what I wanted, or needed!
Truck is now in a "no run" state.
Purchased a TFI module and the pick-up coil for the distributor. I have discovered that the distributor has a gear on it with a roll pin. I can handle the roll pin, no problem. Pulling the gear is all together different. So I went ahead and replaced the TFI. I put the distributer back in, buttoned up the rest of the engine and got ready to run. Positioned the dist. as close to the last know running postion as posible (on my marks). It ran for about 45 seconds and then stalled. CE light was on so I ran the koeo codes. 89 (as ussual) 14 (PIP failure). Cleared codes and restarted with exact same results. 3rd time engine would not restart!
Ran the TFI troublshooting codes on the OLD TFI. All the results indicated that the pick coil was bad.

SO I have a code 14, PIP failure. And the numbers off of the old TFI telling me the pick up coil is bad!

I am torn between taking the old dist. to the machine shop and having them pull the gear and install the new pickup coil I purchased
-or-
just buying a remanufactured dist. w/o the module and returning the pick up coil.

I need help with 2 things!!!

What do they do to "remanufacture" a distributor??? Is there an advantage to purchasing remanu. dist. over just having mach. shop re-do old dist.? Mach. shop is cheaper route.

I need pin point test on the code 14.

THANKS
WP

 

You have mail.

 

THANKS KEN,
I will run through as much of this as I can. looks deep!

 

BLACK TRUCK LIVES!

Went ahead and got the refurbished distributer w/o the module. pick up coil was shot, no crank position!
put the newly purchased TFI module in, too. engine starts and runs.
i think the timing is one tooth off!
idles rough...BAD!

STILL HAS THE EXACT SAME MISFIRE! RUNS THE SAME!

set the code 89. stalled, producing a code 14!

 

Reset the dist. I went one tooth in the wrong direction.
Timing set up correctly right away. 10 degrees before, spout out. aprox. 30 degerees before, spout in. light stays right in the same place ,consistant. Was jumping around all over the place. Engine sounds better.
STILL HAS THE SAME MISFIRE!
Ran a compression test!
CYL 1st REV(aprox) MAX
#1 120 172
#2 90 130
#3 120 170
#4 100 162
#5 95 170
#6 90 160

I am concerned about #2. haven't done a wet test..yet
carbon deposits?
burnt/leaking valves?
ANY ADVISE!

 

Anybody know what kind of compression values I should see.
Book is a little vague...110psi min