Engine upgrade in an 88' manche

[comanchelover]

Hi MJ Lovers, I have an 88' Manche 4cyl 4spd 4x4 shart bed that i bought new in 88'. (A slick salesman talked me into the 2.5L, said it would out last the 4.0 and get better mileage. Lied flatout) Any way, I picked up a 2.5L 4cyl w/5spd Ax5 out on a 97' wrangler w/80K so I can get it runnin again. Am I better off using the TB manifold off my old engine and keep everything else the same, or should I convert to the multiport FI manifold with a 97' wiring harness and what other differences are there in the engines? Also, what problems am I going to have getting the 97' AX5 to work with the hydroulic clutch cylinder on the drivers side instead of the passenger side in the 88'? What about the speedo? Are they different?

Thanks for your help?

[Geonovast]

For power and efficency, you're better off with the 97 motor. However;

 

To move to the MPFI You'd have to swap all the wiring over...and being that its from a Wrangler, there's gonna be a lot of differences and you'll need to rig things to work. You may be able to lay it in as a second harness.

 

As for the trans, you have two options. The 97 motor will bolt directly up to it, if you use your current clutch kit. I would swap tranmissions though, external slave setups are so much better. All you'd have to do is modify the clutch line and bleed it.

[hopper]

Check the bolt up on the yj trans, mine clocks the t/c different than the

manche.I don't know if the 97 is the same mine is an 89.

[Eagle]

If you have the MPFI computer and harness, I would update the 'Manche to the newer system. You'll get more power and better economy.

 

Here's the deal: After Jeep introduced the MPFI 4.0L, a lot of people with the older, carbureted 4.2L engine in their YJ Wranglers were feeling left out. So Jeep came up with a kit to convert the carbed 4.2L Wranglers to MPFI. Basically, the kit is "just" the manifolds, injection, ignition, ECU, and engine room harness from a '94 Wranger.

 

So ... if Jeep could split the system up to use just the engine controls to convert the older Wranglers, I see no reason why you can't swap in an engine that's already set up for it and just use the engine harness from the Wrangler in your MJ. Your speedo is mechanical and has NOTHING to do with the engine controls, so don't worry about it.

[Geonovast]

Check the bolt up on the yj trans, mine clocks the t/c different than the

manche.I don't know if the 97 is the same mine is an 89.

 

If it is, you can swap just the housing/external setup and throwout bearing retainer and keep your current trans, which can all be done with the motor out and trans in the truck.

[comanchelover]

Thanks Guys for all the info. I am going to install the 97' engine and AX5 as one unit and so the info on setting up the slave will be real helpful. Still haven,t decide on using the old tTBI manifold or the MPFI. A buddy who is helping is leanig on keeping it TBI.

Thanks again.

Wes

[Eagle]

Just my opinion, but while keeping the TBI is less work in the short term, converting to the MPFI will give you better performance and probably better gas mileage. Since you were unhappy with the performance before, why do it over again?

 

Here's the skinny on the 2.5L engine (copyright, me -- permission to reproduce is NOT granted)

 

The original carbureted version was rated as producing 105 horsepower at 5,000 RPM and 132 foot-pounds of torque at 2800 RPM. The throttle body injected version produced 117 horsepower at 5,000 RPM and 135 foot-pounds of torque at 3,500 RPM when it was introduced in the 1986 model year. This was raised to 121 horsepower at 5,250 RPM and 141 foot-pounds of torque at 3,250 RPM for model years 1987 through 1990. The final, multi-port injected version produced 130 horsepower at 5,250 RPM and 150 foot-pounds of torque at 3,250 RPM.

[comanchelover]

Thanks for all the info. I have gone with the mpfi and am using the computer and harness out of the 97' Wrangler. However the ecu has 3 connecters and the harness only has 2. I haven't been able to get any info on it. Does anyone know what the third connecter is for? Thanks