93 auto upshifts only at high rpm??

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willisonTfosdik
Posts: 2
Joined: Tue Jul 19, 2011 10:37 am

Post

I've got a bone stock 93 for a DD.

It's been flawless for a couple of years. All of a sudden it won't shift right. Here are the EXACT symptoms & what I've checked. What's next?

Won't upshift any gears until 4000-5000 prm but does shift.

makes the 1-2 shift about 27mph

makes the 2-3 shift about 46mph

will make the 3-4 shift around 75mph if you back off the gas a little
Immediately locks the converter after it goes into od.


IF YOU WIND THE MOTOR TO LESS THAN SHIFT POINT & BACK OFF YOU GET NO ENGINE BRAKING BUT IF YOU MANUALLY PUT IT IN THAT GEAR YOU GET ENGINE BRAKING.

It's been doing this for about 2 weeks while I ckecked fuses & stupid stuff.

One morning when I left for work it shifted perfectly, like it used to, all the way to work in mixed driving.
I was afraid to shut it off. lol
When I went to lunch... no shift... back to what it had been doing.
THAT made me think it's electrical but just a SWAG

I did the self diag posted in the FSM & all 10 binks are the same.

What's next??

NO I DON"T WANT A 5 SPEED!!!!!!!!!!!!!!! :gapteeth:

Thanks in advance for any help.


compactfean
Posts: 2602
Joined: Thu Dec 03, 2009 10:28 am
Car: 89 240sx s13 sr gt3071r 23psi
B14 sentra ser sr20de-t 7psi
daily
Location: reno nv

Post

i would start with checking the tps.

willisonTfosdik
Posts: 2
Joined: Tue Jul 19, 2011 10:37 am

Post

Sorry I left that out.

TPS has perfect sweep from .480 to 9.76... no glitches... nothing

I have taken every connector apart & ck'ed for green fuzz... nothing.

I have searched the forums & read everything I could find before I posted my question.

I don't understand the part where if in D it has no engine braking in 1st-2nd- 3rd (returns to idle) when you let off the gas but does in each gear if you put the shifter there.

compactfean
Posts: 2602
Joined: Thu Dec 03, 2009 10:28 am
Car: 89 240sx s13 sr gt3071r 23psi
B14 sentra ser sr20de-t 7psi
daily
Location: reno nv

Post

There should be a vacuum line that goes to the trans...at least on alot of toyota and old school chevy trucks.

User avatar
youngun21a
Posts: 293
Joined: Mon Mar 13, 2006 7:55 am
Car: 240sx 1993 Automatic

Post

I was just going to say the TPS,but u beat me to it...But anyways my did the same thing till yesterday that I fix it,,it was doing it for a month now the only reason I didn't check or fix it was that it ran great,the shift were a litte bit hard but it felt like a manual it wouldn't shift till a certine RPM or if i let go of the gas then it would shift..but it will shift fine and it would respond quick with the press of the gas that's why I didn't want to fix it till the day before when I would stop at a stop sign it would try to die on me..So I pluged in my consult cable fired up my laptop and everything was fine only thing was the tps was at 1.09 closed so it was way off then i set it back to .45 and now it runs fine just like before..now to your question TPs could be going out or like compactfean said ur vacuum line..also look under u transmission if nothing got upluged...

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