Help: LBZ ENGINE missing/stutter

[heathgu]

Hi Everyone,

I have been fighting this vehicle for 7 days now and i am all out of answers.

Here is a video of what is happening.



The vehicle was running when it arrived at my place. 600miles to my place. It has 40000 miles on the engine. Has vvt 4094, head studs, airdog, robs tuning, stage 4 mikel trans. Other then that stock engine.

I have changed the wiring harness 3 times now, ecm, tcm, gpcm, maf, map, cp3, cp3 regulator, injectors 2 times now, ultra sonic cleaner the rails and lines, bypassed the airdog and filters, replaced the airdog filters added new diesel, cam sensors, crank sensor, coolant temp, fuel temp, added a fuel pressure guage, grow plugs, compression tested the engine which was 380psi or close.

I even took all the wiring out of another vehicle that is running perfectly i have here and the problem is the same on this silver patrol.

I have had the trans apart for a check over. All looked good. Could i have damaged the torque converter rpm pickup and this is causing the problem?

What could be cause the engine stutter. I have put a brand new ecm in this truck with complete stock tuning. Only the security turned off to run in the conversion.

And help would be appreciated, i am almost ready to burn it to the ground. I have over 100 hours labour in the and no results yet.

Thanks Heath

 

[RPM Motorsports]

Did you check to see if the reluctor wheel is loose on the crank? Sounds like you replaced everything else.

 

[heathgu]

Just finished checking the crank reluctor wheel. All look good..

 

[RPM Motorsports]

Is it a steady miss/stutter or Intermitent? Cracked/plugged pickup tube in the tank?

 

[adeso]

anything look out of place with the logs?
rail PSI etc? maybe try turning off an injector at a time to see if it changes anything?

 

[heathgu]

Just put a line directly into a new fuel drum. Thru a filter into the engine.
No change. Will email the log files to anyone who can help.

I don't know enough about tuning to say. But the rail does fluctuate a lot when it starts to miss..

 

[adeso]

did you send a log to Rob? he is good about looking at it and getting back to you

 

[adeso]

Just pulling ideas off the top of my head, I would put positive PSI to the CP3 (lift pump) then think about looking at the FPR, maybe unplug it (should command max rail) and rev it and see what the rail does.
Or just unplug the FPR and see what it does

 

[heathgu]

I have changed the cp3 regulator and the Fpr sensor also...
Rob did take a look at the logs and said the pilot was a little funny.. I have replace all the fuel components on the engine now. Everything.

 

[RPM Motorsports]

Clean the grounds on the block, front of block down by the pan, on each side. Also clean the ground from the drivers side head to firewall.