89 with a rebuilt 94 motor?

[sik4wheeler]

Yes I mean the 89 flexplate. Thanks for answering that. It atleast eliminates one thing. What would the CPS act like if it is banged up from taking the old motor out and putting it back in again. It is relatively new though.

 

[Bouncy]

The CPS can get cracked from pulling and installing a motor. It is usually best to remove it before taking out the motor.

That is IF you took only the motor out. I usually pull motor and trans together and deal with it later.

Remember the cps is only plastic with a magnetic pickup in the center. Plastic cracks and the pickup can get out of alignment.

Pull CPS and try a different one. Testing them seems to be a PITA to me.

 

[sik4wheeler]

Well i pulled the motor tranny complete and put in the 94. I will be checking that as well as testing it to be sure that is not part or the entire problem.

 

[sik4wheeler]

Update. Got home turned over and kept pumping the skinny pedal till it fired up. Got it to rev up and then I kept it around 3000rpm or so and it was nice and smooth. I let it idle down and then gave it some more gas and it did the popping stuttering thing again, and then I pumped the pedal and got it to rev up again.

 

[sik4wheeler]

any ideas

 

[sik4wheeler]

Since I have the adj. timing crank sprocket should i set it up advanced or
OEM standars.

 

[Bouncy]

OEM standard seems to be the ticket with an OEM motor.

 

[sik4wheeler]

Will advancing it 2 degrees give me any benefits?

 

[sik4wheeler]

Update. I put the front of the motor back together and hooked up all the accessories. I ran it at 2.25k rpms for about five minutes. the didnt jump at all until i let the rpms drop near 1.75k and then the rpms dropped of real quick and jumped around a bit. then i reved it up and let it drop to idle quickly and then tried to smoothly raise the rpms and it did sputter a bit and then tried it again and it reved up fine. I feel so close yet far away.

 

[bhansen99xj]

I think the 4 bolt throttle body will not work with a Renix set up. I think the signal to the 'puter is different. Otherwize this would be a common swap. It is done using the Renix head on the H.O block but the electronics from the Renix motor must be on the H.O so that means the Throttle body as well needs to be Renix for it to run properly.

I agree on this one. I didn't read all the posts so I don't know if it was mentioned or not.

I replaced an 89 motor with a 92....used the intake and exhaust manifolds from the 89 on the 92 block and all was well...

 

[sik4wheeler]

I have put the Hesco adapter on. I just have not set-up the TPS yet, it's loosely screwed in.

The tps is now setup to spec.

 

[sik4wheeler]

AS long as I can get the motor above 2k everything is okay. So the problem only occurs between 1 and 2k rpms.

 

[sik4wheeler]

Its seems the the rpms drop off very quickly after 2k. The issues are mainly between 1.5k and 2k rpm.

 

[sik4wheeler]

Also I still havent got the exhaust installed since it is not in driving shape. What gives.

 

[88 comanche man]

i have just done the same swap and had the same problem. It is almost a sure bet that it's the dizzy of out 1-2 teeth . mine was off 2 teeth advanced would idle perfect but stumble and back fire like a mother over 1500 rpm . worked like it was on NOS if you just mashed the pedal .It took forever to get it indexed right but works perfect now

 

[sik4wheeler]

When you give it gas should the fuel pressure rise to aboujt 40psi? It seems that when the pressure goes up it runs worse than it drops off some and runs better.

 

[89xj]

When you give it gas should the fuel pressure rise to aboujt 40psi? It seems that when the pressure goes up it runs worse than it drops off some and runs better.

yes, when under throttle the engine vacuum drops and the fuel pressure(vacuum assited fuel pump regulator) goes up to around 40. it seems your fuel pressure is good. your problem really sounds like a timing issue, most likely with the distributor.

 

[sik4wheeler]

Okay so say it was timing. Why would I beable to get it to rev up and run strong at times?

 

[89xj]

Okay so say it was timing. Why would I beable to get it to rev up and run strong at times?

under load while driving or in park and reving the engine?

maybe a bad MAP.

 

[sik4wheeler]

In park and reving. You have to pump the pedal as if it had a bad accelerator pump. I can occassionally get it to work fine but, only for a short time.