Todds1987iroc

I got a set of high flow runners for my TPI and a corvette TPI intake and am going to put them on 1987 IROC. When I do this I will lose the space for the cold start injector. This seems to be a common problem and when I did a search about this some people said they used an 89 chip and removed their injector. Others burned their own chip to enrich the fuel at startup. Others just disconnected the injector a remove it. I disconnected my injector last night so I could see how it would start this morning without it. I was not happy about how hard it was to start. So can I use a 1989 chip in my 1987 computer to enrich or prime the fuel at startup since they did not use the cold start injector? Or do I need to get a 1989 computer too?

Tim Burgess

The '89 ECM is different from the '86 - '88 ECM. It also requires a VATS input to fire the injectors, unless the VATS feature is disabled in the PROM.

joker37

So long as the computers are the same the prom will fit, but a stock '89 chip will have vats enabled. This means a no start, unless you have vats removed from the chip. Other then that the '89 prom will have the enrichment programed into it, letting you drop the cold start like you want.

As for what ecm you have, you just have to read the part # off the ecm and see if you can find a chip from a car with the same ECM in 89.... i belive that the 89's did use the 165 (both my 89 5.7 and my 88 SC V-6 both use the same ecm), so it shouldn't be too hard.

Joker

SATURN5

... wrong. All 86-89 TPI use the 127165 ECM. However the VATS info is correct.

1227165
16198259

Application: 1986 2.0 L4 TBI “P” LQ5 w/ MT
1986-89 5.0 V8 TPI “F” LB9
1986-89 5.7 V8 TPI “8” L98
1987-91 truck 2.5 L4 TBI “E” LN8
1991 truck 2.5 L4 TBI “A” L38
MEMCAL IDs: “P”: CRY, CRZ, …
“F”: AUM, ACXT, AKFM, AKFR, …
“8”: BUA, AANK, AANL, APYP, APYU, AUJM, …
“E”: ADHF, AMJW, ASWY, AXAA, …
“A”: AUXH, …
EPROM type: 27C128

Tim Burgess

Oops - you are correct - I was thinking of the PROM IDs; '86 - '88 PROM IDs are 0x32, & '89 is 0x6E. Attached is an '89 PROM file for a 350, auto, APYN. You can use Tunercat to modify the .bin file & disable VATS & a PROM eraser & programmer to modify your existing PROM.

Todds1987iroc

Well it looks like I am going to get into prom burning and make a custom 1987 chip to make up for the removal of the cold start injector. If I had someone do this for me who would you trust?

Morley

Go with the '89 ARAP if you are going to burn a chip anyway, start with the best GM had to offer.

Tim Burgess

Here's the ARAP load.....

Todds1987iroc

The file looks like it is for a automatic car. I have a 5-speed 305 TPI car. Is there a big differance?

Tim when I get the stuff to burn my own chips Can you help me?

Tim Burgess

Sure. There's also lots of good info on the PROM board. Tim Sifford (traxion) has done some write ups on tuning, what you will need & what's available. Basically, the TCC clutch & shift light are controlled by the same pin on the ECM, so it's OK to use an auto PROM for a manual application, & the shift light will light up when TCC lockup normally occurs - unless the PROM is modified to do otherwise.