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Hi Todd, First I must correct a misconception I caused regarding the CPR. It IS vital to the running of the car after warmup, by Controlling (Regulating) the Control Pressure (CP). This CP is a reduced pressure derived from the main System Pressure (SP) coming from the Fuel Dist., and is always lower than SP. The CP value determines mixture—the lower the CP, the richer the mixture (like maybe 17psi CP for a real cold start, then gradually rising to say 55psi for running (based on a SP of around 75psi... just general numbers).
The CP is applied to the top of the FD plunger. The lower the CP, the higher the plunger goes (for a given airflow), and the richer the mixture. But the CP should level off, when warm, to that ~ 55 psi or so. It seldom happens, but if the fuel return (bleed off) from the CPR ever got blocked, the CP would rise to = SP, and the engine would probably not even start with all that pressure on the plunger. It gets pretty complex, but I wanted you to get a general idea.
Don't sweat the Blue wire. The "ground" is probably due to the back-circuits I mentioned. If really grounded it would blow fuse #7, which feeds the FI relay input. I doubt you have a relay problem as such, but the FI (pump) relay could drop out momentarily if it lost negative pulses from the coil to 31b, (or anyhing that made the coil crap out), so make sure both coil primary terminals are making good contact. Same thing for fuse #13, which powers the FI relay Coil. Bad contacts there could cause intermittent relay operation. And for good measure, give fuse #7 the treatment too. If #7 is intermittent,like #13 it affects everything the FI relay does—the pumps, the AAV and CPR heaters, the Lambda relay and the whole Lambda system. All that stuff is controlled by the "Fuel Pump" relay switching power from fuse #7.
Look for the simple stuff first, ie, the "known suspects".
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Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.
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