Bad Idle (Have researched for days)
10-28-11, 09:36 PM
#27
Primary screws look great and the dashpot seems to be functional but the white part on it is always showing. I never seen a green pin when i checked. I would actually like to disable the accelerated warm up and have it when the cam is always off of the pin if that is possible?
I unplugged the bac and it made no difference at all.
My car doesn't have the cruise control. Don't think that particular one came with it.
I unplugged the bac and it made no difference at all.
My car doesn't have the cruise control. Don't think that particular one came with it.
The White part of the Dashpot should jut out when the throttle mechanism pulls away from the Dashpot and then becomes pressed in to the Dashpot when the linkage rests against it. If you move the linkage away from the Dashpot the plastic part fully extends and you can with your finger press it back in to the Pot and you will encounter resistance when doing so. When you release the plastic part it should spring outwardly w/ease. All of this info I have offered is found in the FSM along w/pics. In addition, the Pot is to release from the throttle linkage when the engine speed is 2700 to 3100 rpm.
10-29-11, 01:47 AM
#30
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Thanks again for all the great information. I understand this stuff is in the FSM but none of it really explains how to fix it.
I'm almost positive that the white piece on the dashpot is ALWAYS out. What type of problems could this cause?
I have always thought of myself as a great mechanic, but not being able to fix this choppy idle is really causing me to doubt myself. I hope I can get it straightened out.
Will work on it some tomorrow when I have plenty of time so hope it doesn't rain or get too cold.
I'm almost positive that the white piece on the dashpot is ALWAYS out. What type of problems could this cause?
I have always thought of myself as a great mechanic, but not being able to fix this choppy idle is really causing me to doubt myself. I hope I can get it straightened out.
Will work on it some tomorrow when I have plenty of time so hope it doesn't rain or get too cold.
10-29-11, 11:29 AM
#31
Don't fret because these cars are a pain to work on when it comes to idling for there are so many different variables at play that all need to get along to cause a proper idle. With that being said, when you look at the Thermowax it has a piston which will press outward much like the TPS. As Karack has suggested you could disable this mechanism to see what is or isn't causing the problem. One thing you could do is to place a rubber cap/plug on top of the upside down screw found underneath the Thermowax piston and use a cap that is about 3/4 to an inch long. Put the cap in place before starting the car and make sure the top of the cap rests against the piston above it. Doing this will effectively disable the Fast Idle mechanism so when the car is started it will not idle at 1500 or so rpm but will quickly drop to as low as it will go w/o the Fast Idle playing a role. This will tell you if the idle still stays high whether or not it was due to the Fast Idle aspect. If it stays rather high then it cannot be caused by the Fast Idle.
Another thing is your mention of the Dashpot. If the White part operates as previously suggested then you need to look at the following. When the rpm is increased the throttle linkage that rests upon the Dashpot will separate from it and progressively the gap between the Pot and the linkage increases. If the linkage was always too far from the Pot then the White part could never recede back in to the Pot. Another side of the story is if the Pot is not screwed into a proper position then it might be too far from the linkage to begin with and cause what you are currently seeing. So either the Pot position needs to be adjusted "or" the throttle linkage is too far from the Pot or perhaps a combination of the two.
The linkage pulls away from the Pot when the engine rpm rises above 2700 to 3100 rpm as stated in the FSM. You can have someone with their foot on the gas pedal keeping the rpm at this range while you check to see if the Pot is in the proper position and if not just loosen the lock nut and then rotate the housing of the Pot and then retighten the lock nut. If you don't have a helper then you can guesstimate what 3000 rpm is w/the engine turned off simply by pressing on the throttle linkage to pull it away from the TPS. I believe, but not a 100% certain, that the linkage pulls away from the TPS which allows the pistion to fully extend when the rpm reaches 3000 rpm. So you can eye when the front linkage allows the TPS to fully extend but still touches the linkage and use this as the 3000 rpm position then look at the Pot and see if the White tip just comes into contact w/the throttle linkage.
