What should the volts be I see tpi tbi setting but not for the carb? also would hte tps make th ecar backfire though the exhaust? when the car was running I had about .85 on the scan tool.I knpw the car is not suppose to be running when checking this.

 

On my 84Z the TPS should read .48volts with the Ing on,Eng off & A/C solenoid(if equipped)disconnected.Some though are as low as .40 others as high as .55volts depends on the year/eng.When my old TPS went south.I tested it & it was reading from .90 to as high as 1.72 volts(original tps).I couldnt adjusted to the proper voltage.It would jump from .32 to .90+ volts.Then go up to 5volts at around 1800rpm.drop back to .90-1volt & gradually climp up to 5 volts again(WOT).At any rate,it never back fired at any RPM.

 

TPS should read from (around) 0.40 volts to (around) 4.0 volts at WOT. A bad TPS will, like BLACK Z said, give inconsistent and non-linear readings. A bad, or misadjusted, TPS should not normally cause back fire, but it will cause temporary rich and/or lean conditions that can contribute to back fire.

 

carb tbi and tpi cars call for something diffrent?
so a carbed car is about .48 I think the tpi cars are .54?

Would a out of adjustment one cause a backfire thought the exhaust?