# 1985 300ZX won't rev beyond 2000 rpm.



## Durett (Jul 6, 2004)

Hello, has anyone seen this problem before?
I have a 1985 300zx non turbo automatic and it will not rev above 2000 rpm. 
In restoring and resolving this problem i have replaced the air mass sensor, cylinder head temperature switch, throttle valve switch, fuel filter, all fluids, set idle and timing, replaced all vacuum hoses both inside and out, checked grounds around the engine, installed K&N cone air filter and 240SX throttle plate. This problem has come and gone twice before, this is the first time it has remained solid. The car idles smoothly and when it runs - it runs just fine. 

As a side note i am currently getting a error from the computer saying that the throttle valve switch is defective or the wiring is bad. I have replaced the switch and verified that the wiring is good via the service manual. The manual says to replace the computer. I swapped in another computer and the symptom (rev over 2000 rpm did not change). There are no other errors given. 

Thanks in advance for any help.
Jerry


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## Durett (Jul 6, 2004)

*Finally resolved problem.*

The transmission computer (mounted behind the spare tire in the wall of the car) had cold solder joints where the plastic connector attaches to the circuit board. I desoldered the old solder and resoldered the pins. Car immediately lost the 2000 rpm limit and is running just fine. 
Jerry


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## Zen31ZR (Mar 24, 2004)

Interesting problem, and solution. Glad it worked out for you. :cheers:


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## 0341TODD (Nov 15, 2003)

Wow, I hope that doesnt happen to me......


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## Zen31ZR (Mar 24, 2004)

0341TODD said:


> Wow, I hope that doesnt happen to me......


 Yeah us 5-spd guys will _never_ have that problem.......


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## JAMESZ (Mar 12, 2004)

0341TODD said:


> Wow, I hope that doesnt happen to me......


You wont have to worry if you get rid of your craptastic slushbox.


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## Zen31ZR (Mar 24, 2004)

Ouch, double pwnage. :cheers:


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## 0341TODD (Nov 15, 2003)

Hey atleast I can play with my radio, drink a Coke and talk on the Phone while Im smoking Mustangs (v-6 or otherwise I dont have to shift-- 

Yes Yes, when the slushbox goes to crap then I will switch it over to a 5 speed

Speaking of which-- does a t-5 and a t-56 use the same bellhousing?


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## Zen31ZR (Mar 24, 2004)

0341TODD said:


> Hey atleast I can play with my radio, drink a Coke and talk on the Phone while Im smoking Mustangs (v-6 or otherwise I dont have to shift--
> 
> Yes Yes, when the slushbox goes to crap then I will switch it over to a 5 speed
> 
> Speaking of which-- does a t-5 and a t-56 use the same bellhousing?


 Dunno about that. Bellhousing maybe but the trans itself the T56 is bigger. Can you say custom driveshaft?

And I've been driving manuals for many years, I can do all the stuff you described above while driving my car too.


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## asleepz (Feb 24, 2004)

I can adjust the radio and talk on the phone while driving... On the highway


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## JAMESZ (Mar 12, 2004)

SKD_Tech said:


> I can adjust the radio and talk on the phone while driving... On the highway


So can soccer moms and look at what kind of problems they cause on the highway. Now SKD you dont want to be like a soccer mom do you? I didn't think so.....

And Todd your excuses are what make all of our cars faster then yours.


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## asleepz (Feb 24, 2004)

JAMESZ said:


> So can soccer moms and look at what kind of problems they cause on the highway. Now SKD you dont want to be like a soccer mom do you? I didn't think so.....
> 
> And Todd your excuses are what make all of our cars faster then yours.



You mean it's bad to be a soccer mom? Looks like I need to get rid of my keychain then.

Yes manuals are faster than autos. Get used to it


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