Lock-up questions
10-26-2006, 07:18 PM
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Lock-up questions I just installed a transgo kit to try to solve my converter woes. I don't know if it really worked. What exactly is lockup supposed to work?
If I'm going 60 and I let off the gas, is it supposed to stay at the rpm it is set at (2000) or so, or is it supposed to sit there for a second and then drop to 500-1000?
My car seems to not be able to make up it's mind on what it wants to do, but the higher I get in speed the more it does the latter.
If I'm going 60 and I let off the gas, is it supposed to stay at the rpm it is set at (2000) or so, or is it supposed to sit there for a second and then drop to 500-1000?
My car seems to not be able to make up it's mind on what it wants to do, but the higher I get in speed the more it does the latter.
10-26-2006, 09:19 PM
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OK I shouyld have explained my situation better. I have a FUddle 3400 with the tune set to lock the converter at 40. I can't really remember what it felt like stock becuase I never paid attention to the way the shifts felt before the TC.
I want to knowif this is normal and if not what it means.
If you let off the gas at say 60 should the RPMs stay at 2000, declining in unison with speed, or will it fall back to 500-1000 by itself, while the car is still going like 57 until you hit the throttle again.
I want to knowif this is normal and if not what it means.
If you let off the gas at say 60 should the RPMs stay at 2000, declining in unison with speed, or will it fall back to 500-1000 by itself, while the car is still going like 57 until you hit the throttle again.
10-26-2006, 09:48 PM
#5
The rpm will fall off because the input sprag at least in the od position is free wheeling and the converter unlocks at zero throttle ,However when you come back into it slowly you should be able to feel a distinctive bump when the converter clutch comes back in ,
Hope this helps
Hope this helps
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10-26-2006, 10:17 PM
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Not true, with the stock tune the converter will remain locked until you reach a low enough speed. Stock tune calls for a 35mph unlock so your RPMs will not fall to idle and you cannot coast. The car will decelerate if you don't keep your foot on the gas, producing a "braking" effect. If you do not fall below the set unlock speed, it will only unlock when you push the brake pedal. With that shift kit you should feel a very noticeable bump during lockup.
For the converter to unlock at zero throttle that has to be changed in the tune. If the converter does fall to idle and your car coasts (which is kinda nice and I will probably have my car tuned that way) your TCC is unlocked.
Hope this helps.
For the converter to unlock at zero throttle that has to be changed in the tune. If the converter does fall to idle and your car coasts (which is kinda nice and I will probably have my car tuned that way) your TCC is unlocked.
Hope this helps.
10-26-2006, 10:23 PM
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Damn performabuilt got my hopes up. It seems to act exactly like what he described, though it seems to do it if I keep it in 3rd too. I do have a tune, but I don;t know if he hnaged anything like that. Now I'm just really confused.
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10-27-2006, 10:17 AM
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Originally Posted by performabuilt
But if it works exactly as I described then I would say reguardless you do have lockup working ,
10-27-2006, 10:37 AM
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my lock up clutch is goin bad in mine, but before it went bad the car would lock up at 35mph on a flat road with very light throttle and it would stay locked up until i got below 35 or hit the brakes. after i let off the brakes though it would bump back into lock up if it was above 35. what its doing now since the clutch is going bad is i'll be cruising and it will make a grinding noise and it will unlock randomnly, but locks back up after a while. and when im cruising when that happens and let off the gas the rpms drop to idle.
10-27-2006, 11:21 AM
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Originally Posted by RocketCutlass
my lock up clutch is goin bad in mine, but before it went bad the car would lock up at 35mph on a flat road with very light throttle and it would stay locked up until i got below 35 or hit the brakes. after i let off the brakes though it would bump back into lock up if it was above 35. what its doing now since the clutch is going bad is i'll be cruising and it will make a grinding noise and it will unlock randomnly, but locks back up after a while. and when im cruising when that happens and let off the gas the rpms drop to idle.
10-27-2006, 04:02 PM
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What do you mean by lower, a lower stall than stock? I don't think that will sell very well lol.
