Need help. Bucking loss of power.

[eaglescout526]

48 minutes ago, joeCor said:

Thanks yea it’s hard to find solid info 

https://4wdmechanix.com/moses-ludels-4wd-mechanix-magazine-tuning-and-troubleshooting-the-2-5l-jeep-tbi-four/

 

My second go to bible for the 2.5L

[Tex06]

On 5/13/2025 at 10:00 AM, joeCor said:

No you've got a different setup. My point was it could be another shared power line to two sensors. 

 

I've never really messed with Renix, but I'm pretty proficient at electrical troubleshooting. I've got the full set of electrical manuals for all motors (1992 year) so that's where I would start.

 

Does anyone know how much the 2.5 engine management system changed from AMC to Chrysler? 

[eaglescout526]

1 minute ago, Tex06 said:

Does anyone know how much the 2.5 engine management system changed from AMC to Chrysler?

The whole damn thing changed. 
 

3 version of the 2.5L exist. 
Carb fuel feedback 84-85

Renix TBI 86-90

MPFI HO 91-01

[joeCor]

On 5/11/2025 at 2:21 AM, Tex06 said:

I basically had a bad solder joint that fed both my tps and map in my main wiring harness. Was able to track it down using a wiring diagram after seeing my TPS +5V was dipping to 1.7-2.7V while the engine was running (and only while plugged it....unplugged there was no electrical load on the solder joint so I measured 5VDC every time I unplugged the connector. 

 

 

When you changed the coolant sensor, you probably moved/jostled/pushed on that wiring harness if it's like the 4.0 in any way. 

 

Feel free to call me, I have every manual made for the 91 & 92 model year Jeeps bc of this issue.... not sure how much the 2.5L changed after the switch to Chrysler but I've got ADHD and a decent internet connection if the manuals don't cut it. 

 

Had high hopes for your idea Tex. I got 5v with key on and doesn’t drop below 4.7 while running. That’s for the TPS and MAP