bjr23,
Sounds like you have a bad front pump.

 

Well I got the distributor changed yesterday. Fired up and timed it with the SPOUT out and it runs as good as it did before (hopefully without the stalling or the no-start issue). I haven't had a chance to do some extended testing on starting or long drives. I did come across some weird things though. I turned the engine to line up the timing marks on the crank but the rotor was pointing toward the very end of the driver side fuel rail. I should of taken a picture but didn't. It lined up with one of the wires though but not #1 I don't believe. It was the rear plug on the passenger side of the motor (closest to the firewall). I put it back to that point when reinstalling it and used that wire to set my timing. With the firing order being 1-3-7-2-6-5-4-8, I don't think that i'm out 180 degrees assuming the wire that I used was #4 which would equate to the #7 cylinder. It has me a little stumped but it's running good. Could there be a different harmonic balancer on this engine and I just got lucky in the timing lining up correctly on the #4 cylinder? From the firing order, it seems like the mark on the harmonic balancer could be 180 degrees out. I'll keep you updated if this fixes the problem all together though. Thanks again subford!

 

I've since done a little more investigation and I think I have the style of pump that has a selector valve built into the pump. Running off the rear tank keep over fillling the front tank (return valve issues)? My problem of finding a pump online is that they don't show one with the tank selector valve on it. Where can I find one of these? bjr23

 

None of the trucks have a pump with a selector valve built in unless you are talking about the shuttle valve for the return fuel from the fuel pressure regulator (FPR) and that one is in the module (FDM) and not the pump.

In your 93 you can replace the FDM or the whole unit with sender and all.
Any auto parts store will sell you either one.

The FDM:


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jimjoebob99,
Sounds like your harmonic balancer has slipped in its rubber. If you replace the harmonic balancer then you should be able to use number one to time it.

 

Well that didn't take long at all. Went to fire the truck up to go and get some lunch today and it just kept cranking and not starting. I didn't have time to see if it was physically sparking but it still didn't start when I pulled the SPOUT either. So now i'm thinking a loose connection or I had a problem with the computer all along that showed all the indications of the PIP sensor. I made sure that I cleaned and di-electric greased all the connections that I took apart yesterday. I drove it around the block a few times and started it 6 times in a row after I was done with the job. I checked the distributor and it's not loose. It's really starting to get on my nerves. I'm hoping that I find something really simple with it now. I'm going to physically verify spark, with the SPOUT in and out, when I get home. It's driving me crazy!

 

If you do not have spark with the SPOUT out then I would say you have a bad ICM.
If it is the ICM make sure they sell you a BLACK one. A gray one will not work right and will give you a code in CM memory.
If you have spark with the SPOUT out and the injectors are not firing then I would say computer.

 

Well when I got home to check spark, I got nothing. Pulled the connections off of the solenoid (starter relay) and cleaned everything really good and checked all the grounds. Tried again, with the SPOUT in and out, and no spark. I can hear the injectors clicking and I can smell raw fuel from so much cranking and no fire. I burned the wire off to the started because I cranked it so much so I went and got a new solenoid (on the starter) because I couldn't get the nuts off to change the cable end (it was all rusted up anyways). I bought a new ICM while I was at it too.

On a side note: The guy tried to sell me the gray one at AutoZone as it was the only one they had listed for my truck. He tried to look up the 302 also and it came back with the same part number. I told him that i'm not purchasing it unless it was the black one (I had the black one in my hand) and tried to explain to him that the grey one was for the push start system. He didn't believe me so he cross referenced the OEM part number on the black one and finally got a different part number. Point being, these auto part stores and their computer databases are junk and it's always best to do some research before you go and they give you the wrong part.

Well I got the starter fixed and the new ICM in the truck, tried to crank it and still turning and not firing. Wiggled wires to no avail. Double checked all my connections and found nothing wrong. I pulled a plug wire off and checked to find no spark again. After fooling with it for about 20 minutes it finally fired up. I let it idle and while I was putting my tools away, it just died. Cranked right back up though. I drove it down (this was tuesday) to the local bar because I had to shoot pool league that night. After we were done I went out to start it to go home. Well 20 minutes later, I was walking home angry. I had one of my friends take me up to get the truck yesterday. Looked over all the wiring really good, checked incoming power to the coil, good there. Cranked and cranked and no fire again. I pulled the wire off of the coil and grounded a screwdriver off of the block and tried to see if it would arc a spark to that. Nothing. I'm wondering if I have yet another bad coil or a loose wire. Spent another 20 minutes trying to start it and got nothing so we pulled out the tow strap. I had it in neutral so that I could still crank it while I was being towed (that truck is a bear to drive without the power steering and power brakes) to see if it would fire. I finally got it to fire up about 2 blocks from my house. I was so pissed off I could of spit nails. We unhooked the strap and I parked it in the yard, shut it off and then got the no start issue again. I locked it up and slammed the door and was done with it for the day. I think that if I would of tried to do anything I would of probably smashed something that I didn't want to. I'm at a loss for anything now. It's just aggrivating.

