Up & Down RPMS at Idle + Check Engine Light
12-23-2005, 10:55 AM
#1
PoloRican Rotary
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Up & Down RPMS at Idle + Check Engine Light
Ever since Mazda did the new flash on my car, when I start it up and let the clutch out the RPMS go up and down from around 1.5-3k(when engine is cold). When I press the clutch in it goes away for some reason. Or if the engine is warmed up it wont do it either. That's strange, isn't it? Then all of a sudden I'm at the mall this morning, I come out and start the car and the Engine Light comes on. Does anyone think its the Catalytic Converter? Any ideas? BTW Sometimes my car has trouble starting. Like it almost flooded or something. It only does it some times though. I'm thinking its the converter. I scheduled an appointment for the 26th. But what do you guys think? 
12-23-2005, 11:31 AM
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Originally Posted by cas2themoe
Ever since Mazda did the new flash on my car, when I start it up and let the clutch out the RPMS go up and down from around 1.5-3k(when engine is cold). When I press the clutch in it goes away for some reason. Or if the engine is warmed up it wont do it either. That's strange, isn't it? Then all of a sudden I'm at the mall this morning, I come out and start the car and the Engine Light comes on. Does anyone think its the Catalytic Converter? Any ideas? BTW Sometimes my car has trouble starting. Like it almost flooded or something. It only does it some times though. I'm thinking its the converter. I scheduled an appointment for the 26th. But what do you guys think?
-Sam
12-23-2005, 12:16 PM
#4
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id like to know the cel code but my first impression is you have an intake leak or a dirty mafs. the otehr thing that can cause this (besides the car just being cold) is the switch on the tranny that lets the car know you have shifted to neutral. if that sticks it can cause this. i just dont know why it would stick when cold and not when warm
12-23-2005, 12:40 PM
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PoloRican Rotary
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I dont know. So it could be the new clutch setup or an intake leak? Hmm Hopefully they can figure it out Monday. I'll ask for the code. How do YOU know what code goes with each problem?
12-23-2005, 12:52 PM
#7
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Mine does the same thing. Whenever the engine is cold and I crank it it idles high and when I let the clutch out in neutral the rpms all a couple hundred for a second or 2 and then they recover, little strange but I live with it unless this is causing some kind of harm?
12-23-2005, 06:06 PM
#12
Metatron
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Problem solved....
I had the exact same problem - runs fine but very lumpy unstable idle. Then a CEL every fourth of fifth time I started up....
A friend (who is a Mazda tech) put it on the WDS, found the fuel trims were way out of wack and diagnosed an intake leak. Sure enough, the little tube that goes from just below the throttle body (to the SDIAS, up front) had pulled off. Reattached, idle evened out, and he reset the CEL.
S
A friend (who is a Mazda tech) put it on the WDS, found the fuel trims were way out of wack and diagnosed an intake leak. Sure enough, the little tube that goes from just below the throttle body (to the SDIAS, up front) had pulled off. Reattached, idle evened out, and he reset the CEL.
S
12-23-2005, 06:24 PM
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I must admit, you know your stuff! As far as driving it, I'll just drive the wife's TL tonight just to make sure I don't mess anything up(if I haven't already). 
Originally Posted by zoom44
hehehehe damn im good
12-25-2005, 07:59 AM
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ye su have a intake leak and time your idel is jumping around it has to do with air coming into the motor at dif rates. this why u always here carb motors idel ruff
12-25-2005, 08:36 AM
#17
Originally Posted by StealthTL
I had the exact same problem - runs fine but very lumpy unstable idle. Then a CEL every fourth of fifth time I started up....
A friend (who is a Mazda tech) put it on the WDS, found the fuel trims were way out of wack and diagnosed an intake leak. Sure enough, the little tube that goes from just below the throttle body (to the SDIAS, up front) had pulled off. Reattached, idle evened out, and he reset the CEL.
S
A friend (who is a Mazda tech) put it on the WDS, found the fuel trims were way out of wack and diagnosed an intake leak. Sure enough, the little tube that goes from just below the throttle body (to the SDIAS, up front) had pulled off. Reattached, idle evened out, and he reset the CEL.
S
If so wouldn't that be a vacuum leak?
12-25-2005, 06:36 PM
#20
Originally Posted by StealthTL
I had the exact same problem - runs fine but very lumpy unstable idle. Then a CEL every fourth of fifth time I started up....
A friend (who is a Mazda tech) put it on the WDS, found the fuel trims were way out of wack and diagnosed an intake leak. Sure enough, the little tube that goes from just below the throttle body (to the SDIAS, up front) had pulled off. Reattached, idle evened out, and he reset the CEL.
S
A friend (who is a Mazda tech) put it on the WDS, found the fuel trims were way out of wack and diagnosed an intake leak. Sure enough, the little tube that goes from just below the throttle body (to the SDIAS, up front) had pulled off. Reattached, idle evened out, and he reset the CEL.
S
12-25-2005, 10:33 PM
#22
Registered User
If it was a leak wouldn't it do it all the time and not when the engine is just cold? Mine only cycles up and down when it is cold, also it doesn't do it if you hold the clutch in or just leave it out.
12-25-2005, 10:54 PM
#23
There is a switch on the tranny that tells the ECU that it is in gear....might be that. I seem to remember something like this on an old thread? Aussie maybe??
There is a different map when the car is open loop and cold....the leak would affect it much more than when it is in a feedback loop (closed loop when warm) mode.
There is a different map when the car is open loop and cold....the leak would affect it much more than when it is in a feedback loop (closed loop when warm) mode.
01-02-2006, 09:22 PM
#24
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The DTC is PO850. The most likely culprit is the neutral switch on the transmission. Crawl under the car with an ohmmeter and test it. The neutral switch has the white connectors, the black connectors are for the reverse switch.
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