Low RPM hesitation - Page 2 - The Unofficial BMW M5 Messageboard (m5board.com)

nebpor · 7th July 2008, 14:08

I cleaned all those as well! If the m5 has a cam position sensor then one of the plugs is that - i cannot recall what the other two were at the moment. Look on realOem or the service manual - its in one of them

Lantz · 9th July 2008, 18:33

Well I plugged it in and no difference at all im afraid ( I think it may have been for the airpump ). So much for a cheap fix...

I went for a drive and the car is much slower than usual and hesitates throughout the rpm range. Feels almost like its not firing on all cylinders or something. It ran fine before I gave it to the garage!

Im really getting sick of it, the more money I spend on it the worse it runs.

Ill see if I can remove the plugs and post pictures on here, maybe that will help with a diagnosis.

Lantz · 9th July 2008, 21:34

Ok, I removed the coil packs from cylinder 1 and 2.

I have 2 questions:

1. At the top of the long tube going to the spark plug there is a block made out of many sheets of thin metal. On Cycl 1's coil pack 2 of the sheets had let go around the edges. Is this an issue?

2. There was oily residue on the coil pack and when I put a socket over the spark plug and took it back out it too had oil around the base. Is this normal? If not what could cause this?

Very grateful for any ideas because I am running out

Lantz

///Manuel · 9th July 2008, 23:18

2. It's oil seeping through the spark plug hole gasket. You need to clean the hole off and purchase a new gasket as well as possibly the valve cover gasket itself if it leaks.

Lantz · 10th July 2008, 15:10

Thanks, I doubt its the valve cover gasket as its brand new.

I will look intp the spark plug gasket!

nebpor · 10th July 2008, 23:39

Lantz, this sounds similar to issues I have with a misfire - the coil pack isn't sealing properly, so it's letting moisture in ... taking coil 5 off and drying it with a rag always works!

Glad you're getting there, there is nothing more frustrating that doing work only for something else to break

woods · 11th July 2008, 01:02

Quote:

Originally Posted by Lantz

Ok, I removed the coil packs from cylinder 1 and 2.

I have 2 questions:

1. At the top of the long tube going to the spark plug there is a block made out of many sheets of thin metal. On Cycl 1's coil pack 2 of the sheets had let go around the edges. Is this an issue?

2. There was oily residue on the coil pack and when I put a socket over the spark plug and took it back out it too had oil around the base. Is this normal? If not what could cause this?

Very grateful for any ideas because I am running out

Lantz

Oil in the spark plug well can cause the hesitation you're having. The oil shorts the plug to ground causing a weak spark. Pull the valve cover, replace the spark plug gaskets, clean all the oil out of there and see what happens. Another $10 fix - fingers crossed.

Cheers.

Lantz · 11th July 2008, 18:49

Gave it to my mechanic today, he reckoned they didnt install the valve gasket properly, and so oil was seeping in causing the misfire. At least I wont have to pay for it.

Will also change sparkplugs and sparkplug gaskets just to be sure.

Thanks again for all your help, you guys are a true asset in these situations!

Regards

Lantz

Lantz · 23rd July 2008, 21:19

Well I got it back from the mechanics with a new valve gasket and the misfire is still there

I have a few questions:

1. I just read something posted by Kurt Ramsden stating that the coil packs contain oil for cooling and this can seep out causing problems. Is this correct, and if so should I replace the coil pack?

2. What is the easiest way to test a coil pack?

The fault codes are clean, and no its not in my head

I ordered 6 new Y6DC plugs but got the wrong ones from BMW today ( bosch r6 or something with three metal bits going to the electrode).

After washing it yesterday I played with the throttle linkages a bit and found out that it doesnt keep a very steady rpm at say around 2000, its sort of wavers a bit. I have a 500km trip to sthlm planned on Friday, would it be wise to take the m5?

Any ideas?

Lantz

farrell · 23rd July 2008, 22:25

Lantz
Don't drive it.
Get misfire sorted as engine damage could occur.

Had a coil pack failure on a new customers car last Sat.
Mis-fire on part throttle 1500 rpm up.
No fault code & no misfire logged. = typical EOBD1 !

Plug was black confirming the worst.
No need to test with Ohm meter.
1 coil & 6 plugs later = happy bunny.

Cheers
Farrell