Idle tune question.
01-29-2009, 06:51 PM
#1
TECH Resident
Thread Starter
iTrader: (11)
Join Date: Sep 2002
Location: Louisiana
Posts: 966
Likes: 0
Received 0 Likes
on
0 Posts
Idle tune question. What table do I need to work with if I wanted to richen it up just at idle. My wideband is showing between 15-19.0a/f. I have the rest of it lined out nice but I can't figure out how to give it more fuel at idle. Am I missing something? Does the wideband give an accurate reading at idle?
01-29-2009, 07:47 PM
#2
Theoretically, all you have to do is richen the corresponding cells in the VE or in the MAF table. But, if it's in closed loop, and depending on where your fuel trims are, "richening" it may or may not do a damn thing.
Do you have a run log? Can you post that along with the tune?
It's possible it's just seeing extra oxygen from overlap. I've tuned plenty of bigger cam cars that were 17/18:1 at idle.
Do you have a run log? Can you post that along with the tune?
It's possible it's just seeing extra oxygen from overlap. I've tuned plenty of bigger cam cars that were 17/18:1 at idle.
01-29-2009, 08:12 PM
#3
TECH Resident
Thread Starter
iTrader: (11)
Join Date: Sep 2002
Location: Louisiana
Posts: 966
Likes: 0
Received 0 Likes
on
0 Posts
I've tried changing all the table you mentioned above and it just seemed to jack up the rest of the tune. I don't have the car or the Hp tuners with me but I will post it up tomorrow.
As soon as it comes up off idle it goes between 13.4-14.2 and WOT is 12.7. So I figured it might be something like overlap causing the wideband to show inaccurate numbers. It does smell rich at idle and it got worse with the changes I tried, so you made me feel better about it when you brought up the overlap issue. I have it running and idling (750rpm) about as good as it gets.
As soon as it comes up off idle it goes between 13.4-14.2 and WOT is 12.7. So I figured it might be something like overlap causing the wideband to show inaccurate numbers. It does smell rich at idle and it got worse with the changes I tried, so you made me feel better about it when you brought up the overlap issue. I have it running and idling (750rpm) about as good as it gets.
01-30-2009, 12:49 PM
#5
TECH Resident
Thread Starter
iTrader: (11)
Join Date: Sep 2002
Location: Louisiana
Posts: 966
Likes: 0
Received 0 Likes
on
0 Posts
Yes it idles great, everything is perfect except for the WB reading at idle. It is right under the drivers seat where the plug in the floorboard is.
02-04-2009, 09:48 AM
#6
TECH Resident
Thread Starter
iTrader: (11)
Join Date: Sep 2002
Location: Louisiana
Posts: 966
Likes: 0
Received 0 Likes
on
0 Posts
Well I figured out what I was doing wrong. I wasn't tuning the secondary VE table everytime I changed the main VE and the afr was never changing. I didn't post up my tune or my logs because I was convinced I had to figure it out myself. I'm happy to say my first tune worked out very good. I'll post up my tune for some of you veteran tuners to look over for me later. Thanks
Trending Topics
02-04-2009, 01:22 PM
#8
FormerVendor
iTrader: (9)
Join Date: May 2003
Location: Jacksonville, Fl
Posts: 1,573
Likes: 0
Received 0 Likes
on
0 Posts
Take a second look at the difference btw the two tables. Your MAP resolution is halved on the secondary table.
As best I know / can tell GM never intended to have these vehicles run in pure MAP mode (SD). The "backup" table was merely intended as a failsafe to guard against MAF failure leaving you stuck on the side of the road.
If you upgrade your OS to the last and in my opinion the best of the 4th Gen Fbody OS's the 2002, you will not have to worry about / use an interpolation scheme to tune.
As best I know / can tell GM never intended to have these vehicles run in pure MAP mode (SD). The "backup" table was merely intended as a failsafe to guard against MAF failure leaving you stuck on the side of the road.
If you upgrade your OS to the last and in my opinion the best of the 4th Gen Fbody OS's the 2002, you will not have to worry about / use an interpolation scheme to tune.
02-04-2009, 08:52 PM
#10
TECH Resident
Thread Starter
iTrader: (11)
Join Date: Sep 2002
Location: Louisiana
Posts: 966
Likes: 0
Received 0 Likes
on
0 Posts
No sir, not SD.
A buddy of mine has a tiny issue with a surge on a 98 6 speed Z28.
What would cause one to idle fine and out of no where get a surge for a few seconds then go back to idling fine? It only does this every few days, not an all the time issue. Just thought I'd throw that one out to you guys while I have your attention. BTW, thanks to all you guys who have help me with understand this thing call tuning!
A buddy of mine has a tiny issue with a surge on a 98 6 speed Z28.
What would cause one to idle fine and out of no where get a surge for a few seconds then go back to idling fine? It only does this every few days, not an all the time issue. Just thought I'd throw that one out to you guys while I have your attention. BTW, thanks to all you guys who have help me with understand this thing call tuning!
