LS Fuel Pressure?

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bobdog

4x4 Addict!
Location
Sandy
I have a 6.0 LQ4 LS in my Jeep controlled by a Holley Terminator X Max computer. It has a non adjustable regulator and a return to tank.

When I bought it ran an inline pump and ran 60 PSI. I had fuel pressure issues in Moab a few weeks ago and was towed out. I hate being that guy.

I have replaced the inline pump with a 2 pump in tank unit using a switch to run one pump at a time and keeping the other in reserve as a spare. The pumps are 340 lph each which is more than the engine should ever need.

I now have 64 to 65 PSI. Should I even worry about this? The Jeep runs great. I hate to buy a new regulator if I don't have to but will if I have too.

Thanks for any advice or opinions. This is my first LS series engine. Im learning as I go.
 
Greg

Greg

I run a tight ship... wreck
Admin
Location
Grand Junction, CO
Most guys use the Corvette filter/regulator that is set at 58 PSI, which has a return line for excess fuel. They're super common and pretty cheap @ $60-80 IIRC. I've used them on a few LS swaps.

hotrodfuelhose.com

Corvette style filter/regulator with AN6 adapter fittings

Corvette style fuel filter & pressure regulator. These corvette style regulators are most often used for completing an LS swap with a return-less style fuel rail. Use this regulator with AN adapter fittings to successfully install your LS Return-less engine into any project. This OEM spec...
hotrodfuelhose.com hotrodfuelhose.com
 
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bobdog

4x4 Addict!
Location
Sandy
Basically what I have now except mine is a Holley unit. Me googling this morning comes up with the same issue as I have using that regulator.
I’m wondering whether the 5 more psi is a problem.
 
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bobdog

4x4 Addict!
Location
Sandy
It says it is good for 110 gallons per hour. One of my pumps should be 90 GPH. What I have should work but maybe not.
 
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bobdog

4x4 Addict!
Location
Sandy
Greg said:
Most guys use the Corvette filter/regulator that is set at 58 PSI, which has a return line for excess fuel. They're super common and pretty cheap @ $60-80 IIRC. I've used them on a few LS swaps.

hotrodfuelhose.com

Corvette style filter/regulator with AN6 adapter fittings

Corvette style fuel filter & pressure regulator. These corvette style regulators are most often used for completing an LS swap with a return-less style fuel rail. Use this regulator with AN adapter fittings to successfully install your LS Return-less engine into any project. This OEM spec...
hotrodfuelhose.com hotrodfuelhose.com
Click to expand...
This one is only rated for 255lph. It would probably be much worse
 
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bobdog

4x4 Addict!
Location
Sandy
I should mention that the AFR is 13.5 to 14 at cold startup. When it warms and goes closed loop the computer should keep everything tuned correctly? I really don’t think I should have issues but I am slightly concerned about running on the edge or maybe a little over with the regulator I have
 
Greg

Greg

I run a tight ship... wreck
Admin
Location
Grand Junction, CO
Where are you seeing 64-65 PSI? Gauge on the fuel rail? That Holley regulator you linked to is set to 59.5 PSI, if you're seeing higher pressure than that past the regulator, I'd replace it as it seems to have failed.
 
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bobdog

4x4 Addict!
Location
Sandy
Holley terminator has sensor at rail and displays it on screen. I’m pretty sure regulator has not failed. I believe it is probably just over its flow range. Pressure is a constant 64 psi. It is actually much more stabile than before under any throttle position. It varied a few psi with the old pump. The engine is maintaining AFR perfectly. Any reason 5 psi high is a deal breaker
 
85CUCVKRAWLER

85CUCVKRAWLER

Active Member
Location
Tooele
5 psi is not a deal breaker. Generally, youre supposed to be at 60 all the time, as thats what the LS needs. Anything below 55 will be an issue. That holley sensor is probably just off a few psi +/-.
 
NYCEGUY01

NYCEGUY01

Well-Known Member
Location
Willard, UT
In all my swaps I use an adjustable regulator that’s probably overkill but I like setting it where I want.
I always just set them right at 60.

As far as 14 afr at idle or cruise with little load that’s fine, your extra few psi won’t be an issue either.

Your learn tables are probably showing some corrections going on with the higher pressure now compared to before but in time it will slow down if you are still allowing it to learn. I like to lock it down pretty good after I get the fuel tables set where I’m happy.
 
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bobdog

4x4 Addict!
Location
Sandy
85CUCVKRAWLER said:
5 psi is not a deal breaker. Generally, youre supposed to be at 60 all the time, as thats what the LS needs. Anything below 55 will be an issue. That holley sensor is probably just off a few psi +/-.
Click to expand...
I have concidred the sensor being off and maybe the old pump being a little low on pressure. I should install a manual gauge.
 
85CUCVKRAWLER

85CUCVKRAWLER

Active Member
Location
Tooele
bobdog said:
I have concidred the sensor being off and maybe the old pump being a little low on pressure. I should install a manual gauge.
Click to expand...
every sensor is going to be off a few psi +/- its just the physics of it. You can put an analog gauge in to double check everything. But, who cares a few psi give or take at 60+?
 
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