Quote:
Originally Posted by docnabimmer
FUEL AIR SPARK these are the 3 things i would make sure are working well...if plugs are new, coils are new, injectors working then I would look at the Fuel Pump? you are at a mileage where most Fuel Pump fail.
I ask you to check out E46fanatics and some important links under GENERAl Info especially the section diagnosing Fuel trim misfires etc etc etc....M54 problems tend to extend to ALL the platforms that use these engines...
FYI_ I had just went thru a single cylinder misfire that turned out to be a soft failing 165k mile original BMW fuel pump.
All is well now post replacement.
|
Thanks for responding.
Fuel pump is not that old, and one of the first things I checked when the previous hard start/no start problem occurred was the fuel pressure - was up above 50 psi. Will check the links you reference. I will also check the fuel pressure again.
A bit more on the issue. If I reset the error codes the rough running and misfire immediately goes away, so clearly, whatever this is, it would appear that the ECU is turning off the injector feeding Cyc1.
Engine also runs fine if I turn it off and back on, and it idles perfectly. It is ONLY when I throw the throttle down and get the RPM above 3700 RPM that the shutdown of fuel to Injector 1 seems to occur. Now, more I think about this, that could be fuel pressure related, or fuel constriction related since demand for the fuel increases, but why only Cyc1 being affected? Cyc 1 IS however the Cylinder at the end of the fuel rail but cannot imagine that has a bearing on the problem. The quest continues.