Tuning or tranny trouble?

Reply Subscribe

Thread Tools

Search this Thread

Oct 20, 2005 | 08:18 AM

Blk02Ls1A4

Thread Starter

On The Tree

iTrader: (3)

Joined: Oct 2005

Posts: 178

Likes: 0

From: Myrtle Beach, SC

Tuning or tranny trouble?

Ever since I installed my heads and cam I have noticed the car do something weird, that it probably shouldnt. Car is an A4, when coasting down from say 55mph, converter is locked, It feels like the car stumbles, drivetrain unloads then loads up again making the car buck slightly. It will do this twice when coasting from 55 to 0, once at maybe 50 and then at 43 or so. Has anyone ever experienced this or heard of this happenng after a h/c swap. Ps... stock converter is still in there, but that will change at Christmas.

Oct 20, 2005 | 08:43 AM

Ragtop 99

TECH Senior Member

iTrader: (7)

Joined: Nov 2001

Posts: 9,491

Likes: 1

From: Bethesda, MD

That is a tuning issue. A locked converter couples the tranny directly to the engine. If you have tuning issues such as bucking/surging that's when you'll notice them. When the converter is unlocked, its fluid coupling filters out of the impact of bucking and surging.

Oct 20, 2005 | 08:46 AM

foff667

LS1TECH Sponsor

iTrader: (2)

Joined: Jul 2003

Posts: 7,986

Likes: 3

From: Clermont, FL

yeah it'll be more pronounced with the stock converter & those 2.73 gears

Oct 20, 2005 | 01:18 PM

Blk02Ls1A4

Thread Starter

On The Tree

iTrader: (3)

Joined: Oct 2005

Posts: 178

Likes: 0

From: Myrtle Beach, SC

Well that is good to hear, i'm glad that I wont be needing a new tranny. But, how does one go about fixing this? I have EFILive's Flashscan and have a decent understanding of how to use it, I am just at a loss as to what could be the cause of this.

Oct 20, 2005 | 08:43 PM

zrater

TECH Enthusiast

Joined: Jan 2005

Posts: 658

Likes: 0

From: wisconsin

same hear...............

Oct 20, 2005 | 09:09 PM

foff667

LS1TECH Sponsor

iTrader: (2)

Joined: Jul 2003

Posts: 7,986

Likes: 3

From: Clermont, FL

I havent seen a true "fix" posted...a lot of attempts & theories but no true fix...in auto cars i've gotten it the best I could & set the lock/unlock points so you didnt feel it set in...manuals I've just tried to get it as good as possible...again taller gears will help out as well. Sorry Im not one of those "a good tuner can fix it" guys...thats my experience...and for anyone that says do a search you find threads..yeah ive looked through all the threads some people have been able to alleviate it but i dont believe anyone has completely gotten rid of it with big cams...if someone thinks they can give it a shot on his stock stall 2.73 geared car to prove your theory

Oct 20, 2005 | 10:28 PM

Blk02Ls1A4

Thread Starter

On The Tree

iTrader: (3)

Joined: Oct 2005

Posts: 178

Likes: 0

From: Myrtle Beach, SC

Thanks for the comments foff667, I really appreciate it. It isnt all that annoying, it was just a little weird. Before the h/c swap I could feel the drivetrain unload when in 4th while just barely coasting, then when I got back on the gas I could hear the gears re-engage. Now when it unloads the engine is like "ok lets get going here" and re-loads it, I guess this sounds normal now that I think about it, with the added power and different manners. Hopefully a 3200 stall and 308 or 323 gears will help mask it.

Thanks Again Fellas!