Small problem with my Clutch/Tranny
03-24-2006, 04:44 AM
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Small problem with my Clutch/Tranny
During these colder winter months I havnt driven my car much... But when I do, and its real cold Ill start my car like normal, release the clutch with the car in neutral and let it warm up. sometimes it dies... sometimes it almost dies. Well today, I did it on a perfectly level surface and my car wanted to move foward... not like it was in first gear... but slower. I was in a closed hanger so I didnt see how far it went. I ended up pressing in and releasing the clutch a couple times... then finnally pulled the ebrake and released the clutch to let her run for a while... and thats what happened, she didnt die.
Now.. I have pretty thick racing tranny fluid... could it be the cause? Why would my car move foward in neutral?
Now.. I have pretty thick racing tranny fluid... could it be the cause? Why would my car move foward in neutral?
03-24-2006, 07:13 AM
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Originally Posted by 3312DC,Mar 24 2006, 07:44 AM
During these colder winter months I havnt driven my car much... But when I do, and its real cold Ill start my car like normal, release the clutch with the car in neutral and let it warm up. sometimes it dies... sometimes it almost dies. Well today, I did it on a perfectly level surface and my car wanted to move foward... not like it was in first gear... but slower. I was in a closed hanger so I didnt see how far it went. I ended up pressing in and releasing the clutch a couple times... then finnally pulled the ebrake and released the clutch to let her run for a while... and thats what happened, she didnt die.
Now.. I have pretty thick racing tranny fluid... could it be the cause? Why would my car move foward in neutral?
Now.. I have pretty thick racing tranny fluid... could it be the cause? Why would my car move foward in neutral?
03-24-2006, 07:45 AM
#4
I daily drive mine all winter and sometimes, I start it in the morning when it's been sitting outside in the extreme cold. What you describe, I believe to be quite normal.
1. You have very thick oil (not sure why and not sure how thick, but you might want to reconsider this, even for summer driving unless yours is a track car). Thick oil will offer tremendous resistance to all the moving parts inside the engine. It now has to use some of its power just to turn a much larger opposing force. No biggie, the Idle Control will manage.
2. Now add in the viscosity of the tranny fluid.
3. Now throw in a cold start. In neutral, you are spinning all those tranny gears. Also, the tranny fluid is cold and it's settled to the bottom of the pan and over a period of storage or many hours of being parked in the cold, the upper 1/2 or more of the tranny is "dry" (more resistance). Have you heard of "viscous couplings"? These are used in AWD cars where the power is transferred to the other drive wheels with a torque sensing transfer case. This transfer case uses fluid to relay power and not a solid direct mechanical connection. Your tranny is acting in a similar manner. When you engage the clutch, you begin to spin the tranny, but the viscous action of the fluids acting upon the gears and various shafts in there, will actually transfer some power to the back wheels.
OK, after you start the car in the described condition, you not only have the resistance of the oil in the engine, but now you have the added resistance of the fluid of the tranny trying to turn the propshaft. This is just enough extra load at such a low rpm, where the engine is still trying to stabilize its idle, that it can slow the engine down enough it can die.
Recommendation: Put in neutral, hold clutch firmly on floor, start engine. Continue to hold clutch on floor for a bit longer (1/2 minute, more if really cold). When you begin to release the clutch, have foot on brake (or ebrake applied firmly). Release the clutch slowly and be prepared to push it back down if the engine rpm starts to drop. You may have to do this repeated till you can get the fluid in the tranny moving to get it on its way to warming up just a little bit. If this process is too slow, then be prepared to counter the decreasing rpm with a little gas when releasing the clutch. It's just that in these conditions, the Idle Air Control mechanism can't respond fast enough to the decreasing rpm. You need to introduce the added load slowly or give it a little gas to help it along. Once the clutch is fully released, the IAC can take over and you can warm up "feet off".
1. You have very thick oil (not sure why and not sure how thick, but you might want to reconsider this, even for summer driving unless yours is a track car). Thick oil will offer tremendous resistance to all the moving parts inside the engine. It now has to use some of its power just to turn a much larger opposing force. No biggie, the Idle Control will manage.
