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General Forums => The Mess Hall => Topic started by: Backroads on October 11, 2010, 07:52:11 PM
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New to the forum, just got into a 90YJ and decided here would be a good place to NOT hear people tell me to just do a 4.0 or 350 swap :thumbsup:
As I said, its a 90 yj, 5 speed, 231. Got it from a friend who hyrdolocked it, then as most jeeps do...it threw a rod a month or so later and did this...
(http://i413.photobucket.com/albums/pp218/BackroadsXJ/YJ/DSC03015.jpg)
so the hunt was on for a swap. Another buddy of mine just happened to have a 93 YJ tub sitting in his yard, with a good 2.5 sitting in it. The past few weeks I've pulled the old 2.5, and cleaned everything up. Got the donor 2.5 ready to be lifted out as soon as I can get back to work on it.
So it brings up a couple issues, I'm hoping someone can help me with....but before I say that I want to state this project is #1 priority is to get it back on the road and reliable...asap. I'm not really interested in or have time right now to get into a drawn out build (or I probably would have gone 4.0 or 350...)
I was planning to reuse the original trans, clutch and flywheel on the new engine (I know for a fact everything is good, and was driving a month ago) Will the 93 bolt up to the 90 trans with no problem? No spline differences or anything?
If I was going to convert to FI, do I need to swap out the dash harness to work with the FI engine harness or will that plug into the firewall at the fuse panel without modification? (I have both dash harness' but the donor has some stuff cut off :eek:
What other issues am I going to have to deal with?!
Thanks for any help!
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If the donor is complete you might as well grab everything off it and convert it to MPFI. You will want to swap all of the engine harness and probably the dash harness as well. Some things are different. electrical speedo, no clock, etc... Grab his gauges as well. Grab his gas tank and fuel pump, grab his emissions, etc...
You can use your transmission if you want to. It will bolt right up. Basically swap everything till it runs.
Otherwise swap your intake on the donor and keep it TBI.
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Thats my hangup. The donor is about 85% there. No gauges, interior etc. Old rotten fuel lines and everything in the rear.
But good to know about the trans, at least I know I can get the engine in place, then figure out what to do with my wiring and emissions stuff.
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Thats my hangup. The donor is about 85% there. No gauges, interior etc. Old rotten fuel lines and everything in the rear.
But good to know about the trans, at least I know I can get the engine in place, then figure out what to do with my wiring and emissions stuff.
The fuel lines should be hardlines from the firewall to the back tire. Then it goes into the fuel filter and then a rubber line. From the firewall it should be hard plastic.
For the gauges you could probably reuse your harness. You would want to check the pin-outs so the right gauges get the right signal. The clock on the last gauge was replaced with a 4WD indicator in the first slot and all the other gauges moved down. Your speedo is manual and the PCM will need to see the speedometer signal to run properly. Swapping the sender for a electronic one is simple. For the main dash gauges you could go aftermarket.
Also if the tank is there you could do a 20 gallon conversion if it's not a 20 gallon to begin with. If you have a 15 gallon tank in yours it will look tiny in comparison. If you have a 20 gallon tank or want to keep your existing tank, you could add an inline fuel pump and mount it on one of the crossmembers. This will pull through your old pump.
Overall, I think parts should be easy to come by as they are old and people don't really want them.
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Thanks a lot for all your help! I got the other engine home last night, so now I get to finally start putting things back together. I was looking into new mounts, but I see they offer (quadratec anyways, its about 30 mins from my house) 2 different mount kits for a 2.5 YJ. 87-90, and 91-95.
Being that I'm putting a 93 engine into a 90, which kit do I use? and whats the difference. They look identical in the pictures...
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It probably doesn't matter as long as the engine is in the same place. If you can snap some pics of your mounts and we'll be able to compare them with the new ones.
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did you do block damage? I blew the block and took out the came and front cover at the same time when my blew!!
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I'll have to get pics of the mounts....but they are all literally destroyed..
but ya, many holes in the block! more pics of the blow up
(http://i413.photobucket.com/albums/pp218/BackroadsXJ/YJ/DSC03014.jpg)
didnt see this one til I took off the PS pump!
(http://i413.photobucket.com/albums/pp218/BackroadsXJ/YJ/6b1aee3f.jpg)
and the last one, and actually with a shot of the mount on the 90 2.5
(http://i413.photobucket.com/albums/pp218/BackroadsXJ/YJ/DSC03019.jpg)
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Gonna bring this one back, The swap is now complete and after working out last weeks bugs (http://4bangerjp.com/forums/index.php/topic,9114.0.html)
Ive found I had a leaky tank, which I suspected was the fuel pump gasket...which it was NOT. Its the older 14.5 gal steel tank.
Now when i got the engine (93 era FI) I got the tank and pump as well. Its the larger 20gal plastic tank. It looks like it should bolt up no problem, has similar outputs on the fuel pump. Just a slightly different vent setup.
My question is, can I use this tank and pump on my TBI engine? (i left it TBI when I did the swap) Or is the pump not right or any issues there?
Also, the wires on the pump in he 20gal tank are cut, can I just splice my old plug into them?
