BMW 320 Coupe Gearbox quirky!!

Honest John Back Room » Technical matters
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Sun 19 Dec 2004 14:31
BMW 320 Coupe Gearbox quirky!! - TheGrocer
Hi Room
I have a BMW320CI Coupe on a 2002 plate with 30k on the clock. The box is manual and I have noticed when I pull away in 1st gear a bit sharpish as I change into second the revs stay at the same level as if the accelerator is stuck. Is this a fault or is it a quirk of the BM engine management trying to maintain revs whilst changing from first to second. It doesnt do it at any other time ie second to third and is behaving very well in all other areas. The gearbox is a little clunkier than the other 3 series I have owned but nothing too bad.
Any thoughts???
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Sun 19 Dec 2004 17:15
BMW 320 Coupe Gearbox quirky!! - Dude - {P}
If this is from first start-up with a cold engine, this is quite normal as the engine will be programmed to run on a rich mixture (hence higher revs), until properly warmed up.
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Sun 19 Dec 2004 18:17
BMW 320 Coupe Gearbox quirky!! - Dynamic Dave
Moves across to Technical Matters.

::Kick::

DD.
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Sun 19 Dec 2004 21:01
BMW 320 Coupe Gearbox quirky!! - Aprilia
If this is from first start-up with a cold engine, this
is quite normal as the engine will be programmed to run
on a rich mixture (hence higher revs), until properly warmed up.


Yes, but this would apply when he changes up from 2-3 and 3-4 etc. as well.

I find it a puzzling query because I don't think the 'box has a position switch (i.e. the engine management doesn't "know" which gear is selected).
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Sun 19 Dec 2004 21:13
BMW 320 Coupe Gearbox quirky!! - TheGrocer
The problem happens when cold or hot and only from 1st to 2nd. I have checked that I am not leaving my foot hanging onto the acelerator pedal. The throttle works well in all other gears and the performace of the car is first class. I just wondered if (having never had a 6 pot high revving engine) this was a quirk with the 320ci
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Sun 19 Dec 2004 21:30
BMW 320 Coupe Gearbox quirky!! - Pugugly {P}
Is it still under warranty ? Safer to go for a diagnostic check, doesn't sound right to me..
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Mon 20 Dec 2004 14:45
BMW 320 Coupe Gearbox quirky!! - Peter D
The ECU knows what gear you are in by monitoring the Revs and the road speed thus the gear you are in buy if you stay in 1st and take your foot off does the car slow down straight away or is there a delay there too. Regards Peter
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Mon 20 Dec 2004 15:54
BMW 320 Coupe Gearbox quirky!! - Aprilia
The ECU knows what gear you are in by monitoring the
Revs and the road speed thus the gear you are in
buy if you stay in 1st and take your foot off
does the car slow down straight away or is there a
delay there too. Regards Peter


In this case described the engine revs 'flare' during the 1-2 gearshift whilst the clutch is depressed. Hence engine rpm and road speed are not related at this time. It would be *possible* for the ECU to work out the gear during the period immediately before the gearchange, whilst the clutch is fully engaged - I don't know whether the ECU does this or not.

A lot of vehicles have a 'throttle damper' (either mechanical or electronic) to slow down the throttle's return to idle - this helps eliminate driveline shunt and throttle oscillation - but I would expect this to affect all gearchanges equally.
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Mon 20 Dec 2004 19:35
BMW 320 Coupe Gearbox quirky!! - TheGrocer
You guys are being really helpfull so thanks for that....

I have only had the car a couple of weeks and I think I will get it checked. Engine revs "flare" thats a great expression and fits the symptom. Interested about the throttle damper, Do 320cis have them? assume they must have perhaps thats it and I just havent noticed the flare in other gears due to lower revs in 2,3 4 & 5?
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