Tuned 5.3 Silverado: trans slips, revert tune and trans is fine?
09-24-2012, 07:06 PM
#1
Tuned 5.3 Silverado: trans slips, revert tune and trans is fine? I have a 1999 Silverado short wide with the 5.3 and 4l60e. Just did true duals, trans fluid change, new trans filter, and a Corvette servo with a blue spring in it. Everything was working great, shifts are more firm both on the 1-2 and 2-3 but not harsh.
I tried tuning using the EFI Live auto VE/ MAF setup I used to tune my car. For some reason the VE table that was created was bad low...(example: stock tune value of 1.254 would be .197 in the table created by the program) so I just kept the stock VE table (LT fuel trims were decent, never went over -6%).
The maf table it created looked good so I copy/ multiply and pasted it into the truck tune table and smoothed it.
Then I went to try to check the results and around 4k rpm the trans felt like it was slipping so I let out. I tried again down the road and it did the same thing. I reverted to the old tune file and the trans quit slipping up top.
What could cause this? Also any ideas why the VE table correction created by the Auto VE is so low?
Tune before and after as well as log are attached. I appreciate any help. My buddy has a Chevelle that was tuned by Wait4Me and his trans does something similar (only much worse). I thought it was odd since it feels like the slip starts to happen instantly around the same RPM so maybe his is a similar problem.
EDIT: log file used for the auto VE is too big to upload
I tried tuning using the EFI Live auto VE/ MAF setup I used to tune my car. For some reason the VE table that was created was bad low...(example: stock tune value of 1.254 would be .197 in the table created by the program) so I just kept the stock VE table (LT fuel trims were decent, never went over -6%).
The maf table it created looked good so I copy/ multiply and pasted it into the truck tune table and smoothed it.
Then I went to try to check the results and around 4k rpm the trans felt like it was slipping so I let out. I tried again down the road and it did the same thing. I reverted to the old tune file and the trans quit slipping up top.
What could cause this? Also any ideas why the VE table correction created by the Auto VE is so low?
Tune before and after as well as log are attached. I appreciate any help. My buddy has a Chevelle that was tuned by Wait4Me and his trans does something similar (only much worse). I thought it was odd since it feels like the slip starts to happen instantly around the same RPM so maybe his is a similar problem.
EDIT: log file used for the auto VE is too big to upload
09-24-2012, 07:53 PM
#2
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I would recommend you don't zero out shift times... you can cut them down from stock, but don't zero them (for example, my silverado was at 25% of stock times). Also, you still have torque reduction enabled...
09-24-2012, 08:55 PM
#3
I will readjust the shift times. I had seen a few tunes with them zeroed so I assumed it was normal. But they are zeroed in both tunes correct?
For the torque reduction, I am seeing the tables zeroed out. Is there some other place they should be adjusted/removed?
I'm guessing the problem is related to the changes in the MAF table. IIRC I increased the MAF table 4-8% to correct the discrepency between commanded and actual a/f ratio. I would expect raising the MAF table to make the truck expect more delivered torque rather than less though.
For the torque reduction, I am seeing the tables zeroed out. Is there some other place they should be adjusted/removed?
I'm guessing the problem is related to the changes in the MAF table. IIRC I increased the MAF table 4-8% to correct the discrepency between commanded and actual a/f ratio. I would expect raising the MAF table to make the truck expect more delivered torque rather than less though.
09-24-2012, 09:48 PM
#4
The thought hadn't occurred to me, but I believe last time I checked fuel pressure at the rail the gauge I was using said 53# instead of ~58# like my car.
If the pressure at the rail is lower than expected I suppose that could be causing some issues trying to tune similar to if the wrong IFR table was being used with aftermarket injectors?
The truck runs fine on the stock MAF and VE. Unless I am forgetting something or accidently manipulated something, the MAF table should be the only difference...the tune with the "corrected" MAF table being the one that causes the trans to feel like it's slipping above 4k rpm.
If the pressure at the rail is lower than expected I suppose that could be causing some issues trying to tune similar to if the wrong IFR table was being used with aftermarket injectors?
The truck runs fine on the stock MAF and VE. Unless I am forgetting something or accidently manipulated something, the MAF table should be the only difference...the tune with the "corrected" MAF table being the one that causes the trans to feel like it's slipping above 4k rpm.
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10-01-2012, 09:49 AM
#8
No updates, been raining a lot and when it wasn't I tried to take the car to the track but got some bad gas so it was down over 6mph in the 1/4 before I realized what was going on.
The truck doesn't shudder, it just revs normal up until around 4000rpm and then feels like it's slipping, the RPM keeps rising but the truck is noticeably slowing down. Hasn't done it again since I put the old tune back in. I'll mess with it sometime this week if the weather clears up.
The truck doesn't shudder, it just revs normal up until around 4000rpm and then feels like it's slipping, the RPM keeps rising but the truck is noticeably slowing down. Hasn't done it again since I put the old tune back in. I'll mess with it sometime this week if the weather clears up.
10-17-2012, 05:44 PM
#10
Haven't messed with it so far getting ready too but I can't figure out why my calculated VE map looks like crap.
My values created by a long drive after applying the filter are all .8xx-.9xx instead of 1.xxx-2.xxx and I have made sure the map is g*kPa versus like RPM like it's supposed to. The MAP readings during the log look fine so I do not know where it got or calculated the trash data from.
My values created by a long drive after applying the filter are all .8xx-.9xx instead of 1.xxx-2.xxx and I have made sure the map is g*kPa versus like RPM like it's supposed to. The MAP readings during the log look fine so I do not know where it got or calculated the trash data from.
10-18-2012, 08:31 AM
#12
Will do, I will try to grab my laptop on lunch break. I used the same calc_pids just a month or so ago to tune a friends truck with headers and do a touch up on my car for the new MAF.
Looks like the rain is going away today so I should be able to try putting the wideband on the truck again. BTW last time I did run the power wire for the wideband to the red jumper box near the battery since I couldn't find an easily accessible and reliable switched 12v source, any recommendations on a good place to get that from?
Looks like the rain is going away today so I should be able to try putting the wideband on the truck again. BTW last time I did run the power wire for the wideband to the red jumper box near the battery since I couldn't find an easily accessible and reliable switched 12v source, any recommendations on a good place to get that from?
