AMC 2.5 to GM 2.5 swap

[TFGgarage]

1986 2.5TBI AX4 with 4wd

I haven't wrenched on my Comanche for a while because I still can't figure out why it randomly dies on me. It will idle until its out of gas but if you start driving it'll randomly die on me, could die before i get out of the driveway or 5 miles down the road and when i cycle the key it will run for another minute or two before shutting off again. I have spark and fuel until the engine stops turning. Had a fancy diag guy come out with an oscilloscope and he also checked all the sensors but that got me no where.  Ive also replaced/cleaned all of the grounds and electrical connections that Cruiser recommends but still no improvement. Fuel Pressure is steady 15psi at the TBI. I keep running into dead ends on the electrical system and I want to yank it all out and make it carbureted like god intended. I was thinking about pulling out the AMC 2.5 and throwing in a GM 2.5 so i can get a vacuum advance distributor and an intake manifold for a carb.

 

I wanted to see if anyone has any better ideas or if anyone has done something similar. I am newish to posting on forums so if yall have any links for old threads on this topic please send them my way!

 

Thank yall for all the help so far, can't wait to get this MJ back on the road!

 

[eaglescout526]

5 minutes ago, TFGgarage said:

throwing in a GM 2.5 so i can get a vacuum advance distributor and an intake manifold for a carb.

No. Don’t even bother my friend. Your gonna lose so much horsepower and torque that you’ll regret it in the end. The 2.5L was designed specifically by AMC for the Jeep and Eagle lines for the off-roading and capabilities. 
 

Now if you’re really hating on the Renix TBI that much, you can get carb manifold and such from the CJ, Eagle and early XJ and swap stuff in and get it to run or set up a carb HEI combo and run that too but you’ll also lose horsepower and torque. But only a small amount compared to that engine swap you want to do. 

8 minutes ago, TFGgarage said:

Had a fancy diag guy come out with an oscilloscope and he also checked all the sensors but that got me no where.  Ive also replaced/cleaned all of the grounds and electrical connections that Cruiser recommends but still no improvement. Fuel Pressure is steady 15psi at the TBI. I keep running into dead ends on the electrical system and I want to yank it all out and make it carbureted like god intended.

Most techs don’t even know how to work on these Renix systems. It’s before their time. Cruisers tips are mostly geared towards the 4.0L. 
 

Hows the coolant look? Exhaust fumes clear or some slight cloud? 
Does it stumble and act like it loses power while driving? 
To me it dying while driving or at idle would make me think the CPS is getting heat soaked or on the way out. That needs to be tested by seeing how many VAC it is outputting. 
 

Oh and a carbed 2.5L is garbage. I swapped it out on my XJ for the Renix TBI.