WTF

[justin95ta]

heres the problem, a while back when i put my bbk shorties on one of the o2 sensors managed to unscrew itself and my car started blowing black smoke out the back when i got the o2 sensor back in the smoke cleared up but the tranny got all fubar, if i am just driving "normal" it wont shift til 3000rpm if im racing and leave it in drive it will shift out of every gear at 3500rpm, but i can still pull the shifter down to 2 or 3 and it wont shift until i move it up. i posted this on LT1tech and was told to check and/or replace the speed sensor, well i just replaced it and the tranny hasnt changed. any thoughts or suggestions?

[jdawgs94z]

hey man,when your driving on the highway is the car running at around 3k rpms at 70+mph?my car is doing this too,maybe we can find an answer for both of us,i too have posted his on ls1tech and z28.com but havent got any answers that work ,is the tranny a 4l60e?

[Alex94TAGT]

Hey Justin,

Sorry, I forgot about this. I just read the message you sent me over at LT1tech...


You say you got an SES light immediately after installing the throttle body? Did you ever have the DTC code pulled? (Are you still thinking about purchasing a Scanmaster LT1)?

Perhaps this was simply coincidence, but it is more evidence supporting the idea of a TPS problem (which is used heavily in the computer's control of the transmission).

I think the next logical step is to test the TPS. If you don't have some form of scan tool, then at very least, we could check the voltage readings. If you don't have one already, I'd recommend purchasing a digital voltmeter. You can get some alligator clips for the ends of the test leads, which you can use to 'probe' the TPS electrical connector using needles.

We can go into this more if you feel comfortable doing so...

[Alex94TAGT]

Forgot a few thoughts:

I know you said the tranny problems started after the oxygen sensor ordeal, which I still feel is unrelated and coincidental. But, did you install this new throttle body at about that time as well? I should have asked this earlier.

If this is the case, do you still have the factory throttle body? You could try swapping everything back to that. If the problem goes away, you've found your problem. If the problem still occurs, then I'd continue testing the TPS as explained in my first post above.

[jdawgs94z]

me

[Alex94TAGT]

Jdawg --

Nothing at the other sites has helped thus far? What all have you been told to check? Did this occur after any specific work was done to the vehicle? Do you have an SES light on the dash?

As I told Justin, I'm really no expert on the automatic transmission. I've never owned one. But, there are a few things that may be causing your problem, from what I've seen within the computer programming:

-Faulty TPS sensor readings --perhaps due to aftermarket throttle bodies
-Faulty VSS (vehicle speed sensor) / mph readings. Not only will this screw up shift points, but it might prevent the torque converter from locking up.
-Something causing reduced line pressure within the transmission. Certain pressures must be maintained in order for the tranny to shift properly.
-Random burnt/kinked wires? Hopefully this would throw a DTC code.

Dunno, I'm just tossing out ideas. Good luck to the both of you...

[jdawgs94z]

alex,that was the most advise on my problem i've had so far,thanks,i just rebuilt the tranny,and when i was taking it out of the car,my bro-inlaw was working the jack and dropped the tranny while it was still hooked up to some wiring and the dipstick tube,so i think he messed it up,so i might have to check the wiring for continuity,but i'm gonna check out the speed sensor too,i just hope i can get it fixed because with it running at 3k rpm's on the highway it has cut my gas mileage in half

[justin95ta]

jdawg- i unfortunately have the 2.73 rearend so i run about 2k at 80mph the only thing good thing about the 2 series is that i get alright gas milage on trips.

alex- i will be ordering my scanmaster at the middle to end of the week and will be overnighting it for obvious reasons. i had one of the guys at auto zone hook up the diagnostic thing to my car but it didnt help, i think alot of that had to do with the fact that he was an idiot, my TA is a 95 and he was arguing with me about it being OBD1 he told me its OBD2...should've known, not to go to autozone!! as far as getting into this further have at it, i dont know a ton about trannys but i am a quick learner.

[jdawgs94z]

yeah i have 3.23's ,but i should be cruising at 2200rpm's at 70 mph

[justin95ta]

i thought about upgrading to 3.23's but i am more of a road racer and think that i am gonna go with 3.08's for a little better pull and still keeping some of that topend speed.

[Alex94TAGT]

Justin,

If you're getting a scanmaster, then I wouldn't worry about the voltmeter testing. The scanmaster will tell you more about the TPS readings than the voltmeter can. (TPS voltage + TPS percent as read by the computer).


Yes, the fruit at autozone was wrong, but I guess it's really GM's fault for designing the 1995's that way. Your car should be OBD1, but because of the OBD2 DLC connector, you would have had to jumper the connections to get that scan tool to work anyway...

Just the same, if you're getting a scanmaster, it doesn't matter. You'll soon be able to read your own diagnostic codes, as well as all the other sensor readings...

[justin95ta]

yeah he wasnt the brightest crayon in the box.

[turtle]

justin95ta said:

yeah he wasnt the brightest crayon in the box.

LOL that is so true ;D. I think it's a requirement to have absolutley no automotive knowledge whatsoever to get a job there.

[Alex94TAGT]

I remember going in to Autozone and asking for some "ignition wire looms/separators." After explaining it a few times, the poor guy still had no clue what I was referring to. I just quietly pointed behind him, where there were a bunch hanging on a shelf.

I think it's fun going there. Makes me feel smarter than I really am...

[turtle]

alex94tagt said:

I remember going in to Autozone and asking for some "ignition wire looms/separators." After explaining it a few times, the poor guy still had no clue what I was referring to. I just quietly pointed behind him, where there were a bunch hanging on a shelf.

I think it's fun going there. Makes me feel smarter than I really am...

Case in point ;D.