![]() | Home > Technical (L322) > 4.4L M62 engine possible misfire/lumpy idle? |
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holidaychicken Member Since: 06 Nov 2013 Location: Kent Posts: 1086 ![]() ![]() ![]() |
You could check for oil leaking into the spark plug bores or air leak or PCV valve pipes disintrigated or MAF but would have thought you would get some sort of error reading, what diagnostics are you using?
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mattstevenson2005 Member Since: 01 Jan 2011 Location: Manchester, UK Posts: 737 ![]() ![]() ![]() |
Hi mate,
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holidaychicken Member Since: 06 Nov 2013 Location: Kent Posts: 1086 ![]() ![]() ![]() |
There are a few write ups already on the net,
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johnboyairey Member Since: 11 Jan 2013 Location: surrey Posts: 2035 ![]() ![]() ![]() |
did all my timing chain and vanos stuff a few years ago, however, mine started to misfire recently. i wasnt getting any codes, and the fuel trims were ok to. it was definitely worse on lpg, but it did it on petrol too. -but not as much. i changed the plugs, and it was a bit better, but still happening. it was a sort of flat spot, from just off the idle up to about 1500. so, if i drove it in manual mode, shifting the gears, i could overide it somewhat. my milage is 167k, so after changing a couple of easy things, that i had to hand, like MAF and the throttle butterfly unit. it was still the same. so i was thinking one or more coilpacks were going a bit dry. (had already checked i wasnt filling the plug wells with oil.) i noticed that you can buy these secondhand, and they vary in price, however, they are the same a some bmw 6 pot engines, so dont search for rangie ones, use the code on top of the coilpack, something like 1748017 through ebay...and you can pick them up for under a tenner each, i bought six as a set, and another two from another seller, all for about £45, fitted the lot, and all good now. i thought about proving the dodgy one(s) and keeping the 'good ones' but i lobbed the whole lot!
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holidaychicken Member Since: 06 Nov 2013 Location: Kent Posts: 1086 ![]() ![]() ![]() |
That's really good information, i am bound to need coil packs at some point, it has had everything else ! |
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mm289 Member Since: 11 Mar 2016 Location: Hampshire Posts: 207 ![]() ![]() ![]() |
Not had this engine in a RR but had it in an E38 and did about 40k in it self maintaining all the way (sold it with about 160K and still running sweet)
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holidaychicken Member Since: 06 Nov 2013 Location: Kent Posts: 1086 ![]() ![]() ![]() |
The faultmate lets you view each cylinder for how smooth it is running i think which may help to track down the fault easier |
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Rewmer Member Since: 14 Jan 2013 Location: Essex Posts: 142 ![]() ![]() |
First thing to pop into my head was idle air control valve.but now I've said that, I don't even know if they have them. No7 - 2003 V8 Vogue |
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johnboyairey Member Since: 11 Jan 2013 Location: surrey Posts: 2035 ![]() ![]() ![]() |
On my older throttle butterfly valve, it would sometimes run a for a drive, with a higher than normal idle. And be ok the next drive. I had already attended to the actual flap with some rag soaked in petrol, to clean any intake 'grease' |
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holidaychicken Member Since: 06 Nov 2013 Location: Kent Posts: 1086 ![]() ![]() ![]() |
Could the intermittent increased idle be the battery low voltage trigger than increases the idle when the battery is low? |
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holidaychicken Member Since: 06 Nov 2013 Location: Kent Posts: 1086 ![]() ![]() ![]() |
Any update on this OP?
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mattstevenson2005 Member Since: 01 Jan 2011 Location: Manchester, UK Posts: 737 ![]() ![]() ![]() |
My original issue eventually turned into a real misfire and the error was logged in the ECU. It was cylinder 7 coil pack that was faulty in the end, replaced the coil pack unit and now it works perfectly again |
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holidaychicken Member Since: 06 Nov 2013 Location: Kent Posts: 1086 ![]() ![]() ![]() |
Good result then |
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SteveBaker Member Since: 26 Jan 2017 Location: Hampshire Posts: 3 ![]() ![]() ![]() |
Evening all,
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