I'm planning on swapping in a digital dash in my 91 convertible (305 TPI)
Can I reuse my engine harness or do I need to swap that also ( from a 88 digital dash TPI car).....?
What TPI difference is there between the two (88 and 91 TPI)......?
Thank you

 

Speed density vs MAF

 

No 9th Injector among other items

 

Most of the DIC information will not be available to you after the swap unless you replace ALL the wiring in the car. The Interior harnesses that lead to the rear lights in your 91 do not have the circuits needed for the DIC. ( Doors, Hatch, rear lamp monitoring ) The Engine harness in your 91 also doesn't have the sensor circuits needed for the DIC, ( for headlight monitoring, Wiper washer fluid level, ect. )

The change from a MAF TPI to a SD TPI will not be a simple plug-&-play swap. They are different systems that require different wiring and are not directly compatible. & Let's not forget VATS; 88 MIGHT have it, but it might not,... the 91 does for sure.

In Short - The more 88 digital dash wiring that you have to work with,... the "simpler" this whole project will be for you.

 

I have the whole digital dash and all harness ........all special sensors and the 88 CPU.....also have the 88 steering column with radio controls.......
But my 91 TPI is SD and the 88 GTA is MAF......
Make the 91 MAF.....? Or make digital dash work with SD....?? What is easier...??
Special sensors for lights( lights is just special wireing ) coolant windshield washer doors and trunk ( have all that )
All engine vitals come from the different senders for digital gauges....
Basically rewire the whole car (the 1991) with harness from the 88 GTA.......
What am I missing.....??
Trying to figure it ALL out before I take the 91 apart......
Thank you

 

Myself,..... I'd convert to the 91 engine to MAF.

 

Converting the 88 harness to MAP isn't really a big deal, or just run the 91 engine with the MAF, the computer really isn't going to care as long as you use the proper ECM either MAF/SD. If I ever get another 3rd gen I would like to find a true digital dash car, not because of anything other than I haven't owned one yet

 

I TOTALLY advise AGAINST using an 88 harness in a 91 car, there are so many differences. It will be easier to rewire the 91 harness to use the digital dash. Anyway, you will need the digital cluster, the DIC, all the sensors, the connectors and the whole 88 dash carrier as the 91 carrier is different. Maybe that list isn't even complete as no one has done that before.

Not going to be an easy undertaking! So be careful.

I've started doing that here:

https://www.thirdgen.org/forums/inte...dash-swap.html

There you'll find the basic information on the electrical parts and other stuff. Still a long way in the process...