My money is on ignition issues. Whenever a boosted car suddenly develops misfires under boost, for me the primary culprit is the ignition system.
Check the wires for arcing to valvecover and/or eachother, and look at the spark plug insulators for "carbon tracking"; evidence left by the arc running down the insulator to the shell instead of across the gap in the combustion chamber. This video goes into it a bit: http://www.youtube.com/watch?v=qhdtrXa65t0 You can combat it effectively with dielectric grease. New wires tend to come with some pre-applied to the boot, which can make it seem like you needed new wires, when all you needed was the dielectric grease. Regards, Vito Caputo On Mon, Aug 02, 2010 at 10:14:05PM +0000, Robert M wrote: > > Greets! My 94 FMII car (installed circa 2000, RC550's, 12psi, BBBT, > original fuel pump) is cutting out under high boost/high rpm conditions. I > sent a datalog to FM and Jeremy replied, > > "Your ATS & CTS look fine. You've got plenty of injector > on-time. So, if you're leaning out I'd have a look at your fuel pressure to > see > if your pump is bad or filter is clogged. Should be running around 35 psi at > idle & around 45 psi if you pop the vacuum hose off the regulator. In boost > it raises pressure 1:1. " > > I finally checked the pressure today and got 35 idle/44-ish with the vac > source removed. Max pressure (checked with the fuel line output blocked) was > ~77psi. > > I did notice that the behavior doesn't start immediately, but rather appears > once the car is good and warmed up. > > What's the next step? I probably am due for a filter, but it seems somewhat > unlikely that I'd get good numbers in the garage with a clogged filter, no? > > All input welcome- thanks in advance! > > _______________________________________________ > Miatapower mailing list > [email protected] > http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower _______________________________________________ Miatapower mailing list [email protected] http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower
