Do Large cams idle lean?

[zapp168]

This is my first large cam, I got the car to idle, but it likes the 17 AFR range.
It is an 02 camaro with headers and a 231 237 / 592 602 at 112. If I try to richen it up it idles bad and stalls when put in gear, as long as it is lean it idles actually, well......nice. the AFR goes to normal as soon as you touch the pedal even in park. Is this normal? or do I have more work?
Thanks....

[Stoichiometric]

Are you getting any misfire codes? I wonder if you are getting a false reading from the wideband if misfires are letting unburnt air/fuel into the exhaust?

[mr.prick]

i have found that most all problems with idle are cured
with the RAFIG process.

[kbracing96]

Problem you can have with big cams and overlap is that you can get air passing right though the cylinder into the exhaust making the WB say it lean when its really not. I would tuning it so it idles nice and forget about what the WB says. :)

[WHYTRYZ06]

i have found that most all problems with idle are cured
with the RAFIG process.

how do u do the rafig process?

[oztracktuning]

Try lots more timing at idle and use TPS fuelling where possible.

[zapp168]

I am getting no misfire codes, it seems to idle perfectly just at 17 AFR as soon as I flick the gas it goes right it line, driving it is fine too....As for RAFIG, Honestly I have been reading, I am having trouble finding the "rafig process" in "tutorial form", I slowly increase idle airflow tables until the car idles.
I know......I have bit off more than I can chew with this cam :( . I have it running fine in SD, then I tune the MAF and the car runs fine. when I switch back from SD car runs crappy. I am goin to leave it SD to drive and read more....Thanks everyone!!!!!!!

[dfe1]

My guess is that you're getting erroneous data from the wide band at low air flow rates (i.e. idle). That can be a result of sensor placement, or the sensor itself. As for your problems switching between SD and MAF, with no other changes, the VE table will be completely different in SD than it will be when the MAF sensor is in use.

I'm running a 232/236/114 cam-- not terribly different than the one you're using-- and it idles surprisingly well at 850 rpm. Lately, the wide band readings have been moving around at idle- they'll be 14.7:1 one minute and 16.1:1 the next. There's no way the AFR is moving around that much and from experience I can tell you that idle quality goes to hell when AFR is legitimately over 15:1. I think my wide band problem is the result of a leak in the exhaust system, I just haven't had a chance to get under the car to find it. You may hae the same type of issue.

Don't worry about "The RAFIG Process"-- it's simply a procedure designed to streamline the idle air tuning process. In essence, you monitor the combined short term and long term idle air correction and use it to determine the amount to increase or decrease desired air flow. If you have the engine idling satisfactorily, you've already done "The RAFIG Process", you just didn't know it.

[mr.prick]

RAFIG
http://forum.efilive.com/showpost.php?p=45554&postcount=4

[The Alchemist]

Problem you can have with big cams and overlap is that you can get air passing right though the cylinder into the exhaust making the WB say it lean when its really not. I would tuning it so it idles nice and forget about what the WB says. :)

Exactly whats happening here, I see it all the time. You need a 5 gas to properly measure richness or leaness at idle which most tuners don't have. A wideband only measures O2 in the exhuast of which there is heaps of at idle with a bigger cam due to overlap. This will make it "LOOK" lean when really it isn't.

Mike

[zapp168]

Thanks guys, beats tearing my hair out....I tried he MAF tuning as suggested and the car did not like it....LOL. I am going to post another topic / read about tuning procedures leaving the MAF installed....Thanks again!!!!!!!

[slowhawk]

I'd say the wideband is reading wrong at idle.That Cam is fairly small to tune in OLSD and should idle easilly at 14.7-1. Just did a car yesterday with a 236/238 Cam and it idles at 850rpm with 14.5-1 A/F.Was pretty quick/easy to do.

[zapp168]

I'd say the wideband is reading wrong at idle.That Cam is fairly small to tune in OLSD and should idle easilly at 14.7-1. Just did a car yesterday with a 236/238 Cam and it idles at 850rpm with 14.5-1 A/F.Was pretty quick/easy to do.

Funny thing was, I was surprised that it took no time to get it to idle and run and I was all smug with myself for about 2 minutes....When I saw the gauge goin lean I kept trying to correct it then the idle got worse and worse, I kept chasing my tail :doh2:......I could definitely use some "finesse" on my idle tuning......I noticed that you are doing alot more SD tuning, would love to pick ur brain with my car sometime.....my idle is fine, then sucks, then is fine again, but it is my car so it lives on the back burner. Thanks again:grin:

[limited cv8r]

If you have access to a 4 or 5 gas analyser do you just use the CO% to calculate your AFR . eg. 0.1% CO = 14.72 AFR , 1.0% CO = 14.11 AFR. etc.?

[dvx]

I have the same issue with my 228/232 111 cam. Crusing AFR is dead on. But when coming to a stop my wideband shows lean spikes and the car surges a bit until I come to a stop. Then it idles fine but the wideband shows lean. I've tried to manually adjust the VE and MAF tables, but no matter what I do it still idles lean according to my wideband. I'm not really concerned about it since it idles decent, but I would like to get rid of the surging that comes with the lean spikes when slowing down. I've done RAFIG multiple times, my IAC counts at idle are ~20 - 30 (depending on timing), moved the timing all over the place and messed with the cracker/follower tables but can't seem to get rid of it.