2. Now add in the viscosity of the tranny fluid.
3. Now throw in a cold start. In neutral, you are spinning all those tranny gears. Also, the tranny fluid is cold and it's settled to the bottom of the pan and over a period of storage or many hours of being parked in the cold, the upper 1/2 or more of the tranny is "dry" (more resistance). Have you heard of "viscous couplings"? These are used in AWD cars where the power is transferred to the other drive wheels with a torque sensing transfer case. This transfer case uses fluid to relay power and not a solid direct mechanical connection. Your tranny is acting in a similar manner. When you engage the clutch, you begin to spin the tranny, but the viscous action of the fluids acting upon the gears and various shafts in there, will actually transfer some power to the back wheels.
OK, after you start the car in the described condition, you not only have the resistance of the oil in the engine, but now you have the added resistance of the fluid of the tranny trying to turn the propshaft. This is just enough extra load at such a low rpm, where the engine is still trying to stabilize its idle, that it can slow the engine down enough it can die.
Recommendation: Put in neutral, hold clutch firmly on floor, start engine. Continue to hold clutch on floor for a bit longer (1/2 minute, more if really cold). When you begin to release the clutch, have foot on brake (or ebrake applied firmly). Release the clutch slowly and be prepared to push it back down if the engine rpm starts to drop. You may have to do this repeated till you can get the fluid in the tranny moving to get it on its way to warming up just a little bit. If this process is too slow, then be prepared to counter the decreasing rpm with a little gas when releasing the clutch. It's just that in these conditions, the Idle Air Control mechanism can't respond fast enough to the decreasing rpm. You need to introduce the added load slowly or give it a little gas to help it along. Once the clutch is fully released, the IAC can take over and you can warm up "feet off".
03-24-2006, 08:24 AM
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Believe it or not, most RWD sportscars on a lift will spin the rear tires very slowly if the car is cold, even if it is neutral. Same with my 300zx turbo, s2k, every rwd LSD equipped car I've came into contact with. It can be surprising the first time.
03-24-2006, 08:54 AM
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Originally Posted by xviper,Mar 24 2006, 08:45 AM
I daily drive mine all winter and sometimes, I start it in the morning when it's been sitting outside in the extreme cold. What you describe, I believe to be quite normal.
1. You have very thick oil (not sure why and not sure how thick, but you might want to reconsider this, even for summer driving unless yours is a track car). Thick oil will offer tremendous resistance to all the moving parts inside the engine. It now has to use some of its power just to turn a much larger opposing force. No biggie, the Idle Control will manage.
2. Now add in the viscosity of the tranny fluid.
3. Now throw in a cold start. In neutral, you are spinning all those tranny gears. Also, the tranny fluid is cold and it's settled to the bottom of the pan and over a period of storage or many hours of being parked in the cold, the upper 1/2 or more of the tranny is "dry" (more resistance). Have you heard of "viscous couplings"? These are used in AWD cars where the power is transferred to the other drive wheels with a torque sensing transfer case. This transfer case uses fluid to relay power and not a solid direct mechanical connection. Your tranny is acting in a similar manner. When you engage the clutch, you begin to spin the tranny, but the viscous action of the fluids acting upon the gears and various shafts in there, will actually transfer some power to the back wheels.
OK, after you start the car in the described condition, you not only have the resistance of the oil in the engine, but now you have the added resistance of the fluid of the tranny trying to turn the propshaft. This is just enough extra load at such a low rpm, where the engine is still trying to stabilize its idle, that it can slow the engine down enough it can die.
Recommendation: Put in neutral, hold clutch firmly on floor, start engine. Continue to hold clutch on floor for a bit longer (1/2 minute, more if really cold). When you begin to release the clutch, have foot on brake (or ebrake applied firmly). Release the clutch slowly and be prepared to push it back down if the engine rpm starts to drop. You may have to do this repeated till you can get the fluid in the tranny moving to get it on its way to warming up just a little bit. If this process is too slow, then be prepared to counter the decreasing rpm with a little gas when releasing the clutch. It's just that in these conditions, the Idle Air Control mechanism can't respond fast enough to the decreasing rpm. You need to introduce the added load slowly or give it a little gas to help it along. Once the clutch is fully released, the IAC can take over and you can warm up "feet off".
1. You have very thick oil (not sure why and not sure how thick, but you might want to reconsider this, even for summer driving unless yours is a track car). Thick oil will offer tremendous resistance to all the moving parts inside the engine. It now has to use some of its power just to turn a much larger opposing force. No biggie, the Idle Control will manage.
