GM TBI conversion

[vangremlin]

I don't know if this topic has been posted before, but I found this on line and wanted to share it with everyone.  This is for converting to the GM TBI found on late 80s and early 90s 4.3L V6 engines.  The link is for a 258 engine in a jeep, but I'm sure an Eagle would be very similar.  Its a pretty thorough description of how to do the job.

http://www.viciouscustoms.com/TBI/junkyardtbi.asp.htm

[doc65]

Van,

I'm actually going to do this to the SX4 SOON, I have a throttle body, all the sensors, a couple computers, and just cuz I decided the time to pull it was worth more than the cost I got it for, a wiring harness coming from an 89 S10 Blazer that I got off ebay for like $36 shipped.  I've done a bunch of research, have like a dozen different links to different installs from CJ's to Scout II's with 258's.  Further down the road I'm going to go to a full on MPFI 4.6 Balanced & blueprinted Stroker(my own, NOT a Titan), at that point I'll probably move the TBI setup to the Wagon.

bonus is that both types of FI get rid of the air injection *(@# as it would make the computer think that you were running way lean and it would then compensate by dumping more fuel in
 

[vangremlin]

It'll be great to see your progress on this project.  Hope you can take lots of pictures and document it well!

[captspillane]

Great link. That's the basis for the Howell TBI kit. You can buy all new ready to go for $1200. The junkyard version still needs a Vehicle Speed Sensor and an electric fuel pump, so you will likely still have $400 into the conversion. The huge advantage is that you don't need a Crank Position Sensor. It's a great way to go.

My CJ8 was featured in Jp magazine. The previous owner was the editor's brother. They installed the Howell TBI kit for a few miles and then immediately installed the Hesco MPI kit for comparison. The difference in performance and fuel mileage was measureable, but very slight.

[doc65]

You're right, I do still need a VSS & fuel pump, but the VSS can come from a number of early Wranglers or Dodge trucks in the late 80's early 90's(Dakota's & Van's as well) & the pump from numerous 80's Ford & Lincoln products(most notably Crown Vics & Towncar's) I'm about $80 into it so far, including  the harness, 2 TBI & 2 Computers, even if I were buying both the remaining bits new from Checker/O'reilly I'd only be at about $250, but I plan another trip to the wrecking yard for both bits & I'll pull at least 2 each & probably be $20. I figure that with fairly minimal effort I should be able to do it for about $150 including incidentals like hose, new filter, etc

oops... I forgot to calculate the cost of the adapter plate in, again if you buy it $80ish(Ebay)-$150(AFI/Howell), I got a plate remnant of 6061 5/8" thick that's big enough to make like 7 for under $35 total, probably make a few extras & sell them to defray costs 

[captspillane]

The dodge and wrangler VSS has a larger set of female threads that go on the transfer case adaptor and a smaller set of male threads that connect to the speedometer cable. The smaller side has the exact same male threads as the back of our Eagle speedometers. The larger side has the exact same threads as a CJ would have. It threads into the same transfer case adaptor as an XJ.

I'd like to know if you come across a vehicle that has a speedometer cable with those threads at both ends. A '91 Jeep Wrangler or Dakota must have the same small threads at the VSS but I don't know what is at the other end inside the dash.

[doc65]

I grabbed a couple of VSS from like 92 Dakotas, CHEAP, the side that goes to the trans/t-case is bigger, the output is small.  not sure yet, what I'm going to do, but I'll find a way to make it work.