Does anbody know if I will lose power by putting a engine from a 89 into my 91? My 91 originally had the 4.0 High output but the 89 motor has way lower mileage but am I going to regret this???

 

The non HO engine has about 20hp less and there are some differences with the cylinder head and injection system.

 

As far as I know a lot of stuff is needed for the change, a lot of the sensors are different, throttlebody is also different and the throttle cables connect differently.

 

I heard 8 hp less from cruiser. I personally like the renix motors better, much easier to do testing on. I'm not a fan of OBD.

 

You could just take the 89 block and plug in all your 91 accessories. Everything that makes a jeep engine "HO" is external, nothing really about the block and internals are different if I'm not mistaken

 

Yes and no. As far as i know for the fuel injection, it is still MPFI. And the fuel pressure regulator is mounted on the rail.

Hell yeah. Dont need no stinkin CEL

x2. Only differences i know of is the head, intake (everything on the intake) etc. And of course the accessories

 

Put the Renix engine in as a long block. Use your dizzy, flywheel/flexplate, manifolds, thermostat housing, valve cover if it's different, and use the intake gasket for your 91.

You will have no regrets. Any questions, post them up.

Ain't no stinkin' 20 horsepower difference......

HO stands for Highly Overrated BTW.

 

By long block do you mean the 4.3L ?

 

I mean strip the 89 down to the head, block and oil pan, front cover and transfer your 91 stuff over to it.

 

ahh i see