Starting Problems

[jlmaw]

I recently helped out oldest son repair a non starting problem in his 1990 GMC 6.2L 4x4 suburban. He had pulled into his driveway and the engine stopped. There was no sign of ignition or that any electrical connection would provide power to the lights, interior dash or any other usual display when the ignition would be turned. He had talked to a diesel repairman who suggested that all signals to the ecu funnel through the starter solenoid regardless of the battery charge level.
Since it was his vehicle, he was urged to crawl under the vehicle and do an observation of the starter lash up to determine if there was a fault. He could see the ends of two wires, which in reality was the same wire, that were drooping from the starter. He loosened the starter enough to have access to the starter and could then fashion two connections (I have always used the push pull male female connections) on the wire ends and connected them together. Since both batteries were toast, that meant a trip to NAPA where good old dad purchased two new batteries which were installed and connected.
A short glow plug warm up and the the engine turned, caught and fired with a glorious plume of smoke and continued to run until the shut down. What we learned from this is that the diesel tech was correct that all power cycles through the starter solenoid, passes through the ecu and then powers the rest of the assembly to start the engine. How that wire parted is still a question, but we can live with the results.
I am passing this information in case someone else has a sudden power failure and needs to find the answer.
The 6.2L engine has over 200,000 miles and is still going strong as it should.

[Robyn]

Hello and welcome

Sounds like the fusible link went away.

The 90 diesels dont have the computer doing much. The IP is mechanical and there are only two main electrical connections, the shut off solenoid and the cold advance.

If the truck is an auto tranny there will be the TPS sensor on the pass side of the IP.

The computer (PCM/ECM) controls the EGR the converter clutch and has influence on the glow plug inhibit system (Hot starts)
The computer system also controls the speedo to some degree as it is electronic and is fed from a speed sensor through the VSSB.

All in all the 88-91 6.2 trucks were the last of the good ones.
The check engine (SES) light does not usually indicate something that is about to shut you down like the newer ones will.

Good luck and enjoy the forum.

OH BTW I have noticed that we (parents) always get the bill. :D

Any time we can help just let us know.

Best to ya

Robyn

[moondoggie]

Good Day!

Thanks for posting your info. That helps all of us - now your good work can be found when searching.

Blessings!

[jlmaw]

Hey Robyn,

Thanks for the info on the GMC suburban. In our search for problems, all the fusible links were good. The starter wire that was severed and which caused the problem was caused by the shield which was installed to reflect some exhaust heat, and apparently when the mechanic worked on the transmission, he must have pushed the shield away to get to some necessary bolts. This
out-of-position metal shield eventually wore through the solenoid wire and disabled the vehicle. I can't tell you how relieved I was when the engine kicked over.
Yeah, we parents do a lot for our kids. In fact, the suburban was a gift to Steve when we upgraded to a 1997 6.5 L which has been

[garre1tt]

I had a burn through of the battery cable to the starter wire on a PCS move from Montana to California.
Nice thing about the diesel as it will continue to run untill shut down. Parked the RV for the night and tried to restart to get the family some pizza and would not crank.
With the 6.5 the auxillaries will still work (lights, stereo, ect). Used the towing insurance to the Grants Pass Chevy dealer on the weekend and they had me back on the road the next day.

The burn through was my falt but I have an excusse. I change the starter in the driveway and It was -15. I could only work for about 15 min at a time before I started to freeze. Thanks to the TDP I had the right tools to start. The cable was the last thing to deal with and I just shoved it up out of the way right on to the heat shield that burned it in half.

Thanks to the chevy dealership in Grants Pass, OR

Michael D

[Robyn]

In reference to "The heat shield that was pushed out of the way"

Far too many mechanics just slop stuff together and dont pay attention to detail.

When you look at a new rig there are wire ties and clips and heat shileds and all sorts of little goodies that were placed at strategic places for a reason.
Along comes BUBBA the mechanic and he does not want to take the time to remove the stuff properly and or in many cases things break and he wont replace it but instead just walks away.

Far too many wiring issues can be directly traced to shoddy workmanship on the part of some mechanic that simply is too lazy to do it right.

The factory clips and wire fasteners only get about a 3 on the scale of 1-10 by me. Most of the stuff was designed for assembly only and when asked to come loose in a couple years breaks and there is no way to get a fresh one.

ZIP TIES to the rescue :D These little things can save the day if used properly and every tool box should have a handfull.

The factory never installs anything just beacause it looks kewl especially under the hood.
Those little clips and gizmo's that hold things cost $$$$ to make and install so they are there for a reason.

I get really anal about that sort of thing. If I can't replace the original stuff I try and fashion something that will work as good or better than what was there.

"The voice of experience says"
Leaving ones wiring and hoses untied can leave thee stranded along side thy expressway during very uncomfortable times with smoke and or oil spewing forth from thy underhood area. Thine wife will be unamused and forbid thee from thy bedroom for many months. :(
Thy wallet will suck into a vacuum as the tow truck pulls up leaving thy children hungry and unhappy.
Thy employer will threaten thee with demotion or worse should ye be late again for work due to car troubles. :eek:

Moral of the story, fix it right ;) teach the young one the virtues of doing things properly.

Good luck and have fun

best to ya

Robyn