I was driving for the road and the vette just died. It restarted but had a check engine light. Got home checked the code . It was a code 33. New MAF sensor. Checked burn off relay and power relay. Any suggestion on this problem. Thank you

 

Follow the procedure in the FSM, if you replace the MAF, replace both relays with it as a rule.

 

 

Code 33 is not always due to a malfunction. It could be due to a poorly calibrated MAF sensor (erroneously high calibration), incorrect min air adjustment or increased airflow with respect to tps and rpm due to modifications.

Code 33 is set if: unlimited airflow > 45 gm/sec with tps < 14.8% (~1.10 volts) and rpm < 2200, or unlimited airflow > 45 gm/sec when engine is first started. It is a crude plausibility check of the mass airflow with respect to tps and rpm and is primarily intended to catch an open circuit on the maf signal input.

This car is dangerously close to setting a Code 33 due to modifications: https://datazap.me/u/tequilaboy/inte...0.00&tmax=1.11

Here's a log showing a Code 33 being set by a car with even more airflow than that shown above: https://datazap.me/u/tequilaboy/code...2104-2094-2142

The error flag is set about 5 seconds after the actual failure is detected. Note the dropping mass airflow signal and the fixed unlimited airflow signal behavior. The default airflow calculation (which is too low) is replacing the mass airflow signal as the failure is detected. The car then runs lean since the default airflow calculation is not a good fit with the actual sensor behavior due to the increased airflow (relative to stock). Note the mass airflow signal vs throttle position before and after the failure, or just look at the O2 sensor voltage: https://datazap.me/u/tequilaboy/code...2104-2094-2142

Code 33 or a high maf signal in general should not cause the engine to stall unless it is so rich that it causes it to flood itself out (the maf signal will still be limited by the max maf vs rpm table).

;--------------------------------------------------
; Max Air Flow vs RPM
;
;
;
; TBL = Grams/Sec
;--------------------------------------------------
ORG $06F2 ; gms/Sec RPM
;------------------------------------------
LC6F2 FCB 23 ; 23 0
FCB 23 ; 23 400
FCB 30 ; 30 800
FCB 48 ; 48 1200
FCB 68 ; 68 1600
FCB 89 ; 89 2000
FCB 111 ; 111 2400
FCB 141 ; 141 2800
FCB 170 ; 170 3200
FCB 200 ; 200 3600
FCB 220 ; 220 4000
FCB 236 ; 236 4400
FCB 245 ; 245 4800
FCB 247 ; 247 5200
FCB 247 ; 247 5600
FCB 247 ; 247 6000
FCB 255 ; 255 6400
;--------------------------------------------------

Max maf vs rpm table expressed as equivalent max load for some perspective. 255 = 100%, so < 400 rpm would be the worst case for over-fueling due to a high maf signal.