I read on TPIparts.net web site that to eliminate the cold start, plug it and then use a 89 PROM. Is this all I need to do is get an 89 PROM for 305 AUTO TPI? Tony

 

A stock 89 prom from gm most likely has the vats turned on, if you try to use it in your 86 the car won't start. You may need a custom chip.

 

What Jon said.

I would delete the cold start by yanking the injector, no chance of it leaking as they are prone to do.

89 had no cold start, but VATS will need to be disabled.

later
Jeremy

 

To use the '89 PROM, you could either remove the cold start injector and plug it, or you could just simply disconnect it and leave it in place. But like John and Jeremy have said, the '89 PROM would have VATS enabled.

So if that's all you want or need to change, then instead of the '89 PROM or a completely custom PROM, you might be better off going with TPI's '86-'89 Programming Service. You can have the '89 program, while disabling both the cold start injector and VATS. Your fan's on/off temps can be reprogrammed too, if that's something you've considered.

 

Thanks - I did a carb to TPI swap and could never get the fans to work off the ECM anyway. I used an aftermarket system to kick the fans on, it uses a temp sensor that is in the intake manifold, I used the port the CTS sensor used to be in I have the 9th injector plugged and the rear fuel rail is plugged already as well. I will check out the TPIs reprogram to correct for the VATS and the obviously no Cold start like the 89.
Tony

 

So where did you put the cts then if im not mistaken you need the cts hooked up to the ecm for your motor to run right.

 

I removed it totally from the intake. I used that hole for the aftermarket temp sensor to control the fans. The computer does not need the CTS to function. It is hard to start in the morning, but that is why I am getting the updated 89 programming without the 9th injector set-up and VATS turned off, no air pump either.
Tony

 

the cts is esentially your choke, and a lack of one does cause a hard to start when cold condition. it tells the computer what temp your car is at so it can set the appropriate air/fuel mixture. not only that but it is also a sensor that allows you to operate in closed loop(relying on sensor imput instead of pre-programmed tables for air/fuel) so without it you are probably running constantly in open loop and suffering lower mpg. also i believe the sensor for fan on is located in the passenger side block somewhere in the middle under the heads. if im correct this plugs into a coolant jacket. you caould simply relocate your sensor there and put the cts back. again i could be wrong about the fan on sensor(or whatever its called).