I have a 2001 RCSB with a 5.3, and a 5 speed. It has EGR delete, EVAP delete, power steering delete, ABS delete, rear O2 delete. I have an aftermarket Fuel cell with a bosch 044 fuel pump, -6an feed and return, I have a russell back flow valve in line. Truck maintains fuel pressure after turned off.

The truck has a 224R cam, and long tubes.

Its tuned well, runs awesome and driveability and idle are awesome.... BUT the truck will not fire up hot. some times I can cycle the key for prime 3 times and it will fire up enough so I can blip the gas pedal to keep it running long enough to stay running, but its very rare that I can easily restart it after i shut it off when its hot.

99% of the time it cranks, and pops and farts like an old car with the distributor 180* off. its getting very frustrating. My tuner is a friend who has had HP tuners for years, and done a fair amount of tunes. recently he has had this issue with my truck, and one other which is a 1976 C10 with a 01 LM7 swapped in it. similar mods, and same issue.

I have replaced the FPR with a new delphi unit. Ive checked leak down, and its good to go, 58 psi at prime, 55 psi at idle, 52 psi held after key off, 45 psi the next morning.

What should he be looking at in the tune? what should I be looking at with the truck itself?

If i can get him to email me the tune file, can some one take a look at it and see if something stands out as being off?

Thanks for any help!

 

That's the same problem with my gmc...ended up having to swap my pcm and do a retune, something in my file was corrupt. The truck would start cold but not when hot.

 

Sure, post the tune up if you can.

It never hurts to have more eyes on it to see what could be a cause. My first thought is the base running airflow or something similar could be off and causing the problems.

 

i just asked for him to email me the final tune file. I am not sure if he will send it but if he does, I will post it up.

 

He won't send me the tune file. Said that he knows my issue is a voltage drop to the injectors and coils, and that he wants me to run jumper wires direct from the battery to the coils, and injectors... I'm done... looking for a new tuner, or buying HP tuners my self.

 

Why won't he send it?

Do you have a wideband sensor? What intake do you have? Sounds to me like you need enrichment fuel on a hot restart. Metal aftermarket intakes are notorious for this.

 

Only assuming you payed for the license and the tuning, that file is yours and he should send it.

 

It's a stock LM7 with a cam and long tubes. Factory wiring harness.

 

It's really hard to screw up a bone stock engine, just put everything in the tune back to stock and start over.

 

Either that or he should put the tune back to stock, and refund your money