Torque Converter

[Ferr3t]

Hey all, I've searched this forum and have been unable to find any information on this particular question: Is there any way to tell when your torque converter has locked up, other than by "seat of the pants" feel? I know that some people have installed lean burn indicators in their 90s civics and was wondering if there was any way to do such a thing with a tc on an automatic car. I know that my car has a locking TC, here's a direct quote from the owner's manual:


"Your Honda's transmission has four
forward speeds, and is electronically
controlled for smoother shifting. It
also has a "lock-up" torque converter
for better fuel economy. You may
feel what seems like another shift
when the converter locks."

That's all that it says about the TC in the entire manual. Any info would be appreciated.

As always, thanks a ton.

-Ferr3t

[Duffman]

Tachometer

[Nevyn]

It might be possible to wire in a light to the Torque Converter lockup solenoid (if your car has one) that lights up when the solenoid engages lockup. The only other way is to watch the tach for the lockup drop - it'll be smaller than a shift, but still noticeable - say, 300 to 500 RPM, depending on design.

If I get a chance to bum around with my buddy, he's got a '99 Accord V6 auto, I can get you more definite info.

[i_am_socket]

My Corolla apparently has multiple stages of TC lockup: none, semi locked, and fully locked. No idea what "semi locked" means.

[Nevyn]

Semi-locked is when the stator clutch in the middle of the TC is allowed to slip in a limited function, but isn't fully engaged or disengaged. Check out the howstuffworks page on TC's:

page:
HowStuffWorks "How Torque Converters Work"

video:
HowStuffWorks "How Torque Converters Work"

[wagonman76]

My cars have a pin in the data connector connected to the TCC lockup solenoid wiring. Not sure about the cars of today, if it is that simple. But at worst you could get a wiring diagram and run your own wire. But also on my cars, the difference is night and day whether the TCC is locked or not. Newer cars seem to be much smoother.

But I agree, best way is to watch the tach if you have one. Once you are familiar with what you are identifying, eventually you'll probably be able to just go by feel.

[RH77]

I have a '98 Integra and understand your question. The Honda 4-speed automatic has 3 lockup positions: partial, half, and full. If you select D3 on the shifter, it will not engage the torque converter -- otherwise, the TC can engage in 3rd or 4th gear in D4.

So how to know? The easiest way to know, is to watch for a small drop in RPM. Full lockup is about a 500 RPM drop, with the other two slightly less.

Lifting the gas pedal and re-applying the throttle will definitely tell you if you're in lockup. If the engine RPM goes up with no drop, it's not engaging. If it slips down a bit -- you're engaging.

Personally, I have a quite the issue with TC engagement. Coolant temp is a big factor. The Honda Transmission Control Unit (TCU) is the "End-All Be-All" in transmission decisions. If you engine-off coast, then it confuses the hill-logic control circuit, and will not engage the TC until the calcs satisfy a condition of higher-speed cruise. It uses engine load, speed, acceleration, deceleration, and throttle position to determine if a your going up or down a hill.

Long story short, gaining access to a shop manual will help tremendously.

Best FE to you...

RH77

[Christ]

Find the wiring that goes to the TC lockup solenoid, and get a wiring diagram.

You can connect a light to the lockup solenoid's switched side, which will light up when the solenoid is active... it's kinda the same thing as a Vtec indicator light, a common thing among people who think Vtec is some ungodly power-adder in Hondas.

"The Vtec just kicked in, y0!"

[Ferr3t]

Thanks for the information everyone, and I do have a Tachometer Wagonman, so I'll try to keep an eye on it. I think that I can feel it engage/disengage but trying to keep my eye on the tach, vacuum gauge and the road and be hard sometimes for a newbie.

Originally Posted by RH77

I have a '98 Integra and understand your question. The Honda 4-speed automatic has 3 lockup positions: partial, half, and full. If you select D3 on the shifter, it will not engage the torque converter -- otherwise, the TC can engage in 3rd or 4th gear in D4.

So how to know? The easiest way to know, is to watch for a small drop in RPM. Full lockup is about a 500 RPM drop, with the other two slightly less.

Lifting the gas pedal and re-applying the throttle will definitely tell you if you're in lockup. If the engine RPM goes up with no drop, it's not engaging. If it slips down a bit -- you're engaging.

Personally, I have a quite the issue with TC engagement. Coolant temp is a big factor. The Honda Transmission Control Unit (TCU) is the "End-All Be-All" in transmission decisions. If you engine-off coast, then it confuses the hill-logic control circuit, and will not engage the TC until the calcs satisfy a condition of higher-speed cruise. It uses engine load, speed, acceleration, deceleration, and throttle position to determine if a your going up or down a hill.

Long story short, gaining access to a shop manual will help tremendously.

Best FE to you...

RH77

I have a Chilton's manual for my vehicle but it lacks alot of information about the j30a1 V6 model that I have, most of the focus is put on the four cylinder models. Thanks for the information, how exactly does your coolant temp affect your lockup? Does it run too hot?

Originally Posted by Christ

Find the wiring that goes to the TC lockup solenoid, and get a wiring diagram.

You can connect a light to the lockup solenoid's switched side, which will light up when the solenoid is active... it's kinda the same thing as a Vtec indicator light, a common thing among people who think Vtec is some ungodly power-adder in Hondas.

"The Vtec just kicked in, y0!"

Thank you also Christ, I'm pretty sure that I have wiring maps in my guide.

[Christ]

Before you do any wiring, either get a factory service manual, or get a Helms or Haynes tech book... don't trust Chilton's for wiring, they have been incorrect on wiring diagrams on at least two occasions that I can personally speak of. One of them cost me an engine wiring harness, with a 1991 Honda Civic.