Me&my86MJ Posted October 18, 2015 Share Posted October 18, 2015 Has anyone done this swap? What is required? I see the newer style has injector ports near each cylinder chamber,can those be blocked off/sealed? Cab my TBI sit on top of newer style intake? Would i just need to run vacuum/fuel hoses to meet ports on opposite side? A link to anyone/anywhere that has already done this would be awesome, as well as any advice or good jeep tech. Link to comment Share on other sites More sharing options...
mnkyboy Posted October 18, 2015 Share Posted October 18, 2015 Jeep Driver was working on this swap,he adapted the TBI to the MPI manifold. This is the build but the pics aren't displaying, http://comancheclub.com/topic/44902-po-boys-88/ Link to comment Share on other sites More sharing options...
Me&my86MJ Posted October 18, 2015 Author Share Posted October 18, 2015 Thank you mnkyboy, kinda figured you would know or know where to point me to find some good info. Link to comment Share on other sites More sharing options...
dasbulliwagen Posted October 18, 2015 Share Posted October 18, 2015 I don't see why it wouldn't work as long as you adapt everything you need to keep the computer happy. I would like to try this myself when I build my spare engine for my 87. Link to comment Share on other sites More sharing options...
shelbyluvv Posted October 18, 2015 Share Posted October 18, 2015 Jeep Driver is on a vacation from this forum. Link to comment Share on other sites More sharing options...
Me&my86MJ Posted October 19, 2015 Author Share Posted October 19, 2015 Thank you for the heads up about jeep driver, shelbyluvv. Link to comment Share on other sites More sharing options...
81Chero Posted October 26, 2015 Share Posted October 26, 2015 I heard it will fit/work in an earlier Renix vehicle also, so I looked and looked in the local yards and ended up finding a '01 Dakota with the 2.5/5spd. I ALSO heard that besides the manifolds, the long-block was EXACTLY the same.. Things kinda slowed and my orig 88 motor while quite old, still is getting great mileage considering so I stopped being interested in swapping. But one thing, I tried to swap starters at one point and they're different, Also the alternator wouldn't swap over. Can't remember what wouldn't work at this time though. It's been a bit and can't remember which sites I joined when I got the Comanche that I asked that Because, the Idea at the time was to freshen up the dakota one and swap it in the Comanche since I didn't know the prior history of it, and didn't want to get stuck somewhere. But it just runs too good to go through all that work. E Link to comment Share on other sites More sharing options...
mnkyboy Posted October 27, 2015 Share Posted October 27, 2015 The alternator won't swap,pretty much everything on the front of the engine all the way down to the timing cover is different. Not sure what the change was with the starter but the break is around 1993. It's just the block,rotating assembly,and head that didn't really change. You can take any stripped down AMC 2.5l and dress it as a TBI,MPI,or even carburated. Link to comment Share on other sites More sharing options...
Me&my86MJ Posted October 29, 2015 Author Share Posted October 29, 2015 So the newer 2.5 intake to with tbi swap, any pictures anyone? The idea for me is better air flow for intake and also more room for a better flowing exhaust manifold/header. Link to comment Share on other sites More sharing options...
mnkyboy Posted October 30, 2015 Share Posted October 30, 2015 Not sure how much your going to improve flow with the tiny TBI choking it up. Here's the 2.5 TBI,2.5 MPI,and 4.0l TBs next to each other. Link to comment Share on other sites More sharing options...
Me&my86MJ Posted November 2, 2015 Author Share Posted November 2, 2015 Well I can only do what I can with the knowledge I have,which isn't as much as I would hope at my age. I understand that the tbi will be a choke point, but my current intake manifold is akward and kinda rectangular and tight to the head,leaving minamal space for headers. I understand doing the whole MPI swap would probably be best,but I feel that is much more in depth a job involving changing harnesses, brain,fuel pump,injectors instead of tbi, and probably more I am sure I am forgetting. I want to keep it as simple as possible for the time being and later possibly do,the MPI swap/conversion Link to comment Share on other sites More sharing options...
Me&my86MJ Posted November 6, 2015 Author Share Posted November 6, 2015 This right here is the main reason I want to figure it out. Link to comment Share on other sites More sharing options...
mnkyboy Posted November 7, 2015 Share Posted November 7, 2015 My pacesetter header came off a buddies TBI 2.5l,it was for an MPI but bolted right up. Link to comment Share on other sites More sharing options...
Swampy Posted August 16, 2017 Share Posted August 16, 2017 I know this is an old thread but is there more information about tbi to mpfi swap? Link to comment Share on other sites More sharing options...
Jeep Driver Posted August 16, 2017 Share Posted August 16, 2017 I know this is an old thread but is there more information about tbi to mpfi swap? I've done it and it works, what do you want to know? Link to comment Share on other sites More sharing options...
88whitemanche Posted August 16, 2017 Share Posted August 16, 2017 What's the size block off bolt/not sure what it is called you used to block off the egr port of the old intake manifold ? Just noticed in your pic you have the updated intake manifold what did you use for the injectors or did you block them off? Link to comment Share on other sites More sharing options...
Swampy Posted August 17, 2017 Share Posted August 17, 2017 I know this is an old thread but is there more information about tbi to mpfi swap? I've done it and it works, what do you want to know? Hey, sorry to bother. I would like to pick your brain for a bit about converting from a tbi to mpfi. I like the little 4banger and it would be awesome to be able to keep it and get some more performance out of it. What parts would I need to swap to make the conversion? Intake manifold, injectors?? Can you swap from tbi to mpfi without swapping the engines? Link to comment Share on other sites More sharing options...
