How do you have the system wired in?? Coils grounded on cylinder heads?? Red/white wire has power when cranking??

 

I will have to investigate this & report back, I was also thinking it could be something with a ground or something on the coil or injectors.

i am getting spark at all 8 cylinders I checked with test light for spark plugs, I have not tested coild wires and I am currently unaware of how the truck is wired

will have to research all that from scratch and compare it against my setup and add to this post, I appreciate you grinding this out with me today bud

 

No problem man. And while you're checking things out check fuel pressure. Check the exhaust for any leaks too

 

fuel pressure is good, i have an mechanical dial directly on the fuel rail
and I have a elecrtonic gauage inside the cabin as well, they read 60 psi both
I redid all the plumbing in march and it worked out real well

this is kind of the setup I have

i have not seen any exhaust leaks either, however am not quite sure what to look for, there does not appear to be any smoke or exhaust coming from the long headers or the mufflers
but there is alot of unspent fuel & small amounts of smoke coming from the tail pipes when running the truck with the current problem.

 

How did you make out with all of this??

 

i will have to make time over this weekend, going to look at coils & injectors, spray & power, also smoke test intake manifold

 

I posted this up on the Holley forums as well. One of the remote tuners who's also a member here says to check the ground wire on the back of the head where the WO2 sensor is located

 

"so when I uploaded this tune to the ECU, it had a severe power draw from the battery and dipped below 5v almost instantly when turning over the key
and the engine did not crank at all, and it did not sound like the fuel pump was priming.

the battery eventually restored itself to 12.5v and I turned the key on & attempted to sync back to the ECU and the GCF has fallen off completely".

The tune is not your big issue.
Until you get the basic electric system sorted, the tune/ecm programming can/will be corrupted and/or lost.

 

this is the holley diagram I refencing for holley.com for my 558-102 harness
I do not see any specific ground associated with WB02, or is WO2 some other term I am overlooking?

 

Yea I'm not too sure what ground he's talking about either. The only ground I can think of would be the 2 on the back of the cylinder heads for the coils etc

 

so i figured out the TB issue, which makes no sense, it is as follows:

so apparently my original TB was a 12570800 and not a 12679525, which GM has superseded with part number 19420713.....

so I picked up a Dorman 977-161 which is compatible with 12570800 & 19420713 and the TPS resets just fine, that was half the price of an AC Delco or OEM GM 19420713

the new GM part number that supersedes both the 12570800 and the 12679525 is the 19420713, which makes NO SENSE TO ME AT ALL

why would they consolidate TB part numbers that are not compatible 12679525 & 12570800 into a single new superseding part number 19420713 that works for both???

I also replaced the intake manifold gaskets and the truck ran fine for about 40 miles, then the same high AFR issue came back.

before I replaced the intake manifold gaskets, I turned on the truck and sprayed brake cleaner near the injectors next to the head and cylinder #6 seemed to
respond to the brake clean spray and "bogged" the truck down for some reason.....

I confirmed the two grounds on the back of each of the heads are good. I do not think it is an electrical issue, but what do i know, lol

I found another used intake on eBay for $75, it shows up this Friday. but I am going to also test the injectors and see if they are getting current & check their resistance

not really sure whats going on, considering the truck ran fine for about 40 miles when i replaced the intake manifold gaskets only revert back to the same high AFR....

I tried to run some datalogs when the truck was running fine for that 40 miles, but for some reason they did not save to the SD.

any feedback on these symptons is greatly appreciated, will also report back after testing injectors this weekend...

 

driver side ingition coil harness is faulty

found by accident when testing injectors with stethescope, touched that coil harness the right way and it started running fine

i learned about everything else but coil harnesses thus far, lol

just reporting back on this long winded, long timeframe rookie fix, thanks for all your input guys

 

my truck is having the same exact problem. Have you figured it all out? What was making the fuel run too lean and making the power shut off?

 

I chased what I thought was every problem in the book, MAT, MAP, WB02, gaskets, intake vacuum.

It ended up being the ignition coil harnesses on both sides, I bought GM ignition harnesses from Summit
for half the price GM dealer was selling.

Also got a dual post battery, my Holley harness does not like to share power with other parts of the vehicle.
In my case it was also the radiator fans pulling too much power.

I plan to split the power draw from the battery by adding a second battery so all other vehicle components pull from
the second battery. But for now the truck runs just like it should, when the fans kick on from the thermostat, the headlights
will dim a little, but that could also be cause my alternator is too small