idle

iTrader: (5)

Hey guys! I know this has been asked many times and there have been many responses; I've read most of them. Just looking for a more custom response.

So, I took my car to the tuner and I've been having some rather annoying, light throttle surging under two circumstances:

1. The car surges/bucks at light throttle, particularly in lower gears.

2. The motor surges at idle, but only when coming to a stop (in neutral, RPM's oscillate between 700-1200).

Now the details:

The oxygen sensors are in open loop. The car, on the old tune, ran terribly rich and fouled out two sets of plugs. We (the tuner and myself) are thinking the oxygen sensors are fouled out too; what do you think? If we get the oxygen sensors working correctly, will that help fix the surge/buck?

JakeFusion

iTrader: (7)

As I posted this in your other thread, I'll post here as well. If you're in Open Loop, the O2s aren't doing anything (hence open loop). I would recommend you run it in OL for the time being. Set your Closed Loop enable to 285 degrees to disable CL.

Once you get in running in open loop, lean out the idle some more 400-800-1200 cells, and zero out the follower tables up to 1600 RPM.

To lean it out, park it and let it idle. Play with the bi-directional controls (if you have HPT) and see where the idle improves. Turn off adaptive spark, and add .5 to the 14.7 number until it idles clean (and your MAP number starts to drop - adding timing also helps here - you may need 28-32 degrees at idle with that cam). However, as you lean it out, you'll notice you have no throttle response. Start reduced the number by .1 at a time (say you're at 16.1... reduce to 16 and so forth) until it's still clean and you have throttle response. If that number is 15.5 in the tune, then 14.7/15.5 is the number you need to multiply your VE table by in the 400-800-1200 cells (.95). Then you want to smooth into your next few rows in the 1600 and 2000 columns. Reflash and see if it does better. You're running rich on decel if you're bucking.

Also, like I said, you need to reduce timing as well if you're bucking on light throttle. I have a cam with 16 degrees of overlap, and I don't buck anymore. Getting the VE dialed in down low, adjusting the follower table, running in OL, and reducing timing all helped. See below for my timing map (notice the 1400-1800 RPM cells in the lower airmass areas):

hiltsy855

iTrader: (35)

Jake - Good suggestions. Are you running MAF-less in your tune?