cruiser54

Confirmed over the weekend the difference in ECUs used on Renix 4.0s.

I was sure there was a difference but I used my neighbor as a guinea pig with his 87. I let him use one of my 89 to 90 ECUs as long as he installed it.

He came back from the test drive smiling from ear to ear.

Last night he installed the later model Renix TCU, I'll have a report back in a day or so.

zebvance

Noticeable difference in power? Can you explain why, how, and how much power?

cruiser54

Yes, noticeable difference even to the non-gearhead.

87 had 173 HP, 88 had 177 HP, 89 and 90 had 182 HP.

ECU is the only difference.

I've been swapping them for years. Just got the response from my friend when I let him put an ECU from my parts Jeep into his 87 and go for a drive. He loved it.

I'm also advocating elimination the c101 connector, post 27, as a matter of course. Don't do it when you change the ECU as I'd like to see you guys experience the drivability improvements from each upgrade individually.

RusNorthID

Damnit cruiser you really know how to make a guy wanna kick himself in the nuts i just let one from my 90 donor xj go to the scrap yard with the shell. Ohwell looks like ill just make a trip to pull&save thanks for the info because ive been saying the Comanche is just gutless

RusNorthID

Considering i have the c101 would i also most likely have the 173hp ecu? Also i remember i had a 89 limited & 90 Pioneer and the 89 ecu went out i switched the 90 in and all it did was backfired. I went and bought a 89 ecu and away it went. So what I'm asking is will any renix ecu work? Or do i need to find a part number

cruiser54

Don't make this too complicated.
C101 means you have an 87 or 88.

87 and 88s both benefit from the 89 to 90 ECUs.
As well, they benefit from C101 elimination. Not necessary, but strongly suggested.

cruiser54

Kinda why I brought this up. We need to be saving some of this good stuff.

Cash for Clunkers cost us 24,000 XJs.

RusNorthID

just curious if there was a reason my 90 ecu wouldn't run my 89. I don't wanna pull a ecu that wouldn't work. And after a full tune up and ground refreshing i feel my mj is still pretty weak in comparison to my 90 i just parted (rusted badly) the only parts left where the seat belts heater core ecu(back bolt was rounded) i wish i would have taken the ecu now haha

cruiser54

Shoulda worked perfectly. Perhaps the 90 ECU was not good?

RusNorthID

Nope the 90 ran fine before and after lol weird

cruiser54

Real weird.

cruiser54

Cody reported back last evening on changing his TCU from the standard 87 model to an 89 model I had from a parts Jeep.

Better shift points with less lugging and definitely noticeable.

I knew they changed the TCU after 87 due to customer complaints, and 88 and later seem to work great. My wife's 88 shifts like my 90.

alpine.adrenaline

I wonder if the same goes for the 2.5L.

Thexjfiles

Shameless plug...Ive got an 89 ECU that needs a new home...

cruiser54

Frickin spammer!!

Auto or manual BTW? LOL!!!