A friend has a 93 LT1 396 stroker with a SC on it. He had PCM4Less do a tune, and the guy said Bryan sent a note back saying he needs to get an ignition box and pull 1* for every pound of boosthe owner bought the Mallory 685 box and map sensor and harness. What does he do with the old sensor, Keep it for fueling? I know the mallory will pull timing but with the old sensor not there it falls on it's face if you rev it up. I suppose that's because the Pcm doesn't see a load? I am thinking he needs to keep the old map sensor for fueling and the new map sensor on the 685 box to control timing. Sound right?

 

Yeah put the old map sensor back where you got it and run a tube from the manifold back to the new 2 bar map sensor and just mount that to the engine compartment on some velcro or something. All the new map sensor does is work the timing retard. the old one works the engine management system.

 

Thanks! that's what I figured, just wanted to make sure.