velly velly strange

[Jonn]

Bad attempt at a Elmer fudd voice, anyway, my 91 2.5 Lumina, been running great after all the parts, while back i put in a new tcc sol. as well. Never had any problems with tranny or tcc. BUt, seem to have started this just after all the new parts (all engine sensors including tps,map, ign mod, crank sensor,O2)
What its doing is well... tcc locks fine just when it should, unlocks when it should and as it always has, IF you are giving it just a faction more than cruise throttle, OR if you are on a very slight up hill grade where you have a bit of throttle on, in those places you cant tell anything is different than before.
BUT... Get on a cruise on level ground, no matter what speed as long as its above lockin speed, the convertor will lock ok, and stay locked as long as you apply light throttle, but back off the throttle a TINY ( Imean tiny, like 50 rpms? like maybe 1/16 pedal lift) and it will instantly unlock, reapply throttle, locks right up, lift a smidge, and unlocks, you can do this all day as long as you cruise, what it seems like is for example, the TPS has turned into a ON/OFF switch that within a 1/16 inch pedal movement, it locks/unlocks the TCC.
I mean its really a small amout, when you lift and it unlocks, you cant even tell any decrease in engine rpm by ear, no decrease in speedometer setting, its that quick.
I may be dumb but seems more electrical to me than a actually tranny malfunction, if you run it a bit past that magic throttle spot, tranny seems fine, so does lockup/unlock. I just dont know where to start looking/
P.S. what about a VSS? speedo is controlled by the VSS as is from what i read so is the TCC, tho partically, but my speedo isnt "off" any more than it has ever been.
What else has control over the TCC (leaving out ECM) anyone have a clue?

[KenInKenmore]

what year and model engine size, it could just be the fluid your using in your tranny... cause most autos are fluid controlled, not computer controlled

[Jonn]

Originally Posted by KenInKenmore

what year and model engine size, it could just be the fluid your using in your tranny... cause most autos are fluid controlled, not computer controlled

In my orginal post i said a 91, 2.5

A year ago fluid and filter was changed, DexII for refill, been fine a year now. IT is very hard to explain but it doesnt seem like the tranny itself, more like elecrtical. I am going to try a test light hooked up to TCC wires while driving just to see if the electric current does indeed shut off/on.
Soon as i can find out whicj wires to hook it to.
The only thing that hasnt been replaced outside the tranny is the brain box. Every sensor and switch, and every Ign. part as well.

[jeffcoslacker]

First things first. Wanted to make sure we have our terms straight. The convertor should lock up when you drop the throttle, release when you give it gas. Is that what's happening? I wanted to be sure you don't have some reversed operation happening, cuz that would lead me in a different direction entirely.

[jeffcoslacker]

I remember all the 2.5's having wierd problems of all kinds that traced back to the vacuum line going to the MAP sensor being collapsed or split. Please check that before we go any farther.

[Jonn]

Originally Posted by jeffcoslacker

I remember all the 2.5's having wierd problems of all kinds that traced back to the vacuum line going to the MAP sensor being collapsed or split. Please check that before we go any farther.

The line to the MAP is fine, i cannot fins any vac leak any place.
As for the lockup operation, it works as it should like from a standing start, goes thru all 3 gears, hits about 40 mph, and it locks as it always has
, NOW, if you are on even a slight grade,like 2 %, it continues to stay locked, mainly cause you are giving it a little throttle,(holding throttle) and the grade is forcing you to keep the throttle on, but if you level off where the throttle is no longer needed, and you lift the pedal a thousands of a inch, it will unlock, push it back that tiny amount, and it will relock.
You can lock/unlock all day like this on level ground because you cant keep giving it more and more throttle cause you will end up speeding.
Ok, say i hit 40 and it locks, the highway has rises and dips, tho slight, if i hold throttle steady, it will stay locked up the rise, unlock on the down side, relock up the next one, you have to seem to have a slight load on the engine, tranny, and throttle for it to stay locked.
Very hard to describe how little of load/throttle change there is to make it do this.
Also, if its locked, and i hit a steaper grade on the hiway at say 55, and i hold throttle steady, and the hill is steap/long engouh that it does eventually slow to around 40 mph, it will stay locked till the proper time (40 mph) to unlock. Just like it always had.
Also again, if it locks on the hiway at 40, and you slowly, very slowly keep increasing throttle, it will stay locked up and down hill as fast as you want to go, TILL, you back off throttle a smidge...(will unlock if you floor it too)
Trying all i can to describe this to ya....But its so very slight throttle movement its hard to really understand, i suspect electrical or vac.
Could it be the new MAP i just put on?
Now in a non related, or maybe a related weird thing, the idle is perfect all the down to .0000001 mph, soon as wheels stop turning, idle dips real low and stays there.
Soon as you start releasing the brake, and a wheel starts turning (even less than one full turn) the idle will go back up to normal, it never did this befor, anytime. And it isnt the vac difference in the brake applied/realeased because i still have the brake on, juuuusssst loose enough that the wheel can creep, related ya think?

