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10th February 2011, 17:32 | #1 |
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Revs drop while braking
Wierd issue, this...
If I'm cruising along, and pop it out of gear, and start to brake, the revs obviously fall off - but rather than fall to idle (~800 RPM), it falls a bit further (~600 RPM), which makes the engine quite harsh (akin to being on the edge of stalling). Once the car stops, the revs stay at ~600 for half a second and then it returns to normal idle. And all of this is while out of gear Any ideas? Car idles fine, if I pop it out of gear but let it coast it idles properly as well. |
10th February 2011, 18:56 | #2 | |
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You are probably upsetting your vacuum pump by letting the revs drop and then braking which needs to use vacuum. The decrease in vacuum upsets the calibration of the fuel input by the ECU. Colvert. |
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10th February 2011, 18:58 | #3 |
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Not really a 'Weird issue'
More like weird behavior. PMSL. |
10th February 2011, 20:28 | #4 |
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I highly doubt a loss of vacuum would cause the engines RPM to drop, when the brakes aren't connected to the engine as it's out of gear.
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10th February 2011, 20:34 | #5 |
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The vacuum brake servo is connected to both the brakes and the engine. It sounds to me like a vacuum issue.
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13th February 2011, 15:04 | #6 |
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13th February 2011, 15:15 | #7 |
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13th February 2011, 18:02 | #8 |
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Revs drop while braking
My son passed his test last year, and I was eventually banned from trying to teach him myself because things have changed since I passed my test (probably about 1960)
The main thing was that changing down when approaching lights etc is frowned upon - you are told to coast and brake, hence the probable reason behind the enquiry. I was told that brake pads are cheaper to change than clutch or gearbox. (I still go down the gears though!) |
13th February 2011, 21:29 | #9 |
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Me too!
Mike |
13th February 2011, 21:59 | #10 | |
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