I just started getting a DTC 33 error reading on my LT1 Scanmaster. When I checked their manual, it says "MAF sensor signal too high - typical cause- bad MAF" but when I checked Injuneer's site, it says" MAP sensor, signal voltage high, low vacuum". No other codes are listed, so what's the most probable cause........ bad MAP? or bad MAF? or something else? We just installed a tranny cooler. Could I have knocked off a vacuum line from somewhere in the process that I can't readily find?

 

thats MAP voltage high which means low vacuum. I would take a vacuum reading at the intake and see where you are at. stock motor you should have right about 19 inches and that would be about 1.5Volts at the MAP sensor.

 

With a relatively aggressive cam, ported heads and intake, I've always had low vacuum. I wonder why it's showing up now. I'll take a look at my Scanmaster's output and see how low it is.

Thanks