AchillesGr

iTrader: (1)

i have a few thoughts for idle setup and i would like your opinions guys.
first of all , my car has the ISC connected.
i am thinking the folowing steps:
1) warm up the car with the problematic idle.then turn off.
2) set all idle speed at the pfc to "0" ( to force manual idle and turn off the ISC control)
3)close the AAS completely .
4)open a litle the TAS ( so the engine does not die)
5)start the car and adjust the TAS to 650-700rpm
6)then slowly open the AAS to stabilize the revs to about 750
7)set again the decired idle at the pfc so to turn on the ISC control.

thats it.

why to follow this?
with that way i am making sure that the ISC works at a minimum duty cycle since the main air source will be the TAS and AAS .

now, if i have plenty of unused duty cycle spare to use the pfc will control idle better especialy under e/l or a/c when the solenoid will need to force more air in the engine..

also when i set the revs at step 5 i ensure that the idle does not fall under the 650-700.

i would like to hear some comments from you guys...
one question i have is if it is OK to hold buterfly a litle open with the TAS. i read somewhere that the TAS must be set up so the buterfly jyst barely toutches the throtle body and keep completely closed the buterfly.

thanks

arghx

iTrader: (3)

I don't see anything wrong with trying it as a new approach to see if it works. That is very similar to setting an idle on Hondas. Their service manuals call for unplugging the Honda ISC valve, adjusting the idle pretty low with the Honda air adjust screw, and then plugging the Honda ISC valve back in to raise the idle up. Now if you have porting it may be a little trickier though because the engine doesn't make as much vacuum at low rpms. Also, when I am controlling idle with the ISC I like to keep Idle IG control on (the default setting) but O2 feedback off.

One thing to keep in mind though is the idle behavior when you decelerate. It is very common for the idle to stick pretty high, or sometimes do the opposite and stall. The deceleration behavior is heavily influenced by the fuel cut settings under the rev/idle part of the Commander and the adjustment of the dashpot on the TB. First I would set all the fuel cut settings to the same value, maybe 1200 rpm. Adjust them higher in small increments (20 or 50 rpm) if the engine likes to stumble or stall out. Adjust the settings lower if the idle sticks.

If you've set all the other idle screws and you cannot completely eliminate a sticking idle with the fuel cut settings, try loosening the dashpot so that it touches the throttle less. If you are having an idle stumble that you cannot fix by raising the fuel cut settings, try tightening the dashpot a bit more so that it contacts the throttle more.

AchillesGr

iTrader: (1)

thanks arghx,
i will try it and post the results.
arghx, i need to fit a cat since i do not have any for noise reasons. can you suggest one from your experience?i see in many threads that you know these cars very well..
i am thinking the bonez. i have no air pump. do you think that it will be a problem?
thanks

AchillesGr

iTrader: (1)

arghx,
I just folowed the steps above and all idle speeds were ok.
the problem started when I try to relearn the idle.first of all I saved my curent data with datalogit ,hit the initialize all data from the hand controler,and move all saved data from the pc back to pfc.
as the engine was warmed already,I started the car and waited to complete the learning idle.the idle bunches up and down a few times.after a few minites the fan came up and it continued the learning with electric load on.after 5 min I turned on the ac for another 5 mins.
the problem is that after about 30 mins when I hit the pedal and let off the idle sticks 200-300 rpms higher for a few seconds.
why that?
is the learning not completed yet?before the initialization all was ok.I have the idle-ig control off. I tried to turned it on but I did not see any diference.
I do not understand what has changed...
I read somwere that pfc learnes for days..
is it true?
am I wrong trying to learn with the engine warmed already?
do I have to run the learning again with cold motor?
thanks...

arghx

iTrader: (3)

I have never run a cat with a Power FC. People speak highly of the Bonez though. But you may not be able to pass an emissions test (with a tailpipe sensor) without an airpump hooked up. There are some workarounds though. People will lean out their maps and put denatured alcohol in their gas tank in an attempt to pass. That may get the job done without an airpump if you heat the cat up enough through some low load highway driving. I don't have any firsthand experience though, they stopped having emissions test around here in 2005.

