Tuning out a few bugs please help
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From: Fort Collins, Colorado Springs
Tuning out a few bugs please help alright so i put a fairly good sized cam in the 230's ported heads headers full exhaust ls6 intake and a few other odds and ends here is the problem the car will idle pretty good but if it has to set too long it will almost die out then surge? i could see this problem but it idles fine for a good while then starts surging. also if i am just idling around a parking lot (rolling around in gear not pushing in clutch or on gas at all) and it starts bucking harder and harder what can i do to correct this im using HP Tuners. another thing is i keep throwing a ses light for egr cause i eliminated it and we turned off the codes but it still comes on? any way to correct this thanks all
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im not sure what all we have changed its me and a buddy and they have been doing the tuning but im sure we have adjusted the fuel map spark curve stuff like that its running great but the idle is just pissing me off
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From: Fort Collins, Colorado Springs
the idle is set at 950 and i know this drivability is gonna be shitty just wondering if anyone has had similar problems or can give me some pointers to dial it in
Maybe Desired Airflow, Throttle follower, Throttle cracker. These are usually related to idle problems. I read somewhere that if you raise the timing in the lowest map 0 rpm area of the timing table it can help with idle issues, I do believe it was more for fast idle while rolling in neutral but more info is better then less. Mine used to buck at low speed but was due to running way to lean. Good luck
No problem. You should try to get a wideband it will help a lot. I just reread your origanal post. One more thing to check, would be to log your MAP values at idle and let it heat up and see if you get a change in MAP pressure. Mine will run great for an hour or so then out of no where it runs real lean and the MAP value increases 7kpa. I have checked for vacuum leaks and can't find any, so I have to pressurise the intake and see if can find one that way. It only does it when the all the parts get hot. Sounds alot like what you desrcibed.
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Incorrect fueling is the major cause of surging/bucking and this is including idle surging. Fueling has everything in the world to do with a good idle. Most people try and jack the timing sky high trying to cover up the problem but its not the correct way and doesn't always help.
surging is overfueling. big cams cause overlap which given enough time (aka low rpm) can allow fresh air from intake to leak over to exhaust side and confuse the WB. with big cams, at idle, don't listen to the wideband, just sniff the exhaust, listen to your engine, and watch the MAP.
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From: Tyler, TX.
surging is overfueling. big cams cause overlap which given enough time (aka low rpm) can allow fresh air from intake to leak over to exhaust side and confuse the WB. with big cams, at idle, don't listen to the wideband, just sniff the exhaust, listen to your engine, and watch the MAP.