Cascade Crew

RSFreak · Posted: Mon Mar 07, 2011 7:28 pm Post subject: adjusting idle speed?

The idle speed on my T/A drops to about 500 RPMs when in gear. In park or neutral it idles at around 750 - 850. It seems like its gonna die when the RPMs drop when the car comes to a stop. I'd like to have it idle around the same speed as when in park/neutral. What values do I need to change in the bin to accomplish this? I am using an '89 305 TPI auto trans bin with the $6E mask in Tunerpro.

Twilightoptics · Posted: Mon Mar 07, 2011 7:31 pm Post subject:

You need to re-set minimum air followed by a tps adjustment. No tuning needed for a stock motor. Should be around 600rpm in gear.

RSFreak · Posted: Mon Mar 07, 2011 7:42 pm Post subject:

With the LT1 cam it is still basically stock, right?

aaron_sK · Posted: Mon Mar 07, 2011 8:09 pm Post subject:

What chip is this, John? Gabe and I upped the idle speeds in the BIN I e-mailed you.

RSFreak · Posted: Mon Mar 07, 2011 9:09 pm Post subject:

Thats with the most recent bin you sent me. I'll know better after driving to work if the tranny is performing better or not, but it still idles low in gear.

Twilightoptics · Posted: Mon Mar 07, 2011 9:16 pm Post subject:

aHH. Didn't know of the updated cam.

RSFreak · Posted: Mon Mar 07, 2011 9:47 pm Post subject:

The LT1 cam is only slightly more aggressive than the stock 305 TPI cam. Think that would make a difference?

popballz · Posted: Mon Mar 07, 2011 9:48 pm Post subject:

mine does that after its warm, when its cold it runs great!

so do we have the same problem or is yours just from upgrades?

RSFreak · Posted: Mon Mar 07, 2011 9:54 pm Post subject:

I got kind of a Franken-'Bird going on here. Its got a '91 long block and TPI with an LT1 cam running an '89 tune. I'm running the '89 bin because the later TPI setup deletes the 9th injector which is needed for cold starts. '89 was the last year for the f-bodies with the MAF and '165 ecm.

Twilightoptics · Posted: Mon Mar 07, 2011 9:58 pm Post subject:

It makes considerably more power in an '87+ 305 than the stock cam, also has a wider lobe seperation angle.

It's enough that the ECM isn't completely sure what to do with it.

RSFreak · Posted: Mon Mar 07, 2011 10:04 pm Post subject:

I know I need to get some data logging equipment and get a tune dialed in.

Alphius · Posted: Mon Mar 07, 2011 10:58 pm Post subject:

Didn't we turn the idle up to 650 in gear on that chip Aaron? Maybe the IAC is sticking. Or minimum air isn't set right.

I don't know a ton about the TPI computer, but shouldn't it target an idle speed and "just work"? Stock chip was set to do 550 in gear if I remember right.

RSFreak · Posted: Mon Mar 07, 2011 11:15 pm Post subject:

There are two variables in the bin called IAC Target Speed Deadband for Park/Neutral and IAC Target Speed Deadband for Drive. The first is set to 50.00 RPM. The second is set to 12.50 RPM. Not sure if these are the values I'd need to change or not.

aaron_sK · Posted: Tue Mar 08, 2011 7:09 am Post subject:

Alphius · Posted: Tue Mar 08, 2011 8:41 am Post subject:

RSFreak · Posted: Tue Mar 08, 2011 3:20 pm Post subject:

I don't have an ALDL cable yet. I noticed today that at idle in gear it idles very rough like it has a BIG cam, not like its misfiring, just very lopey.

I wouldn't discount the IAC sticking. I'm sure its plenty dirty. Embarassed

Twilightoptics · Posted: Tue Mar 08, 2011 4:12 pm Post subject:

You guys understand what the minimum air adjustment does right?

RSFreak · Posted: Tue Mar 08, 2011 4:17 pm Post subject:

I'm gonna guess its the minimum amount of air the engine needs to idle? Confused

Twilightoptics · Posted: Tue Mar 08, 2011 5:56 pm Post subject:

Basically. It's giving the engine the most air it can, with minimal room for the IAC to close. Most aftermarket or tuned setups like your hot idle IAC counts to be at about 20 (out of 160) open in gear. So you open the throttle, the IAC counts drop because the ECM sees it doesn't need the IAC open as far, to achieve the desired idle.

After you set this you must reset the TPS so all other functions are appropriate.

Alphius · Posted: Tue Mar 08, 2011 7:36 pm Post subject:

John, if I find my ALDL cable you might be able to persuade me to part with it if it's for a good cause. Razz