BMW 5-Series E39 (1996 - 2003) - 98 2.5 Car wont idle or its erratic

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Sat 13 Jun 2009 15:19
98 2.5 Car wont idle or its erratic - track
My 98 523i wont idle, when first started unless you keep blipping the throttle it just dies, when it gets warm it will sometimes keep running but sounds like its off a pot or 2. Could this be a classic case of idle control valve being stuck? There are no fault codes etc.

Edited by Pugugly on 14/06/2009 at 12:08

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Sat 13 Jun 2009 16:00
89 2.5 Car wont idle or its eratic - bell boy
might also be a case of old age in plugs
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Sat 13 Jun 2009 16:48
89 2.5 Car wont idle or its eratic - track
sorry typo, ita 98 not 89!!
Just had all new plugs, filters, oil etc. Idle valve and throttle body have been cleaned and checked.
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Sun 14 Jun 2009 11:24
89 2.5 Car wont idle or its eratic - topbloke
dont know if it the same as other bmw engines but there is a breather system on these that split, its known as a cyclone valve may be worth a search,Regards TB

Edited by topbloke on 14/06/2009 at 11:26

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Sun 14 Jun 2009 11:32
89 2.5 Car wont idle or its eratic - topbloke
try these links

www.bba-reman.com/forums/Topic37558-1-1.aspx?Highl...e

www.bba-reman.com/forums/Topic59718-1-1.aspx?Highl...e

may give you some idea's s to what to look for/at
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Sun 14 Jun 2009 17:42
89 2.5 Car wont idle or its eratic - track
great info, there is indeed a valve of that description under the inlet and also I have noticed oil in the intake. Fingers crossed that is the issue. Will update tomorrow after Ive tinkered.
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Sun 14 Jun 2009 17:54
89 2.5 Car wont idle or its eratic - track
I should of metioned I have checked the compression etc on the car and all pots are within 5psi of each other.
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Wed 17 Jun 2009 21:38
98 2.5 Car wont idle or its eratic - track
On 1998 523i , 2.5 single vanos engine M52B25.
Ive put a new idle control valve and new cyclone valve in now and I still cannot get a good idle. It gets a bit juddery and occasionally 'pops' in the intake manifold. When cold it generally just stalls a lot, when warm it just ticks over but poorly as just described. So far Ive checked all pipes for splits / leaks, replaced the idle valve and the cyclone valve with new genuine BMW parts, put new spark plugs in and replaced the DME. Compression is spot on and within 5 psi of each other right across the board. As soon as the throttle is opened its sweet as a nut and pulls really well. What else could it be?
There are no fault codes to go off either.

Edited by track on 17/06/2009 at 21:38

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