Post your efi/4.0 swap conversion questions here

[ericarmstrong]

I was considering running  a low psi 50gph carb pump back at the tank and the high pressure pump just before, if not under, the engine bay. I figure this way I'll only need the small length of EFI line I have hooked to my TBI setup(saving $$$).  I was going to use the factory AMC fuel sending line as my return. If what I've read is correct the return line is fairly low pressure.

[shanebo]

is that EFI fuel line expensive?

[tougeagle]

I was considering running  a low psi 50gph carb pump back at the tank and the high pressure pump just before, if not under, the engine bay. I figure this way I'll only need the small length of EFI line I have hooked to my TBI setup(saving $$$).  I was going to use the factory AMC fuel sending line as my return. If what I've read is correct the return line is fairly low pressure.

The return line is low pressure. EFI hose isn't that expensive, and you'd be spending more money and possibly stealing pump amperage by using an additional pump. Back at the tank, you only need about 3 - 4 feet to make it all work. It's 4-6 dollars a foot.

[ericarmstrong]

If I run new lines it will be stainless steel efi line. I think metal required for inspection here, and wont settle for less than stainless if im going to bend custom lines. Last time i looked steel efi line was costly. I'll probably end up doing that this the end, but figured i could use this pump i have on my bench to save a buck or two. I hope the grand cherokee alternator has enough juice to push a carb pump as i have lots of electronic "toys" hooked up already.  If my budget forces me to i could always transplant some of the GC's metal line.  What i overlooked with my origonal idea was that i will haved to add a line to handle the higher gph feed. I still like the carb pump idea as a "primer" for the efi pump. This carb pump sucks and the efi pump i have is a pusher.

[tougeagle]

If I run new lines it will be stainless steel efi line. I think metal required for inspection here, and wont settle for less than stainless if im going to bend custom lines. Last time i looked steel efi line was costly. I'll probably end up doing that this the end, but figured i could use this pump i have on my bench to save a buck or two. I hope the grand cherokee alternator has enough juice to push a carb pump as i have lots of electronic "toys" hooked up already.  If my budget forces me to i could always transplant some of the GC's metal line.  What i overlooked with my origonal idea was that i will haved to add a line to handle the higher gph feed. I still like the carb pump idea as a "primer" for the efi pump. This carb pump sucks and the efi pump i have is a pusher.

make sure you use flexible line between engine and body. You can fuel line right off a 96 and up Cherokee, and just bend the steel sections how you need it, the rest is braided and would snap right onto the fuel rail. the problem is not the alternator getting juice to the pump, it's the fuel pump relay and fuse itself, both limited to 20 amps, which cannot be changed. You don't want to take amperage away from your EFI pump. EFI pumps are good enough that they do not need a pusher pump. Your engine will not make nearly enough horsepower for a pusher pump to be of any use... most efi cars these days do not have pusher pumps unless they have dual tank setups or something. You will be fine with the stock 5/16" feed... your engine won't make nearly enough power for you to need more than that. If you were in the 4-500 hp range, that would be a different story. I have an 87 gph fuel pump, and it's totally overkill, but I got it because i plan to eventually turbocharge my car and will need some extra flow. What is listed in the writeup is what you need, any modifications to the fuel line or system beyond that are honestly just wasted cash, it won't makea  difference.

[ericarmstrong]

If I ran the carb pump it would be  wired to a separate dash switch, fuse, and relay (like my TBI pump is now). It adds a sort of kill switch option.  The pump I was going to use was based on a inline ford setup and originally came with a primer pump in the tank. I only chose it to save $$$ and may change my mind. Why do you specify 96 and up cherokee line as opposed to the 94 grand line I'm working with?

[tougeagle]

If I ran the carb pump it would be  wired to a separate dash switch, fuse, and relay (like my TBI pump is now). It adds a sort of kill switch option.  The pump I was going to use was based on a inline ford setup and originally came with a primer pump in the tank. I only chose it to save $$$ and may change my mind. Why do you specify 96 and up cherokee line as opposed to the 94 grand line I'm working with?

If that 94 grand line is braided, you can use that too. I specified 96 and up xj because i know xj line is braided at that time.

[shanebo]

Hi Toug,

What would you recomend for a good all around fuel pump...and also what injectors are you running in caroline.

Thanx
shane

[shanebo]

I was also meaning to ask you too...Are there any junk yards near you that might have the desired xj computer?

I could drive up there to get it...And I was wondering...If I throw you some cash for gas and time ya think you could acompany me in pulling the computer out? I just know Ill screw something up or leave something behind if I dont have a knowledgable watchful eye....I know your super busy...and Im in no rush..I just want to get this right the first time

Thanx
shane

[tougeagle]

I was also meaning to ask you too...Are there any junk yards near you that might have the desired xj computer?

I could drive up there to get it...And I was wondering...If I throw you some cash for gas and time ya think you could acompany me in pulling the computer out? I just know Ill screw something up or leave something behind if I dont have a knowledgable watchful eye....I know your super busy...and Im in no rush..I just want to get this right the first time

Thanx
shane

the fuel pump i use is a "replacement pump" for Edelbrock performer EFI kits, 87 gph, 220 shipped from summit, and I was surprised to find it's a Walbro. You'd be fine with a Bosch pump mentioned earlier, what I have is overkill for my current application but I have plans to eventually turbocharge mine once I'm out of school and I had to get another pump anyway. You need a pump that pushes 70-90 psi, at least 50 gph to be on the safe side. The less the pump has to work to keep pressure at the rail, the better.

I use 24lb/hr Ford Racing fuel injectors, Bosch design III (full plastic) injectors that use the older style (more common) injector clip, same kind of clip you'd find on any cherokee 91-20??. Mine may be just a bit undersized, but I am running a 2.5" exhaust with a cherrybomb and no muffler, and .030 pistons. I have to run them at 50 psi. Unless your engine is overbore, you should be fine with 24-26lb/hr.

it's very rare to come across a 94 or 95 cherokee with a manual and engine wiring harness/computer in a yard around here. Most of them within hours of hitting the yard get engines and drivetrains yanked, my assumption is probably from CJ crowd or something. You'd have an easier time going to www.car-part.com. Just make sure to specify automatic or manual when looking because there is a difference in wiring, though slight. Though, if you do find a yard on car-part or through phone calls in the denver/north front range area, lemme know and I will find a day to come and help you. I can generally ask for mondays off from the shop if my boss doesn't have anything planned in advance. I would love to help you do it, but you def will need to locate one first...

[shanebo]

Thanx Toug!! Ill start looking for a jeep here in a few weeks....I got alot of stuff to get before I am at the computer point. Ill let ya know way in advance.

 

[shanebo]

Before I start looking I got one more question Since I have the stock automatic do I need to get a computer wired for the automatic?

[mudkicker715]

No sich thing for an eagle.

[IowaEagle]

Our transmissions are totally mechanical.  I guess the throttle rod is the only part that is not actually part of the transmission but a very necessary component.

[shanebo]

Thats a load of my mind!!! Thanks!!!

Should I try to find a jeep with a standard tranny for my computer to avoid the excess wiring the automatic will have?....Sorry Im so full of questions...Im venturing into uncharted territory