M5 3.8 Running Rough

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elleryjoseph View Drop Down

Newbie

Joined: 23-February-2003
Location: United Kingdom
Status: Offline
Points: 1

Topic: M5 3.8 Running Rough
Posted: 24-February-2003 at 00:02

its just a thought but when cold the car ir running on a rich mixture,when warm it becomes lean you may well have a air leak in your induction system causing a iregular &incorect air to fuel ratio,ods are im correct

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m5er

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Joined: 15-February-2003
Location: United Kingdom
Status: Offline
Points: 7

Posted: 20-February-2003 at 18:37

The misfire and the mysterious pool of water around no. 1 spark plug well have disappeared !

I didn't need to replace the coil pack, I just cleaned it best I could and put it back.

The car has never had an under-bonnet steam clean as far as I know and I admit I'm baffled as to where the water came from !.

The car is booked in for an inspection II service soon, I've warned the bank manager in advance ! I'll post any interesting bits arising from the service on this forum.

Thanks again to the guys in this forum.

Trev Harris

93 3.8 M5

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Posted: 19-February-2003 at 22:37

Glad to be of some use - mine had also lost number one (and number six!). I hope this proves to be the end of your misfire.

I'm happy to say I've had similar help with little niggles on my car without which I'd no doubt have spent a fortune. Not this forum, but the principle is the same. Out of interest, how much did you pay for your coil pack, and from whom did you buy it ?

Has your car ever had an under-bonnet steam clean ? I know that this is a no-no on this (and most) engines because water gets into places you don't want it - for example under the top cover and down the plug recesses.

m5er

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Joined: 15-February-2003
Location: United Kingdom
Status: Offline
Points: 7

Posted: 18-February-2003 at 18:41

Got time to check around the ignition system today. Removed the coil pack from No.1 cylinder and found a pool of what seems to be water in the spark plug well. Mopped the water up replaced the coil pack and the misfire has disappeared.

Thanks to Kurt Ramsden for sort of pointing me in the direction of the plugs/coil pack.

Now, where did that water come from, that's the question. Hope it's not the cylinder head leaking !. Don't seem to be using/loosing any coolant though.

Will check again tomorow and post the result here.

BobN

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Joined: 02-February-2003
Location: United Kingdom
Status: Offline
Points: 6

Posted: 17-February-2003 at 19:51

Had the same with a 520i. A hairline crack was enough to cause it to happen. Sourced new one from Swedish and German - MUCH more reasonably priced than BMW

Bob

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Posted: 16-February-2003 at 17:25

It could be one of many things, but I had a very similar problem with my 3.8. It was caused by a faulty coil pack which was diagnosed and fixed by a main dealer. Each plug has its own pack - they are directly above the plug itself under the black cover on the top of the engine. It's worth having a look at them - if they are failing they often leak oil (they are oil cooled and have their own little reservoir inside).

Good Luck

m5er

Newbie

Joined: 15-February-2003
Location: United Kingdom
Status: Offline
Points: 7

Posted: 15-February-2003 at 14:09

I need some help folks !

Since Thursday morning the M5 has been running rough when warm...

Symptoms: Starts fine and runs OK until the engine is warm. Then I start to get a misfire and the power is down.

Any clues???

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elleryjoseph Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 23-February-2003 Location: United Kingdom Status: Offline Points: 1	Topic: M5 3.8 Running Rough Posted: 24-February-2003 at 00:02
	its just a thought but when cold the car ir running on a rich mixture,when warm it becomes lean you may well have a air leak in your induction system causing a iregular &incorect air to fuel ratio,ods are im correct

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m5er Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 15-February-2003 Location: United Kingdom Status: Offline Points: 7	Posted: 20-February-2003 at 18:37
	The misfire and the mysterious pool of water around no. 1 spark plug well have disappeared ! I didn't need to replace the coil pack, I just cleaned it best I could and put it back. The car has never had an under-bonnet steam clean as far as I know and I admit I'm baffled as to where the water came from !. The car is booked in for an inspection II service soon, I've warned the bank manager in advance ! I'll post any interesting bits arising from the service on this forum. Thanks again to the guys in this forum. Trev Harris 93 3.8 M5

Guests Members Profile Send Private Message Find Members Posts Add to Buddy List Guest	Posted: 19-February-2003 at 22:37
	Glad to be of some use - mine had also lost number one (and number six!). I hope this proves to be the end of your misfire. I'm happy to say I've had similar help with little niggles on my car without which I'd no doubt have spent a fortune. Not this forum, but the principle is the same. Out of interest, how much did you pay for your coil pack, and from whom did you buy it ? Has your car ever had an under-bonnet steam clean ? I know that this is a no-no on this (and most) engines because water gets into places you don't want it - for example under the top cover and down the plug recesses.

m5er Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 15-February-2003 Location: United Kingdom Status: Offline Points: 7	Posted: 18-February-2003 at 18:41
	Got time to check around the ignition system today. Removed the coil pack from No.1 cylinder and found a pool of what seems to be water in the spark plug well. Mopped the water up replaced the coil pack and the misfire has disappeared. Thanks to Kurt Ramsden for sort of pointing me in the direction of the plugs/coil pack. Now, where did that water come from, that's the question. Hope it's not the cylinder head leaking !. Don't seem to be using/loosing any coolant though. Will check again tomorow and post the result here.

BobN Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 02-February-2003 Location: United Kingdom Status: Offline Points: 6	Posted: 17-February-2003 at 19:51
	Had the same with a 520i. A hairline crack was enough to cause it to happen. Sourced new one from Swedish and German - MUCH more reasonably priced than BMW Bob

Guests Members Profile Send Private Message Find Members Posts Add to Buddy List Guest	Posted: 16-February-2003 at 17:25
	It could be one of many things, but I had a very similar problem with my 3.8. It was caused by a faulty coil pack which was diagnosed and fixed by a main dealer. Each plug has its own pack - they are directly above the plug itself under the black cover on the top of the engine. It's worth having a look at them - if they are failing they often leak oil (they are oil cooled and have their own little reservoir inside). Good Luck

m5er Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 15-February-2003 Location: United Kingdom Status: Offline Points: 7	Posted: 15-February-2003 at 14:09
	I need some help folks ! Since Thursday morning the M5 has been running rough when warm... Symptoms: Starts fine and runs OK until the engine is warm. Then I start to get a misfire and the power is down. Any clues???