Jeep Driver Posted August 18, 2017 Share Posted August 18, 2017 No bother. This is not a MPI conversion, I converted an MPI intake to TBI and retained Renix. I have no idea what results you'd get just swapping the intake. I would not convert to MPI, I have many thoughts on this but all I'm going to do is tick people off. In fact, I'd put my engine up to any stock MPI anytime. The way this engine runs compared to the stock engine is apples to oranges. In the vid below you'll notice a what sounds like a blip in the throttle, I'm starving for fuel at mid throttle. New Bosch pump and still starving, I'll have to resolve this issue but what I do know is that demand for fuel/air is much greater than the stock pump can supply. Plus, this engine only has about 60 miles on it and about 2 hours or so of run time, it's not even broke in yet. You'll have to look at the big picture, cam timing, header, exhaust...etc.... The stock TBI intake is pure garbage, it just is. And you'll have to bypass the coolant around the intake, the heated intake destroys HP and is completely unnecessary. I'm effectively running dual open exhaust, no Cat. Those who claim that the 2.5/4.0 must retain some 'back pressure', it's just nonsense. AFE header. It's up to you but I don't think you can alter just one part of the whole and expect a great deal of change. If you swap intakes you'll need to at least go the the header. Oh, and sensors too.....all mine are NOS Renix or Mopar.........it's takes a lot to get it to run right. Link to comment Share on other sites More sharing options...
Swampy Posted August 18, 2017 Share Posted August 18, 2017 No bother. This is not a MPI conversion, I converted an MPI intake to TBI and retained Renix. I have no idea what results you'd get just swapping the intake. I would not convert to MPI, I have many thoughts on this but all I'm going to do is tick people off. In fact, I'd put my engine up to any stock MPI anytime. The way this engine runs compared to the stock engine is apples to oranges. In the vid below you'll notice a what sounds like a blip in the throttle, I'm starving for fuel at mid throttle. New Bosch pump and still starving, I'll have to resolve this issue but what I do know is that demand for fuel/air is much greater than the stock pump can supply. Plus, this engine only has about 60 miles on it and about 2 hours or so of run time, it's not even broke in yet. You'll have to look at the big picture, cam timing, header, exhaust...etc.... The stock TBI intake is pure garbage, it just is. And you'll have to bypass the coolant around the intake, the heated intake destroys HP and is completely unnecessary. I'm effectively running dual open exhaust, no Cat. Those who claim that the 2.5/4.0 must retain some 'back pressure', it's just nonsense. AFE header. It's up to you but I don't think you can alter just one part of the whole and expect a great deal of change. If you swap intakes you'll need to at least go the the header. Oh, and sensors too.....all mine are NOS Renix or Mopar.........it's takes a lot to get it to run right. So I would need the MPI intake, new header, cam timing, sensors and fuel pump? I have to do a tune up on my engine anyways so I might as well do this too right? Link to comment Share on other sites More sharing options...
Jeep Driver Posted August 18, 2017 Share Posted August 18, 2017 Well, I don't' know that it will be just that easy................ You'll need to make an adapter plate, plug the injector holes. NOS TBI with 52lbs injector. Link to comment Share on other sites More sharing options...
Swampy Posted August 18, 2017 Share Posted August 18, 2017 Dang I was hoping it was a little eaiser than that. I don't have the proper tools to make an adapter plate Link to comment Share on other sites More sharing options...
Swampy Posted August 18, 2017 Share Posted August 18, 2017 Does the cam from an mpi motor fit in a tbi? Link to comment Share on other sites More sharing options...
Me&my86MJ Posted September 1, 2017 Author Share Posted September 1, 2017 On Wednesday, August 16, 2017 at 3:44 AM, Jeep Driver said: I've done it and it works, what do you want to know? Did you have to change power steering pump? Also what thermostat housing do you have on there? I totally agree that the older style with 90 degree bends and heated was a very poor design. What did you use for adapter plate and how did you seal bottom besides bolts, did you use 91 and up tb gasket or just reviewed? I have already obtained the intake and exhaust manifold to do swap, now I just need to plug injector holes and make a plate correct? Link to comment Share on other sites More sharing options...
Jeep Driver Posted September 2, 2017 Share Posted September 2, 2017 On 8/31/2017 at 11:56 PM, Me&my86MJ said: Did you have to change power steering pump? Also what thermostat housing do you have on there? I totally agree that the older style with 90 degree bends and heated was a very poor design. What did you use for adapter plate and how did you seal bottom besides bolts, did you use 91 and up tb gasket or just reviewed? I have already obtained the intake and exhaust manifold to do swap, now I just need to plug injector holes and make a plate correct? You have to find a '92 intake, the PS bosses need to match the AMC accessories to get the belt alignment. You'll have to make your own adapter, MPI gasket below and TBI gasket above. Thermo housing is still available, AMC type, you can use the Chrysler style, just make certain you make a provision for the temp sender, crucial. Link to comment Share on other sites More sharing options...
omega_rugal Posted September 2, 2017 Share Posted September 2, 2017 How do you control de ignition? your coil is not connected... Link to comment Share on other sites More sharing options...
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