Idle surge logged

[Tennpenn83]

Finally captured a log of my wandering idle... attached is the log and the tune on the car.

any thoughts?

BTW, engine mods are :

K&N Typhoon CAI
LS4 TB
2.8" pulley
42.5 lb/hr GM Stage 2 injectors
dual-pass endplate with opt B
heat exchanger
NGK BKR7E's gapped at .035"
ZZP midlength header/3"cat-less downpipe/full 3" exhaust

[Cinpro]

are you having to put your foot on the gas to keep it running? your TPS is all over the place and so is your MAP sensor.

[Tennpenn83]

No, the car does this entirely on its own. I don't touch the gas and it happens frequently at stop lights snd such. But only when the car is at a complete stop, not coasting in or out of gear.

[Tennpenn83]

bump... anyone else with thoughts?

[cobaltssoverbooster]

i have the same thing sometimes when stoppping in my balt out of gear clutch out or clutch in the car will dip idle to like 500 when stopping for no reason. tried to change paramaters to correct it but got nowhere so you should be ok. i do not touch the gas pedal either so its something in the controll unit programing mabe a emissions test or something.

yours does it more than mine though, like 5 or 6 dips and mine just dips once and its back again.
how often is it?

[Tennpenn83]

i have the same thing sometimes when stoppping in my balt out of gear clutch out or clutch in the car will dip idle to like 500 when stopping for no reason. tried to change paramaters to correct it but got nowhere so you should be ok. i do not touch the gas pedal either so its something in the controll unit programing mabe a emissions test or something.

yours does it more than mine though, like 5 or 6 dips and mine just dips once and its back again.
how often is it?

usually happens when it is colder outside. here lately it's been at almost every stoplight/sign but with it warming up a couple days last week, it didn't hardly do it at all.

usually it will continue to do it until i'm starting off moving again. this log was irregular in the fact that it corrected itself

[cobaltssoverbooster]

wow thats something wierd goin on

[Tennpenn83]

yeah... tell me about it..

other than that, it runs like a champ... dyno'd at 250 whp last year with prob a lot more on it now with a full exhaust and more cooling, and a slightly more aggressive tune...

idle is the only prob

[evilmonkitar]

would a vacuum leak be the cause? i googled that once since my car did the same, kinda surged a little at idle and vacuum leak came up as a possible culprit. i do have a small one.. hose going into the back of my boost gauge leaks a little in boost..

[Tennpenn83]

I don't believe so, as I have checked and rechecked but it wouldn't hurt to look again.

[dont_blink]

You cam sensor is probably out of whack. Also, is 4950 right for the LS4 TB? Also, your MAF table is 100% stock, yet you have an intake and full exhaust. Explain.

[Tennpenn83]

You cam sensor is probably out of whack. Also, is 4950 right for the LS4 TB? Also, your MAF table is 100% stock, yet you have an intake and full exhaust. Explain.

4950 is a little high on the scalar for the LS4 tb, but it takes a bit of the touchiness out of it. most people go with 4500 and it works fine, i just recently played around with that number and liked how it felt afterwards

don't really have an answer for the maf table being 100% stock as I am beginning on the tune after it was tuned by someone else.

with it being a little warmer out, it doesn't seem to do it as much, a lot less often than when it was cold out

[BoostedYards86]

he had someone tune him. i looked over his tune for him and it was very disturbing to say the least. his commanded afr is really lean, and his maf is stock. the tune needs a lot of work to say the least. I would definately be afraid to run the car WOT. LS4 tb alone runs a whole point leaner...let alone intake exhaust and a 2.8" pulley. Very unsafe. Jordann Ill check this stuff out later for you. I have class right now.

[Tennpenn83]

he had someone tune him. i looked over his tune for him and it was very disturbing to say the least. his commanded afr is really lean, and his maf is stock. the tune needs a lot of work to say the least. I would definately be afraid to run the car WOT. LS4 tb alone runs a whole point leaner...let alone intake exhaust and a 2.8" pulley. Very unsafe. Jordann Ill check this stuff out later for you. I have class right now.

thanks a lot man

[FunkyStickman]

Yeah, definitely doesn't look good, it needs a good, solid, baseline tune. With intake/exhaust mods, the first thing you should do is calibrate the MAF table, because almost everything the engine does is based off of that.

[BoostedYards86]

try to use this one. see how that works and lemme know.

[jrhdpaintball]

boosted yards do you mind if i give that a try also... i have ls4 TB but not on car at the moment... would i just need to turn down the etc scaler to 2950.00 like on stock TB, or is there something else i need to adjust?

my zzp tune is JUNK...

[Tennpenn83]

well, i found out what was causing the weird idle... during the install of my GM Dual-pass endplate a year ago, I had to remove the intake manifold. just the other day, i fould that there were 5 bolts out of 7 that were so loose they could be tightened by hand. i am uneasy about putting locktite on there because they are all aluminum bolts and head and manifold.. but there is no more idle surge.

reason i didn't see it... how often do you take off your supercharger?

[jrhdpaintball]

hmm ill have to check this as well... this surge is so annoying

[eclipse5302]

he had someone tune him. i looked over his tune for him and it was very disturbing to say the least. his commanded afr is really lean, and his maf is stock. the tune needs a lot of work to say the least. I would definately be afraid to run the car WOT. LS4 tb alone runs a whole point leaner...let alone intake exhaust and a 2.8" pulley. Very unsafe. Jordann Ill check this stuff out later for you. I have class right now.

I know this isn't the same car, and I'm guilty of not looking at the tune or scan since I'm on my non-tuning notebook, but I did deal with some mean idle surging on a 600 inch 8-71 Ford BB with a Fast XFI, (16) 36lb injectors, and a true S/C hat (TB). BTW, I'm assuming you don't have some sort of other "problem".

Generally, from what I understand, this is caused by one of two things...lean mixture or too little timing. Changing either one will effectively "load down the engine", which should get rid of the idle surge (hunting). For me, I ended up doing both to get the engine to behave.

It may not be entirely relevant, but for a first-time tuner, it definitely was an extreme engine to learn on.

Edit: I didn't read the last post, sorry. Hopefully this information can help someone who is trying to get rid of some surging when nothing else is wrong...