We swapped in an L98 350 inplace of the stock 305 into a 1986 IROC. When we go to start, it runs for a second or two and then dies. I think the cold start injector is functioning fine. I don't think the injectors are firing, no voltage on the injectors and no voltage present at inj1 and inj2 fuses. This was tested by cranking the motor and observing. I'm thinking something is not properly grounded somewhere, but don't know where to look. Any help would be appreciated.

 

Does anyone know where the ECM grounds to? What color wire and where it is located in the harness coming out of the ECM?

 

ECM should be grounding on the back of one of the cylinder heads along with other grounds. You should have had 2 ground wires going to each cylinder head, make sure one of them didn't get "lost" or broken during the swap.

 

There are 2 grounds to each head, I did break one going to the drivers side head but I fixed it, soldered on a new connection. Any idea which head has the ground for the ECM, and what color the wire is?

 

Don't know which one is the ECM ground off the top of my head. Make sure the nuts on the ground studs are tight and that you didn't/don't break any off while tightening (its very hard to see back there). Make sure your engine to chassis ground strap is making good contact too.

 

I've been there before. Right after my L03>L98 swap. I used an '86 harness in a '90 car and the plug under the dash that goes to the engine harness changed between years. The injector power wires were in this plug and consequently not hooked up. What I did was just connect the injector power wires (Pink w/black stripe) that come from the fuseblock to the injector wires on the ECM harness. This powers the injectors normally except you just bypass the plug. Make sure you have a good connection. I soldered mine to make sure. If you need more details, let me know and I can go out and look at it in the morning. HTH.

 

We are not even getting power to the fuseblock. I don't think it's the same exact problem you had as this is an 86 harness in an 86 car with all of the 86 sensors and accessories. I am wondering about the prom we are using, it is a program from a 88 Corvette. Could that chip address things differently?

 

I don't think the PROM would have anything to do with you not getting power to the fuseblock. I would check the bulkhead connector on the driver's side firewall. Make sure the connection is clean and tight. When you turn the key on, does the engine light come on? If so, then your ECM has power and is grounded. If not, then you've got a bad connection somewhere related to the ECM.

 

Good info, I'll have to go try a few things and get back to you. I don't remember if the engine light comes on or not. I didn't see anything out of order that I remember though. I'll go crank it and find out.