02 Trans Am auto trans stock

I can't find the info, so I'm hoping someone here does.

Specs for the tps? The volts with throttle closed. Is it .56v as usual?

Same for the iac. What are the steps range it should be in while in park; park with ac on; gear ac off; and gear with ac on? I see ranges, but it's a broad range. I've seen 30-80 steps.

Thanks in advance.

 

TPS voltage is correct, should be about 0.5v with throttle closed.

IAC counts will vary from car to car, especially based on load. My notes from my various stock LS1 F-bodies put IAC counts anywhere from 13-22 in park/neutral and 10-20 in gear (stock idle rpms, A/C off). You can expect those numbers to jump up a bit with the A/C running or any significant electrical load.

 

Cool. Thank you. I think my iac steps are way higher than those. I'll look into it and see what's goin on.

Ben

 

Here's what i got. Fully hot.
The tech 2 shows 40-42 counts for 650ish rpm idle speed in park.

in gear it drops down to about 35-36 counts in gear for a 550ish rpm speed in gear.

Throttle position shows .57v. Any thoughts?

 

Tech 2 reads in counts and not steps.

 

What problem are you trying to diagnose? I don't see any issue with counts in the 30-50 range as long as everything is operating fine. Again, every example will be a little different.

Are you having some sort of idle problem that you're trying to track down?

 

Once the car is put into gear; the idle(550ish rpms) seems too low for the alternator to keep up. The voltage output goes below 12.5 with the ac on. You can tell its low output not only by the gauge, but also the blower motor speed slows down. Ac is not cooling as it should. Once the fans come on high the volts are closer to 11.5. I am able to verify voltage thru the tech 2. Alternator is new and checks out good. I bump the idle speed up to about 600 with the tech 2 and the voltage jumps above 13.5. I ohm'd the alternator to the block, block to the battery ground and alternator to battery ground and they're all below .5 of an ohm. Closer to .1. Soon as the engine comes up off idle the voltage output starts coming back up. Wondering if there's something I'm missing so I'm chasing things down.

Trying to fix the issue before i start modding and tuning the car.

 

These cars came stock from GM with that idle speed (550rpm in gear for an auto), so there's nothing abnormal there.

Even when they were brand new, the voltage would dip into the mid 12s with a full load (including A/C on max); 11.5 is pretty low though. Interesting that you can bring voltage so much higher with just a 50rpm bump in idle speed (seems like that would be the simple solution with very little downsides here).

The other consideration is this "new" alternator. It might check out good on a test machine, but that doesn't always translate to excellent real world results. What brand is the unit? If it's a rebuild from one of the big auto parts chain stores, then I'd consider it as good as junk to be honest. Never had great results from those. However, if it's a quality brand like Powermaster then I would trust it. Only alternators I've ever had great results with have been OEM originals and replacements from Powermaster.

 

The alternator is a powermaster 150 amp. Wonder if the pulley diameter is larger than factory? Does anyone have the diameter spec of a factory pulley? If it's smaller on the factory compared to the powermaster; that could be the issue. If it is; I'll bump the idle speed up to fix the issue.

 

Has anyone done a one wire alternator on these cars before?