Steve40th

Just curious who here has had there Car run wierd on the dyno, yet run fine on the road or another dyno? Can the dyno be hooked up worng? Can haveing the wires they use to read rpm etc make your ignition misfire, DELTEQ?, ASR on, E Brake on etc etc. Just curious as I am trying to find out why my car ran LEAN (according to the tailpipe AFR readings, 14 to 1), yet dumped black smoke on 2 different tunes. F/P made no difference either.
I posted here two, and here are some updates

DYNO operator/equipment errors? Are they possible? - Corvette Forum

F-BIRD'88

An engine that is misfireing (for any reason) will show a lean air fuel ratio.
Because an engine that is missfireing is not consuming the oxygen. The oxygen goes right out the tail pipe. A AFR meter (even wide band) reads excess oxygen on the exhaust to determine the AFR. It will read lean wether the engine is actually tuned lean or there is unused oxygen in the exhaust. it does not know the difference.

Steve40th

So, I need to look for a misfire? The plugs, wires are all new. Injectors dont leak, and DELTEQ coils are good. I will recheck the valvetrain, Comp R's, and check for vacuum leaks as this is a speed density. Thanks

F-BIRD'88

A intake vacuum leak can be real confusing. One cylinder will be lean( even misfiring from excess leanout {airleak}) while you try to tune it out by richening up the jetting. now all the other cylinders are over rich but the AFR meter still reads lean, because of the unconsumeed oxygen of the missing cylinder(s).
The other cylinders soon can join in (over rich fouling) missfireing adding even further unconsumed oxygen on the exhaust. The AFR meter does not know the difference.