the idle IG control, from what I've seen, stabilizes the steady state idle but has little to no effect on free revving or deceleration behavior. So when you're just sitting there it smooths out the idle and the vacuum signal:





As I tried to point out in my previous post, first you set the air adjust and throttle adjust screws. After that you may need to adjust the fuel cut settings (F/C A.E. F/C EL etc) and the dashpot on the throttlebody. I'd start by setting all three F/C settings in the Commander to 1200. Lower all three in increments of 20 or 30 rpm at a time and see if that corrects the problem. If you lower those settings too much, you may find that you have the opposite problem: the idle will now stumble or the car will cut off. So be careful when you play around with the fuel cut adjustment settings.

If you can't fix the problem with the fuel cut settings, the mechanical dashpot on the TB may also have to be adjusted. The plunger slows the closing of the throttle plates. If you loosen it, you may reduce the chance of the idle sticking, while tightening it will reduce the chance of a stall when decelerating or free revving.



Also note that when you are decelerating or coming to a stop, the idle will probably stick high by a couple hundred rpms (not too high though) until the vehicle stops moving. That is built into the PFC to reduce the chance of stalling, and is not directly adjustable unfortunately.

From my experience, you might notice a little improvement over time, but don't expect too much. Focus more on PFC and throttlebody adjustments.

I've tried it every which way. I don't think the idle learning has a big effect on the idle sticking or stalling problem. The TB adjustment and the rev/idle settings in the Commander seem to matter more in my experience.

AchillesGr

iTrader: (1)

arghx,
thanks for the help.today I tried all the above.the dashpot is ok,the Tas closes completely,same the secondary throtle and the Aas is open one turn.
I wanted to check if there was an air leak someware so I close completely the Aas.with the Aas and Tas closed the engine reved about 700 rpm. so no air leaks.also I have the injector breather connected.
I suspected that this 200-300 rpms over idle for a few seconds is caused by pfc and not the throtle body.
a very interesting thing is that when the idle is stabilized to 800(where it is seted) and i aply an electrik load so to go to the e/l rpms(850) ,the engine revs to about 1200 and the fals to 850 after 3-4 secs. same when I turn on the a/c. engine revs to 1200 and then fals and stabilizes to 950.
I suspect that the pfc still learning (engine ran time since initialization about 1Hour) or I have a sticky isc solenoid.
I am thinking to remove the isc and clean it with wd40 but is this the cause?
why the problem (engine rev to 1100-1200 for a few secs and the drop to correct rpms) occures when I aply e/l or a/c?
please not that this occures and if I let off the pedal but I am sure that that the throtle body is ok.
thanks!

arghx

iTrader: (3)

Little known quirk to the PFC: it will advance the ignition timing and increase ISC duty when E/L engages, whether or not the the target E/L speed is higher than the base idle speed. Because of its propensity to overshoot, I actually set my E/L speed 50rpm lower than my base idle speed.

I've had good luck with these speeds:

850 AE , F/C 1370
850 E/L, F/C 1370
900 A/C, F/C 1370

that was on an FD with a basic streetport. basic idle speed is actually right at 850, then bumps up to 900 with E/L engaged. I think the A/C idle speed is around 950? I don't remember, I hardly messed with A/C idle on that car.

on my personal car with bigger porting, I like it to idle a little higher. The speeds I use are:

1000 AE , F/C 1500
950 E/L, F/C 1500
950 A/C, F/C1500 (this car does not have A/C though)

with those target speeds and idle IG control on, believe it or not it actually idles at about 950 with or without E/L engaged.

Setting the E/L and A/C target speeds closer to the base idle speed seems to help control the idle speed spiking behavior you are noticing.

neit_jnf

iTrader: (17)

I'm trying to fix my idle and I'd like to know if the factory O2 sensor and the airpump must be connected and working for the pfc to learn the idle? Will the pfc learn the idle without them? thanks!

arghx

iTrader: (3)

turn off O2 feedback and the answer is no

BigIslandSevens

iTrader: (4)

Does the Fuel cut adjustments affect whether the injectors turn off during decel? I have a issue with that .

arghx

iTrader: (3)

yes they do. is your TPS in spec though?