So my car has been down like 5 months... I have been trying to figure this one out and I am racked.
The car is 02c5z auto swap, motor swap, c6z diff etc... that combo has been together now for about a year.

I was at the track and had made 2 runs, I was going to run a guy that ran the exact same time as I did on motor the last run, so I was going to pull my air filter(which I had done before with no issue) to pick up a tenth or so.
Well when I launched the car it came out of the hole and immediately went lean on the wideband... like off the chart. I got out of it and coasted down the track, checked my codes to no avail. Turned the car off and back on, I hit it on the way back to the pits and it did the same thing, On its face lean anything over half throttle.
That was the start of my problem, which it has gotten worse regarding how much throttle I can give it and how hard it will go lean. NOW it is to the point where I can start it up and it will just sit there idling lean, eventually if I let it idle long enough it will stoich out around 14.8 or so...

If I give it any throttle it will try to die.... So we checked the following:
Fuel pressure, never drops off
Throttle blade is opening and closing accoriding
Throttle percentage is being reported to the computer and HP tuners

I changed the computer out thinking that may have been the problem, NO.
We put one of those test lights on the injector plug in, a noid light I believe, and it will sit there and flash(dim IMO) until I go to press the gas, when I press the gas, the light will go so dim I can barely see it or all the way out when I press it harder, then the car will die.

I have checked over my grounds and my car isn't throwing in relevant codes, just for the Evap I deleted. The car, since the problem was converted over to speed density, which we thought the maf might have been the issue but is still is doing the same thing.
I really don't have a clue besides a short or a ground I missed

What ground do the injectors use?

 

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seek and you shall find your answer.
also, how did you check your fuel pressure? did you test it under load or while revving it? this sounds like a pump and/or regulator to me.

 

The injectors are grounded through the ECM. You will want to carefully ck all your grounds. Good luck!!!

 

I can post the 02 schematics for you and the PCM connector views so you can do continuity checks. Just not home now. If you need anything else like FSM diagnostics let me know.

 

You may be a victim of a wire on the injector harness wearing through to intermittent grounding on the fuel rail. On the driver's side, near the back of the motor, the wiring wrap is rubbing on the fuel rail, and sometimes causes what you're experiencing.

 

You need to ACTUALLY measure the Coil and Injector voltages with a METER!

Check the INJ-1 & 2 Fuse/s. Make sure its TIGHT in its fuse holder.







At PCM Fuse 16,, Make SURE that you have full battery voltage. Check it under load when you mash the throttle causing it to lean out. If that voltage goes LOW, the relay will drop out and kill your injectors.

Where this is going is a defective IGNITION SWITCH. If the " HOT in Run & Start " power coming from the ignition switch is failing,, it will cause this issue.

Please read the voltages on all the fuses. Look on TOP of each fuse. You will see two test points. Measure each one to chassis ground.

You did properly secure little skinney engine ground wire G-106 to the engine ground above the starter CORRECT????



Also,,, swap out the relay. It could be failing under load..


Hope this helps

Bill

 

Thanks guys, I have gone over every ground on the car thanks to Bill's grounding diagram... I was starting to believe it could be a slight short or momentary short on the power wire going to the injectors. I have been pulling my hair out over this **** for quite some time now. I will check the little wire, like you suggested Bill, but I put it all back together just like it came apart with both of the ground wires tapped together so I wouldn't lose them.

 

Read those voltages!!!

BC

 

Here is the link from Bill's experience discussed in Post 6. You will find the issue in Post 5 below.

https://www.corvetteforum.com/forums...e-misfire.html

Here is a link to the PCM connector views that might help. Bill already provided the schematics.

https://www.dropbox.com/s/6du2ahrizx...Views.pdf?dl=0

 

Thanks guys, I will check the voltages when I get over to the shop in the next day or two... I just wanted all the info so I can go over there with a plan.

 

this sounds crazy .....but...but...but.......do u know pressure and volume is not linear proportional to each other......another word --------------> if u have good pressure ...that don't means u have correct volume flow under loaded condition .....its kinda professional thing..unless u want to purchase a $1200 flow / pressure gage .....Z06 is a little more equipment require for diagnose rather than throwing parts at the problem and hoping eventually it goes away

 

1 more thing...your digital volt meter can not keep up in milli sec which it is the rate of the injectors pulse under a load ...so .....unless
u are on a scope checking voltage really not able to eliminate the possibility of offenders at large