fuel problem

bignasty02 · 06-29-2008, 06:38 PM

i have had this problem for a while now and i have done everything i can to try to fix it.. the truck has dual tts lift pumps dual exhaust s&b intake fuel rail fitting and boost valve stage 5 suncoast 3 star billet converter.. i have had my friend tune the truck with efi.. it made 460.. but it will not smoke for anything... the truck only make 20 lbs of boost.. we have changed everything in the tune that we can think of and it wont smoke... it just dosnt feel like it has 460. the truck dosnt pull hard at all. i think it is boost and fuel problem but dont know were to start i have changed the filter and everything no diff.. i can not figure it out someone please help.... thanks..

GmcLbz · 06-29-2008, 06:52 PM

Have you logged rail pressure yet?

bignasty02 · 06-29-2008, 07:06 PM

yes it is about 21 or so..but i dont understand why i am only getting 20 lbs of boost. the tune has been modified to add fuel also and i dont even get a haz it only smokes at take of and it is a little puff not much at all...

gr8shot · 06-30-2008, 09:54 AM

Well you can always get a different tune and try that. talk to one of the guys on here who run EFI and get a tune from them. I don't know how much your friend knows about efi, but thats just a guess. Another thing to try is (if you can) run your tune on someone else's truck and see what kind of results you get with it. That's an easy way to tell if its your truck that's the problem, or if its the tune thats the problem.

**TYREBOYZ_DEMAXIN** · 06-30-2008, 12:01 PM

if that truck is making 460 smokeless RWHP then you have a heck of a tune or a problem and i venture to say a problem.there is a chance that the injectors or CP3 pump is going bad,just a thought also have the injector control harness checked.

bignasty02 · 06-30-2008, 01:02 PM

Quote:

Originally Posted by gr8shot

Well you can always get a different tune and try that. talk to one of the guys on here who run EFI and get a tune from them. I don't know how much your friend knows about efi, but thats just a guess. Another thing to try is (if you can) run your tune on someone else's truck and see what kind of results you get with it. That's an easy way to tell if its your truck that's the problem, or if its the tune thats the problem.

the tune im running is the same tune my friend runs on his truck.. it smokes like crazy and make 30 lbs of boost.... his truck runs.......

bignasty02 · 06-30-2008, 01:05 PM

Quote:

Originally Posted by TYREBOYZ_DEMAXIN

if that truck is making 460 smokeless RWHP then you have a heck of a tune or a problem and i venture to say a problem.there is a chance that the injectors or CP3 pump is going bad,just a thought also have the injector control harness checked.

The injector balances are all the same.. they are flowing perfect... the tune is asking for 4900 at idle and it is getting 5100 at 2 grand it ask for 16000 and it is getting 17300 so it has fuel there isnt a problem with that.. i dont know why it wont smoke though.. the way my friends truck smokes is crazy and it is the same tune...

gr8shot · 06-30-2008, 02:16 PM

Is his truck the same engine as yours? If his is an LLY, LBZ, or LMM that might have an effect on how it would perform on an LB7. I'm not really sure, don't know, but its a thought. Someone else could tell you for sure if that could matter.

bignasty02 · 07-01-2008, 11:20 AM

the egine is the same they are bouth lb7s.. one is an 02 model and the other an 03...