My car is running badly and does not appear to be getting the proper ignition advance. When I took a look at the ECM I found a Hypertech chip in it. I looked the number up at Summit and found it was for an 88 with a 350. My car is an 86 (I have a mild 355 in it). Could this be the issue since all other components and wires check out?

 

i would bet that that would be the cause.... 86 ecm is different than the later years.

try gettin a 88 350 ecm if you still have the coldstart injector on TPI

else ditch that 9th injector with a 89 ecm which i hear is a good ecm. you could probly pick up a stock 89 L98 chip for it for cheap too that might work as good if not better than that hypertech

 

run some codes and see what you get

 

There are no codes, thats another part of my problem.

 

are you at least gettng #12, I ask becauce mine wouldnt pull any codes at all and it was the ECM

 

I do get #12.

 

The '86 ECM is a 1227165. The '87, '88, and '89 ECMs were also all 1227165s. The CALPAK devices should be interchangable. The ECM firmware and hardware are all the same. I'm using a $6E PROM in my '86 with no trouble (other than the pesky rear tire wear issue).

However, the supporting hardware may be different. The '86 should have been equipped with the cold start valve and separate control. That will work with or without the ECM programming. I'm still using mine.

The programming on the devices, however, may not be best suited for the other application. If your 355 still has 19lb/hr injectors, the stock (even though it is Hypertech, its basically stock) programming would have injector constants and the resultant pulse widths for 22 lb/hr injectors, and may not be delivering adequate fuel. You may also have an inconsistency in the detonation sensor and ESC hardware. Regardless, the ECM should work.

 

I’m glad to hear I don’t have to worry about the hypertech chip right now. The running issues have seemed to subside now that I have broken the engine in for a bit. I did change my injectors to #23s and added a knock sensor for a 350 when I rebuilt the engine. Does a 350 use a different ECS module?

 

The ESC should be the same.

You could do better than the HyperTech program, however.