Okay, the truck will all of a sudden just die... it will not start back up, it cranks, but just no combustion....

Things we have done:

Fixed the common red/white splice...
new battery
New coil
new fuel pump assemb
New Distributor
New sparkplugs/wires
Relays are fine

Now, tonight, we have found that by wiggling the wiring harness/bundle right before it leads into the PCM will get it to start... just to make sure, we have tested this theory twice... but, for some reason, cannot get the truck to shut down by doing the wiggle test, hmm...

Stripped the hockey tape off and checked the wires all the way towards the ground and up to the injectors..
We do get power on pin 3 (the lead to the notorious splice) and good ground on the 11 and 12 pins of the pcm.

Any thoughts or recommendations? thanks

 

When it doesn't start do you get good fuel pressure (with a fuel gauge)?
Do you get fuel spraying out of the injectors?
Do you get spark at all plugs?

 

Thanks for the fast reply, were going to be working on it for a few more hours tonight... then hit tomorrow

well, just got done removing pin 3 to check for any corrosion at the computer... looks good...

Yesterday, when it would not start, we had no spark at all... but after the splice, it could be a different story now..

Unfortunately, for once, we hoped it did not start so we could check the plugs again, and wiggle different spots on the wire bundle by the computer to get a more specific answer... but after reassembling the wire to pin 3 to the pcm it started right away.

I am still not sure if its going to die again... too early to tell, and didn't really do anything accept unplug the harness from the pcm for about an hour or so... (maybe the pcm did a reset on us and that was it?)

As far as the fuel pressure is concerned, we don't have a tool to test, but we might take off each injector 1x1 and test the spray itself, and if that was the case, wouldn't it idle rough?...

Last night it died, but I had him try to start it by himself, then I resorted to wiggling the bundle next to the pcm, and voila - it started... but can't pinpoint if thats actually the issue... If it was, I should be able to turn it off by wiggling it more right? but that does not work...

Still confused as to what exactly it is... I am thinking electronic problem, but who knows...

 

just got back from a test run after we put pin 3 wire back on the pcm..

seems like it has more power then before.. still letting it run to see what happens.. Could it have been the computer resetting? We did reset it yesterday via battery, but is it a possibility it actually reset from disconnecting the wire harness from the computer??
Curious about that....

Next thing we will do is test the injectors for sprayage... don't know what else we can do haha

oh - and there is a new EGR installed


Okay, so it died, restarted up just fine - but, seems like there is power loss... Tomorrow we will pick up a fuel pressure tool and check that out... maybe it might be an injector.. or two?

 

Okay, just ran the pressure test at the relief valve on fuel rail...
On idle its @ 41 psi

 

We were going to test the injectors, but how do we go about doing that? the rail would force us to test 4 at the same time... thoughts?

 

Ya just lift up one side, just a bit to see the spray pattern of each one.

 

the injectors may not be the issue. we took them all out and flushed them by using battery+carbcleaner+tubing.. all sprayed out the carb cleaner just fine.... ill post back after we test run it tomorrow.

 

How has the truck been running since you disconnected the PCM and fixed pin terminal #3? I can't tell you how many times in my career as an automotive technician I have seen big driveability problems because of loose connectors/terminal.

 

well, there didn't seem to be any problem with pin 3, all ground pins and power pins seemed to check out fine. we took the wire from pin 3 just to check for corrosion, there was none, so we reassembled... The harness and wire bundle we unwrapped and checked the whole bundle all the way until it wraps by the injectors.

After we re-assembled, the truck has not died since... but cannot say for sure if that did it or not.

test drove it for 20 minutes, runs fine, but seems gutless. I think next we are going to check the carb plate and clean the carb a little while were at it.