I did that check too- it holds pressure according to spec. Date: Mon, 2 Aug 2010 18:54:08 -0400 Subject: Re: 94 FMII Cutting out at high boost/rpm From: [email protected] To: [email protected] CC: [email protected]
I think you should test the fuel pressure regulator. When the engine is running at idle, 35-45 psi is not a problem. Holding the return line closed and getting 70+ mean the fuel pump is OK. But will it hold pressure after the engine is off? It should hold about 40psi for 5 minutes after cutoff. If the pressure drops quickly after shutoff, the FPR is bad. When the FPR is bad, you will show the 40+ psi when running, but once a load is put on it, pressure drops because of heavier fuel use and the FPR is not holding back pressure high enough. Another simple test is to remove the FPR and blow thought it. If it flows, its bad. Ken Bogart ----------------------------------------------------- 96 Montego Blue FFS Coldside (His) 97 Black & Tan (Hers) 90 Crystal White (sons) ------------------------------------------------------ http://www.miatacare.com http://www.cincimiata.com http://www.bcchallenger.org MiataMail.com list owner On Mon, Aug 2, 2010 at 6:14 PM, Robert M <[email protected]> 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
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