Hey Fellas, I took the IROC out today to get some scan data. After my drive
I reached under the dash and pulled the 10-amp ECM fuse to clear the ECM
in preparation for a chip I was going to burn to make some changes to the
AE arrays. After I burned the new PROM I came back out to the car, reinstalled
the ECM 10A fuse and inserted the PROM into the ECM and hooked the laptop
back up and turned the key to the initial key-on position. I noticed right
off the bat that I did not hear the Walbro intank pump prime. Then I noticed
that the SES light and Security light were not illuminated as usual. I turned
the key and there was nothing whatsoever. I did notice though that the temperature
gauge cluster would rise to the extent of it's travel while turning the key
to the cranking position as it always does when the engine is cranking leading
me to believe that I was getting power. I had a suspicion that it may have
something to do with the VATS, but I was under the impression that you know
you have issues with the VATS if the Security light is flashing at you.

And then I realized that the PROM I burned had VATS turned off under the
flags and that possibly causes the security light not to illuminate?? Can
anyone confirm/deny this?

So I pulled the PROM out of the ECM altogether and turned the key back to
the "On" position expecting to see the SES light, security light, and the
fans to kick on but they didn't. So then I came back upstairs and thought
about it for a minute. Maybe I fried the ECM? No problem I'll swap in the
spare '165. So I did, and this time it did the same thing for about 10 seconds
(No response whatsoever) and then after I turned the key off and removed
the key altogether and then turned it to the key on once more it responded
and the SES, Security light, and fans kicked on (No PROM was in the ECM at
this point). To verify if it was an ECM issue I swapped back to the other
ECM and this time it was fine. So I don't believe this is a ECM issue. And
I visually inspected all the fuses but I want to run a continuity test on
the ECM fuse with my DVOM just to be sure. Seems like it had something to do with the key more than anything but I'm not sure.

So does this sound like a bonafide VATS issue to anyone? (Pending the result
of the continuity test of the 10A ECM fuse)

It did something like this to me about 2 weeks ago but it was very quick
since the car started up (I put the key in, did not hear fuel pump prime,
no SES or security, no response to the key being turned but the temp gauge
cluster traveled to it's furthest extent, and then bang it fired right up).

Thanks and sorry for the lengthy post, just trying to make sure I give all
the pertinent info.

Thanks,

Brian P
89 IROC-Z 355

 

Allow me to add that when I tried to flash any SES codes by jumpering the
A+B pins on the ALDL it did not even respond (No SES flash at all). And that
was with the PROM in the ECM by the way.

Thanks alot,

Brian P

 

I may be reading this wrong but why don't you just reburn the chip with VATS enabled or at least back how it was before this all started.

 

It's a good suggestion but I find it redundant due to the fact that I removed the PROM altogether just to eliminate the possibility. The way the car was acting was as if I had removed the ECM from the car altogether as there was no response to the ALDL pins A+B being jumpered.

I did a search on the board regarding VATS and it seems like I had all the symptoms all except for the fact that the ECM did not respond in any fashion whatsoever. All the posts I read were people stating that they could get the SES light to flash DTCs.


Thanks,

Brian P
89 IROC-Z 355