pwrliftin Posted October 22, 2009 Share Posted October 22, 2009 I have an 86 mj with the 2.5. It has stock rims and suspension and that thing is a tird! any ideas to put a little more power under the hood to get it movin? id like to lift it and put bigger tires, but theres no way with the lack of power Link to comment Share on other sites More sharing options...
MiNi Beast Posted October 22, 2009 Share Posted October 22, 2009 turbo, header, 4.0 throttle body I think, roller rockers, but all in all regear the axles and you'll be all set. Link to comment Share on other sites More sharing options...
Geonovast Posted October 22, 2009 Share Posted October 22, 2009 4.0 Throttle body upgrade only works on 91+ 2.5s, from a 91+ HO 4.0. Up to 90 is throttle body injected, all 4.0s are MPFI. Link to comment Share on other sites More sharing options...
MiNi Beast Posted October 22, 2009 Share Posted October 22, 2009 4.0 Throttle body upgrade only works on 91+ 2.5s, from a 91+ HO 4.0. Up to 90 is throttle body injected, all 4.0s are MPFI. Yeah sorry never had one of them little 4 banger unless it was in a car :rotfl2: Link to comment Share on other sites More sharing options...
Eagle Posted October 22, 2009 Share Posted October 22, 2009 I have an 86 mj with the 2.5. What transmission and what axle gearing? Link to comment Share on other sites More sharing options...
pwrliftin Posted October 22, 2009 Author Share Posted October 22, 2009 I have an 86 mj with the 2.5. What transmission and what axle gearing? 5 spd, don't know the gearing but i know its the dana35 Link to comment Share on other sites More sharing options...
Pete M Posted October 22, 2009 Share Posted October 22, 2009 make sure nothing is wrong with it. A clogged cat, a bad sensor, clogged fuel filter, bad injector, failing fuel pump, etc. can cause power issues. Link to comment Share on other sites More sharing options...
Geonovast Posted October 22, 2009 Share Posted October 22, 2009 make sure nothing is wrong with it. I know what's wrong with it. His 4.0 is missing two cylinders. Link to comment Share on other sites More sharing options...
Eagle Posted October 22, 2009 Share Posted October 22, 2009 5 spd, don't know the gearing but i know its the dana35 A 5-speed should have 4.10 gearing. With stock tires, it should feel halfway decent around town up through 3rd gear, but will sort of run out of steam over about 50 MPH once you hit 4th and 5th gears. It's difficult to judge whether or not yours is "normal" because we don't know how you drive, or what kind of vehicles your frame of reference is based on. The MJ isn't a rice rocket. It weighs over 3,000 pounds and the 2.5L was the base, econo-box engine. That combination was intended for getting you from here to there, with decent gas mileage. It was not intended to set the world on fire. Link to comment Share on other sites More sharing options...
pwrliftin Posted October 22, 2009 Author Share Posted October 22, 2009 make sure nothing is wrong with it. I know what's wrong with it. His 4.0 is missing two cylinders. Funny funny. just found one on cl, needs lifters, rockers and push rods. Would not hesitate, but have no where to drop the engine in. I just got a new injector for it, havent put it on yet but hopefully it helps Link to comment Share on other sites More sharing options...
Geonovast Posted October 22, 2009 Share Posted October 22, 2009 You may also consider an MPFI conversion down the road. Link to comment Share on other sites More sharing options...
pwrliftin Posted October 22, 2009 Author Share Posted October 22, 2009 5 spd, don't know the gearing but i know its the dana35 A 5-speed should have 4.10 gearing.quote] I'm used to driving trucks, but the only ive owned was a 350 chevy and 4.3 vtec s10. not really used to a 4 banger Link to comment Share on other sites More sharing options...
mnkyboy Posted October 22, 2009 Share Posted October 22, 2009 what do you mean by "no power" I have a 2.5L TBI,AX4,3.55 gears and 31X10.50's only mods are cold air intake,no cat and a flowmaster muffler. the truck actually suprises people,it can burn the 31s if i get on it hard enough,runs 75mph+ on the interstate no problem and can out accelerate some small cars. only time i notice a problem is climbing steep hills. its not a rocket but i wouldnt call it a turd. Link to comment Share on other sites More sharing options...
Geonovast Posted October 22, 2009 Share Posted October 22, 2009 I buried the speedo on my 2.5 the day I bought it, AX-4, 3.55 gears. But then again, mine's MPFI Link to comment Share on other sites More sharing options...
pwrliftin Posted October 22, 2009 Author Share Posted October 22, 2009 what do you mean by "no power"its not a rocket but i wouldnt call it a turd. Well the more i tear into this truck, the more i realise what a total idiot the previous owner was. everything is rigged up and his methods are giving out now. I'm just really glad I'm an ok mechanic and my dads an awsome one cause we have some work to do lol Link to comment Share on other sites More sharing options...
dasbulliwagen Posted October 22, 2009 Share Posted October 22, 2009 Get a new 02 sensor for it too. Mine was horrible when I got it, and I limped it around like that for a while, then put an 02 sensor in it just because, and it made a huge difference. Ive also done the cold air tube, removed the engine fan for an electric one, and re-geared to 4:10's and have noticed minor gains. Next would be a throttle body spacer, gut the cat, add a header, cam, change to 4bbl carb intake manifold, port and polish the cyl head, go to maximum overbore in the cylinders, add a turbo..... it all depends on how much you want to spend in time and money. There are a bunch of guys on here that will tell you to just swap in a 4.0, but to many of us that just isnt feasable, and it is more fun "tuning" on a 4 cylinder. But that will only get us so far before we start seeing diminishing gains. If the 4 is all you have to work with, by all means do it! Just remember though that it is still just a 4 cyl and you can only expect soo much. Link to comment Share on other sites More sharing options...
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