just like the title says... im trying to figure out if different IACs or TPSs will change the pcm tune? example if it was tunned with a old dirty IAC.... would putting a new clean IAC effect the tune?

and my other question, if i tune with a old TPS, would a new TPS in the future effect the tune any?

thanks guys... cause i installed another IAC sensor, and it stalled again this morning... but only when the engine is cold.. once it gets 1 click warm, its fine.. all this started when the old IAC broke... maybe the 1 i replaced it with is bad... as its aged too.. but i have another aged IAC i can try... im 100% sure its the IAC...

also when i installed it, i had the pintle all they way compressed... so i would say 200 count?

but ill be doing the BBC tb swaps this week before droping it to the dyno sometime next week early... and i would like these questions answered...

 

this shouldnt have any affect just reset your iac

 

are you sure about this? anyone else care to give their input? I was told maybe it was maybe trying to relearn on the other cold start morning...

what is the exact step by step of the reset IAC? how positive are you that sensors don't effect the tunning? I really need to know this..

 

I am currently running with no IAC. I will say it may affect the drivability with cooler coolant temps(OL) but once it hits 160F i will suggest the drivability is the same. My IAC is fully seated. I also ran with IAC functional and I dont think I could tell at all SOP. Not sure how much additional CFM's IAC gives while under acceleration AE or PE but I dont think it amounts to much.

Keep in mind the CL A/F is determined by NB02 feedback.

As far as the TPS I think I read once that the ECU assumes it is at zero % .52V even if it is at .70V. I dont believe it will affect the tune if reasonably close. Mine is set permanently at about .60 and non adjustable.

 

thanks for the help.. so basically.. i was asking these questions..

so i can get my dyno done with the old 454 TPS and IAC that is on the unit, but works fine... correct? and when i do afford the money to swap in the new sensors... everything to my tune should all be fine still, correct?

 

The old TPS is easy to check out. just watch for smooth progression of Volts from .5X to 4.5 on V meter as you advance the throttle. Same in datalogs. As far as IAC it should be apparent if it is functional on cold start and CL at idle. My CL idle was 1400 rpms so that was not cool. In data logs it showed zero steps. As I said I could never get it right do to wiring error. I cant see how a IAC will affect a dyno tune other than on PE it may flow a few xtra CFMs if wide open on steps.

 

damn, thanks for explain that in that way, it made perfect sense... and when the IAC is at 0 steps that means it all the way extended correct? And when you buy a new IAC, is it fully compressed or extended? sort of confused there...

but i started the truck up just about 1hr ago for the 1st time today.. and it started fine and idled great then went into CL and idled fine... so maybe like i was told from someone else, the pcm just had to relearn itself some more that 1 time... cause i did reset the bat, and i had the ab terminals jumped..

 

fully closed is zero steps. some say at idle should be 5-10 steps max. full open is 200 steps. I think in my 350 cid with 7.4L TB I have my coolant tables at about 99 max. i guess 200 would be OK for PE?

New IAC? not sure. I will guess it comes ready to install in package. ECU will cycle itfully closed then will reopen it to wherever it should be for cranking start. Not sure if it readjusts after a certain MPH is achieved. maybe it goes through another adjustment? something tells me that is in stickies.

 

thanks for all the help and answers... im going to just use the old sensors for now. would you happen to know the wire diagrams for the TPS and IAC sensors on the BBC tb? i need to do that swap tmrw... I might just start rebuilding the tb tonight...