Would the computer be something that could keep the ignition system from firing? The problem seems worse since I changed the distributor, should I take it back and get another one? Nothing that i've done has made the problem any better, only worse. How would I check if it's getting a pulse to fire the coil? I'm determined to fix it without breaking down and taking it to the dealer. I can't let it beat me. Would there be any main wires that I could trace that would affect the ignition system to see if there good? I love the old beast but this is getting rediculous. Thanks!

 

It can, when you have no spark just unplug the computer and then do your trouble shooting with the computer unplugged. Then you will know it is not the computer stoping the spark. Use a test light on the tach (-) side of the coil and it should flash while cranking. And while you are there look very close at the plg with the two wires that plugs onto the coil. This plug has cause this kind of a problem before.Just the red wiring coming from the power relay to all the solenoids and the computer or the wire coming from the Ignition switch that goes to the POS (+) side of the coil and the ICM.

 

So the ignition system will still spark with the computer unplugged? I'll try that first.

I tried to do this yesterday with my test meter but I wasn't sure if it was a pulse or a bad connection between the lead and wire. I'll get a test light and try it again. If it is pulsing, the coil should be firing correct?


I know that when I key up the ignition, I do get power at the ignition coil. Would I also need power at the ICM for it to work right? What about grounds, would they play a factor in this system or is it isolated to keep from sending interference through something it's not supposed to? Would you happen to have a diagram of this subford? Thanks for your continued support!

 

Yes it will.
Yes the coil will fire if it is pulsing.
Yes you do need power at the ICM for it to fire.The Ignition ground is inside the distributor.


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Alright, thanks subford. I'll check the pulse first with a light to see if i'm just overlooking a bad coil. I'm not sure though because it did it before and after I changed it. Then i'll unplug the computer and see if spark returns. If not, then i'll do some wire tracing with my meter. I'll let you know how it goes.

 

Make sure you look very close at the plug with the two wires that plugs onto the coil. This plug has cause this kind of a problem before.

Another 95 Ign Diagram:


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Ok, so I cranked it to check spark when I got home, nothing. I checked if there was a pulse going to the coil (I couldn't find a test light and didn't have time to go and pick one up so I used the VOM). Key on (with a battery that i've been cranking a bit) 11.5v and cranking, a steady 8.5v. No sway in the meter readings while cranking. I disconnected the battery, unplugged the computer, reconnected the battery and tried to check spark. Nothing yet again. Same readings on the pulse and voltage. So I started to check continuity comparing it to the first chart that you sent me. I disconnected the connector to the ICM, the coil, and the distributor. I checked all readings through the pins in the connector and not peircing the wire. I have continuity between (the numbers in parenthesis are the circled numbers on the diagram) coil pwr (2), ICM pwr (5), and CPM pwr (22). Between coil - (3) and coil - (4). Between gnd (9), gnd (28), and the base of the distributor. I also checked continuity between the base of the distributor and the negitive battery post. I didn't bother checking any of the other wired as some of them look like they have diodes in them and i'm not sure how they would check out. I didn't know where the pin locations were on the computer so I didn't check those, and besides, I had it disconnected. Should I have ohm'ed out the wires to see the physical resistance to see if there was a short? I didn't have enough help to do that but I can probably recruit a friend today to do that. I checked out the coil plug pretty good and the wires are flexible and i'm getting good contact to the coil.

Aside from splitting the harness and seeing if there are two wires that are crossing and/or shorting out, is there anything else that I should check before I start taking the warranted parts back and swapping them with new ones? Do you have the physicall coil resistance measurements so I can verify that it's still good? It was a cheap coil too. I know that I ask a whole lot of questions and I thank you greatly for your help! You make working on a truck very informative and this site is an awesome place for knowledge.

 

For the Ignition coil I get from small wire blade to the other small wire blade (no wires attached) 0.25 Ohms and from the small wire blades to the coil HV output 7.5 K Ohms (7,500).

I think I would take the distributor back and get another one.