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take a look at these:
http://www.jeepforum.com/forum/f12/tbi-vs-mpi-fuel-pump-compability-1080029/
http://www.jeepforum.com/forum/f12/metal-plastic-fuel-tank-swap-1088945/
if i remember correctly the gist of it is that tbi will work with the mpfi tank and pump but you have to make sure your fpr is still providing the injector with the correct pressure (may need adjustment)... (read the threads i was looking at doing the same thing end of the summer when my metal tank sprang a leak but i patched it as i had to start concentrating on school)
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like chadrc said, the pump should work but you need to adjust the pressure (or at least verify it). The downside is that you will move way more fuel than you need and will heat up the fuel as well - since you will be running lot less pressure the flow will increase substantially, will bleed off the return though but will have the downside i mentioned. One thing you might run into is the lack of adjustment at idle due to increase flow which might result in lack of pressure at top power, what i mean by that is that when you need minimal flow you will adjust the regulator too low due to backpressure thru the return orifice of the pressure regulator and when running at top power to not have enough spring weight on the regulator to keep the pressure you need since the flow thru the return will be less - you'll have to try and see if that's the case or not
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Thanks for the comments guys....I understand what your both saying, gonna give the links a look at take it from there.
I'm assuming there is no TBI style pump that fits the newer style tanks?
I'm not so much worried about the size of the tank, I just happen to have 2 spare plastic tanks that are of the 20gal flavor :hump: I'll report back with my findings..
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I haven't looked at the pumps but you might see if you can swap the fuel pumps. Not the fuel pump assemblies but the pumps. Otherwise you could omit the pump all together and run an external pump.
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I haven't looked at the pumps but you might see if you can swap the fuel pumps. Not the fuel pump assemblies but the pumps.
that wont work. the tbi pump is too big to fit the mpfi sender.. its covered in one of those links.
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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 :brick:
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..
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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 :brick:
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?
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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.
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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.
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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?
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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.
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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!
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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.
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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.
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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
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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!
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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
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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.
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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.
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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.... :brick: 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. :eek:
Oh well just more from the peanut gallery....
Dave
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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.... :brick: 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. :eek:
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
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So you all think some sort of inline check valve should be installed on the supply line to keep fuel in the line after the initial prime...
What about FPR then? Adjust the stock one down and see where it ends up or just go with an adjustable right off the bat.
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So you all think some sort of inline check valve should be installed on the supply line to keep fuel in the line after the initial prime...
What about FPR then? Adjust the stock one down and see where it ends up or just go with an adjustable right off the bat.
the stock one is adjustable so you don't need another one. A Mallory for example would have a larger return valve and that would def work better to offload the extra flow but you can always add that later if you run into that issue.
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First thing I'd do is see if I can blow air backwards through the pump,
What does the Rail check valve look like, I have a Regulator on the rail,
is the regulator acting as a check valve? Cause there is no other part on
mine that could be a check valve and the rail has nothing on it I've looked
through it before...
Yep I dropped some numbers on the math.
When you look the MPI
pump up on the NAPA web page its a similar style pump to the pics for the TBI pump.
I really believe you could simply shorten the pipe that eh MPI pump is hose clamped to
and install the TBI pump and strainer. The napa web page has a picture of the MPI
fuel pump and gauge sender assembly and you can see how it would work.
I think its a easy fix.
Dave
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nice work :thumb:
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Thanks for seperating, I guess I should still update here since I cant reply in the FAQ thread?
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Well I just dont get it :puzzled:
'new' pump setup is in, new soft lines from the pump to the hardlines on the frame. Everything seemed kosher...but of course it didnt work!
I only put a few gallons of gas in it, because after all the siphoning of gas I've done through this whole ordeal is literally making me sick, I didnt wanna have to pump it back out!
Despite all that my fuel gauge is reading 3/4 of a tank!!!
So I found this statement in searching
'The fuel level range is different resistance so it will require some mods to make them read correctly but you should be able to use the assembly in the poly tank and make it work'
I'm guessing thats part of the problem.
Second, it runs like complete crap. It was running fine before any of this, it just leaked.
It started right up, but just runs really rough, if I give it throttle, it idles up but never really smooths out. Its kinda hot rod-ish.
I've got 2 sources to test before I'm officially out of ideas.
The tank I put in had 2 'rollover' check valves coming off of it with a vacuum line T'd between them. I ran that line to my evap canister. wrong?
MAYBE my fuel filter is clogged, or something. I can see it spraying fuel in the throttle body though so I dont know about that.
any ideas?
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i can think of 3 things
1. you mixed the pressure and return lines
2. your pump sits too low and pressed on the bottom of the tank and you don't get enough pressure
3. your return is too low in the tank and you get too much pressure
you can figure it out easily with a fuel pressure gauge, not sure if you have one
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i can think of 3 things
1. you mixed the pressure and return lines
2. your pump sits too low and pressed on the bottom of the tank and you don't get enough pressure
3. your return is too low in the tank and you get too much pressure
you can figure it out easily with a fuel pressure gauge, not sure if you have one
you make good points, and I thought about those. I verified via my manual that I do have the pressure/return lines correct.
I really hate the thought of dropping the tank again but I know these dumb plastic tanks like to warp and its possible it is hitting. What could I do about that though?
The whole assy shouldnt be any longer than it would have been with the stock HP pump I swapped out.
also..the tank I used doesnt have anything in it. Just bare bone empty plastic tank. The other one I have has sort of a 'tray' at the bottom below the tank...think that matters? I took the pump from the other tank and used it in this one...
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I recently had to replace the pump in my 94 YJ and I had to shorten the pump hose
by about 1/2 an inch, I also drilled a hole in the return pipe because the rubber gadget
that it has on the bottom end can block it if the tank is too tight to it.
You don't have to drop the tank to tell if the pressure and return are reversed,
just unhook the hose from the filter and turn the key on briefly, the fuel
should come from the tank not from the engine end.
(Be careful a LOT of fuel comes out, I use a hose into a can to catch the fuel...)
Dave
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rent a fuel pressure gauge, that will tell you for sure what's happening there.