alpine.adrenaline

Yeah, the Renix TBI. The ECU I used was S100801103C. After looking up that part number I found it's specific to a Wrangler, don't know if that matters.

cruiser54

I have no idea on the 4 bangers.

cruiser54

Here's some comparison photos between the stock Renix 52mm throttle body, a 60mm Renix throttle body, and an HO throttle body:

DirtyMollie

My '86 TBI 4 banger's factory ECU is pn S100801103A. It's missing the label that would have the year week on it like I've seen in other pictures, but the small label that has the pn on it also has the 4 digit as well, and mine is 8543 I think - so again making sense that it's a late '85 date on it.

Mine has weird idle issues, so due to that and the reported HP increases, I plan on snagging a new one from the local pick 'n pull ASAP. Local yard actually has a few 2.5l XJs in the 89-90 year range, so I'll report back once I get the swap made.

cruiser54

Check the hoses here:

khardysius

Just reading through this and would like to thank everyone for sharing so far.

For those of you who have upgraded their ECU to 89/90, what was your MPG gain?

I'm pretty happy with my 19ish MPG with stock lift, 30" tires, and 746 injectors. Would love to have more power and smoother idle from a ECU upgrade, but don't want that at the loss of fuel mileage. Thanks in advance for any info!

khardysius

What years were the 60mm TBs?

Hayden98XJ

Cherokees never came with a 60mm TB. That one has been bored out.

cruiser54

You won't lose any MPGs

cruiser54

Yes. www.strokedjeep.com

khardysius

Thanks, boss!

cruiser54

And you'll gain smiles per mile.

cruiser54

Alright, any progress reports?

Baddad

So this is the sticker on my ecu in my 90. I had to replace the ecu a few years ago and was told this is for a a/t 4.0. Is it the right one?

cruiser54

That's an early ECU. 1987 .