Need Help: 8835 RPM, 22.8+AFR, 21psi, and ALKY

[DoubleD]

since my thread in the general tech section is getting absolutely no response, I thought maybe you guys could help out.

The conditions in the title only occured for a couple of powerlogger frames, but it could have ended in disaster anyway, so I need to find out WTF is going on.

I essentially hit the soft cut Main limit on the 2step (TH400 RMVB, so I was "accidentally" testing the main limit) and all hell broke loose. Please see the attached powerlogger file of the incident. The powerlogger/ecm saw an RPM reading of 8800 rpm for part of a second and cut the fuel injectors while Methanol was presumably still spraying (20 psi of boost at the time). I got out of it obviously, because the car bucked so hard I almost hit my head on the steering wheel. Luckily the motor is not hurt, and doesn't show signs of damage at this point... This is what the 2step is supposed to prevent isn't it?

I am really not sure what may have caused this. I thought that it may be an issue between the GENII and extender extreme G chip with spark control in conjunction with the Baileys 2-step, but I cannot be sure. The only connection I could see being the problem is wire B4 which is tapped by the Translator, and spliced by the 2-step. is there a particular connection scheme this must follow? It currently goes ECM->GEN2 tap for spark control->2step splice->engine.

What could have caused this?

I kinda wish I had a chip that was burned for no rev limit at this point, but it still seems odd that this reading is so out of whack.

I'm hoping at least someone can chime in with some ideas at least.

Please help me out. Very hesitant to drive the car knowing that this could happen again.

Thanks - DD

View attachment Strange RPM Limit error.ZIP

 

[turbocliff]

Can view the .dat file, and dont use powerlogger... wish I could help-

 

[DoubleD]

I can post screenshots of the powerlogger screen in any configuration you want. Can try and export to CSV if that would help as well. I think you can do that with the PL.

Thanks Cliff.

-DD

 

[DoubleD]

So this did cause a headgasket failure after all...

 

[jasjamz]

You got off lucky, my last two 8000 rpm incidents costed me a block.:frown: If your oil pressure is off even a tad bit you better check the torque on the mains. If one is loose, it's cracked.

 

[DoubleD]

I'm quite sure the car didn't actually go to 8835 rpm if you look at the log. 8835 is just what the computer saw at the highest point for a split second (essentially when the 2step should have been limiting the RPM)