4L80E Swap trying to rule out tune
06-25-2018, 06:27 PM
#1
4L80E Swap trying to rule out tune Ok, cant get it out of 2nd. Scanner shows second gear no matter what Im doing with the shift level. So sitting in my garage and running the car shifting through the gears nothing happens. Using the scanner with the car off I can hear solenoids clicking when I command 1st, 3rd, and 4th but no clicking when I command 2nd. I was assuming it was because I was already in 2nd. So I tried the 3-2 solenoid to on and heard nothing.
I did a segment swap on a stock file and made the tuning adjustments from there. Can I rule out the tune as being the problem with this trans? I get no codes when scanning.
New fun facts - 1st is now 1st and 2nd is now 2nd. All other positions are 1st. Reverse never shows up on the "trans current gear". Reverse is always "inhibited". Im assuming because in the scanner 1-2 solenoid is always on.
Help?
I did a segment swap on a stock file and made the tuning adjustments from there. Can I rule out the tune as being the problem with this trans? I get no codes when scanning.
New fun facts - 1st is now 1st and 2nd is now 2nd. All other positions are 1st. Reverse never shows up on the "trans current gear". Reverse is always "inhibited". Im assuming because in the scanner 1-2 solenoid is always on.
Help?
06-25-2018, 08:46 PM
#2
Are you running a neutral safety switch, or MLPS? You say your scanner is showing 2nd gear only-what screen are you looking at? Gear commanded? Do all detents register correctly in your scanner based on shifter position? I'm just trying to rule out that the neutral switch is not the issue... If you are running one. Typically 2nd gear starts, without up shifts, means FAIL SAFE. The computer is seeing a problem and won't allow, or command a 1st gear start-just 2nd gear ONLY. Or, if you have no power to the trans-blown fuse, or wiring issue-it will start off in 2nd gear and stay in 2nd gear. So, put us in the drivers seat. If I sit in the vehicle and start it up and put the shifter into the D4 position, take my foot off the brake and step slightly on the gas-is it taking off in 1st gear? If it does take off in 1st gear, if I get going fast enough will it eventually shift into 2nd?
When you did the segment swap did you do WRITE ENTIRE? I have read, but do not know it to be true personally, that if you do a segment swap, you must do a WRITE ENTIRE.
When you did the segment swap did you do WRITE ENTIRE? I have read, but do not know it to be true personally, that if you do a segment swap, you must do a WRITE ENTIRE.
06-26-2018, 11:05 AM
#5
There is no neutral safety on this swap (car is 69 Chevelle). The BP Automotive harness did not come with a NSS wire.
Odd, because before today it said park in park, reverse in reverse, park in neutral and then 2nd for everything else. Seems like every time I start the car the "trans current gear" says something different. I guess I'll start up and go for a drive and try to switch gears with the scanner.
It always says reverse inhibited even though when I shift in to reverse the trans is definitely in reverse.
The PRNDL status either says D2 or D4 all the time. Im surprised it says anything as there isn't a PRNDL switch on this trans either.
Odd, because before today it said park in park, reverse in reverse, park in neutral and then 2nd for everything else. Seems like every time I start the car the "trans current gear" says something different. I guess I'll start up and go for a drive and try to switch gears with the scanner.
It always says reverse inhibited even though when I shift in to reverse the trans is definitely in reverse.
The PRNDL status either says D2 or D4 all the time. Im surprised it says anything as there isn't a PRNDL switch on this trans either.
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06-28-2018, 07:09 PM
#10
Subeone is correct. The pressure manifold is used to calculate shift times-as in how long it takes the trans to shift after the shift is commanded, and also to see when the trans is slipping to set "incorrect gear ratio" codes.
The MLPS/NSS is used essentially as an inhibitor-meaning whatever forward gear you select, that is as high as the trans will shift. For example-L1, the trans should stay in 1st gear and never upshift. D2-trans will take off in 1st, and then shift to 2nd-but NOT INTO 3rd, or 4th!. Same for 3rd-1, 2, 3 only.. The 80E was used in 1993 & 1994 WITHOUT an external MLPS, so I know it's possible. Like truckdoug says-every swap I've done we always use the MLPS/NSS for simplicity, and because every computer & harness I've used has the wiring in place to do so.
The MLPS/NSS is used essentially as an inhibitor-meaning whatever forward gear you select, that is as high as the trans will shift. For example-L1, the trans should stay in 1st gear and never upshift. D2-trans will take off in 1st, and then shift to 2nd-but NOT INTO 3rd, or 4th!. Same for 3rd-1, 2, 3 only.. The 80E was used in 1993 & 1994 WITHOUT an external MLPS, so I know it's possible. Like truckdoug says-every swap I've done we always use the MLPS/NSS for simplicity, and because every computer & harness I've used has the wiring in place to do so.