Anyone worked with the 16196397 yet?

**Terminal_Crazy** · 01-22-2017

Originally Posted by Xnke

I haven't had any kind of luck hunting down the voltage drop issue-I am about to stuff a 22,000uF capacitor filter across the switched power and another across the battery power and hope that's enough to limit the voltage drop during cranking.

I'll have the wideband in the pipe tomarrow, and should be able to get some fuel table feedback to try and get the PCM to at least attempt to control fueling-it's still Scrooge Mcduck rich, immediately after it fires.

It's really, really strange-it will start and run for a few seconds every single time-with absolutely no regard to temperature or weather, just like a factory truck. But after the initial crankup and first firing, it immediately struggles to not drown in fuel. I'm hoping by leaning out the main and idle VE tables some, I can at least get it to run long enough to get the alternator on board, and hopefully that will cure the voltage issue.

The odd thing is that the relays aren't chattering and nothing else seems to have an issue with the voltage-just the PCM. And it does it will all four functional PCM's I've got-I managed to rescue the dead ones.

Have you tried cracking the throttle blade to allow more air in, or remove a vacuum pipe. It might just allow it to keep it running long enough.

Mitch
Terminal Crazy

**Xnke** · 01-23-2017

It does make a difference, but opening up the throttle a bit gets it into a surging, lopside chug that belches raw fuel out the exhaust as vapor-you can literally light the exhaust on fire with a lighter. BIG boom after it's "idled" a minute! Opening the throttle too much causes a rapid RPM surge then it stalls out lean. Never does foul out the plugs-just soaks them in fuel. Gotta hand it to the GM DIS coil packs-they're blasting away like a champ.

I have some time this evening, so I plan to go back out to the combustion lab and see what I can do as far as getting the idle straightened out and try the capacitor trick-it may be something as simple as trying to pull switched power from the wrong place, too, so who knows what I'll end up having to do to fix it yet.

**Xnke** · 01-25-2017

Found a bad relay contact in the switched ignition line-was dropping 2.5V across the contact. This made a significant difference, but still hasn't fixed the massive amount of data corruption on the ALDL line-but at least it's talking now.

**Xnke** · 01-25-2017

So I've made another terrible video for Youtube, to try and explain better what's happening here. I still don't have a clue what's going on, maybe VATS is killing it, maybe it's super rich, I can't tell.

The wideband shows 13-14 AFR's when it starts, but when it would normally shift to the running table, I can't tell what happens because the engine either stalls out and dies, or I have to pedal the crap out of it to try to keep it running. The datastream is wigging out the whole time too, at least I have a datastream. Unfortunately, I haven't kept it running long enough to accurately measure the *running* PCM voltage. I still don't think it's an issue, though, because swapping to unpatched stock code and a 1 bar sensor lets the truck idle and free-rev OK, as long as I've changed the injector flow constant and the blower is bypassed.

Fixing the voltage issue did solve the super-rich chugging issue where it would fill the whole lab with fuel vapor, though! Gotta take a win where I can get one.

**RobertISaar** · 01-25-2017

i can't make any sense of the datastream issues..... I've seen vehicles have issues before with this PCM, but they were solved with a single tweak to the ADX. is it still freaking out if you use scan9495?

**Xnke** · 01-26-2017

https://www.youtube.com/watch?v=nrXr...ature=youtu.be

There's a video of last night's work-I am building a little VATS module to test and see if that's the issue. Who knows, it's ten minutes to get one going.

Possibly another update tonight.