I do have a good lockup when it is "locked" no slippage. lock and unlock are firm .
I have checked manuals and the internet and cannot find anyone with this same problem.. Any insight appreciated

[jeffcoslacker]

It almost sounds like the TCC is beginning to drag a little. The actual lockup mechanism, I mean, not the solenoid. Does it do it when you first start driving? Cuz the lockup shouldn't be active until full operating temp is reached. You could unplug the TCC, let it cool overnight and drive it with it disabled the next day, see if the drag on your idle at a stop is gone. Then you'd know what you got.

The only other thing I wonder is, possible in any way that you just never noticed that aspect of the idle before this other started happening? I ask because in the shop, when I'd have one running on a lift in nuetral, the wheels turn, fluid motion causing residual movement in the gears and things. When I'd grab the tires and stop them from moving, the idle would momentarily "gag", then idle down slightly. I always assumed it was because it put a slight amount more load on it to not be able to turn the parts anymore, having to "fight" them with fluid pressure instead of having them move with it. I suppose this could be related to the VSS, that's one sensor I never had occaision to deal with.

I wonder if this is in any way related to what you noticed.

I had a lady describe exactly what you are describing right before her TCC began failing to unlock completely. I wonder. And it was not the solenoid, she'd had it replaced a couple of months before. This was the torque convertor actually going bad.

Anyhow, what I was getting at on the other reply is the convertor should LOCK when coasting or cruising, UNLOCK when you give it power or start up a hill. The reason being that the slip when unlocked allows additional torque by way of allowing higher RPM"s same road speed. Then when load is nuetral (cruising) it locks, allowing for better fuel mileage by eliminating slippage and decreasing RPMs relative to road speed.

[Jonn]

Originally Posted by jeffcoslacker

It almost sounds like the TCC is beginning to drag a little.
No, you have to really be in the car to tell, and im sure you would agree if you were, it isnt dragging im sure, ill swear/gaurentee its the IAC slowing the idle even more, why i have no clue.
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The actual lockup mechanism, I mean, not the solenoid. Does it do it when you first start driving? Cuz the lockup shouldn't be active until full operating temp is reached.
Well i dont think it does it (except for the slow idle) when cold, i have a drive long enough from my house that by the time i cab reach 40, car is already warm.
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You could unplug the TCC, let it cool overnight and drive it with it disabled the next day, see if the drag on your idle at a stop is gone. Then you'd know what you got

Actualy i did unplug it, and tranny acts fine, shifts fine, but the slow down at a stop is still there.I dont think from way it feels it is the tranny causing the slowdown, Feels like the IAC actually slows it
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The only other thing I wonder is, possible in any way that you just never noticed that aspect of the idle before this other started happening? I ask because in the shop, when I'd have one running on a lift in nuetral, the wheels turn, fluid motion causing residual movement in the gears and things. When I'd grab the tires and stop them from moving, the idle would momentarily "gag", then idle down slightly. I always assumed it was because it put a slight amount more load on it to not be able to turn the parts anymore, having to "fight" them with fluid pressure instead of having them move with it. I suppose this could be related to the VSS, that's one sensor I never had occaision to deal with.

No i know it never did this before, but i also did drive it a long time with the IAC unplugged because i assume the MAP was goofy and car would always idle real high, driving or sitting still. Now that i replaced all the sensors, i wanted it all to work right, and thinking back, it did untill the last thing i replaced, it MAP, thats about when the idle drop, and weird tcc crap started happening.
I supose the idle slow down could be normal and didnt before because the IAC was unplugged and or one of the other sensors were bad, and now its "normal" I can live with the slowdown if its "normal" just aggrivating not knowing if its a indeed a malfunction.
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I had a lady describe exactly what you are describing right before her TCC began failing to unlock completely. I wonder. And it was not the solenoid, she'd had it replaced a couple of months before. This was the torque convertor actually going bad.

I spose it could be the convertor going bad, BUT. (see below)

Anyhow, what I was getting at on the other reply is the convertor should LOCK when coasting or cruising, UNLOCK when you give it power or start up a hill. The reason being that the slip when unlocked allows additional torque by way of allowing higher RPM"s same road speed.

