Poor fuel would make the ECU pull things back quickly. I’d assume the OAR would start to head towards positive as it sensed rubbish fuel. If OAR stays at -1.0 you’re good!
I have Tesco 99 and Shell 99 on my doorstep and always ran Tesco 99 as it is much cheaper. During tuning my car I asked Stu which fuel is best and he said Shell 99 every time for more consistent results and quality, so on his advice I always use V-power 99 now.
Stu from MSD explains things far better than I ever could so give him a call.
Wow it went to 0.98 just on a straight bit of road then finished it off up a hill , changed almost straight away, I have read Stewarts Sanderson blog before, how did you know about this little trick ???
Thanks for the tip , I will run it abit first just in case , then get some logs done 👌
I data logged my MSD multimaps the other day and mine was sitting perfectly on -1.00, I always use 99 octane(v power or momentum) just currently trying the esso synergy +, seems to be better on fuel and the same price as momentum, winner winner👍🏻
Im having the exact same issue with MSD420 multi maps. I’ve just reset my ecu learning today. And will keep trying. The best I’ve had is -0.90 and i always use shell vpower. I’ve just read the post from msd. Any help would be appreciated. Many thanks Jonathan.
I’ll try tomorrow thanks. Just find it so strange as i must of done nearly a 1000 miles before today’s reset. Now done around 50 miles and it’s still at the 0.80 start point. Had you done a lot of miles before trying this?? @robroy
Older thread I know, but I’ve recently gone to MSD420 and multimaps and have been working with Stewart on my data logs and tuning. I also have Turbosmart 50/50 CBV and NGK one step colder spark plugs.
My OAR seemed to be sticking at -0.80 and only recently moved to -0.85. We think there may be a leak between solenoid and CBV, but I will be looking at this more soon. It is possibly a few psi as TIP desired and TIP actual are different by around 2-3 psi… plus WGDC looks a little off.
I have tried long 3 psi pulls up hill as Stewart suggested, although I am now going to try this in 5th/60th gear as suggested by @gixxerboy since I was in 3rd/4th last time I tried this 🙂
If you’re interested, I did this 2nd gear pull in 380ps map slot purely to check my knock vs ignition correction per cylinder as I was concerned about ghost knock when viewing some earlier data. However, I have left these off this graph as there was no knock and ECU advanced all cylinders just fine.
I am really loving data logging on the Cobb, it really is an amazing tool and how ECU’s work is such an interesting field. Stewart at MSD has written a number of blogs on the Ecoboost ECU, specifically on the RS mk3 if you are interested in further reading. Fascinating stuff!
This reply was modified 4 months, 1 week ago by richard31337.