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Question for owners of 1998 S70/V70 with manual transmission V70-XC70 1998

posted by  Mike91 on  Mon Apr 22 06:43 CST 2013
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last visit: Wed Sep 17 19:52 CST 2014
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Does anyone on Brickboard own a 1998 S70/V70 with manual transmission ?

I own one that is non-turbo. It exhibits an over-rev condition of several hundred RPM during the shift interval when clutch is depressed and throttle is released. The over-rev is caused by the Idle Air Control (IAC) system. The IAC valve is being commanded by the ECU to open whenever the throttle plate is more than slightly open.

The IAC behavior is also noticeable with the car sitting still and manual transmission in neutral. With the throttle closed, the engine idles normally at 800 RPM. Depressing the throttle slowly will allow the engine speed to be held at 1000-1200 RPM. Depressing the throttle a bit more to slightly past the 1200 RPM point causes the IAC valve to start opening. Without depressing the throttle any further, the engine speed increases to 2000-2500 RPM within a few seconds. The only way to reduce engine speed is to release the throttle slightly, then the engine speed will drop back to 800-1000 RPM.

I am trying to find out if anyone else has a 1998 manual trans S70/V70 that exhibits the same off-idle behavior with the car sitting still in neutral. Turbo and non-turbo cars may behave differently, so I hope someone has a non-turbo S70 or V70 similar to mine.

Thanks,

Mike







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    Question for owners of 1998 S70/V70 with manual transmission V70-XC70 1998

    posted by  packard8 on  Tue Apr 23 18:04 CST 2013
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    last visit: Thu Oct 16 15:16 CST 2014
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    No, I have not seen that behavior. The idle increases between shifts by maybe 100-200, but I don't consider that excessive. When revving the engine at a light it goes easily to 1200 rpm, then seems to go to 1600-1800 quickly, but it is controllable. Have you cleaned the throttle body and IAC? I use bicycle chain cleaner and Q-tips for the IAC. I also added some hose clamps since the fit seemed to be getting loose.

    1998 V70 5-speed one owner 349k.








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      Question for owners of 1998 S70/V70 with manual transmission V70-XC70 1998

      posted by  Mike91 on  Tue Apr 23 20:49 CST 2013
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      last visit: Wed Sep 17 19:52 CST 2014
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      My car typically behaves like packard8's. Posts on the volvospeed forum indicate that the strange IAC behavior is programmed into the manual trans ECU. It is not really a problem but may affect driveability when the car is almost coasting with a small throttle opening.

      My original concern was a rare backfire during the shift interval. I havent noticed that problem after fixing a small vacuum leak plus cleaning the throttle body and IAC.

      Mike







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      Question for owners of 1998 S70/V70 with manual transmission V70-XC70 1998

      posted by  KlausC on  Tue Apr 23 20:37 CST 2013
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      last visit: Fri Oct 24 10:15 CST 2014
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      I attribute that quirk to the American standard ECU. Of course, I haven't found a 'cheap' Euro ECU for my 1996 NA and I don't know what it would do for the EGR and the SAS.

      It is too late to complain to Volvo, heck, the mechanics don't even know how to fix these 'antiques' anymore.






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