Ultra Z

iTrader: (1)

After installing a fast 90mm set up I've had the hardest time trying to get this thing to idle. I got it pretty close now but cold starts suck and coming to a compleate stop it will sometimes surge like a bitch.

I guess the main problem is I can't get the IAC values to drop into place. The counts are currently stuck at 0 and the more I try to close the blade the worse it runs.

I'm assuming if the IAC values are 0 then changing the values in the idle tables will do nothing? Like idle air flow and and p/n air flow tables? Or do they?

Is it possible to get the car to idle with the IAC values stuck at 0? Like I said it's pretty close right now even with the value at 0.

I plan on going to the dyno for some wb tuning soon and I'm hoping this will help clear this up a bit but still would like to get it closer before I go so I don't have to spend all day at the dyno.

Any help at all will be appreciated!

P Mack

iTrader: (6)

Is this an f-body (not drive by wire)? Have you drilled a hole in the throttle body blade or is there already one there? Is desired Iac position 0 also? Are you using hptuners?

Viper

iTrader: (6)

I had to completely remove my set screw to get the IAC counts to go to 30. With the set screw in, they were always at zero. This is a ported Bo White TB. I have a hole drilled from when I had a TR224. I guess if I want / need higher counts I could drill a bigger hole or dremel where the TB shows zero. However I worry that will mess up WOT 100% TPS readings.

Ultra Z

iTrader: (1)

This is on a f-body and no I have not drilled a hole because the IAC value is 0 which means I have too much air going threw as is. I guess I could try to remove the set screw compleatly but the problem with that is, when I try to close the throttle blade it begins to run worse and worse till the car won't idle long enough to even get an IAC value. What tables should I change to try to get it to idle while closing the blade?

P Mack

iTrader: (6)

I would drill the hole and close the set screw a little. But before see what fuel trim cell you're in at idle, and tps% also. I'm thinking your tb may be open so much because you don't have the hole, that it thinks your not trying to idle because your holding the throttle open. If it thinks that it won't try to stay your idle rpm and the IAC could just stay at 0.

Viper

iTrader: (6)

P Mack

What fuel cell are we supposed to see at idle again? 20?

Ultra Z

iTrader: (1)

No actually my tps sensor is at 0%. I did have that problem before but I corrected it. I'm in fuel trim cell 20.

P Mack

iTrader: (6)

Hmm, that's weird. I would have thought you would have needed more airflow than that, unless you have a stock cam or something. What size of cam do have? And desired IAC position is 0 also?

P Mack

iTrader: (6)

You should see 20 on cold starts, 19 ac off, 18 ac on, 17 park/neutral ac off, 16 park/neutral ac on.

Ultra Z

iTrader: (1)

It's an ARE forged 346 with a 226 226 569 569 114 cam and stage 2 ARE LS1 heads

My fuel cell values are fine.

My desired IAC are set at stock settings.

P Mack

iTrader: (6)

Not sure what you mean by desired IAC are at stock settings. I am talking about logging the desired IAC pid with the scanner while idling. Anyway, i'm surprised that thing will idle with that size cam, no throttlebody hole, and the throttle blade closed that much.

Ultra Z

iTrader: (1)

Oh, I thought you were asking about a table that I don't have on my version of ls1 edit.

When I scan the IAC values they stay at 0 during idle, part throttle, and wot.

The car dose seem to like it when I open the stop screw but only to a point. After opening it too much it starts to surge and this also brings my tps to .8% which should be with in range.

You think it would help to drill a hole in the throttle blade eventhough the IAC pid is at 0? As far as I know when the IAC pid is at zero that means it's closed all the way because it's getting too much bypassed air. So wouldn't drilling a hole cause more air in a situation where it's already getting too much?

Viper

iTrader: (6)

Wait a minute, your getting zeroes at part throttle and WOT? That's not right at all. I'd make sure your IAC sensor is even putting out a signal. Even if it's zero at idle it should go up as you press on the gas.

As far as the TPS being at .8%, you can reset the TPS so it reads 0 again.

Turn on car, set the set screw where you want.

Turn off car, unplug TPS sensor.

Turn on car so you set an SES for no TPS sensor.

Turn off car, plug in TPS sensor.

Turn on car, TPS wll recalibrate and use the new TPS position as zero.

But first I'd swap with a buddies IAC sensor or check if your getting anything out of the plug end from the wiring harness.

P Mack

iTrader: (6)

Yep I think Viper has it right. That's why i was asking about your desired IAC position. If the IAC position is at zero, it could mean it doesn't want anymore air, but it could also mean it's stuck, or even that it's not being logged correctly. Desired IAC will show you how much air the car wants.

P Mack

iTrader: (6)

And just to make sure you're understanding me, "desired IAC position" is seperate from "IAC position".

2001 Pewter WS6

iTrader: (43)

I drilled my Fast 90 and have the blade closed all the way. My TPS voltage is at .41, my TPS position is at 0% and my IAC Counts are around 35. I couldn't get it right until I drilled it.

Viper

iTrader: (6)

P Mack

Not to steal this guys thread, but if the desired and actual IAC position are within 1 or 2, does that mean I'm darn close? I ran a log on the way to work today and the variance was really small.

P Mack

iTrader: (6)

Yes, desired and actual will usually be very close, the only difference is the response time of the iac motor.

LittleRedZ

iTrader: (5)

My friend has the same problem I'll tell him to come here.

Ultra Z

iTrader: (1)

Ok I did some more logging and I found that my desired IAC count is 136-138 and my actual IAC count is still 0, so what dose this mean and what should I do to correct this?