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5.3 swap fuel system question.

9

92xjRJ

NAXJA Forum User
Location
Arroyo Grande, CA
So I am in the very beginning stages of this swap I have a 93 xj country. And the swap motor is a 2006 L59 and my question is since this motor runs on slightly lower fuel pressure then the non flex fuel models would the inline corvette filter/regulator still work or would I have to find another way?
 
The L59 has the regulator at the tank correct? If so then yes, you would need to regulate it differently, my advise too you is install an adjustable regulator on your firewall so that way you can use the Jeep fuel lines (feed and return) and have the regulator in an easy to adjust spot. Then you only need a foot or two of fuel line from the regulator to the fuel rail.
 
clydefrog said:
The L59 has the regulator at the tank correct? If so then yes, you would need to regulate it differently, my advise too you is install an adjustable regulator on your firewall so that way you can use the Jeep fuel lines (feed and return) and have the regulator in an easy to adjust spot. Then you only need a foot or two of fuel line from the regulator to the fuel rail.
Click to expand...


yeah the L59 has the at the tank regulator, so i would run that inline with the vette filter? or just run the adjustable one at the firewall? Run the stock lines and pump? thanks for the input!
 
92xjRJ said:
yeah the L59 has the at the tank regulator, so i would run that inline with the vette filter? or just run the adjustable one at the firewall? Run the stock lines and pump? thanks for the input!
Click to expand...
Mine will be at Pismo in a couple of months if you want to check it out.
 
No need for the regulator at the firewall. Buy the corvette filter/regulator and run a walbro 255 pump. If you have issues with too much fuel, just have someone tune it out via HPT. This way you only have to run a single line to the rails and you deadhead the fuel rails.

You are going to have to flash the PCM anyway and pay someone to do it, so may as well get a decent bump in power/driveability while you are there.
 
the_midwesterner said:
No need for the regulator at the firewall. Buy the corvette filter/regulator and run a walbro 255 pump. If you have issues with too much fuel, just have someone tune it out via HPT. This way you only have to run a single line to the rails and you deadhead the fuel rails.

You are going to have to flash the PCM anyway and pay someone to do it, so may as well get a decent bump in power/driveability while you are there.
Click to expand...


Hmm ok I'll have to look into that. The only thing holding me back is the fact that I just replaced the fuel pump and would rather not do it again.
 
The stock fuel pump simply won't flow enough volume. You can get by on your pump for starting it and idling around, but when you get into heavy loads, your long fuel trims will start to go positive. Look around at all the guys that have done LS swaps. Most if not all end up upgrading their pump to not risk leaning out. Some of the real late model guys may get by with it, but I'm sure they are having to run positive long fuel trims to compensate. You are also pre-97, which was the change to the higher flowing pump. I used a post 97 pump, but still had to upgrade to a walbro 255.
 
the_midwesterner said:
The stock fuel pump simply won't flow enough volume. You can get by on your pump for starting it and idling around, but when you get into heavy loads, your long fuel trims will start to go positive. Look around at all the guys that have done LS swaps. Most if not all end up upgrading their pump to not risk leaning out. Some of the real late model guys may get by with it, but I'm sure they are having to run positive long fuel trims to compensate. You are also pre-97, which was the change to the higher flowing pump. I used a post 97 pump, but still had to upgrade to a walbro 255.
Click to expand...

Damn alright lol I guess I'll be adding that to the list. I appreciate it!
 
The stock pump (if you have the metal tank which you do in your '93) the stock pump flows more than enough. You should get close to 70-80 psi out of it and you only need 60 psi for the motor you have. I don't know about the volume that the stock pump will do but you should be more than fine. I would def get a new pump though (at least I did). My fuel trims are fine and even at WOT pulling a grade I 'might' see positive fuel trims climb to 2-3 which is not a concern. If other people have had issue though then maybe a Corvette setup is better? I am one person though and the stock setup on my '87 is more than adequate and still is.
 
mine was running fine with the stock 96 pump.

i only changed it to a 255 because it was on the shelf, and i had the gas tank out for other shenanigans
 
So from what I have been reading is that the L59 requires 55-62psi, and does not require a zacuum as fuel pressure remains constant through out all loads. So I think I'll just give it a go at first and then if it doesn't work it's not to hard to drop the tank and throw a new pump in. Thanks for all the input guys it's more then helpful!
 
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