Toast 120 Report post Posted May 2 I need someone who's in the know to give me their honest opinion on an issue i've got at idle, it's persistant and BMWorkshop haven't been able to diagnose it. Preferably someone who's owned a S50 series motor could chime in, maybe come for a drive and give an opinion? Cheers Quote Share this post Link to post Share on other sites
M3AN 4084 Report post Posted May 2 What's the issue and what diagnostics have been undertaken to date? Quote Share this post Link to post Share on other sites
Toast 120 Report post Posted May 4 On 5/3/2025 at 10:29 AM, M3AN said: What's the issue and what diagnostics have been undertaken to date? sounds like a slight misfire every 10 seconds of idle, hasn't done it in the past, only at idle. Runs well, all coil packs test good, new spark plugs, BMWorkshop said nothing was amiss but commented that it's not a model they deal with regularly (then it was stored for 3 years). Back on the road again last week and after some new fuel, oil change and an Italian tune it seems to be mint other than this. Not sure if it's an "issue" or if I'm imagining things. Might pay to get the injectors flowed and cleaned? Quote Share this post Link to post Share on other sites
M3AN 4084 Report post Posted May 4 An injector service is cheap enough and with some miles under the belt always advisable but something every 10 seconds or so probably doesn't line up with an ignition cycle, I'd expect more frequent "misses". Have you done a DIS VANOS diag? What about a smoke test? These things, certainly as they get older, are prone to vacuum leaks. Also, never diagnose startup or idle issues until the SAP has done its thing, it creates all sort of bumps, lumps, and noises during warm up. Happy to listen to it, or plug it in, if you can drag it to Epsom at a suitable time. 1 Quote Share this post Link to post Share on other sites
euroriffic 626 Report post Posted May 10 Mine also does this. Figured it was because it was a high performance machine lol. it also has always had a weird flat spot at about 2700rpm, even worse now with the karbonius intake, and can’t be at WOT otherwise rebuilt the vanos a few years ago thinking that was the issue, but didn’t really make a difference. 1 Quote Share this post Link to post Share on other sites
Toast 120 Report post Posted May 12 On 5/10/2025 at 7:36 PM, euroriffic said: Mine also does this. Figured it was because it was a high performance machine lol. I have wondered if it's just the cams and that i'm being overly paranoid, going to check valve clearances before going any further, seeing as it's done 320k km it's probably well past due On 5/4/2025 at 9:19 PM, M3AN said: Also, never diagnose startup or idle issues until the SAP has done its thing, it creates all sort of bumps, lumps, and noises during warm up. Yeah this is all while at a good running temp, the SAP does it's thing when it's cold. I'll do some servicing and take you up on the scan offer once I've done some diligence Quote Share this post Link to post Share on other sites
akapjay 48 Report post Posted Sunday at 08:00 AM I asked a mate who's experienced similar sounding symptoms to @Toast and @euroriffic, and his thoughts are: Quote Likely a Vanos solenoid on exhaust side I would pick, but hard to say as it depends on how much of a miss/lumpy idle it has Quote Share this post Link to post Share on other sites
