Failing fuel pressure under boost.
Failing fuel pressure under boost. I'm tapped out. I've done a search and haven't been able to find this same kind of issue. I know this is a fuel problem but I figured my question would be more appropriet here since it has to do with a boosted application. I've got a heads cam d1sc procarger with lucas 42.5lbs injectors with the walboro inline 255. Initially the fuel pressure was ROCK solid at 60psi. under boost, idle, off lol. It never moved, I wondered if it even worked. Appox. 15,000 mi. later it began to fall. I noticed gas on the 255. So I said screw it, I'll get the racetronix intank and be done with it. Come to find out it was just the rubber hose was not clamped well. So now I've got both. I never really have botherd to look until yesterday. I'ts pullied for 8 and pressure dropped from 60 to 50 at wot. I knew it was dropping afterwards cause my tuner said it was normal. But i've been reading that it shouldent get below 45? Why would it be rock solid then start dropping. Im befuddeled. 
Any help will be appreciated, indeed. Sorry for the long azz post.
Cliff notes: fuel pressure was steady at 60 for 15,000 miles now it drops from 60 to 50 at wot with 8lb boost
.
Any help will be appreciated, indeed. Sorry for the long azz post.
Cliff notes: fuel pressure was steady at 60 for 15,000 miles now it drops from 60 to 50 at wot with 8lb boost
. 
Now this is the problem you see, im retarded lol. I got the complete tuner kit from prochager and had it installed. I do not know of this boost referenced regulator you speek of. If it was not in the kit, then no? Sorry for the lack of info.
Joined: Jun 2004
Posts: 1,501
Likes: 7
From: Ft. Irwin, California (But Virginia is home)
Originally Posted by The Red WS.6
I'm tapped out. I've done a search and haven't been able to find this same kind of issue. I know this is a fuel problem but I figured my question would be more appropriet here since it has to do with a boosted application. I've got a heads cam d1sc procarger with lucas 42.5lbs injectors with the walboro inline 255. Initially the fuel pressure was ROCK solid at 60psi. under boost, idle, off lol. It never moved, I wondered if it even worked. Appox. 15,000 mi. later it began to fall. I noticed gas on the 255. So I said screw it, I'll get the racetronix intank and be done with it. Come to find out it was just the rubber hose was not clamped well. So now I've got both. I never really have botherd to look until yesterday. I'ts pullied for 8 and pressure dropped from 60 to 50 at wot. I knew it was dropping afterwards cause my tuner said it was normal. But i've been reading that it shouldent get below 45? Why would it be rock solid then start dropping. Im befuddeled.
Any help will be appreciated, indeed. Sorry for the long azz post.
Cliff notes: fuel pressure was steady at 60 for 15,000 miles now it drops from 60 to 50 at wot with 8lb boost .
Any help will be appreciated, indeed. Sorry for the long azz post.
Cliff notes: fuel pressure was steady at 60 for 15,000 miles now it drops from 60 to 50 at wot with 8lb boost
.Pretty sure I have your answer, or at least something close. I saw my STS was falling on it's face after 3+PSI w/ a Racetronix and 42lb injectors. The deal is as the boost builds, the injectors have to work harder to push the boost into a cylinder that's above atmospheric pressure. This places additional load on the injectors and decreases the pressure output. That's where a boost referenced fuel pressure regulator comes into play. A boost referenced regulator adds 1PSI of pressure for each lb of boost to compensate for this.
The in-tank regulator is not boost referenced. You also do not a a return style fuel system, which adds to this problem. (no LS1's have a return system...at least not till you modify it.)
And that's how you fix the problem. Make a return system. I have zero feul pressure issues since. Look at the thread below. I wrote down all the crap that is needed to do this:
https://ls1tech.com/forums/showthrea...sure+regulator
Anyhow, this might be of help to you. Good luck.
