At my wits end.. Looking for any idea.

[PlayingWithTBI]

There's little point to replacing a bunch of parts and NOT connecting a scan tool to look at the data stream.

^^^ What he said!

Tried starting fluid, it fires but immediatley dies again.

Because of this, I'm leaning towards lack of fuel. Check your pressure before starting and while/if running.

 

[Shane Dyer]

^^^ What he said!

Not quite sure where getting a scan tool for an OBD1 system would be. Nor breaking much more of the bank than it already has.

 

[89GMCJOHN]

Not sure here - but are these trucks wired to where you must have sufficient oil pressure measured OR ELSE the computer will disable the fuel pump ? I had a 90's Camaro that would unexplainably die as you say and it turned out I had a flackey oil pressure switch . Replaced the oil pressure switch down on the block - (not the sender that sends signals to the dash gage ) and all was well.... you may want to watch the fuel pump control signal when it dies.... i.e is there a correlation etc ....."IF" its configured - wired that way ..... another down and dirty way to see if its fuel pump related would be to temporarily bypass the relay control of the fuel pump (basically wire it direct) and see if it ever shuts off again ...... FWIW.

 

[Shane Dyer]

Not sure here - but are these trucks wired to where you must have sufficient oil pressure measured OR ELSE the computer will disable the fuel pump ? I had a 90's Camaro that would unexplainably die as you say and it turned out I had a flackey oil pressure switch . Replaced the oil pressure switch down on the block - (not the sender that sends signals to the dash gage ) and all was well.... you may want to watch the fuel pump control signal when it dies.... i.e is there a correlation etc ....."IF" its configured - wired that way ..... another down and dirty way to see if its fuel pump related would be to temporarily bypass the relay control of the fuel pump (basically wire it direct) and see if it ever shuts off again ...... FWIW.

Not sure. It just seems odd that it started doing that, but the weird miss at idle has happened for over the past year.

 

[PlayingWithTBI]

Do you have a laptop? $60 for the ALDL cable, TunerPro RT v5 is free and you're set to data log.
Check to see if you have the 12 pin or 16 pin connector in your truck.
http://aldlcable.com/aldl.asp

http://www.tunerpro.net/

Here's a screen shot of a data log on my 88

You must be registered for see images attach

 

[Schurkey]

it's smooth as butter (When its warmed up)

This vehicle runs bad only when cold? I'd be looking at the coolant temperature sensor, and the wire harness connected to it.

Not quite sure where getting a scan tool for an OBD1 system would be. Nor breaking much more of the bank than it already has.

There's several scan tools that will read and record the data stream. There's no point to working on an OBD-1 vehicle without an OBD-1-capable scan tool.

Mine is an ancient Snap-On MTG2500, essentially the same as an MT2500 which is more popular. They'll work on '80 1/2--2009 vehicles if you have appropirate software. My software goes from '80 1./2--1999, and 1996--2006, so I have some overlap between software cartridges from '96 to '99.

Not sure here - but are these trucks wired to where you must have sufficient oil pressure measured OR ELSE the computer will disable the fuel pump ?

I don't have a Camaro wire harness diagram, but typical GM practice is to power the fuel pump via the fuel pump relay AND the oil pressure switch in normal operation. The oil pressure switch can turn the pump on, but it can't turn the pump off unless the fuel pump relay or relay wire harness is defective.

If fixing the oil pressure switch made the vehicle run better...I bet the fuel pump relay was cooked.

 

[Schurkey]

If the EGR valve is partially blocked open by carbon buildup, it can mess with the air fuel ratio during cold engine operation and cause a rough idle. The “inert” gas takes up volume that would otherwise be filled with combustion air. This is what causes the lean condition. Depending on whether you are in closed loop or not the O2 sensor may or may not see the lean condition.

If EGR operation is "displacing air", wouldn't that result in a RICH mixture?

There's actually several things going on when the EGR valve is leaking exhaust gas into the intake manifold.

1. Vacuum is reduced because the combustion is screwed-up. Reduced vacuum is picked up by the MAP sensor, which drives the computer to add fuel.

2. If any cylinder on the bank with an O2 sensor misfires, the misfire is picked up by the O2 sensor as a false "lean" condition, which drives the computer to add fuel.

3. If the exhaust gas is displacing air, the mixture will not have enough air, which represents a rich mixture.

 

[bobby v]

How far is Tonapah lol, I see your read out but have no idea what it means so Ill drive there for you to tell me what's happening haha.
Or I could buy that connector and see what mine says then ask you to decipher it huh.
Im old and this stuff makes my head hurt
Bobby V

Do you have a laptop? $60 for the ALDL cable, TunerPro RT v5 is free and you're set to data log.
Check to see if you have the 12 pin or 16 pin connector in your truck.
http://aldlcable.com/aldl.asp

http://www.tunerpro.net/

Here's a screen shot of a data log on my 88

You must be registered for see images attach

 

[PlayingWithTBI]

How far is Tonapah lol, I see your read out but have no idea what it means so Ill drive there for you to tell me what's happening haha.
Or I could buy that connector and see what mine says then ask you to decipher it huh.
Im old and this stuff makes my head hurt
Bobby V

I'm about 125 miles from the CA border near I-10. What year/engine/trans is your truck? What ECM (mine was a 1227747 before I installed the EBL Flash-2).

 

[PlayingWithTBI]

I'm about 125 miles from the CA border near I-10.

You'll probably be coming down 95 to Quartzsite? I'm about 85 (1 hour at 85MPH lol) miles from there.