LT5 ECM Tuning thread

[ShawnZR-1]

Originally Posted by rkreigh

Hi todd,

I have a question, I had the secondaries removed and unfortunately VA has cut the HC standard down to 48. it's made it impossible to pass.

car does have cats (random ss, probably not nearly as good as stock) and I haven't yet had a wideband to see how rich the car is running but it seems WAY rich at light throttle.

I need some help to tune the car to pass emissions. marc is a bit too far away in chicago. I do have EASE, and I could install a wideband or take the car to a shop with a dyno.

the car is an LPE 390 and has the big 234 cams. do you think there is ANY way I can get this car to pass??? I tried doctoring the gas with alchy a few years back when I had the LPE chip in the car (open loop). it was even more rich and I could get the HC down to about 97 running 2/3 alchy, but I don't think that will work anymore, when I last tried the "cocktail" it still was up to 150 HC and I couldn't get the car to run with as much alchy in the gas. I love the ZR-1, but this is a problem

any ideas (besides moving)

Well, to go along with the "Check Mechanical" before tune, I would pull the plugs and get a read on them. You'll be able to see if they are running rich.

High HC is usually a symptom of incomplete combustion. It's possible the spark is advanced too far or your plugs are fouled.

What kind of test does VA perform? Is it a two-speed, dual load or just an idle test?