Missing caused by transient fueling?
Thread Starter
Staging Lane
Joined: May 2005
Posts: 54
Likes: 0
Missing caused by transient fueling? I finally got my knock sensors desensitized and the false KR issue is gone. In scanning this I decided to log misfires for each cylinder, something I haven't done since getting the car. Timing tables stock, knock learn was in the .5 range and increasing towards 1. Nice to see. The missing surprised me. I throw no codes, but there are misfires across most cylinders, usually in the 2000-2300 RPM range doing about 65-80 with light to no throttle. No missing at idle or mashing the gas. There were about 300 lines in Excel with missing out of a 10,000 line scan. Timing looks OK. I logged DynCyl air and MAP too.
My guess is it's been doing this for some time and I've never known. Because it's light throttle and I have done a VE/MAF tune, maybe a spot in the VE table needs more fuel? Any other thoughts? All I have is a Blackwing and Borla exhaust, bone stock otherwise. Car is strong, had it dyno'd 2 weeks ago and nice numbers for a stock 98 A4 with 70K miles.
I don't have a web site, but will gladly send Excel sheet. I've highlighted all rows with missing.
Thanks!
My guess is it's been doing this for some time and I've never known. Because it's light throttle and I have done a VE/MAF tune, maybe a spot in the VE table needs more fuel? Any other thoughts? All I have is a Blackwing and Borla exhaust, bone stock otherwise. Car is strong, had it dyno'd 2 weeks ago and nice numbers for a stock 98 A4 with 70K miles.
I don't have a web site, but will gladly send Excel sheet. I've highlighted all rows with missing.
Thanks!
Thread Starter
Staging Lane
Joined: May 2005
Posts: 54
Likes: 0
Originally Posted by P Mack
Go back and look at your log. Look at the o2 voltages at the throttle transients and see if they go lean (lower voltage) when it happens.
Another_User and JimmyBlue--your knock sensor posts helped me immensely..thank you.
