HELP!!! 95 K2500HD Suburban NO SPARK

Truck has a 5.7TBI engine. I've replaced plugs, rotor, plug wires, ignition coil, pickup coil, ICM. I've traced the pink wire from my coil to my ignition switch, and the yellow wire that turns into white from my coil to my computer, cant find any breaks in them. The truck ran fine into the yard, but now refuses to start! My question is could my problem be the PCM? If I put the new distributor I purchased today in, will a bad computer fry it? I've changed the ICM twice now as the test's I've done says its bad...I live WAY out of town, so fuel alone to go to the parts house is KILLIN' me! And then parts....ANY ADVICE could be helpful, so let me know!
Parts changed:
rotor, cap, wires, plugs, ignition control module (old style) pickup coil, ignition coil.
This is the second time this prig has done this in about 2200 miles; it's starting to get expensive. The first time, I didn't mess around rebuilding, I ordered a complete distributor off of ebay, bought a coil at AutoZone, and the problem cleared up..so something seems to be causing this issue, does anybody have an idea?
So just to recap...everything I can think of that directly contributes to spark has been changed, with the exception of the computer and the reluctor...can anybody help?! GMMerlin?? :confused:

Checking wires for continuity is one thing. Checking them for proper voltage from the Ign Sw is the only way to go. This could very well be an Ign Sw issue.

Welcome to the forum and sorry to say that The Merlin passed away a while back.

OH NO! That's to bad, GMMerlin was a pretty knowledgable person! In fact, I was on this forum last night and was told to PM him...explains why I couldn't find him to do so I guess..always sux when knowledge like that passes...ANYHOW!
I've checked for voltage so many places that I've just about gone crazy..well crazier anyway..I seem to have all the right voltages in all the right places at all the right times, but stickman if you have ANY ideas where to start probing, I'd love to hear it!!
ALSO: If anyone knows if....if my computer is bad, will I burn up another ICM/pickup coil/distributor if I pair the new distributor I just bought today with a bad computer....
If the PCM is bad, how does a guy know?
WHAT could cause the ICM/pickup coil to test bad?

I just compared the reman distributor I bought at NAPA with the one I bought off ebay...the ebay one is the one I'm trying to troubleshoot; it is made out of aluminium, and the NAPA reman is made from what looks to be cast metal....could this cause the issue I've been experiencing? I have ran the aluminium one about 2200miles or so..I wouldn't expect this to be causing the problem, but any straw I can grasp now would HELP!!!
Thanks stickman...
:runaround::runaround:

being a 1995 with these problems I would check all the wiring and grounds. remove grounds clean and secure.

the ICM can be tested. autozone stores most of them have a wells tester. also the ICM by wells is a lifetime warrantee. also this requires heat silicone compound to be used when mounting. heat will quickly kill the ICM if not properly installed.

I believe you engine has a oil pressure switch . this will kill the fuel as well as the spark. I have found these to indicate lower oil pressure than what the engine really has when they go bad. this if 1995 age I would replace.

bad grounds or voltage spikes will kill a PCM/computer.

bad corroded connections at the PCM are also common with this age.

NEW PLUG WIRES DOES NOT MEAN THEY ARE GOOD !

measure the plug wire resistance and compare that they are around the same value in ohms.

make sure you have voltage to the distributor .

bad plug wires/arcing will kill the ICM.

If the oil pressure switch is bad, will the gauge in the dash register? Also, will the injectors squirt fuel? My gauge is showing 40psi, and the injectors are squirting plenty of fuel...the grounds all show zero resistance, and there is zero corrosion on this truck. :banghead::banghead::banghead::banghead:

Does anybody know if I put this new diz in, and the computer is bad, will it fry this new distibutor and assocciated components that are on it?

If the oil pressure switch is bad, will the gauge in the dash register? Also, will the injectors squirt fuel? My gauge is showing 40psi, and the injectors are squirting plenty of fuel...the grounds all show zero resistance, and there is zero corrosion on this truck. :banghead::banghead::banghead::banghead:

the oil pressure will show if the switch is bad.

the injectors will squirt if the ignition key is to crank. when the key is to ignition on then the oil pressure switch takes over.

