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-   3rd Generation Specific (https://www.nopistons.com/3rd-generation-specific-18/)
-   -   Sudden jump in idle speed (2000rpms) (https://www.nopistons.com/3rd-generation-specific-18/sudden-jump-idle-speed-2000rpms-71206/)

whatreally 11-28-2008 01:16 PM

Greetings all. I have a immaculate, stock 94 R2 that I bought with 8k miles on it about 6 years ago. I now have 58k on it. it is completely original with the stock motor turbos etc. I am not a newbie when it comes to the FD and am somewhat educated on the 13B. Now, it has never given me any major trouble except for the basic RX-7 problems (Y-pipe couping etc). But recently all of a sudden while driving, the idle speed has jumped to app. 2000rpms. Whether it is cold or warmed up doesnt make a difference. Upon startup it instantly revs to 2100rpms then within a second or two it starts to bounce from 1900 to 2100rpms on a very steady rhythm. It does this warm or cold (quite embarassing at the fast food drive-thru window https://www.nopistons.com/forums/pub..._DIR ). When warmed up, I can blip the throttle and it will then fall to about 1100rpm for a second then go right back up. Additionally I have noticed a substantial increase in the rich gas smell from inside and outside the car. Fuel mileage is affected somewhat also. I have jumped the TEN/GND connections and unplugged the map/boost and the ISC for test purposes with no real notable change. Im hoping that someone here has been through this and can offer a piece of advice (no luck with what I found searching this forum). The only thing I think may be left is the lower intake manifold gasket (I cant see if its the metal or paper one) or a loose vacuum line that I may have overlooked. Any advice from a fellow rotaryhead would be greatly appreciated. Thanks.



PS- I plan to get a quick video clip very soon showing exactly what its doing. I figure that would help paint a clearer picture.

whatreally 11-29-2008 02:26 PM

I'm going to remove the IAC and do a continuity on it to see if it's bad. The FSM states 10.7-12.3 ohms. I'll keep this thread updated whenever I found out the culprit so as to help anyone else that may have this problem. BTW, I've uploaded two videos showing exactly what it's doing on a cold engine and on a freshly-driven warm engine just for reference.



94 RX-7 R2 Idle Problem VIDS



http://www.mediafire.com/?sharekey=0f0491c...af6de2f38d93145

fdmonster 01-07-2009 08:13 AM

Sounds like you have a vaccum issue do you have a boost gauge if so see what the vaccum is on the gauge with it running with it smelling rich the vaccum line could have come off the fuel pressure regulator just the first thing to come to mind seen it happen to a lot of types of cars before good luck

whatreally 02-13-2009 09:55 AM


Originally Posted by fdmonster' post='914242' date='Jan 7 2009, 09:13 AM
Sounds like you have a vaccum issue do you have a boost gauge if so see what the vaccum is on the gauge with it running with it smelling rich the vaccum line could have come off the fuel pressure regulator just the first thing to come to mind seen it happen to a lot of types of cars before good luck





no leak, my vacuum is still like 17.


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