Weird one this but thought it was worth posting as I'm scratching my head
This issue is on my F4R conversion running a DTA S40 pro ECU. I haven't changed the ECU or loom on the new build and it was all running fine on the old engine.
So, Built the car and engine and its been on the road since May, in that time I've done about 400 miles without any issues. Until the weekend before last driving home from the old folks (100mile run) when I pulled up at the roundabout off the A1 and the car just cut out, as I came down through the gears it was hesitating but if kept in gear above 2000 rpm it still ran ok until I stopped and it just died.
I had a look around it, couldn't see anything wrong, fired it back up and it started, drove all the way home, a further 5 miles, then it cut out again as I came over the speed bump into my street.
So I thought it was a dodgy crank sensor, so I bought a new one. I also fitted a new fuel pump.
So took it out tonight for a test run. It was absolutely fine for about 10 miles. Took it through the revs, stopped and started at junctions without issue. Then, about 1 mile from home it did it again. once it started up it was asif it had gone into limp mode...
Heres a video of the issue, you can see its at 7% throttle and it just jumps up and down.
http://www.youtube.com/watch?v=Ggiih...ature=youtu.be
I managed to get home at 1000rpm, but it took ages.
It seems to be some sort of electrical problem, the AFR's go really lean as if its cutting the fuel. I can't see any errors in the diagnostic and I've uploaded a known good map to eliminate it being a corrupt file...
Any ideas?
Thanks!