I just mentioned this as one possiblity. had this occur before , only it was intermittent . that was a PITA...

the grounds do get high resistance over time . copper and steel make this occur.

Does anybody know if I put this new diz in, and the computer is bad, will it fry this new distibutor and assocciated components that are on it?

I doubt the distributor or computer could fry each other. shorted wires could though. as the wires age the loom falls off, then the wires wear and short out. this is also true with plug wires . routing is usually not OEM because these plastic pieces and loom have fallen off , or melted to nothing but brittle plastic.

arcing of any kind can damage any computer/electronic control device.

It's raining to hard this afternoon to do any work on this rig...
All the grounds checked good (check the easy stuff first:)), no corrosion anywhere I can see or check(LasVegastruck)...I AM wondering if I should just change that oil switch, just to have a new one...as well as the MAP sensor and TPS...I haven't any idea when or if they've ever been changed...I agree whole heartedly jCat, intermittent SUX! This issue has plauged me for well over a month and a half:runaround:
OPINIONS...would a faulty PCM be intermittent? Or when they fail, do they fail?

Has anybody got anything new today?:banghead::banghead::banghead:

Has anybody got anything new today?:banghead::banghead::banghead:

did you check for crank position sensor failure code ? no signal will cause no spark/also bad connection/wiring could have caused the earlier problem then it came back.

I'm not 100 percent positive, but I don't think mine has a crank position sensor, either way there isn't any codes in the computer tonight...last night I had a temparture code in it; today I replaced the temp sensor as well as the oil switch sensor....whatever I did, I stopped the injectors from squirting fuel. Fuel pump is running, which means relay is correct. Tomorrow I'll check fuses again, and if that's not it I'll have to start at the beginning, grounds, voltage and continuity.
Does anybody know of another way to get fire to this engine? Such as an aftermarket ignition system? Something that's not controled by sensors?
Does anybody out there want to purchase a Chevy 3/4ton HDSuburban?!!

I'm not 100 percent positive, but I don't think mine has a crank position sensor, either way there isn't any codes in the computer tonight...last night I had a temparture code in it; today I replaced the temp sensor as well as the oil switch sensor....whatever I did, I stopped the injectors from squirting fuel. Fuel pump is running, which means relay is correct. Tomorrow I'll check fuses again, and if that's not it I'll have to start at the beginning, grounds, voltage and continuity.
Does anybody know of another way to get fire to this engine? Such as an aftermarket ignition system? Something that's not controled by sensors?
Does anybody out there want to purchase a Chevy 3/4ton HDSuburban?!!

what you need is a repair manual. I thought with all this work and troubleshooting you had one.

the other way would get internet subscription to manual and repair info for this vehicle. with this you canmake tests and determine why the spark is not working. no spark is not all that difficult.


rockauto has this CPS listed http://www.rockauto.com/catalog/raframecatalog.php.

I would remove the old one and check for damage/wiring/connector. these are intermittent when they fail. make sure its seated properly. no signal no spark.

Well, having read the manuals I have read, as well as the internet articles I've read, I understand that my vehicle predates CPS's. Mine uses a pickup coil, relecutor, and ICM on the distibutor in place of a CPS. J cAT, I will look again and make sure I either have, or don't have a CPS. Wouldn't the computer create another code besides 12 if the CPS wasn't fuctioning anyhow?

Well, having read the manuals I have read, as well as the internet articles I've read, I understand that my vehicle predates CPS's. Mine uses a pickup coil, relecutor, and ICM on the distibutor in place of a CPS. J cAT, I will look again and make sure I either have, or don't have a CPS. Wouldn't the computer create another code besides 12 if the CPS wasn't fuctioning anyhow?

the cps is listed for your vehicle and engine. with TBI you will need this to properly operate the fuel and ignition cycle.

these years GM did make changes to this control of the ignition control system, and the pcm DTC code .

the manual you have should have diagrams showing the wiring. also the location of the mounting of the cps.

look up the part and see if you can find on the engine.

j cAT
I've confirmed, there isn't a crankshaft position sensor on this model.