New Cam idle help

[b727pic]

Car has been down for quite awhile sorting out valve train issues. previous tune was spot on pretty much across the board, from start up, thru warmup, and on down the road. After sorting out my valve train issues and installing new cam, I am not sure I believe what the scanner is telling me.

here is abit of back ground,

2004 Procharged GTO (m6) 403CI, AFR 235 heads (EDC custom)

Old cam: 224/232 .600/.600 114 lsa - Idle VE @ 30 KPA/ 800 RPM=47 VE@ 40 KPA 800RPM=52

New Cam: 229/240 .631/.610 117 LSA

Idle was non existent with new cam and old VE settings, idle nicely over 1000 RPM, scanner revealed very lean AFR, cranked in some additional VE got it to idle pretty smooth at approx 825 RPM. In order to achieve a 14.7-15.2 AFR at idle, my VE had to be cranked up to mid 70's which seems way out of whack???

I guess it is what it is, my question revolves around can the small cam size change make that big of difference? should I be looking at base running airflow or some other changes beside simply the primary VE table?

Now that I have achieved somewhat of an idle, I will run the Marcin's idle config and plug the numbers into the spread sheet and see what happens. have to wait for a cold start hopefully that will shed some light on the issue.

Any input is appreciated, I am tired of seeing my car on jack stands.....time to drive

[Rinkrat456]

Ive posted this link probably 10x this week simply because of how well I believe it can work for you if you read it twice before attempting to correct your idle yourself.


So here I go again.
http://www.hptuners.com/forum/showthread.php?t=36318

[b727pic]

Ive posted this link probably 10x this week simply because of how well I believe it can work for you if you read it twice before attempting to correct your idle yourself.


So here I go again.
http://www.silveradoss.com/forums/to...sing-hptuners/

Thanks for the link, looks very thorough. I will spend some time looking it over.

I still a bit in the dark as to why such a drastic change in VE from one performance cam to another. My old cam had Zero overlap, new cam is .05*although lift and duration are a bit larger.

Thanks again, will report back with how the idle log turns out.

[Rinkrat456]

Perhaps after you're done tuning the idle and changing other parameters of the idle quality within the tune, you'll find the end result is a less drastic change in VE because other issues were affecting what you're seeing now.

Things like spark, idle airflow, commanded A/F ratio around idle, cracker and follower tables...ect ect.

[JJhummus]

I just read through your post and all I can say is "NICE"... I have a G8 that I have been fighting a little surge with and just can't get it to go away. I fight the P0300 code constantly and it has a slight hesitation off idle, like a transition is not correct. Anyway, I have a tuner that does this for me know, but am starting to look at buying HPT myself. Thanks for posting this, but is there a way I can get your idle-airflow.cfg file. If not, understood.

[Rinkrat456]

That's not my website and I hold no claim to any of the work that Krambo did when writing that idle 'how to'. You can find the idle-airflow.cfg on the link I provided. It's in big letters to download.

[Rinkrat456]

Just finished bringing a lot of what that link had to offer over to our HPT website here.

http://www.hptuners.com/forum/showthread.php?t=36318

[b727pic]

Just finished bringing a lot of what that link had to offer over to our HPT website here.

http://www.hptuners.com/forum/showthread.php?t=36318

I went through this drill last night, the only thing that changed is that I now need even more ve to keep my AFR anywhere near low enough to support combustion.

At this point I am assuming I have more of a mechanical issue..ie vacuum leak vs a tuning issue. I ordered a new set of Intake gaskets, will install those and give everything another go over once again.

Thanks for all the help, will report back with findings in a week or so.

[code4]

Sure sounds like a vac leak.

Thanks for all the effort rinkrat. Love the screen shots sure helps people like me.

[b727pic]

Rinkrat, thanks for the links and your work appreciate the input.

I have resolved the issue, and its an embarrassing one. My MAP sensor was not hooked up!! My regulator's fuel return line is right over the top of the sensor, did not even see it the other day. Went out tonight after being gone all weekend, looking for possible Vacuum leak sources and stumbled upon this little revelation. I am Sooooo glad it wasn't anything more sinister!!!!

[Rinkrat456]

Nice lol.