YellowToy/A

iTrader: (1)

I put in a 224 228 Cam XER lobe, on a 110 LSA. Right off idle it want to stall and buck. I think I need more air. To get more air I need more IAC motor counts. I also think that if I get more counts that the PCM will give it more fuel.

My friend said to just change the throttle cracker. Is this true? Should I also change the throttle follower? How much should I change them? Should I do something else?

Thanks for the help

Billiumss

iTrader: (11)

What are all of your mods?

Throttle Cracker is for when you are moving not at a stop.

Did you adjust the VE table at all?

Did you drill the TB blade any?

Auto or 6 Speed?

We need a ton more info to help you.

Bill

SSpdDmon

iTrader: (10)

You need less of the throttle cracker/follower with a bigger cam. I took 50% out of my friend's follower and completely redesigned the throttle cracker table so that .5 grams/sec is the most that is seen. He's running a 232/234 cam. Remember, cracker is activated based on RPM and MPH. Follower is based on TPS% change.

To help with the surging, you need to do a couple of other things first. One is get your desired idle airflow in line. Follow the steps using your LTIT's and STIT's to get there. You also want your IAC counts to be about 60~70 during a warm idle (car has been up to temp for 5 minutes or more). You can do this by drilling the tb blade or adjusting the set screw. Last, I like to take ~25% out of the IAC tables. In EFI Live, they're called: Filtered RPM Airflow Correction, Learned Airflow Correction, and Direct Airflow Correction. Because the motor breathes so much better with the new cam, the IAC overcompensates for excessive idle conditions. That's where a lot of surging comes from. 25% is a starting point though. Some cars like 20% and some like 30%.

Surging while coasting at low RPMs (<2,000) can be corrected by timing. Once your fueling is in line, try adding 2-4 degrees timing to the low airflow cells. I've seen cars with timing as high as 45 degrees to help eliminate some of this surging. I personally set my friend's car up with 43. The key is setting up the table with one number from ~2200 to ~1400rpm. The timing table causes surging in stock form because...as the car is slowing down, the cell changes to a different degree of timing. This can cause the car to jump back into the previous cell. Next thing you know, the car is lurching back and forth and your neck is about to snap.

**Keep in mind, all of this was done on an A4. Manuals might be a little different as they use some sort of spark smoothing within the operating system.

YellowToy/A

iTrader: (1)

I got my VE and STIT and the LTIT in line. My IAC counts are 30 at warm idle. My problem is that as the car launches it wants lurch back and forth and stall. I have add 4 deg of timing at low RPM. I will try to add some timing at higher dynamic air.

I increase the RPM to 1000 and let out the clutch. I saw that the IAC count went from 30 to 68. The car starts to move. I let the throttle go to 0%. The RPM drops to 350 RPM. The IAC counts drop to 60. I thought that if I add more air it would stop it from dropping to 350 RPMs.

TAQuickness

iTrader: (28)

Idle and idle transitions are very sensitive to proper AFR and spark. There is a lot of great info in this thread to get you going. Take you time and make small changes until you are satisfied with it. You won't be the first to beat your head on the wall tuning idle.


Edit:
Also, you may want to check the differences between your base spark and your octane spark tables.

YellowToy/A

iTrader: (1)

Any body esle???

MSGHUFF

iTrader: (7)

good info I havent touched these tables yet, its next, but would like to know more about the follower and cracker tables delay decay ect

YellowToy/A

iTrader: (1)

still ooking for more info??????

98Z28CobraKiller

iTrader: (17)

Make sure that the idle spark tables match the main spark tables. Also, ramp UP the timing in the cells below you idle RPM cell. This will add timing when the engine starts to stumble below the desired idle rpm and help into to recover. You may need to play with the idle over and underspeed tables to smooth those out. The stock table over compensates.

nytoy

iTrader: (3)

Is there any way to get the IAC counts up besides adjusting the throttle stop screw open more? I'm getting 0 counts when warm and the car wants to die when I push in the clutch initially.

Then if I'm moving the car rev's to 1500 in neutral untill I stop...this is from the cracking of the TB screw already...

Is there any table that you can add air to? I'm running a 232/234 cam.

Doc

iTrader: (9)

What software are you using? In EFI Live b4307 Desired Airflow.

SSpdDmon

iTrader: (10)

If you don't adjust the throttle body set screw, the only other way to get the counts up is to drill out the hole a little bigger in the blade itself. Some like to add a new small hole on the lower part of the blade. Either way, you need to let more air in to get the IAC counts up.

Desired airflow is what the motor thinks it needs to idle. If you look at your idle trims, chances are they are negative beyond the point the car is allowed to compensate for. Between the throttle body and this table, your car is getting too much air. That's why your idle rpms are hanging.

nytoy

iTrader: (3)

I've heard two different stories about the IAC reading zero, does that mean the car isn't getting enough air or it's getting too much air?

I'm using HPtuners, remind me again what the idle trims are (PID)

SSpdDmon

iTrader: (10)

When the IAC equals zero, it's closed all of the way. In other words, it's not letting any air in because the motor is getting too much. It can't close any more than zero. That's why you need to close off the airway a little by closing the set screw.

Idle trims are usually refered to as RAF. RAFIG for In Gear and RAFPN for Park/Neutral. RAF is the sum of the LTIT's plus the STIT's. This is what you want close to zero. There's a table/curve that can be adjusted based on coolant temp. In EFILive, it's called Desired Airflow. I'm not sure about HPTuners. Log your RAFIG from a cold start and adjust the table accordingly.

nytoy

iTrader: (3)

god what a headache, I've been reading about idle tuning for hours...I still am at loss.

Ah-HA! I have some sort of RAF table, but had wondered what it controlled. So I want the RAF table close to zero? or the in log, if I'm logging I want desired airflow close to zero?

So basically it's getting too much air. It will idle if I give it a "gentle landing". If I just push the clutch in and it drops from 2000 rpms it will die.

SSpdDmon

iTrader: (10)

Ok...your RAF table is the Desired Airflow Table I mentioned earlier. You need to first bring your IAC counts up to about 60~70 at a warm idle. Do this with the set screw (back it out to close the tb).

Once you've done that, you need to log your idle trims with the scanner. Someone esle will have to help you on how to do that with HPTuners. After you log the car from a cold start up to operating temps (should take close to 10 minutes), then you take your STIT's plus your LTIT's and add them to the RAF table. If they're both negative, you'll be adding a negative number or subtracting from your RAF table.

These are two seperate things. Think of it like this - the RAF table is the airflow the motor thinks it needs to idle (kinda like the VE's relationship to fueling) and the IAC is what adjusts for the RAF table being wrong (kinda like the NBO2 sensors adjust for the VE being wrong).

yobabiesdaddy2001

iTrader: (20)

Hey SSpeedmon do you do that stit +ltit copy> paste special> add>

yobabiesdaddy2001

iTrader: (20)

oh and I know this thread is old

SSpdDmon

iTrader: (10)

Sounds right... You basically are taking the average error for the ECT range and adjusting the desired airflow or base running airflow table. Corrections are either added or subtracted.