1995 K2500 Chev Trk - 5.7L In & Out Of Closed Loop - FIXED!

brianp87 · Post by **brianp87** » Tue May 24, 2011 1:26 pm

Tan ground wire at the copmputer. maybe the reluctor is slipping possibly? Id pull it at this point and check really good I like ot verify everything sometimes twice. Although I second guess myself alot

brianp87 · Post by **brianp87** » Tue May 24, 2011 1:41 pm

The rich condition may have to do with this spark advance issue. I cannot explain the o2 simulator affecting this I have no experience in it.

Tim Martin · Post by **Tim Martin** » Tue May 24, 2011 1:54 pm

brianp87 wrote:The rich condition may have to do with this spark advance issue. I cannot explain the o2 simulator affecting this I have no experience in it.

There is times when the system will run perfectly for a minute or two. I tend to think that when I had the simulator connected was when it was working good.

I'll be checking that distributor real good.

brianp87 · Post by **brianp87** » Tue May 24, 2011 1:56 pm

Off the subject but id check really close is the exhaust. Some times the back pressure is marginal and then worse when hot. I can almost always feel an exhaust and tell its an issue

brianp87 · Post by **brianp87** » Tue May 24, 2011 2:02 pm

A timing chain could cause similar spark adv. possibly. Dang -

steven kiser · Post by **steven kiser** » Wed May 25, 2011 1:55 am

what's the history prior to it first crapping out? did the customer fill the tank, install an additive, whatever?

Tim Martin · Post by **Tim Martin** » Wed May 25, 2011 2:10 am

steven kiser wrote:what's the history prior to it first crapping out? did the customer fill the tank, install an additive, whatever?

This is the first time I have ever done work for this company so I know little about the trucks past. I could call the owner and find out I suppose but speaking of finding out.

I did begin checking ground continuity from the ECM to the battery. And on the wire at position A5 on the red ECM connector there is a red/black wire going to position A on the Ignition Module 4 wire plug. There is no continuity between the ECM and the Ignition Module. It's my understanding that this is the ground wire for ignition control. So. I have to find some way to figure it out or simply install new wire. I suppose I'll be getting my Fault Finder Tool out and trying to find the open/broken wire. This could be the issue and fixing it could make me a hero, at least in one persons mind.

steven kiser · Post by **steven kiser** » Wed May 25, 2011 2:27 am

i totally agree. sometimes i want to see things through no matter what for self satisfaction. i still think the answer lies with what was done just before the issue started. it could be something along the lines of it being jumped, running out of gas at a job sight and a gas can full of whatever was dumped in. don't know, seen a lot of issues caused by issues like this, this is where i'd start. good luck. i'll be away for the rest of the week so when i get back i'm going to look for an "it's fixed".

Tim Martin · Post by **Tim Martin** » Fri Jun 03, 2011 2:25 am

Alright guys. I got this stumper in again and Got somewhat upset with it cause it has taken me so long to fix what I define as a simple tbi system. But. After rechecking everything, I felt I was being led to a ground issue. I know this was mentioned by at least one of you guys. But, what I diwas to create new grounds from the body to frame to engine and presto! We hit the fix. I took it out for a test run, runs perfect. Got back, told my other tech to go on a run, he comes back and says it runs as good as any tbi 350 he has ever seen. I verified good data with the scan tool and everything is working exactly as the doctor ordered.

Thanks guys for your help. It is much appreciated.

By the way. WHY DIDN'T I FIX THAT GROUND ISSUE FIRST?

steven kiser · Post by **steven kiser** » Fri Jun 03, 2011 2:36 am

isn't it amazing how we start to second guess or gut feeling and get pissed at ourselves when after days of labor and head banging just do it to eliminate the possibility and it works.

glad it's fixed, now pick yourself up, dust off and tackle another nut buster.

brianp87 · Post by **brianp87** » Fri Jun 03, 2011 6:24 am

brianp87 wrote:Sounds like it could be a ground issue.

Glad you stuck with it and got it fixed. Dont you love it.

Tim Martin · Post by **Tim Martin** » Fri Jun 03, 2011 6:58 am

brianp87 wrote:
brianp87 wrote:Sounds like it could be a ground issue.
Glad you stuck with it and got it fixed. Dont you love it.

I am wondering, what clued you in that it might be a ground issue?

brianp87 · Post by **brianp87** » Fri Jun 03, 2011 8:53 am

I got the idea that it was trying to ground through the o2 sensor. I dont know what a 02 simulator is but it ran ok with that out of the circuit so I was thinking that would be easy to check

ricmorin · Post by **ricmorin** » Fri Jun 03, 2011 10:01 am

That's why with the O2 out it ran ok....stray voltage. Also, the knock sensor is grounded through the block as well. Glad it's fixed.

1995 K2500 Chev Trk - 5.7L In & Out Of Closed Loop - FIXED!

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Re: 1995 K2500 Chev Trk - 5.7L In & Out Of Closed Loop

Re: 1995 K2500 Chev Trk - 5.7L In & Out Of Closed Loop

Re: 1995 K2500 Chev Trk - 5.7L In & Out Of Closed Loop

Re: 1995 K2500 Chev Trk - 5.7L In & Out Of Closed Loop

Re: 1995 K2500 Chev Trk - 5.7L In & Out Of Closed Loop

Re: 1995 K2500 Chev Trk - 5.7L In & Out Of Closed Loop

Re: 1995 K2500 Chev Trk - 5.7L In & Out Of Closed Loop

Re: 1995 K2500 Chev Trk - 5.7L In & Out Of Closed Loop - FIX

Re: 1995 K2500 Chev Trk - 5.7L In & Out Of Closed Loop - FIX

Re: 1995 K2500 Chev Trk - 5.7L In & Out Of Closed Loop

Re: 1995 K2500 Chev Trk - 5.7L In & Out Of Closed Loop

Re: 1995 K2500 Chev Trk - 5.7L In & Out Of Closed Loop - FIX

Re: 1995 K2500 Chev Trk - 5.7L In & Out Of Closed Loop - FIX