Car Won't Shift at WOT
Thread Starter
Teching In
Joined: May 2006
Posts: 23
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From: columbus ohio
Car Won't Shift at WOT UPDATE I just got my supercharger and my Yank 2800 installed on my 97 C5. I got it tuned on the dyno and everything looked good. Just driving around slowly the car is fine. Sometimes when I start to get on it the car will just go into reduced engine power mode and the display will say service traction system. This happens both with my traction controll on and off. If I shut the car off and start it again everything comes on as normal. Now, this does not happen everytime I get on it. If this does not happen the car will pull like normal up to where my tuner set the shift points(we tried 6 different shift points) and then it will just bang off the rev limiter and will not shift.
I would like to know if this is a tuning problem or a tranny and converter problem.
Any help would be greatly appriciated.
I PUT THE STOCK TORQUE CONVERTER BACK IN AND THE CAR SHIFTS PERFECTLY AT WOT. I CAN PUT THE CAR DOWN IN 1ST AND SHIFT ALL THE WAY UP INTO 4TH AND IT WORKS GREAT. THE ONLY PROBLEM I AM STILL HAVING IS IF THE CAR IS IN DRIVE AND I FLOOR IT AROUND 30-40MPH THE CAR WILL GO INTO (REDUCED ENGINE POWER) AND THE DISPLAY WILL SAY SERVICE TRACTION SYSTEM. THIS ONLY HAPPINS IN DRIVE AND ONLY AROUND THOSE SPEEDS. IF I FLOOR IT FROM 70 IT SHIFTS FINE.
IS THIS A TRANNY PROBLEM OR A TUNING ISSUE.
I would like to know if this is a tuning problem or a tranny and converter problem.
Any help would be greatly appriciated.
I PUT THE STOCK TORQUE CONVERTER BACK IN AND THE CAR SHIFTS PERFECTLY AT WOT. I CAN PUT THE CAR DOWN IN 1ST AND SHIFT ALL THE WAY UP INTO 4TH AND IT WORKS GREAT. THE ONLY PROBLEM I AM STILL HAVING IS IF THE CAR IS IN DRIVE AND I FLOOR IT AROUND 30-40MPH THE CAR WILL GO INTO (REDUCED ENGINE POWER) AND THE DISPLAY WILL SAY SERVICE TRACTION SYSTEM. THIS ONLY HAPPINS IN DRIVE AND ONLY AROUND THOSE SPEEDS. IF I FLOOR IT FROM 70 IT SHIFTS FINE.
IS THIS A TRANNY PROBLEM OR A TUNING ISSUE.
Last edited by AdamC5; Jul 19, 2007 at 08:24 PM.
Well though with the power addition you may well have exceeded to trans capability, With the other symptoms I would be inclined to look at tuning or other electrical issue first since there is definatly something going on there.
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FormerVendor
Joined: Oct 2006
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From: D-F/W
I would like to ask you if it makes the 1-2 shift but not the 2-3 shift at WOT when it does hang at the RPM Limiter.
I am going to suggest that the reduced traction issue is definately related to the tune, power mods and converter upgrade. Mostly though the converter. The deal is your TPS and Engine RPM do not agree with a stock table now, and I would imagine though that your tuner addressed this. If so, he would need to make some adjustments.
Our experience with intermittant no upshift at WOT conditions has been very vehicle specific and has required some time with the car. Many times we find that the tuning is the issue. Other times we find that there is insufficient pressure for one reason or another; meaning the shift is commanded but has not occured or is not going to ever occur until the throttle is lifted. Ususally when it is the latter it is specific to the 2-3 shift and ultimately in those instances the 3/4 clutches fail.
Keep in mind my experiences and opinions may not be what is happening in your case, but definately take a look at the tune 1st! See what is being commanded and when... if it is commanding the upshift and it is not occuring it is a mechanical issue related to internal hydraulic configurations.
Hope that helps!
g
I am going to suggest that the reduced traction issue is definately related to the tune, power mods and converter upgrade. Mostly though the converter. The deal is your TPS and Engine RPM do not agree with a stock table now, and I would imagine though that your tuner addressed this. If so, he would need to make some adjustments.
Our experience with intermittant no upshift at WOT conditions has been very vehicle specific and has required some time with the car. Many times we find that the tuning is the issue. Other times we find that there is insufficient pressure for one reason or another; meaning the shift is commanded but has not occured or is not going to ever occur until the throttle is lifted. Ususally when it is the latter it is specific to the 2-3 shift and ultimately in those instances the 3/4 clutches fail.
Keep in mind my experiences and opinions may not be what is happening in your case, but definately take a look at the tune 1st! See what is being commanded and when... if it is commanding the upshift and it is not occuring it is a mechanical issue related to internal hydraulic configurations.
Hope that helps!
g
torque management.
turn it off.
completely.
EDIT nearly the exact same setup.
magnuson,
yank 2800.
started off with 3.15's
ended up with 3.42's.
during the gear changes i had a few minor issues.
dbl check you tires sizes also.
physically measure them.
EDIT: i would sometimes forget to reset the tune for the drag radial sizing. it caused some hiccups.
turn it off.
completely.
EDIT nearly the exact same setup.
magnuson,
yank 2800.
started off with 3.15's
ended up with 3.42's.
during the gear changes i had a few minor issues.
dbl check you tires sizes also.
physically measure them.
EDIT: i would sometimes forget to reset the tune for the drag radial sizing. it caused some hiccups.
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TECH Senior Member
Joined: Apr 2002
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From: So.Cal.
Before looking at the reason for no shifting, you need to resolve the "reduced engine power mode" issue first;
if your PCM is entering "reduced engine power mode", then your tuner needs to adjust the MAF/MAP/airmass/TP "rationality" tables to account for forced induction;
Are you seeing DTC P1514...? Any others...?
if your PCM is entering "reduced engine power mode", then your tuner needs to adjust the MAF/MAP/airmass/TP "rationality" tables to account for forced induction;
Are you seeing DTC P1514...? Any others...?
These two items could be related. I agree I would look for the engine running issue first then adress the trans if that dosent solve both.
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FormerVendor
Joined: Oct 2006
Posts: 3,123
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From: D-F/W
Hmmm... unfortunately we can read HPT files intermittantly as we use EFI Live for tuning. I was going to ask you to send a file.
Be that as it may, I can say that 9 times out of 10 after powertrain changes the issue with a no upshift is tuning related... stay with that and let me know what you need.
g
Be that as it may, I can say that 9 times out of 10 after powertrain changes the issue with a no upshift is tuning related... stay with that and let me know what you need.
g
Thread Starter
Teching In
Joined: May 2006
Posts: 23
Likes: 0
From: columbus ohio
I put the stock Torque converter back in and the car shifts fine now at WOT.
If I floor the car around 30 to 40mph the car wil go into Reduced Engine Power mode and the display will say Service Traction System. This problem only happens at those speeds and only if the car is in drive. If I put the car down into 1st I can manually shift the car all the way to 4th and it is fine.
Is this a trans problem or a tuning issue.
If I floor the car around 30 to 40mph the car wil go into Reduced Engine Power mode and the display will say Service Traction System. This problem only happens at those speeds and only if the car is in drive. If I put the car down into 1st I can manually shift the car all the way to 4th and it is fine.
Is this a trans problem or a tuning issue.
I think you are still dealing with a tuning issue. The reduced power mode the no shift etc is all related some how, Issues like his can be tedious to work out. As stated in and earlier reply I would work to find the cause of the reduced power mode first, I think that will be the KEY and since I noted your using HPTUNER you might do well to try posting in that forum with your issue http://www.hptuners.com/forum/
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