2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

adjusting thermwax for idle

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Old Sep 22, 2010 | 08:35 PM
  #1  
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adjusting thermwax for idle

well i know when its warm out the car starts up fine and idles fine...when its cold it starts and dies..
before i thought it was a vacumm leaks so i read a few threads to were to look.
so i replaced all lines and rechecked for a leak..so i eliminated that from the equation

so now i think it boils down to the thermowax on the throttle body

its a t2 jspec motor with no idle screw...all stock

i read the fsm but i cant see the can

has anyone any better luck adjusting this

my seven keeps dyinig when its cold out
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Old Sep 23, 2010 | 01:30 AM
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From: cold
Turn the screw that rests on the thermowax rod.



the one labeled cam adjusting screw.
Attached Thumbnails adjusting thermwax for idle-fastidlescrew.jpg  
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Old Sep 23, 2010 | 08:28 PM
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do you have a good method of adjusting other than the fsm ..it just dont make any sense ...i cant get to it fast enough when its hot ...theres got to be a better way,
nice pic arghx
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Old Sep 23, 2010 | 09:02 PM
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From: tulsa,ok.
You could pour boiling water over it to simulate a warmed engine condition.

Page two and on explains adjusting the mechanism in the following link. The car in the link is a turbo model.

https://www.rx7club.com/showthread.p...=fast+idle+cam
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Old Sep 23, 2010 | 11:47 PM
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From: cold
the service manual procedure is useless. You just have to do it by feel... it's some oldschool carburetor type ****. The TPS voltage can also be helpful because with the fast idle engaged, TPS voltage should be higher than normal (assuming your TPS was adjusted right in the first place).

I've had luck with this method: start the engine and warm it up with your foot on the gas like you usually do. Get back there and turn the "cam adjusting screw" (with the engine warm) until it raises the idle with the engine warm. This is essentially an "over adjusted" condition. Now turn your screw the other way just until the engine speed drops down to normal. That should be "just right". You can also check TPS voltage (not ohms) as you're doing this. Technically the TPS should be 1 volt completely warmed up with the fast idle disengaged but higher with the fast idle still up.

Another method: with the engine cold, turn the cam adjusting screw until the TPS voltage increases. When the voltage stops increasing, it should be "just right." I've also used this method. I can see TPS voltage easily on my Power FC, but you can also use a multimeter. I forget which wires you would check.

This is why drive-by-wire is awesome (no matter what haters say). You never have to adjust any of this crap on newer cars with electronic throttles.
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Old Sep 24, 2010 | 07:16 PM
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From: ct
update ..i have made a plastitic tube to go in place of the intercooler ,so i can adjust it ...ill try in the morning and post results...you guys are great
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Old Sep 25, 2010 | 10:26 AM
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From: ct
now i have the tube on ..do you think i should adjust it on start up ...i know it will die
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Old Sep 25, 2010 | 10:42 AM
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From: tulsa,ok.
You can't get the car to run at all?
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Old Sep 25, 2010 | 11:29 AM
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Wait.. I was under the impression it wouldn't idle even.... Not die, altogether.

If it's dying straight away, then your problem may NOT be TB-related.

With the car, as it sits - ever so pimp x-pipe, in place, check the connections to the following: AFM, CAS, O2 Thermo-sensor (back-side of waterpump housing, below the bend).

If the those guys aren't on right, the car will start, then almost immediately die.

If it WILL idle, but run rougher than my mom's legs, THEN you may have to go adjusting crap on the TB.
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Old Sep 25, 2010 | 12:25 PM
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From: ct
sorry whats happening is i start it up ,then it dies when its cold.....all them connections are secure...if i tighten the cable it will idle

remember this is a jsec motor
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Old Sep 25, 2010 | 12:29 PM
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Your cold-start disabled? Check thermawax adjustment. If the TPS is in good align, then that's the next phase...

You check the connection on your water thermosensor?
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Old Sep 25, 2010 | 12:43 PM
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From: tulsa,ok.
Was the car dying after cold start before you took the intercooler off, after, or both?
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Old Sep 25, 2010 | 01:07 PM
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yes when i it would die with the cooler on and with the pipe...but if its around 80% outside it would just about hold the idle

now i took a look at it again i see the dashpot ..could that be something to do with it?

also this is a jspec motor so it does not have the cold start air bypass valve ...i do have an old one laying around

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Old Sep 25, 2010 | 01:27 PM
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From: tulsa,ok.
Look at post #81 in the link I provided you and check the picture in that post at the part highlighted as "bad gap." Do you have this stop screw as I don't see it in your provided pic of the same thing.
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Old Sep 25, 2010 | 01:32 PM
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From: ct
no it broke off
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Old Sep 25, 2010 | 01:44 PM
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From: tulsa,ok.
Originally Posted by dennis blackstone
no it broke off
I see. If it did not break off and had the stop screw then there is that little lever that is part of the throttle linkage that would press against the stop screw. With respect to the "little lever" if you you were to press the plastic white piston of the Dashpot all the way in does it affect the movement in the "little lever" as it should not.

EDIT:


In clarifying my point, the "little lever" should not move higher or in the direction of the missing stop screw.
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Old Sep 25, 2010 | 09:15 PM
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I have all this stuff deleted. My solution was using my foot to warm the motor up for about 2-5 minutes, then i drive. At stoplights and signs, i will brake and blip the throttle to keep the car from dying. After it's warm, it will idle at 700-800 rpm fine. I played with my throttle cable until it would hold an idle when warm. It's inconsistent fro day to day from different outside temps/engine temps but i've learned to live with it.

My take on these cars/engines is the least crap you have to troubleshoot, the better off you are.
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Old Sep 25, 2010 | 11:11 PM
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From: ct
ive tried to live with it...i just dont want to drive a car which is annoying...

i think i may have to take the throttle body off to see the cam ...i cant see a thing back there even with a mirror...just need to reset it ...i tested the dashpot it does not effect idle
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Old Sep 26, 2010 | 01:42 AM
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From: cold
uhh did you adjust the screw I talked about? The cam adjusting screw? Without a TMIC on there you can easily access it. If you still have the thermowax rod and the coolant hoses installed you shouldn't have this cold idle problem as long as the cam adjusting screw is set properly.
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Old Sep 28, 2010 | 06:43 PM
  #20  
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thanks arghx i went back out and tried your method and now it holds the idle at start up ...thanks so much ...the only problem i have now is that the idle bounces up and down
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Old Sep 28, 2010 | 06:59 PM
  #21  
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From: tulsa,ok.
Did you readjust the TPS which might be one of your favorite pastimes?
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Old Sep 30, 2010 | 08:09 PM
  #22  
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From: ct
yes i set the tps to 1v still bounces the the idle settles
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Old Oct 1, 2010 | 12:44 AM
  #23  
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From: cold
BAC valve clean?
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Old Jan 10, 2011 | 02:05 PM
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Try setting your TPS via the "test light method". It worked better for me than just setting it to 1 volt with a multimeter.
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