Pulled the scanner today and drove the car.
She stays in closed loop.
Got code 33.
MAF / MAP too high.
I'm guessing this could be the problem?
How bad if at all can closed loop hurt performance?

 

You're car is supposed to be in closed loop. It will only be in open loop at cold start up and at WOT.

Clear the codes, try a friends MAF and see if you still get the code...

 

Even under WOT stays in closed loop.

 

It may read as closed loop on your scanner, but technically it's not as it is not using O2 sensor values to trim the fuel at WOT.

 

max929:

How about telling us the year of your car, and any mod's so we can try and give you the correct answer. DTC 33 is the MAP sensor. You are using a code list from the 3rd Gen's, or a generic list that came with the scanner, if it says MAF/MAP too high. On the 4th Gen's it means "signal voltage high, low vacuum".

Your car starts in "open loop". After the O2 sensors and the coolant warms up enough, and a timer times out, the PCM goes into "closed loop", where it looks at the O2 sensors and adjusts the fuel calculations based on this feedback.

Your scanner would be indicating "closed loop enabled", meaning you have met the O2 sensor, coolant and time reqruiements. Even when you go WOT, the scanner will still report the "closed loop enabled" flag, since GM doesn't call WOT "open loop", they call it "power enrichment" (PE) mode.

What problem are you trying to troubleshoot?

Again, add the basic info like year, tranny and major mods, so people can help you. All 4th Gen's are not the same.

 

I think you guys answered my question.
I'm just learning the in's and out's of the parameters.
My car is a 93 Z28 M6
Hotcam/Headers w/custom y pipe and exhaust/CAI/2.00int/1.60exh ported stock heads/pcmforless chip.
I have this mods done earlier this year. Runs strong but went to the track recently (only got 2 runs in) 14.29 @ 100mph 2.2 60 foot was the best out of the 2 runs.
The suspension is lower S/Tsprings and bilstein shocks.
I have 99 vette wheel 17/18 combo.
I was hoping to get 13's.
In stock form with CAI only I ran 14.47 @ 96mph..so either something is wrong and I really gained no power or the suspension is hurting times.
This was the reason I ran a scanner on her to see if something was not up to par.