Well where to start OK, so I have a 91 Camaro RS 305 TBI that has been swapped out with a 355 TPI speed density set up, so the guy who did the swap had a really, really crappy engine harness it really looked like crap. So I found an original 91 camaro TPI harness on ebay and sent off to get it to replace that nasty harness the car had on. So after putting everything together and making things look nice and pretty, I fired her up and no start so after hours off looking at all these different issues my buddy and I found out that there was no power to the ECM we've been puzzled about this issue and just wired a relay to the ECM and car starts up with that relay wired to it, now another thing I tried using a scanner to run a simple diagnostics on the car and the scanner will not pic up anything! It keeps saying no power... We tried it on a different camaro and the scanner worked fine, for some reason the scanner isn't picking up any power on my camaro and I'm assuming that it's the same reason that there is no power running to the ECM not even if I put a wire straight from the battery to the ECM the scanner STILL wouldn't pick up anything this is very confusing and I'm lost here can anyone help me out?

 

check the 20 amp fuse near the battery it supplies power to the ecm.

 

Yeah it's fine as well...I checked all the fuses under the dash as well and all ok

 

Check the fusable links down near the starter.

 

I know that the bolts on the starter are a bit lose, and I haven't check the fusible links those would be the ones with a white plastic cover right? The ones that look like there encased? OK let's say there OK, what next though?

 

Well not the bolts that hold the starter but the small nuts that hold the wires in place are lose a bit I lost the original nuts and put a nut that more or less fits the same...

 

I believe there are two fusable links on the starter connected to the same bolt as the battery cable. If the nut is loose or the links have failed your car may not have power on some circuits.

 

Did you ever get this problem worked out? I recently was going through a rain storm and lost all my guages. i'm assuming my ecm quit receiving power. I checked my main fuse box and they all check out, the car still drives because i've swapped a tpi for a holley 650 and bypassed the computer on everything, i would just like to get my guages back. Any more suggestions on this would be sweet. I will check the 20 amp fuse by the battery, and fuses down by the starter? Is there any other inline fuse for the ecm?

 

The ecm does not control the guages, they are all connected to seperate sensors under the hood. If all your guages quit at once it's most likely a fuse issue.