2. Now add in the viscosity of the tranny fluid.
3. Now throw in a cold start. In neutral, you are spinning all those tranny gears. Also, the tranny fluid is cold and it's settled to the bottom of the pan and over a period of storage or many hours of being parked in the cold, the upper 1/2 or more of the tranny is "dry" (more resistance). Have you heard of "viscous couplings"? These are used in AWD cars where the power is transferred to the other drive wheels with a torque sensing transfer case. This transfer case uses fluid to relay power and not a solid direct mechanical connection. Your tranny is acting in a similar manner. When you engage the clutch, you begin to spin the tranny, but the viscous action of the fluids acting upon the gears and various shafts in there, will actually transfer some power to the back wheels.
OK, after you start the car in the described condition, you not only have the resistance of the oil in the engine, but now you have the added resistance of the fluid of the tranny trying to turn the propshaft. This is just enough extra load at such a low rpm, where the engine is still trying to stabilize its idle, that it can slow the engine down enough it can die.
Recommendation: Put in neutral, hold clutch firmly on floor, start engine. Continue to hold clutch on floor for a bit longer (1/2 minute, more if really cold). When you begin to release the clutch, have foot on brake (or ebrake applied firmly). Release the clutch slowly and be prepared to push it back down if the engine rpm starts to drop. You may have to do this repeated till you can get the fluid in the tranny moving to get it on its way to warming up just a little bit. If this process is too slow, then be prepared to counter the decreasing rpm with a little gas when releasing the clutch. It's just that in these conditions, the Idle Air Control mechanism can't respond fast enough to the decreasing rpm. You need to introduce the added load slowly or give it a little gas to help it along. Once the clutch is fully released, the IAC can take over and you can warm up "feet off".
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03-24-2006, 10:17 AM
#8
Originally Posted by wupike,Mar 24 2006, 11:10 AM
conclusion: park your car in a heated airplane hangar, not some low-rent cold one! 
This might apply to the S2000. There have been many nights where my car was parked outside for up to 15 hours and the temp got down to colder than -30*C. You don't need to convert to *F. That cold, it's getting to be almost the same. It was tough on the thing, but the car is over 5 years old and it is still tight and as reliable as the day I brought it home. If it were a living thing, I'm sure it be most envious of its brethren that live in places like San Diego or Australia, but then it wouldn't wear the medal of courage for having endured as much.
(Think Marines and see what they go through - tough as nails.)
03-24-2006, 12:10 PM
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Originally Posted by 3312DC,Mar 24 2006, 05:44 AM
Now.. I have pretty thick racing tranny fluid... could it be the cause? Why would my car move foward in neutral?
Next time on flat pavement, release e-brake and try slowly and momentarily put the shift lever against each gear entrance without clutch. You will feel the car trying to move forward while idle speed may or may not droop. Notice how little it takes to move towards each gear entrance for the synchros to work. The lower the gear the more noticeable for the obvious reasons; otherwise, your tranny clearance spec may be out.
I haven't been in such cold temp that C or F doesn't matter, but I thought that with proper weight fluids, the incredibly fast cold idle speed Honda runs would be good enough. Sometimes I kind of hate the 2000rpm fast idle on my S. I just start driving very slowly after I'm set and buckle up (like in 15-30 seconds). I like my BMW fast idle speed which is about 1100rpm.
03-24-2006, 01:13 PM
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Xviper has good recommendation to tackle the potential stalling, but I don't feel too comfortable holding the clutch for 30 seconds, especially when everything is cold. It may or may not cumulate enough extra wear on the crankshaft thrust bearing to make a difference but I would avoid doing that as much as possible.
I just re-read OP's description again and have a question. Does the engine stall on the clutch release itself? Or does it stall by itself after clutch release and everything has been stabilized? If it's the former, I would suggest try slowly engage the clutch after fast idle speed is established and stabilized.
Also, try depressing the brake pedal a few times to release all the vacuum reserve from the booster before starting the engine. This will provide more air at atmospheric pressure for the engine to reach fast idle easier and quicker. This also provides a bonus to keep the full stroke of the brake master cylinder clean from corrosion due to infrequent use.
I just re-read OP's description again and have a question. Does the engine stall on the clutch release itself? Or does it stall by itself after clutch release and everything has been stabilized? If it's the former, I would suggest try slowly engage the clutch after fast idle speed is established and stabilized.
Also, try depressing the brake pedal a few times to release all the vacuum reserve from the booster before starting the engine. This will provide more air at atmospheric pressure for the engine to reach fast idle easier and quicker. This also provides a bonus to keep the full stroke of the brake master cylinder clean from corrosion due to infrequent use.