SlvrRexx

okay heres the background. with my idle vaules set to : all the f/c settings are set to 1400. then the idle a.e is 850 and the other two idles are 900. with these settings my car idle'd pretty good, after i got off the gas it would idle at about 1400 till i came to a complete stop then it would idle down to 900 or so and sit there fine, except when i was between 72-74 degrees. At this temp my car would some times die(this usually happened after driving then turning the car off for about an hour.) what would happen is the idle would never go to 1400 and would just fall to 900 and bog and kill it's self. This didn't bother me too much cuz i thought its just cuz the car is a little cold for the low of an idle.

NOw my question/problem: yesterday i went out and fine tuned my vacuum for mpg. and i thought it would be a good idea to raise my idle values and see if i could get it from stalling at 72-74 degrees. well i raised all my idle values not the f/c ones 50rpms. all of a sudden my car would idle at 1800 till warmed up then idle at 1400. I didn't like this so i changed the settings back to wat i originally had but didn't make a difference. now i still warm up at 1800 and idle when above 74degrees at 1400. N e one have any insight?

SlvrRexx

^^This is with no fan, on at all.

Matt Hey

If you have a Datalogit, in setting 4 'IGN vs WaterT Cool' change the retard at 60 Temp from 15 to 5. Something else is probabely a little out of wack or you need new plugs but this should help rpm recovery so you don't stall as much. Then you can set your idle rpm's back to original values if it works.

SlvrRexx

my plugs only have about 7k on them...:/ they have ran pretty rich for 4.5k cuz i was on break in tune that whole time. its wierd i went driving last nite and when i would start it and it has a water temp of 85 it would idle around 900 at start up. but if i would touch the gas to get it above 1400 it would not go back down to 900 it would stay at 1400 and not come back down.
---this basically all changed after i made my idle around 14.0 afr. with 850prims. not sure if maybe they dont like to open taht little or something... i think ill try and put back the fuel in idle range so i'm back to like 13.3afr.

SlvrRexx

hey 'matt hey' i'm going to have to agree with you that the pfc has a mind of its own, read that in another topic. but today i started my car it went to 900 rpms and stayed there extremely nice, i drove to the next stop light expecting it to be at 1400 but it dropped to 900 but the next light it stayed at 1400 >< damn. stayed at 1400 for two lites then dropped back down to 900 wtf? then the rest of the lites were 1400...... I still haven't tried to put my fuel back into the idle cuz i dont think the 14afrs is causing this wack idle.

----on another note is 1400rpm idle really that bad? yes i know its loud. but will it cause excess heat? excess wear?

Matt Hey

That's some weird behavior alright. I have 850 primary's also and the car idles good as long as the AFR is richer than about 13:1. I go any leaner and it will slowly cycle between 14:1 and 11:1 almost like it has 2 idle settings. What primary injector lag are you running? If it's -.4 then I would try -.3 and see if it does the 2 idle thing. I would rather live with a little richer idle than a high idle. Do you have your air pump or other emmissions removed? Did you try changing the ignition retard for cold coolant as suggested and did it help any?

SlvrRexx

okay update** No I do not have any emmissions left on my 7 least not to my knowledge ;P umm yes my primaries were at -.4 and i moved it to -.3 like you said and now my idle is good once i'm above 78degrees, it drops down to 900-850 no stumbling very nice idle. I didn't have to take any fuel out at idle so i'm guessin i'm getttin 14:1 at idle,if changing primaries from -.4 to -.3 doesn't effect afrs (dont exactly know cuz i already took my wideband out) I also put the the ignition retard for cold starts to 5 like you suggested and it seems to run better/smoother on start up. Thx for ur input matt.

Matt Hey

Changing the primary injector lag from -.4 to -.3 will make everything richer including idle. It's better to have a little richer idle than a high idle IMHO. I think it's removing the air pump that causes the most problems with the fluctuating idle. I wonder if the PFC peeks at the narrow band O2 and expecting the O2 to read leaner than stoic with the air pump and port air injection but it doesn't with these removed so it cuts fuel to get it there but this causes loss of rpm so it adds fuel and thus the cycling. I'll have to test this theory and I'd like to look at the ISC duty cycle to see what is happening. Maybe the next release of FCTune will allow the ISC to be datalogged. Well, glad to see your 7 is running better.

cewrx7r1

iTrader: (2)

When the air pump is removed, you MUST turn the O2 control function off as it will no longer work properly!