Originally Posted by Schantin
Pretty sure I have your answer, or at least something close. I saw my STS was falling on it's face after 3+PSI w/ a Racetronix and 42lb injectors. The deal is as the boost builds, the injectors have to work harder to push the boost into a cylinder that's above atmospheric pressure. This places additional load on the injectors and decreases the pressure output. That's where a boost referenced fuel pressure regulator comes into play. A boost referenced regulator adds 1PSI of pressure for each lb of boost to compensate for this.
The in-tank regulator is not boost referenced. You also do not a a return style fuel system, which adds to this problem. (no LS1's have a return system...at least not till you modify it.)
And that's how you fix the problem. Make a return system. I have zero feul pressure issues since. Look at the thread below. I wrote down all the crap that is needed to do this:
https://ls1tech.com/forums/showthrea...sure+regulator
Anyhow, this might be of help to you. Good luck.
The in-tank regulator is not boost referenced. You also do not a a return style fuel system, which adds to this problem. (no LS1's have a return system...at least not till you modify it.)
And that's how you fix the problem. Make a return system. I have zero feul pressure issues since. Look at the thread below. I wrote down all the crap that is needed to do this:
https://ls1tech.com/forums/showthrea...sure+regulator
Anyhow, this might be of help to you. Good luck.
Last edited by JMBLOWNWS6; Oct 15, 2006 at 01:01 PM.
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From: Ft. Irwin, California (But Virginia is home)
Originally Posted by JMBLOWNWS6
LOL In the inside of the bucket there is a return. It is off the T right under the body passanger seat drivers side! This is the one that people cap off for the stock line for a return. Now Im not saying your wrong or anything. But the system does have a regulator there.
Correct me if I'm wrong, but the reason I heard it's called a non-return system is bacause AFTER the T-block the fuel goes one-way to the engine and fuel rails....and does not return to the tank from there. The return system runs through the rails and then all the way back to the tank. An LT1 has this latter set-up. So do 97 vettes if I remember correctly.
Anyhow.....the ideas is that regulating the fuel right after the rails vs before the fuel ever gets to the engine allows for greater control of the fuel pressure. I'm pretty sure I'm correct on this. I just might have explained this like a retard!
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Verdad Gallardo No your right. But I have had a car we tought the dam fuel pump was bad and it ended up being this. I do agree with the injectors though. I had to upgrade from 42's to 50' to 60's LOL. So I did learn the hard way.
Thanks abunch Schantin and JM, this sounds like it. I know now that I need a bigger injector (wish I'd gotten em first) and am gonna get this thing fixed before I blow something up asap. LOL... I appreciate all the help guys!
If you have a bascially stock LS1 with an ATI ProCharger at 8 psi, the 42lb injectors will be plenty big enough. Once you forge the bottom end and go for more boost, you will want to upgrade to 60lb injectors.
The price on 60lb injectors has dropped to the point where we now use them for all of our installs, that way a customer won't be having to sell off his 42's when he goes for more boost. Since you already have the 42's, I'd continue to use them. 42's are what ATI supplies the LS2 ProCharger kits with, fyi. Bob
The price on 60lb injectors has dropped to the point where we now use them for all of our installs, that way a customer won't be having to sell off his 42's when he goes for more boost. Since you already have the 42's, I'd continue to use them. 42's are what ATI supplies the LS2 ProCharger kits with, fyi. Bob
) lol 
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If pressure drops with load your system is down on volume. If its due to an internal plumbing leak then that's easy enough to fix. If you're running two pumps inline then I suggest you look into the ground on the framerail pump and consider servicing your filter. Adding a boost referenced FPR will exacerbate your problem as the pumps will have an even harder time making enough volume at the higher pressure.
When I had the racetronix installed I made sure to change the fuel filter. I'll look at the ground wire. Nothing seems to be leaking nor is there a strong oder of fuel, like the last time. Just making sure that 60 to 50psi under max boost 8lbs wont blow stuff up. Still cant figure out why pressuer was Rock solid at 60 for approx. 15,000 mi. at any rpm and boost then started to dip.... that is when I had the racetronix installed but still same issue? My tuner did a wideband and said all was well, even managed to squeeze out a few more ponys.
