Need EXPERIENCED opinion on Fuel Issue.
Aug 7, 2011 | 10:06 PM
#11
TECH Fanatic
Joined: Feb 2009
Posts: 1,635
Likes: 1
From: Baton Rouge, LA
Hey guys, so I have a 2001 Sierra ( see sig) Engine is as follows...
2003 6.0L LQ4
Comp 222/224 cam (LS6 Springs)
Ported/Polshed/milled .015 Heads
Shorty headers
8.1 injectors
I'm have a issue after the truck was Professionally tuned, with it running rough, stalls/sputters when hot, a/c on kills engine. My tuner is thinking its an issue with fuel vaporization in the rail, possibly because I'm running the 4.8 return style intake as opposed to the LQ4 returnless style? Anyone experienced this? or something similar? Is this a tuning issue or a hardware issue. Its driving me nuts, because otherwise the truck runs so strong.
Any insight?
Thanks.
2003 6.0L LQ4
Comp 222/224 cam (LS6 Springs)
Ported/Polshed/milled .015 Heads
Shorty headers
8.1 injectors
I'm have a issue after the truck was Professionally tuned, with it running rough, stalls/sputters when hot, a/c on kills engine. My tuner is thinking its an issue with fuel vaporization in the rail, possibly because I'm running the 4.8 return style intake as opposed to the LQ4 returnless style? Anyone experienced this? or something similar? Is this a tuning issue or a hardware issue. Its driving me nuts, because otherwise the truck runs so strong.
Any insight?
Thanks.
That reminds me, I have a free set of Bosch Fusion +4's for a GM 5.3 for anyone that wants them.
Last edited by Suburbazine; Aug 7, 2011 at 10:11 PM.
Aug 23, 2011 | 09:42 PM
#14
Thread Starter
Teching In
Joined: Feb 2009
Posts: 36
Likes: 0
From: Bowmanville, Ontario
Tried deleteing the EGR no Change, any one have personal experience with the xr 275hr. my idle is set to 900 rpm and seems to high? the thing runs like complete **** once its hot, Im sure its a tuning issue, but I dont know how I can verify that. I feel like it should run so much smoother than it does.
Aug 23, 2011 | 10:00 PM
#16
TECH Regular
Joined: Aug 2008
Posts: 400
Likes: 0
From: Ontario, Canada
Tuners blame mechanical issues. Mechanics blame tune issues. I'd start looking for vacuum leaks, ignition system faults then if if you find no issues there, it's the tune.
EDIT - Just seen your from my neck of the woods. That's the problem, I don't know of a single reputable competent tuner around. And the mediocre at best guys charge north of $500. A ******* joke.
EDIT - Just seen your from my neck of the woods. That's the problem, I don't know of a single reputable competent tuner around. And the mediocre at best guys charge north of $500. A ******* joke.
Last edited by blackcash; Aug 23, 2011 at 10:06 PM.
Aug 24, 2011 | 09:50 PM
#17
Thread Starter
Teching In
Joined: Feb 2009
Posts: 36
Likes: 0
From: Bowmanville, Ontario
Tuners blame mechanical issues. Mechanics blame tune issues. I'd start looking for vacuum leaks, ignition system faults then if if you find no issues there, it's the tune.
EDIT - Just seen your from my neck of the woods. That's the problem, I don't know of a single reputable competent tuner around. And the mediocre at best guys charge north of $500. A ******* joke.
EDIT - Just seen your from my neck of the woods. That's the problem, I don't know of a single reputable competent tuner around. And the mediocre at best guys charge north of $500. A ******* joke.
Its to the point where I want to give him one last chance to get it done right, or ask for my money back and go with someone state side.
Aug 24, 2011 | 11:28 PM
#18
Have him email you a copy of the tune and a log, post it here and someone will be able to diagnose the issue. Sounds like the issue starts once it goes into closed loop fueling. Have you checked your trims to see if your o2's are working properly?
Aug 25, 2011 | 12:59 AM
#20
I'd start by checking your fuel pressure on the rail at idle and while driving. Has the fuel pump ever been changed?
Secondly, a cam that small in a 6.0 should not be hard to tune at all, and it should idle quite smoothly around 650 rpm.
Secondly, a cam that small in a 6.0 should not be hard to tune at all, and it should idle quite smoothly around 650 rpm.