Another thing is your mention of the Dashpot. If the White part operates as previously suggested then you need to look at the following. When the rpm is increased the throttle linkage that rests upon the Dashpot will separate from it and progressively the gap between the Pot and the linkage increases. If the linkage was always too far from the Pot then the White part could never recede back in to the Pot. Another side of the story is if the Pot is not screwed into a proper position then it might be too far from the linkage to begin with and cause what you are currently seeing. So either the Pot position needs to be adjusted "or" the throttle linkage is too far from the Pot or perhaps a combination of the two.
The linkage pulls away from the Pot when the engine rpm rises above 2700 to 3100 rpm as stated in the FSM. You can have someone with their foot on the gas pedal keeping the rpm at this range while you check to see if the Pot is in the proper position and if not just loosen the lock nut and then rotate the housing of the Pot and then retighten the lock nut. If you don't have a helper then you can guesstimate what 3000 rpm is w/the engine turned off simply by pressing on the throttle linkage to pull it away from the TPS. I believe, but not a 100% certain, that the linkage pulls away from the TPS which allows the pistion to fully extend when the rpm reaches 3000 rpm. So you can eye when the front linkage allows the TPS to fully extend but still touches the linkage and use this as the 3000 rpm position then look at the Pot and see if the White tip just comes into contact w/the throttle linkage.
10-29-11, 02:45 PM
#32
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Don't fret because these cars are a pain to work on when it comes to idling for there are so many different variables at play that all need to get along to cause a proper idle. With that being said, when you look at the Thermowax it has a piston which will press outward much like the TPS. As Karack has suggested you could disable this mechanism to see what is or isn't causing the problem. One thing you could do is to place a rubber cap/plug on top of the upside down screw found underneath the Thermowax piston and use a cap that is about 3/4 to an inch long. Put the cap in place before starting the car and make sure the top of the cap rests against the piston above it. Doing this will effectively disable the Fast Idle mechanism so when the car is started it will not idle at 1500 or so rpm but will quickly drop to as low as it will go w/o the Fast Idle playing a role. This will tell you if the idle still stays high whether or not it was due to the Fast Idle aspect. If it stays rather high then it cannot be caused by the Fast Idle.
Idc about the accelerated warmup I just want the car to idle right. I can let the car warmup at 750.
Satch thanks again! I am glad someone really stepped up to help me out. It means a lot. If you ever need anything I will do my best to help out.
Thank you too Karack and everyone else who has helped.
10-29-11, 02:52 PM
#33
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I think the thermowax is probably bad. When the screw is not held and you press the throttle just a little, it pushes up in the round metal thing and open the bottom throttle plate (primary or secondary?) just a little. That is causing the high idle and I think the reason it's surging is because of the advance in timing?
10-29-11, 04:03 PM
#34
you can disable it through 2 methods, one as satch mentioned or pull the throttle body off and adjust the fast idle adjustment screw all the way down which will always keep the plunger from holding the cam open. that or replace the thermowax unit with a known good unit. while it's off remove the coolant lines to and from it and see if there is any obstructions in the line keeping it from heating up properly.
doing that will at least get you to a point where you can check the timing, adjust the idle and mixture adjustments as well as check for vacuum leaks.
doing that will at least get you to a point where you can check the timing, adjust the idle and mixture adjustments as well as check for vacuum leaks.
10-29-11, 04:15 PM
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I think I will try adjusting the screw. Is the one to adjust the same one that I have to hold back to get my car to idle right.
I had my car idling at about 750-800 and adjusted the tps sensor to 1k ohms and it made a HUGE difference in the performance and the throttle response. Hopefully it helps on my fuel mileage as I only get like 10mpg or less.
When I got the car though the O2 sensor was disconnected causing the car to run a little rich anyways. I hate how everything was just kind of rigged but it does run really good for an n/a.
I had my car idling at about 750-800 and adjusted the tps sensor to 1k ohms and it made a HUGE difference in the performance and the throttle response. Hopefully it helps on my fuel mileage as I only get like 10mpg or less.
When I got the car though the O2 sensor was disconnected causing the car to run a little rich anyways. I hate how everything was just kind of rigged but it does run really good for an n/a.
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