Hey I was told to change my 85 TPI to density. since density does not uses the coold start injector what do you do with it

 

Block it off (Accel makes a kit), or just unplug the
harness connector from the
9th injector.

The CSI is controlled by a relay mounted
in the front of the TPI intake, so the
ECM doesn't control it, but it will continue
to richen the start mix unless unhooked.

mike

 

No what the advantage of getting rid of the cold start injector?

 

Mike
would it be better to stay with the 85 setup or go density? i was also told by painless to use the 86 ECM with a new aftermarket harness that they sell
I was thinking of reworking the 85 harness and staying 85 or rework it so it will use a 86 ECM

 

It's definately better to uprade the 85 ECM to either the 86-89 style or the speed density setup, depending on your preference and availablility.

I upgraded my 85 setup to an 86-89 MAF setup. Rather than paying through the nose for Painless' harness that isn't long enough to reach the stock computer location, I bought a used harness from an 87 IROC. It was a simple swap. I bought a small-cap distributer so I didn't have to modify the engine harness (I did have to modify the power harness). All I had to do was widen the hole in the kick panel, because the 86-89 harness is about 1/4" wider than the stock 85 harness.

I went with the MAF setup, primarily because my horsepower levels aren't extreme enough for MAF to be a drawback, and I wanted to learn how to burn chips for it before I moved on to speed density.

Anyway... on to the blockoff. If you're running speed density, then you need the blockoff. If you run MAF, you can use a $32b code and keep the cold start, or use a $6E code and eliminate cold start. Since I bought late-style SLP runners that didn't have the cold start provisions, I decided to run the $6E code and eliminate the cold start. Because I only needed to cap off the fuel rail instead of plug the injector hole, I was also to save a bunch of money by not using the accel kit... I just used a cap on the back of the rail.

 

Doing the repin/splice swap from the 870 (1985) ECM to the 165 (86-89) ECM is a breeze. It requires just a few hours of work, a 165 ECM and proper Cal pak for the engine size you are using and the addition of 2 relays and a little wiring for each.