# 92 Gmc Jimmy 4.3 Ltr Cfi Problems!?!



## QWKPHKR (May 6, 2008)

I Got A 92 Gmc Jimmy 4wd Auto, Last Summer I Had To Replace The Fuel Injector/regulator Unit & A Fuel Pump! My Problem Is Now Is That Every Once In Awhile It Will Just Die! But If You Wait Awhile It Will Start Again! When It Does This You Can Hear The Fuel Pump Kicking On, But It Just Cranks! I've Checked Everything That I Could Think Of To Check! I Don't Know If Sumthings Getting Hot & Shuuting The System Down Or What! I Know There's A Common Problem With The Fuel Line In The Intake Cracking & Leaking! I've Been A Diy'r For Sumtime Now & This Is Just Rattling My Brain! Any Help Would Be Greatly Appreciated!

Thanks

Qwkphkr


----------



## BUDFAN8 (Apr 11, 2007)

when you are having this trouble and it just cranks do you know if it is getting only spark or only fuel? that would be the first thing to check to diagnose your problem. my initial guess is its going to be wiring trouble.

i had a 91 sonoma that would do that but it always blew a fuse when it did die. the wire caseing behind the motor had fell apart and one of the wires was grounding on the engine or bell houseing. it would blow the ecm fuse incase yours is doing the same.

any way enough rambleing on next time yours dose it try and check your basics seeif there is fire and fuel and that would be a good start to getting your problem solved.


keep us informed
Bud.


----------



## Raylo (Feb 12, 2006)

That's not a bad thought, Bud. My 1994 S-10 4.3 P/U had a similar wire problem. The auto trans shift linkage impinged on the big wiring harness coming through the firewall in the engine compartment and wore a hole through the outer bundle insulation and the insulation on one wire. In my case I didn't get a no-run, I got a blown fuse every time I shifted from D to OD (when the linkage hit the bare wire and grounded) and a tranny that didn't shift to OD and some other gears. Basically it killed the electronic contol of the tranny and it just operated in some sort of limp mode purely on hydraulics. It's very tight back there but I was able to loop a piece of wire around the bundle and pull it away from the linkage and tie it off, then tape over the bare wire.

It wouldn't hurt all 4.3 owners from that era to have a look at this and/or include as part of basic troubleshooting, especially if you are getting any mystery blown fuses, since it could cause any number of issues. Bottom line is they installed the harness improperly and depending on what wire you bare and ground out pretty much anything can happen.

BTW, my truck was assembled in the Louisiana plant so perhaps it is more likely to affect 4.3 S-10 vehicles with that pedigree.


----------



## QWKPHKR (May 6, 2008)

Well Guys, I Appreciate All The Help! However It Was None Of The Diagnosis That Was Suggested! I Did Take A Bit Of Your Advice Though! While I Had It Running I Started Wiggleing Wires & When I Got To The Fuel Injector Wiring That Runs Into The Intake To The Injector, It Died! Then I Would Just Crank & Crank! So I Wiggled Them Again & It Fired Right Up! So I Pulled Off The Upper Intake & 1 Of The Tabs That Lock The Harness On The Injector Was Broke So Any Vibration Would Cause It To Lose Connection! Thankfully Our Friendly O'reilly's Store Will Have Me 1 Tomorrow For A Meer $14!

So Thanks Again For The Help!

Maybe This Will Help Others That Are Having Problems!

Thanks

Qwkphkr


----------



## liberatedred4 (Jun 18, 2008)

I was just reading your post to see if you tried what I was going to suggest, which states that you did. My sisters 93 S-10 Blazer was having a similar problem. It would start and run fine, but once it got to temp it would shudder and die and would not start untill the vehicle was completley cool. I figured it was a wiring problem, which is not my thing, since it would die once it was at temp. It went to 2 diff. shops and I asked both wether it could be the wiring harness the one said maybe and the other said no way it's the CPI (central port injection). I told my sister we were gonna drive it home as far as it would go before dying and then wait for it to cool and take it the rest of the way. Well a friend of ours came by to take a look at it and I told him my thoughts and so he had us start it and just started moving around wires under the hood, till it died. when I saw it was the wires going into the plenum, I wanted to warn people about the guy who swore it was the CPI. Then I did a few tests to see if it was wires inside or outside the plenum causing it to die. When I opened the plenum the ground wire for the CPI was just hanging there and the crimp inside the clip was wide open . I trimmed the wire back and carfully recrimped the wire inside of the plastic housing clip. Which saved her $100.00 for the new harness. Then it ran great no stalling or shuddering and no dying. Chevy knows the CPI is a bad system thats why they started using the TBI again and why they developed a diff. system.


----------

