TC lock up- cause surging?

[VtheGNMan]

When I am cruising at light throttle at about 55-60 mph, 1700-1900 rpms the car will make a surging sound/surging feel but not where it even increases the rpms or wants to do something like shift gears.
From what I have read this may be the TC lock up -locking up and unlocking or vise versa.
Is this what it sounds like?
From my research it sounds like I can unplug the wire on the drivers side of the trans and drive to test it. Is this correct?
How long can I drive it like this? I have 50 mile trip home and wondering if I can drive it all the way the home or is this too long of a drive to test this out?

Any help would be appreciated.

 

[Mrneg9]

My car just started doing the same exact thing. Bison told me to unplug the plug drive it and see what happens. If it goes away then theres either a short in the wire or the tcc may be failing. I just today ordered a new tcc solenoid. I'm going to unplug mine tomorrow. If it stops then I'm going to take the pan down check wire for grounding out and replace tcc solenoid. I will let you know how I make out. You do the same. Thanks.

 

[VtheGNMan]

Thanks for the input. Any idea how long you can drive with it unplugged?
I have a PL ordered and hope to get it installed before I drive again. Would like to log it to see what is going on. As it was doing it the last time I drove it I was watching SM readings and a couple times the SM caught the TPS reading dipping and jumping back up. So might have a dead spot in the TPS sensor doing it. The drop and rebound could be so quick it would cause a surge but not be caught every time by the SM.

 

[standupjskiguy]

You can drive forever with it unplugged, you'll just lose a couple MPG on the highway.
The TCC just locks the torque converter from slipping.
Back years ago, torque converters didn't have lockup clutches.
My 2 cents, what you describe is not a symptom of TCC failure.
It's more like you are running a bit lean or cam sensor timing is off.

 

[VtheGNMan]

Thanks for the input too. Good to know I can drive it unplugged without worry about how far I drive it. Didn't really want to have to plug it back in 1/2 way to work.
The uncertainty is exactly why I want to put a log on it. It is very intermittent.

 

[gunzandgearz]

Check tps that's probably where your problem is.

 

[VtheGNMan]

That's what I am thinking too as I watched the SM pick up a dip in voltage twice. I have a new one of those coming too.

 

[Mrneg9]

Took my car out today and ot drives fine now. Wierd that it never gives me one problem until I serviced the trans. You better do a search on leaving the plug off for long periods of time. I read onbsome posts that it can overheat thevtrans amd do damage.

 

[gunzandgearz]

One more thing, a converter clutch will not cause a surge like a lean condition it will feel like a misfire, especially on these older units where lockup sol. is on/off style and not pwm, These newer pulse width modulated converter clutches are a little more difficult to diagnose as they are slipped on and not just on or off.The best way to test these older style converters is to lightly apply the brake not enough to brake the car just enough to apply the brake lights in forthgear when the thing is acting up because this will disengage the clutch, if it goes away and comes back after letting foot of brake and converter reapplys this is your problem.

 

[bison]

You can drive forever with it unplugged, you'll just lose a couple MPG on the highway.
The TCC just locks the torque converter from slipping.
Back years ago, torque converters didn't have lockup clutches.
My 2 cents, what you describe is not a symptom of TCC failure.
It's more like you are running a bit lean or cam sensor timing is off.

Bad advice for a car that has lockup hydraulics. The TCC circuit and oil flow through the cooler and lube circuit is less with the converter unlocked.


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[bison]

One more thing, a converter clutch will not cause a surge like a lean condition it will feel like a misfire, especially on these older units where lockup sol. is on/off style and not pwm, These newer pulse width modulated converter clutches are a little more difficult to diagnose as they are slipped on and not just on or off.The best way to test these older style converters is to lightly apply the brake not enough to brake the car just enough to apply the brake lights in forthgear when the thing is acting up because this will disengage the clutch, if it goes away and comes back after letting foot of brake and converter reapplys this is your problem.

If the wire is shorted or is intermittently shorted to ground the converter will still lock or stay locked with brake applied. If the solenoid is stuck then the converter could remain locked even when braking.


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[gunzandgearz]

If that was the case he wouldn't be talking about a problem at highway speeds, an intermittently shorted wire or sol. wouldn't care if it was at 55mph or 10 mph and he would be having a heck of a lot more issues than a surge problem like dying when putting in gear, dying at stop light,converter clutch engagement in first gear the list goes on and on and on if that were happening.

 

[VtheGNMan]

I appreciate the input, all your expertise is greatly valued. I'll update the thread once I have switched the TPS to the new sensor and have the power logger on it. Then we will really know what is going on.

 

[gunzandgearz]

No problem good luck.

 

[VtheGNMan]

Update: Got the TPS replaced and drove it to work today. Seems to have fixed the problem as it didn't do it once on the way in. TPS must have had a bad spot in it. Glad I caught it acting up on the SM.
Thanks guys for all your help and suggestions!

 

[gunzandgearz]

Anytime, glad it fixed it.