We have a late 80's Blazer at the shop ,ZZ4 conversion with superram and the rest stock ZZ4,MAF 88 TPI setup,stock 350 prom.Had 22 # injectors in it and said it was lean,so he put SVO 24# in and then brought it to us.At WOT o2 is only showing .750-.770 mv.fp set at 54PSI.Two of us have TPI conversions at the shop,mine with stock 305 prom ,MAF carwith #19 svo inj,and it shows .850-900mv at wot.The other car is a 80's El'Camino 350 stock TPI 22# inj at 50 psi, Pocket ported cast l98 heads and approx 11:1 comp.O2 is about 850-900 mwith stock prom.WE know this thing isnt making that much more HP than us to out run #24 inj at that kinda pressure.At full throttle on a MAF car even with stock chip i would think it would flow plenty of fuel since its squirting for 22# and has #24 in it at rather high fuel pressure? We dont feel its a prom issue since as stated above both of the other cars do fine with stock chips.Anyone else run into anything simalar?

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86 z28 zz4 ssm lift bars ,3.73 simesed runners and a traction deficient 13.707@101.02,on a 2.16 60 ft on 295/50/15 junk street rubber ,best MPH run 13.82@102.7,69 AMX,390 4 speed sticky tires and other stuff..12.94@102.3

 

if the other cars are 84-88 MAF w/ninth
injector, switch proms. recheck. usually
with a ZZ4 we have to fatten the upper fuel
14-22% to achive better wot A/F (stioch).
blasting the AFPR is one way to achive it
but itll only go so much. is this a scanner
output reading or a volt/ohm meter?
swap O2s with another car. the ZZ4 cam is
aggresive above 1300rpm, the super ram is
flowing more air than a stock TPI. the cam
is drawing more air than stock.
snag a scanner and recheck the blm at wot.
recheck the O2 @ wot.
with all that fuel and pressure something is
not fessin' up.
airdeano

 

>recheck the blm at wot.<

WOT is open loop the BLM is not affected or incremented during WOT operation. This data will be worthless.

>recheck the O2 @ wot.<

O2 sensor is a rich/lean switch around 14.7. Voltage gathered from WOT is not useful because the air fuel ratio you are trying to achieve is outside the sensors calibration.

Tune the car for time. Fastest time (start rich and lean it til it stops getting faster) should dictate your fuel pressure. You also should consider learning how to burn PROMs. I believe that with your combo it will be worth it.

John

Heart of Texas Power and Performance

[This message has been edited by hotpowerandperf (edited October 26, 2001).]

[This message has been edited by hotpowerandperf (edited October 26, 2001).]