My 93 ATX Problem

[sxavior]

It seems like everyone with a 93 has a sob story about their ATX.
My story:
When I am driving on the highway and I either accelerate enough to downshift or I am going up a hill and the tranny downshifts it will not upshift back to the higher gear once I let my foot off the gas. If I come to a stop and turn the car off, it runs fine again. I pulled the pan and changed the fluid but it seems to have made it worse. Could I have over filled the tranny? Bad TPS sensor? Replace ECU with 94 or 95? Oh yeah ever since I have had the car the check engine light will come on and go off at random. I tried to diagnose myself several times with a voltmeter and jumper wire but I never could get it to throw a code.

 

[SHOdownTN]

Kinda the same problems I am haveing, I will keep a watch on this post......

 

[shosleeper]

I had the same problems, had to turn car off to get gears back. Swapped to D4U1, and bought some time, started slipping in D...now I have to start out in 2. Lucky for me my new tranny goes in Nov 20th. Changing PCM's may buy you some time, but you looking down the barrel of a rebuild/replace soon.

 

[93SHO'nOFF]

1-Does this only happen when it downshift's from O/D to 3rd only?
2- Is the O/D cancel switch working?
3- Does it seem to shift late,harsh,or slip in any other gears?
4-Did you check the fliud level or condition of the fluid before you changed it?
5-Does it happen Hot,Cold,or Allways/How frequent?
6-Does the O/D light illuminate or cancel switch stop working if you have the shifter in the lower ranges?
There are several different sensors that can fail to cause shifting concerns with the VSS being one of the most popular,But there are many others that can cause it as well(MLP,TSS,Shift Soliniod's,and the PCM).The 1st thing is to check and see what code's are in the PCM to get a good starting point for diagnosis.The Check Engine Light is going on because it sees something wrong.If your having trouble pulling code's,go to AutoZone and have it tested with a scan tool(I read on this forum they do it for Free). My own SHO had a similar concern but it would downshift and upsift at random,that turned out to be the MLP (Manual Lever Position sensor or TR "Trans Range sensor"is what they now call it).This is an Input sensor for the PCM to let it know what gear it is in buy using a voltage signal.The more info you can give about when the concern happens it makes Troubleshooting a little easier.Let us know how you make out with codes and I'll try to help as much as possible.
Later
Mike

Note:If the Check engine Light comes back on don't turn the Ignition off before trying to test for codes.The PCM may be loosing KAM (Keep Alive Memory) when the key is turned off,This may be why it never has codes when you test it.
Was the PCM you installed a used one?Was the calibration number the same as the original?

 

[sxavior]

We'll it seems that I did overfill the tranny by about 2 quarts. I took out 2 quarts of fluid and after about a day of driving it no longer has a problem. I didn't get to test the overdrive much, but how many rpm's should it be dropping from OD to third? I couldn't notice the overdrive kick off. I still plan on getting the check engine light checked out. What kind of mileage is everyone getting? I am getting max 20 mpg with about 75% highway drivng and a/c always on. I did get 24mpg with only highway driving and no a/c. I've got the 3.2.

Note: I did not change the ECU, I was just wandering if that might be a solution to my problem.

 

[stevemainian]

When I got my SHO, my CEL went on and off all the time.

It was the water pump, and a loose hose coming from the radiator causing it to light.

 

[sxavior]

1-Does this only happen when it downshift's from O/D to 3rd only?
2- Is the O/D cancel switch working?
3- Does it seem to shift late,harsh,or slip in any other gears?
4-Did you check the fliud level or condition of the fluid before you changed it?
5-Does it happen Hot,Cold,or Allways/How frequent?
6-Does the O/D light illuminate or cancel switch stop working if you have the shifter in the lower ranges?
There are several different sensors that can fail to cause shifting concerns with the VSS being one of the most popular,But there are many others that can cause it as well(MLP,TSS,Shift Soliniod's,and the PCM).The 1st thing is to check and see what code's are in the PCM to get a good starting point for diagnosis.The Check Engine Light is going on because it sees something wrong.If your having trouble pulling code's,go to AutoZone and have it tested with a scan tool(I read on this forum they do it for Free). My own SHO had a similar concern but it would downshift and upsift at random,that turned out to be the MLP (Manual Lever Position sensor or TR "Trans Range sensor"is what they now call it).This is an Input sensor for the PCM to let it know what gear it is in buy using a voltage signal.The more info you can give about when the concern happens it makes Troubleshooting a little easier.Let us know how you make out with codes and I'll try to help as much as possible.
Later
Mike

Note:If the Check engine Light comes back on don't turn the Ignition off before trying to test for codes.The PCM may be loosing KAM (Keep Alive Memory) when the key is turned off,This may be why it never has codes when you test it.
Was the PCM you installed a used one?Was the calibration number the same as the original?

Well the ATX was overfilled, and it ran good for one day and now it back to the same crap.

1- I figured out most of the time it sticks from 3rd to 2nd but occasionally it does it in other gears.
2- The o/d cancel switch does not seem to be working.
3- You can tell when it is not going to work because it shifts hard in other gears.
4- Fluid seems to be a little worn/dirty but nothing that it out of the ordinary.
5- I can't figure out the reason why it does it. Seems to be always. Happens about once per trip. I.E. back and forth from work one day, it happened twice.
6- No

I went to autozone the told me that they did not have the tester to test my 93. They did have a tester they could sell me that MAY work ($300) .They told me that it had to be OBD II. I tried to run the CEL code(S) again but the CEL goes off before I got a test.

 

[Axianator]

A couple of quick Q's out of curiosity, sxavior:

- have you had a chance to replace your VSS yet?

- have you verified that the VSS connector is plugged in and that the connection is secure?

 

[SHOdownTN]

Well the ATX was overfilled, and it ran good for one day and now it back to the same crap.

1- I figured out most of the time it sticks from 3rd to 2nd but occasionally it does it in other gears.
2- The o/d cancel switch does not seem to be working.
3- You can tell when it is not going to work because it shifts hard in other gears.
4- Fluid seems to be a little worn/dirty but nothing that it out of the ordinary.
5- I can't figure out the reason why it does it. Seems to be always. Happens about once per trip. I.E. back and forth from work one day, it happened twice.
6- No

I went to autozone the told me that they did not have the tester to test my 93. They did have a tester they could sell me that MAY work ($300) .They told me that it had to be OBD II. I tried to run the CEL code(S) again but the CEL goes off before I got a test.

Autozone folks are miss guided. Sounds like the same folks at my AutoZone, they know nothing about cars. A 93 is not OBD II. It is actually EEC I think it's called and I got my tester from AdvancedAuto for close to $30. It only has a light and a tone.
My car was shifting hard from 1st to 2nd and seemed to slow to shift in the upper gears. Then, it started to hang in gears. Not wanting to shift up or down till the car was restarted. Then, quicky progressed to no upshifts from 1st and where i'm at now. We may have different peoblems but my car is also a 93 ATX. I swapped my VSS and it had no affect on the problem.
Yours could be simple but I think it's on it's way where mine is.