TJ/LJ LS conversion fuel system question

LBarr2002

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Nov 16, 2009
Location
SC
I'm unsure of what I should leave from the stock jeep fuel system when I go to the 5.3.

The jeep has 3 hard lines from the rear. One is supply from the tank. The other two come from the canister in the rear fender well and go to engine vacuum and the purge solenoid.

My engine is an LM4, with return style fuel rails. I have the novak fuel pressure regulator bypass to use the in tank pump. My plan is to use the supply line from the tank and adapt it to the stock LS rail. Return I'll just run a new line and drill/tap a barb in the pump housing. My question is about the evap lines. What do I need, what should I leave, or can I simplify things? I'd like to cap it all off but the tank needs some kind of vent, correct?

I think I could leave it all in place, and since I'm leaving the jeep harness and computer, the purge solenoid could even be hooked up, but will it do anything?
 
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LBarr2002 said:
I'm unsure of what I should leave from the stock jeep fuel system when I go to the 5.3.

The jeep has 3 hard lines from the rear. One is supply from the tank. The other two come from the canister in the rear fender well and go to engine vacuum and the purge solenoid.

My engine is an LM4, with return style fuel rails. I have the novak fuel pressure regulator bypass to use the in tank pump. My plan is to use the supply line from the tank and adapt it to the stock LS rail. Return I'll just run a new line and drill/tap a barb in the pump housing. My question is about the evap lines. What do I need, what should I leave, or can I simplify things? I'd like to cap it all off but the tank needs some kind of vent, correct?

I think I could leave it all in place, and since I'm leaving the jeep harness and computer, the purge solenoid could even be hooked up, but will it do anything?
Click to expand...

Watching this too...wife went 5.3 with hers an it has a hard time starting sometimes. She was told that the Jeep fuel pump can’t supply enough to the LS. An that she needed some new kinda fuel kit...I started tuning the guy out cause I think he’s a bag of dongs but it’s her brother... a 20 year old Chevy mechanic that’s got 40 years experience
 
Ibayne said:
Watching this too...wife went 5.3 with hers an it has a hard time starting sometimes. She was told that the Jeep fuel pump can’t supply enough to the LS. An that she needed some new kinda fuel kit...I started tuning the guy out cause I think he’s a bag of dongs but it’s her brother... a 20 year old Chevy mechanic that’s got 40 years experience
Click to expand...

What year jeep and what was done to the fuel system? Mine is an 04 so that's what I was focussing on in my research, but I believe I read 05-06 stock pump can support it. The 04 pump is in tank regulated to 60 psi, which is not enough. The novak regulator bypass eliminates that.
 
LBarr2002 said:
What year jeep and what was done to the fuel system? Mine is an 04 so that's what I was focussing on in my research, but I believe I read 05-06 stock pump can support it. The 04 pump is in tank regulated to 60 psi, which is not enough. The novak regulator bypass eliminates that.
Click to expand...
Hers is 98
 
Ibayne said:
Watching this too...wife went 5.3 with hers an it has a hard time starting sometimes. She was told that the Jeep fuel pump can’t supply enough to the LS. An that she needed some new kinda fuel kit...I started tuning the guy out cause I think he’s a bag of dongs but it’s her brother... a 20 year old Chevy mechanic that’s got 40 years experience
Click to expand...

Jeep fuel pump is plenty for an LS Swap, I have done 2 TJ swaps one with a 4.8 and the other with a 5.3, both still running on stock TJ fuel stuff with the Chevy ecm tuned good


Get rid of all the evap crap, it’s not needed, run a good vented fuel cap
 
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