That is exactly how it works, just like it is sposed too, but only if there is a slight throttle/slight hill that the car is going up. See i drive the same route every day, and ya learn the cars habits after awhile as i am sure you know, several "hills" that it would start up at 55, and slow due to the incline to about 40 without moving throttle, the convertor would hold till i slowed to 40 and unlock, it still does that exactly the same as before.
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BUT!




Then when load is nuetral (cruising) it locks, allowing for better fuel mileage by eliminating slippage and decreasing RPMs relative to road speed.

It does this too, just like before, start crusing and if passing 40 mph it locks, but will only hold the lock if i can keep a bit of throttle applied, but as i said, i cant do that because i would keep gaining speed and go to fast, soon as the load becomes neutral as you describe it,and you ease up a tiny amount throttle wise, it unlocks again, and all it takes to relock it is such a very slight increase in pedal pressure, you cant even tell you moved the pedal.
I know its weird, and its hard to describe, i doubt the pedal movement it takes would hardly move a tach needle even.

I am thinking about gathering up my old TPS/MAP and sticking them back on to see if at least the problem changes any, or goes back to the way it acted before the new parts.
Appreciate you racking your brain over it too..

[jeffcoslacker]

Originally Posted by Jonn

It does this too, just like before, start crusing and if passing 40 mph it locks, but will only hold the lock if i can keep a bit of throttle applied, but as i said, i cant do that because i would keep gaining speed and go to fast, soon as the load becomes neutral as you describe it,and you ease up a tiny amount throttle wise, it unlocks again, and all it takes to relock it is such a very slight increase in pedal pressure, you cant even tell you moved the pedal.
I know its weird, and its hard to describe, i doubt the pedal movement it takes would hardly move a tach needle even.

I am thinking about gathering up my old TPS/MAP and sticking them back on to see if at least the problem changes any, or goes back to the way it acted before the new parts.
Appreciate you racking your brain over it too..

You must be a lot more sensitive to that than I am. I am only rarely aware of the convertor doing it's thing, and usually only if the windows are down and I can hear the change in pitch of the exhaust when it locks.

My wifes ZX2 had a really agressive exhaust sound, and I am overly aware of it when I drive hers. It drives me nuts in fact, it seems a little hyperactive like you are talking about. But the Ford guys say it's normal on those, so I ignore it.

[Jonn]

Originally Posted by jeffcoslacker

You must be a lot more sensitive to that than I am. I am only rarely aware of the convertor doing it's thing, and usually only if the windows are down and I can hear the change in pitch of the exhaust when it locks.

On this 2.5 convertor lock is very noticable, when it does you can hear the engine change pitch even with quiet exaust, you can feel the rpm's drop/increase, you can even feel a slight surge of speed as it locks, now my daughters Corsica with the 3.1 you couldnt tell this much, in fact the tcc plug is disconnected now because i need to put a new switch in, and the car doesnt even feel like its running to hard on the highway, but this 4 cyl does. I am not a perfectionist, but ya just hate when something works right, then acts goofy, and ya cant find a good reason for it. Im sure there is one, just finding it.....

As for now i am doing nothing but driving it, we just had a foot of snow and i have a small tractor with a blade, and several neighbors that i plow for so that is keeping me busy..Not to mention i had it all done and now we have high winds, so it will be back to the drawing board today.. Had my driveway, about 50 yards clean last night, this morning the Lumina waded thru bumper high snow to get out, hey this thing goes like a 4x4, but i also have dedicated "Winterforce" snow tires and studs..

My wifes ZX2 had a really agressive exhaust sound, and I am overly aware of it when I drive hers. It drives me nuts in fact, it seems a little hyperactive like you are talking about. But the Ford guys say it's normal on those, so I ignore it.

Are Ford guys normal? LOL Hey what am i saying, i have a GM car and a Ford truck....
Anyway, im sure if something is failing it will let me know sooner or later, thanks for chattin about this thing..

[wrightz28]

Jonn,

What's wrong with GM guys having F.O.R.D. trucks?
Atlease you're not asking a question about your rustangs clutch on a all chevy site! -Dylan

[Jonn]

Originally Posted by wrightz28

Jonn,

What's wrong with GM guys having F.O.R.D. trucks?
Atlease you're not asking a question about your rustangs clutch on a all chevy site! -Dylan

Nothing wrong really, fact nothing wrong with what ever car company vehicle gets the job down for ya..
Right now the Lumina is dead in the water, Ign malfunction. So off to sons house where it died at to see if i can get it going. So pissed right now its a good thing my truck isnt running or i would hook a chain to it and drag it home 10 miles upside down and backwards...

in the singing voice of Toby Keith ( I love this car) LOL

no i acatually do like it, just not at the moment...