4bangerjp.com

General Forums => The Mess Hall => Topic started by: Islander on March 18, 2006, 08:39:17 AM

Title: Pre 91 2.5L?
Post by: Islander on March 18, 2006, 08:39:17 AM

What did Jeep do in 91 to make all the majority of all YJ TB spacers, water pumps and electronic upgrades available for 91 up only?  If the 2.5 is the same from 84-02, what gives?

Title: Pre 91 2.5L?
Post by: Jeffy on March 18, 2006, 12:16:37 PM

The intake was redesigned.  As for electronics, MPFI uses a completely different computer then TBI. More sensors with less vacuum lines.

I believe the waterpump on the MPFI's run in reverse till you get to the TJ.

Title: Pre 91 2.5L?
Post by: Islander on March 18, 2006, 12:32:50 PM

So it's MPFI is YJ pre 91, and YJ +91 is TBI, and the water pumps on all YJ's should be the same.  Any worthwhile upgrades to an MPFI intake around?  Got anyideas where I can find out that waterpump question for sure (compare OE part numbers maybe)?

Title: Pre 91 2.5L?
Post by: Jeffy on March 18, 2006, 01:10:37 PM

No,

MPFI is post-'90 (1991-2003)
TBI is pre-'91 (1987-1990)

Title: Pre 91 2.5L?
Post by: Islander on March 18, 2006, 01:23:50 PM

Then why are most TB spacers only available for +91?  You'd think that Summit wouldn't get something like that wrong.  Will a 2.5L with a 4.0L TB take a 2.5 or a 4.0 spacer?

I'm sure you get dumb @ss question like this a lot - I really appreciate your help.

Title: Pre 91 2.5L?
Post by: Jeffy on March 18, 2006, 01:42:05 PM

TB spacers are designed for MPFI, 1991-2003

2.5L MPFI and 4.0L MPFI use the same size bolt pattern for their TB's.  The difference is in the size of the bore hole.  The 4.0L uses a larger hole.  This is convered in the How-To under 4.0L TB Conversion.  Also the Product Reviews; Poweraid TB Spacer.

Title: Pre 91 2.5L?
Post by: Islander on March 18, 2006, 01:50:28 PM

Ahhhh, I see... it's all making sense now.

I'm going to have to wait until monday when I get home to have a closer look at what I'm working with - it'll probably make finding out what I need easier.

Title: Pre 91 2.5 question
Post by: robstein on July 22, 2006, 05:00:00 AM

:? little confused, I have an 88 with TBI (? throttle bodi injector?) is there a spacer for this one or not? :?  :?

Title: Re: Pre 91 2.5 question
Post by: Jeffy on July 22, 2006, 11:38:03 AM

Quote from: "robstein"

:? little confused, I have an 88 with TBI (? throttle bodi injector?) is there a spacer for this one or not? :?  :?

Nope no spacer.  Although some one was going to make some I believe.

Title: Pre 91 2.5L?
Post by: Guardian7 on July 23, 2006, 12:07:39 PM

My ears were burning Jeffy, the status on the prototype pre 91 TB spacer which is finished and will finally be installing next week for testing. The progress has been slow since my freinds machine shop is very busy but we are making headway. We have modeled the part in SolidWorks and created some part drawings. One issue I am concerned with is the mounting studs on the intake which will need to be removed and replaced with 4 bolts. :D

Title: pre 91 TB spacer
Post by: robstein on August 02, 2006, 11:26:22 PM

:shock: Cool, please keep us ALL posted !!