e34 525i - flat spot - Bavarian-Board.co.uk - BMW Owners Discussion Forum

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r6_jyh

Newbie

Joined: 09-August-2004
Location: United Kingdom
Status: Offline
Points: 2

Topic: e34 525i - flat spot
Posted: 20-August-2004 at 13:19

I was wondering if anyone could assist. My car idles fine at about 700 rpm, however there is a flat spot between 700rpm and 1200rpm (very annoying when pulling away from traffic lights), also under very hard acceleration the engine pinks. I have a crack in the cylinder head (which is being resolved), but this really shouldn't be the cause. Over the last year it has only done short journeys, so it might need a good thrashing......Can anyone offer any advice?

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Andrew Rolland View Drop Down

Moderator Group

Go away rain

Joined: 19-August-2004
Location: Scotland
Status: Offline
Points: 6579

Posted: 20-August-2004 at 15:43

This fault is the reason I ended up buying a Beamer. I had this fault on my previous car a 3.0i 24v Vx Senator.

I ended up replacing all 7 Ht leads, 6 spark plugs, cleaning the rotor arm, cleaning the dizzy cap contacts, fitting a new crank angle sensor, fitting a new lambda sensor, stripped and cleaned out the throttle body, cleaned out the idle control valve, resealed all air induction hoses and checked and cleaned numerous electrical sensor connectors.

I also ran through a tank of fuel with redex fuel injector cleaner.

None of the above cured my fault (but each time I did something the engine seemed to be more responsive and smoother but not cured) but thats not say it won't cure your fault.

I had heard that it may have been a fuel injector seal or another seal in the inlet manifold system that was leaking and causing the flat spot. I didn't want to throw any more cash at the Sennie so I got rid of her for my E39 523i SE.

Clean and check out all what I have said and hopefully it will cure it and give it a damn good thrashing to try and burn off any coke stuck to the head and valves.

Andrew

Be exclusive and drive a Petrol 5 Series!

Current
'13 62 F10 535i MSport Auto

Previous
'04 04 E60 545i SE Auto
'03 53 E60 545i SE Auto (Stolen)
'98 S E39 523i SE Auto

r6_jyh

Newbie

Joined: 09-August-2004
Location: United Kingdom
Status: Offline
Points: 2

Posted: 23-August-2004 at 10:32

thanks Andrew. changed plugs, leads, cap and rotor and increased the fuel octane - that seems to have improved the situation, I suppoe I will have to move onto the next things you suggest as well. I am all in favour of a good thrashing - but probably not too wise with the head in its current state.....

Edited by r6_jyh

Author	Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic
r6_jyh Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 09-August-2004 Location: United Kingdom Status: Offline Points: 2	Topic: e34 525i - flat spot Posted: 20-August-2004 at 13:19
	I was wondering if anyone could assist. My car idles fine at about 700 rpm, however there is a flat spot between 700rpm and 1200rpm (very annoying when pulling away from traffic lights), also under very hard acceleration the engine pinks. I have a crack in the cylinder head (which is being resolved), but this really shouldn't be the cause. Over the last year it has only done short journeys, so it might need a good thrashing......Can anyone offer any advice?

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Andrew Rolland Members Profile Send Private Message Find Members Posts Add to Buddy List Moderator Group Go away rain Joined: 19-August-2004 Location: Scotland Status: Offline Points: 6579	Posted: 20-August-2004 at 15:43
	This fault is the reason I ended up buying a Beamer. I had this fault on my previous car a 3.0i 24v Vx Senator. I ended up replacing all 7 Ht leads, 6 spark plugs, cleaning the rotor arm, cleaning the dizzy cap contacts, fitting a new crank angle sensor, fitting a new lambda sensor, stripped and cleaned out the throttle body, cleaned out the idle control valve, resealed all air induction hoses and checked and cleaned numerous electrical sensor connectors. I also ran through a tank of fuel with redex fuel injector cleaner. None of the above cured my fault (but each time I did something the engine seemed to be more responsive and smoother but not cured) but thats not say it won't cure your fault. I had heard that it may have been a fuel injector seal or another seal in the inlet manifold system that was leaking and causing the flat spot. I didn't want to throw any more cash at the Sennie so I got rid of her for my E39 523i SE. Clean and check out all what I have said and hopefully it will cure it and give it a damn good thrashing to try and burn off any coke stuck to the head and valves. Andrew
	Be exclusive and drive a Petrol 5 Series! Current '13 62 F10 535i MSport Auto Previous '04 04 E60 545i SE Auto '03 53 E60 545i SE Auto (Stolen) '98 S E39 523i SE Auto

r6_jyh Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 09-August-2004 Location: United Kingdom Status: Offline Points: 2	Posted: 23-August-2004 at 10:32
	thanks Andrew. changed plugs, leads, cap and rotor and increased the fuel octane - that seems to have improved the situation, I suppoe I will have to move onto the next things you suggest as well. I am all in favour of a good thrashing - but probably not too wise with the head in its current state..... Edited by r6_jyh