Aren't most aftermarket TCs 9.5 inch? I know Fuddle isn't, but there apperently remanufactured GM converters. If your talking about a smaller diameter converter that's probebly a good idea, though I don't know the pros and cons of this because I'm far from an expert in this area.
WEll, the transgo didn;t seem to work, the code came back. Were to go from here?
Aren't most aftermarket TCs 9.5 inch? I know Fuddle isn't, but there apperently remanufactured GM converters. If your talking about a smaller diameter converter that's probebly a good idea, though I don't know the pros and cons of this because I'm far from an expert in this area.
WEll, the transgo didn;t seem to work, the code came back. Were to go from here?
10-27-2006, 04:21 PM
#18
Sorry to hear that, All i can say now is you either have a converter issue , or some sort of leak in the converter circuit, But In most cases that I have seen that the transgo shift dosent fix it its been the converter, 1870 is componet slipping and baring the obvious a clutch gear slip which its my understanding all your shifts feel good its generally the converter,
I do hate you went to all that effort though without results , I feel for you have been there and done that,
If theres anything we can do to help just yell ,
As for the small converter with low stall we allready have the high stall this was for a different market than here and was just an idea .
I do hate you went to all that effort though without results , I feel for you have been there and done that,
If theres anything we can do to help just yell ,
As for the small converter with low stall we allready have the high stall this was for a different market than here and was just an idea .
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10-27-2006, 05:54 PM
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The idea may be good. I don't know what market your shooting for, but if it will actually work to gain mpg, some people may buy it. But people trying to save money on gas don't usually buy these types of cars lol. I don't know how you would market that type of converter, because I doubt those types really look into modifications for that purpose. Also, I imagine the cost of converter and install would be quite expensive and take a looooong time, maybe years, to gain one's money back on the investment. But it may be a money making endevour, with luck on your side.
I guess theres a chance I'll be at your shop having a converter installed soon. No offence but
My money don't come from nowhere. I don't want to get this converter replaced and fine a couple miles down the road I need a whole new tranny either. The parts and labor costs will kill me.
I guess theres a chance I'll be at your shop having a converter installed soon. No offence but
My money don't come from nowhere. I don't want to get this converter replaced and fine a couple miles down the road I need a whole new tranny either. The parts and labor costs will kill me.
10-27-2006, 07:32 PM
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My Fuddles have been approx 10" diameter. The standard,
that I sent back uninstalled to upgrade, and the HP/Street.
They were nohow a stock diameter.
If you are locked (and holding) then the simple test is, roll
on the throttle a hair and watch the tach. Unlockied you
will slide on up in RPM without moving MPH. Locked you will
load up the motor and not move in RPM until speed goes up.
Now, converters with weak clutches or suffering from line
starvation (thank the GM programmers) will not hold much
torque before beginning to slip. But below some threshold
they will hold, then flare softly, then unlock as you roll into
the throttle.
Locked or unlocked at 0% TPS is a tune datapoint, can be
either way. I prefer freewheeling to engine braking myself.
P1870 has popped on mine -purely- from converter slip.
Once P1870 sets the PCM will not attempt to lock anymore
until key off / key on resets this notion.
You really want to get a look at the PCM's TCC_Mode in
circumstances where you'd like it to be locked, but it
isn't. You have to see the intention and whether it says
it's being held off for misfires.
that I sent back uninstalled to upgrade, and the HP/Street.
They were nohow a stock diameter.
If you are locked (and holding) then the simple test is, roll
on the throttle a hair and watch the tach. Unlockied you
will slide on up in RPM without moving MPH. Locked you will
load up the motor and not move in RPM until speed goes up.
Now, converters with weak clutches or suffering from line
starvation (thank the GM programmers) will not hold much
torque before beginning to slip. But below some threshold
they will hold, then flare softly, then unlock as you roll into
the throttle.
Locked or unlocked at 0% TPS is a tune datapoint, can be
either way. I prefer freewheeling to engine braking myself.
P1870 has popped on mine -purely- from converter slip.
Once P1870 sets the PCM will not attempt to lock anymore
until key off / key on resets this notion.
You really want to get a look at the PCM's TCC_Mode in
circumstances where you'd like it to be locked, but it
isn't. You have to see the intention and whether it says
it's being held off for misfires.
