I'm curious as to what parameters the VCM uses to switch between the high vs low octane tables. I'm starting to tune for meth, and most of the manufactures have some sort of extra to buy to act as a fail safe in case the meth ran out, or had a problem. Looks to me like GM has a built in fail safe already in place. Am I seeing this correctly, or going down the wrong track?
Originally Posted by dogn
HUH!!!!!!!!!!!!!!!!!!!!!!!!!!????????????????????
I think someone is still out of it from too much turkey, what the heck was that?
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Old thread but same thoughts I was having. wondering what parameters the ECM must see to switch to the low octane table?
I am currently using IAT to control timing in the "high octane" table. I was wondering if there was a way to force the ECM into the low octane table?
2004 GTO M6, 403, Callies, compstar, wiseco, QTP HV oil pump, QTP 2 piece timing cover, EDC custom AFR 235's, LS6 intake, P1SC-1 Procharger maxed @ 13psi, 224/232 600/600 114 EDC custom cam, JBA shortie headers (thanks California) custom boost referenced return style fuel system with surge tank, walbro 255, staged magnafuel 4303, Dual LC-1, Dual Aeroforce Interceptor gages, Nexus fP and boost gages.
SD with no COS or open knock sensor lead will do it...
Not familiar with COS? I am running a 2 bar OLSD tune.
So based on the Knock sensor idea, how is this theory...
Reference: http://chevythunder.com/2004_gto_pcm_pinouts.htm
if pins 11 and 51 (blue connector) were in a "open" ( or vice versa, not sure whether its NO or NC) condition, this would force the ECM into the "low octane" timing table?
If that is correct, I should be able to use either a relay or transistor that is triggered by output from either a flow sensor sw or Pressure switch sensing Meth/ALKY in essence returning the circuit to its natural state? would a clunky run of the mill relay be "fast enough", or would a solid state circuit have to be utilized?
Or have I over simplified the process?
2004 GTO M6, 403, Callies, compstar, wiseco, QTP HV oil pump, QTP 2 piece timing cover, EDC custom AFR 235's, LS6 intake, P1SC-1 Procharger maxed @ 13psi, 224/232 600/600 114 EDC custom cam, JBA shortie headers (thanks California) custom boost referenced return style fuel system with surge tank, walbro 255, staged magnafuel 4303, Dual LC-1, Dual Aeroforce Interceptor gages, Nexus fP and boost gages.
Don't trust it. Sometimes PCMs are stupid about coding.. you never know what ALL of the real criteria is for the error flag. I had a car that used BS3 for engine management and had the factory PCM left as a ghost to control the dash gauges. After a year and half, it finally set a light at the track one night. It was a rear O2 code that I missed for an O2 that was NEVER plugged in.
Even if it would code that fast, it's not going to move back during that ignition cycle.
Well it was a thought...thanks for the insight!
I guess I will just stick with idiot lights, and my IAT controls to hopefully keep the engine intact.
2004 GTO M6, 403, Callies, compstar, wiseco, QTP HV oil pump, QTP 2 piece timing cover, EDC custom AFR 235's, LS6 intake, P1SC-1 Procharger maxed @ 13psi, 224/232 600/600 114 EDC custom cam, JBA shortie headers (thanks California) custom boost referenced return style fuel system with surge tank, walbro 255, staged magnafuel 4303, Dual LC-1, Dual Aeroforce Interceptor gages, Nexus fP and boost gages.
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