HELP! A4 Trans acting up after H&C install
11-12-2006, 10:27 PM
#1
Staging Lane
Thread Starter
iTrader: (4)
Join Date: Dec 2003
Posts: 52
Likes: 0
Received 0 Likes
on
0 Posts
HELP! A4 Trans acting up after H&C install Since installing a big H&C package a buddy of mine is now having problems with the shifting of his A4. When you take off from a light at normal speed the car shifts through all of the gears and is in to overdrive by 20MPH or so. But under WOT, each gear runs out and shifts at the programmed RPM. He's had the car to a tuner which couldn't figure out the problem. He's now bought LS1 Edit and is trying to fix the problem himself. Has anyone ever run into this? The car even has the stock trans parameters in it but still does this?????
11-13-2006, 09:13 PM
#5
11 Second Club
iTrader: (20)
Join Date: Oct 2006
Location: Virginia
Posts: 3,131
Likes: 0
Received 0 Likes
on
0 Posts
maf has the maf been changed or ported. the ecu uses the maf also as a load meter to determine trans line pressure.if so just stiffen up the line pressure with the tuning software.this should fix the problem.
11-13-2006, 09:34 PM
#6
Staging Lane
Thread Starter
iTrader: (4)
Join Date: Dec 2003
Posts: 52
Likes: 0
Received 0 Likes
on
0 Posts
The MAF is stock and untouched. I just found out today the 4L60E trans also has a vacuum pressure control system built into it from FLP. From what I understand this is suppose to increase the line pressure in the trans. This trans was working just fine with the stock heads and cam. It wasn't till he added the big cam and heads package that it acted differently.
Do you think adding line pressure is going to correct?
Do you think adding line pressure is going to correct?
11-14-2006, 12:26 PM
#7
TECH Addict
iTrader: (10)
Join Date: Jun 2004
Location: Commerce Twp, MI
Posts: 2,918
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by DTSNGIT
Since installing a big H&C package a buddy of mine is now having problems with the shifting of his A4. When you take off from a light at normal speed the car shifts through all of the gears and is in to overdrive by 20MPH or so. But under WOT, each gear runs out and shifts at the programmed RPM. He's had the car to a tuner which couldn't figure out the problem. He's now bought LS1 Edit and is trying to fix the problem himself. Has anyone ever run into this? The car even has the stock trans parameters in it but still does this?????
Either way, the shiftpoints in the PCM are set up based on "MPH vs TPS" for the most part. WOT uses a combination of MPH and RPM enablers before it'll command a shift into the next gear. If the problem is at part throttle, that's MPH based. When you add 4.10's, the operating MPH range for each gear changes. Typically, you need to scale the stock tables accordingly. More advanced tuners will customize them to their preferences. My guess is...if the problem your asking about is the fact that he's into OD by the time he hits 20mph, it's either because he's barely touching the gas OR the part throttle shift speeds were scaled down excessively for the 4.10's. If you have a stock tune, you should copy over the the trans tables from it. Then, scale them down for the 4.10's (just make sure you only scale them once).
Trending Topics
11-14-2006, 12:52 PM
#8
Staging Lane
Thread Starter
iTrader: (4)
Join Date: Dec 2003
Posts: 52
Likes: 0
Received 0 Likes
on
0 Posts
The problem is only at part throttle around town. The car will shift to 2nd, 3rd & overdrive within seconds of light acceleration. Each gear change will happen right after the other. So you'll find yourself in OD going 15-20MPH. Under WOT everything is just fine.
I appreciate your thoughts!
I appreciate your thoughts!
11-14-2006, 09:54 PM
#10
Staging Lane
Thread Starter
iTrader: (4)
Join Date: Dec 2003
Posts: 52
Likes: 0
Received 0 Likes
on
0 Posts
The cam is a 237/242 duration with 603/607 lift @ 112LSA. We've been leaning toward not enough vacuum but are not sure what part this plays on shifting in the A4. I know someone has run a cam this size in an A4 before....... And if it does play a part in shifting how do we correct?
11-14-2006, 10:29 PM
#11
May or may not help, but, here goes. When I have had low vacuum in the past, the PCM has recorded a low transmission pressure code. It shows up in the tuning software & doesn't cause a CEL. Have also seen MAP related issues cause TPS problems such as the TPS going from 0% to 2% (throttle plate closed) because of a MAP problem. Maybe one or both of these are an issue.
How does the brake pedal feel? If it's a bit soft or loose feeling, there may be low vacuum.
How does the brake pedal feel? If it's a bit soft or loose feeling, there may be low vacuum.
11-15-2006, 10:19 PM
#12
Staging Lane
Thread Starter
iTrader: (4)
Join Date: Dec 2003
Posts: 52
Likes: 0
Received 0 Likes
on
0 Posts
I tend to be leaning in your direction with the MAP sensor and low vac as well. I've seen some crazy things with the TPS readings and I know the TPS is OK as it is new. Since TPS plays an important roll in the shifting I guess we'll go down the roads you and others have mentioned. I appreciate your help and welcome any others with thoughts.