Topic: 4 banger transplant. Need some tech advice/info

[Jeffy]

Well after doing some digging I think I might just get another tank thats correct for my wrangler. I'm not overly concerned about the volume of the tank, would be nice but not absolutely necessary, especially if I can fill it and not have it leak all over the place 

I just dont know if I trust the high pressure pump in there, I wheel some remote places and would HATE to have some kind of technical issue I couldnt solve and be stuck somewhere!

I can always carry a spare gerry can of gas though!


So on that note whats the best deal any of you know on a poly 15gal tank for TBI era Yj?s I'm seeing around 120 or so..

What's the cost of the new tank going to be vs. going with an external electric pump?

[Backroads]

But wouldnt that make the external work harder pulling through the existing pump? Or is there a different way to seal the tank or what?

I'm kind of out of my element with doing something custom.

[Jeffy]

But wouldnt that make the external work harder pulling through the existing pump? Or is there a different way to seal the tank or what?

I'm kind of out of my element with doing something custom.

Nope, the external pump won't see the tank pump.  It's commonly done.

[Backroads]

Sorry, what do you mean wont see it? As in it wont make a difference, it wont strain it any harder. Or its plumbed up differently and my pump line and return line are routed differently into the tank?

[Jeffy]

Sorry, what do you mean wont see it? As in it wont make a difference, it wont strain it any harder. Or its plumbed up differently and my pump line and return line are routed differently into the tank?

It will pump as if the old pump isn't there.

[Backroads]

Understood.

Looks like inline fuel pumps for something descent is getting close to 100 bucks...

After reading up on the jeepforum links I PMed the one guy to see how he worked his out using the MPI pump and adding a check valve. If its free in the meantime I might give that a shot. I've got all the parts sitting out there!

[chardrc]

mpfi guys isn't the check valve for your jeeps in the tank/ pump somewhere? because if it is there shouldn't be the check valve problem a guy in the one link was worried about.

[Backroads]

It said in those threads that stock TBI pumps have the check valve in the pump itself. MPI model pumps have the check valve at the fuel rail. So with the MPI pump on the TBI its gonna flow fuel to the injector on key on position, but theres nothing to keep that fuel from running back to the tank after the initial prime until it starts and is constantly running.

The one guy was just saying his was taking a while to start. There never really was an end all outcome to ether thread so who knows if they are still even running that setup.

[chardrc]

idk for sure but i thought I've read about mpfi guess having check valves go bad and having to dig into the tank making me not 100% convinced that the checkvalve is in the fuel rail...

as Sharpxman said in another thread on the forum (when talking about jfrabat's 94yj)

it's either the FPR or the check valve in the pump. if it's all sound should hold pressure overnight or at least not bleed out completely (there should still be pressure the next day, but at a minimum if it holds some pressure for at least couple of hours should be fine)

someones wrong.. but i don't know who.. lol

[Backroads]

I get what your sayin. Common XJ problem too. My XJ is actually getting like that. Where if it sits overnight it will crank and crank and sometimes not even fire. if I stop and start again it fires halfway through the first crank...

I'd be curious which one is right!

[Backroads]

Found this thread, guy claims it was on the pump (on top of).

http://www.wranglerforum.com/f5/check-valve-instead-of-fuel-pump-61631.html

[chardrc]

i actually looked at that thread earlier today. but that setup is more like the tj set up with the fpr on the tank. mpfi yj's had the fps on the fuel rail. and vus had a return line which the tbi needs.

[Jeffy]

mpfi guys isn't the check valve for your jeeps in the tank/ pump somewhere? because if it is there shouldn't be the check valve problem a guy in the one link was worried about.

Only on TJ's and later.  On a YJ it's on the rail.

[dwtaylorpdx]

I don't see a problem, the MPFI pump is going to be moving the
same amount of fuel as it was designed for, I'd just put a adjustable
fuel regulator in, it will run better most likely because the stock one is kinda week.

AS far as heating the fuel, the HP pump and the lower pressure pump both add
heat to the fuel, but not near as much as the pipe in the engine bay does...
And isn't eh fuel pressure at operation only about 15PSI different? Mine is 39 lbs on my MPFI.
its like 14 lbs for the TBI, as I recall. A full bypass adjustable regulator would be the ticket...

The strainer in the fuel tanks needs to be changed every 90 to 100K unless you
do like I did and chase gremlins for 20K miles before I swapped the strainer and
the problem went away....  Of course I also found the pump was being
pushed against the bottom of the tank.... Pressing the strainer into the inlet of the pump.

Oh well just more from the peanut gallery....

Dave

[sharpxmen]

I don't see a problem, the MPFI pump is going to be moving the
same amount of fuel as it was designed for, I'd just put a adjustable
fuel regulator in, it will run better most likely because the stock one is kinda week.

AS far as heating the fuel, the HP pump and the lower pressure pump both add
heat to the fuel, but not near as much as the pipe in the engine bay does...
And isn't eh fuel pressure at operation only about 15PSI different? Mine is 39 lbs on my MPFI.
its like 14 lbs for the TBI, as I recall. A full bypass adjustable regulator would be the ticket...

The strainer in the fuel tanks needs to be changed every 90 to 100K unless you
do like I did and chase gremlins for 20K miles before I swapped the strainer and
the problem went away....   Of course I also found the pump was being
pushed against the bottom of the tank.... Pressing the strainer into the inlet of the pump.

Oh well just more from the peanut gallery....

Dave

flow of the pump increases when you lower the pressure

there's already an adjustable FPR on the TBI

39-14=25