I flashed my car over the weekend with the MHD Stage 1+. Everything seemed to go fine-it said "successful' at the end and the car started right up. I took it out for the first ride today,let it warm up (about 200 degrees for the oil),I did a WOT to 6.5k in 2nd getting on the highway and hit 3rd-then the engine light came on and it ran rough and seemed like it was running on 5 cylinders,I babied it home and turned the car off. About an hour later I went back out and started her up and the engine light is off and she idles fines,you guys have any ideas how it fixed itself? The only other thing I did before that first drive was to install a larger intercooler,it seems like if it was a bad coil or spark plug it would still be running rough-although I did order new Eldor coils and 2 sets of spark plugs (OEM Bosch and NGK 1 step colder) that I will install to just start with new ones...
Car Running Rough after MHD Stage 1+ Tune
- Thread starter spitfun
- Start date
When you flash MHD v9 or V10 it does seem to find any issues with coils or plugs..
This happened to me on one coil…I replaced all the coils n plugs and narrowed the gaps and issue went away..
The misfire, engine light on, then reset when restarted is all standard N54 DME management logic..
As usual decent code reader will show which cylinder (s) are at fault.
This happened to me on one coil…I replaced all the coils n plugs and narrowed the gaps and issue went away..
The misfire, engine light on, then reset when restarted is all standard N54 DME management logic..
As usual decent code reader will show which cylinder (s) are at fault.
spitfun said:
Not really..it was a 300 BHP 450nm motor and with the 35is they pushed it to 335 ish BHP with an over boost taking it to 500nm…
So 400 BHP is 33% up on the ‘true’ reference line…also the MHD V10 version rolls a lot more torque in early which will put much more strain on plugs n coils…not to mention issues like LSPI etc…
Lesser tunes put lesser strain on components…
I’d suggest it’s just being more conscious of what’s happening in the engine…
Twin turbo N54s generate large amounts of torque low down..lugging the engine whilst asking for big torque induces greater strains on the engine..hence the rise of low speed pre ignition on turbo’d engines with auto boxes shifting to high gears at low rpm..
Personally if I’m ‘poodling’ I leave it in comfort mode and don’t prod the throttle too aggressively..makes more than adequate progress most of the time..
If I want to ‘press on’ I put the box in sport / manual mode and spin the engine a bit more…
Seems a bit like unnecessary concern for the engine..but if you had a NA car that was tuned then for sure you’d spin it to get more progress..
I’d suggest it’s just being more conscious of what’s happening in the engine…
Twin turbo N54s generate large amounts of torque low down..lugging the engine whilst asking for big torque induces greater strains on the engine..hence the rise of low speed pre ignition on turbo’d engines with auto boxes shifting to high gears at low rpm..
Personally if I’m ‘poodling’ I leave it in comfort mode and don’t prod the throttle too aggressively..makes more than adequate progress most of the time..
If I want to ‘press on’ I put the box in sport / manual mode and spin the engine a bit more…
Seems a bit like unnecessary concern for the engine..but if you had a NA car that was tuned then for sure you’d spin it to get more progress..
NO go stage 2, perfectly fine on stock. I have enquired many times with tuning companies ref upgraded coil packs etc and they are all very clear that at 400/450 you are not even really near needing them.spitfun said:
My 35i has done around 6k on full MHD tune and full XHP map on the DCT, upgraded downpipes, intercooler etc and its more than enough... MHD can analyse your car as well, try doing a live data run, if the error reoccurs send the result to MHD, also try posting in on their FB page, they are very helpful and an absolute mine of highly qualified tuning brains...
Here are a few charts showing 35is stock vs V9 and V10 and effect of no filter etc.. enjoy..
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If you are getting a fresh set of plugs n coils thats the best move..just fit them and maybe close the plu gaps up a bit from stock..22 thou to 25 thou..you can start stock gaps at 30 thou and narrow till misfire ceases..each car is a seperate case at this level of tune..
Have you had the inlets de-coked or checked?
Have you had the inlets de-coked or checked?
No need to upgrade plugs or coils unless you plan to push the car past 600bhp.
A new set of OE plugs every 20k and some Bosch coils every 60k will be fine. The 3 prong Bosch plugs are actually much better than the NGK ones, I've tried pretty much every plug option over the years and always end up back on Bosch as they are smoother and perform better for cars with stock turbos.
Without a large set of upgraded turbos you aren't going to stress the stock engine components at all. You'll run out of octane on "pump" fuel before you start to reach the fuel system limits.
A new set of OE plugs every 20k and some Bosch coils every 60k will be fine. The 3 prong Bosch plugs are actually much better than the NGK ones, I've tried pretty much every plug option over the years and always end up back on Bosch as they are smoother and perform better for cars with stock turbos.
Without a large set of upgraded turbos you aren't going to stress the stock engine components at all. You'll run out of octane on "pump" fuel before you start to reach the fuel system limits.
