Join Date: Oct 2018
Location: Orange County, North Carolina (formerly from Chapel Hill, but now Efland)
Help Needed - No juice to fuel pump
1989 Spider Veloce with a little over 100K miles. I replaced the clutch and in the process removed the intake plenum to get at the starter motor. Replaced the rubber connectors between manifold and plenum, belts, plugs, cap, rotor, valve cover gasket, fuel filter, oil/oil filter, and remediated the air intake bellows. When all done, it would try to start but that's it. Prior to my work, it started every time. I read through different threads on this forum. Battery is charged and cranking voltage is over 11v. The CTS has just under 2K ohms resistance (ambient temp between 80-90). The TTS shows reasonable resistance between G and W. The AAV is clean and I can see a small opening. Both fuel pumps run when jumpered to a battery. They are not getting any voltage when cranking. If I put a battery to the tank pump, the car immediately starts and runs perfectly. I've taken the main relay out and bench tested it. While I don't know the load on the circuit, when the control is activated, there is clear connectivity between the dependent terminals (30 and 87?). I've tested the circuits to the tachymetric (aka pump) relay. With ignition on, there is battery voltage at terminals 15 and 30. Terminal 31 shows continuity to ground. In start position, terminal 50 shows 9.9 volts (or enough to run the fuel pump I think). Yet and still, there is no voltage to either of the fuel pumps when cranking. The 8amp fuse is perfectly clean and there is continuity between the external leads of the fuse holder. The engine grounds are tight; the passenger compartment grounds under the package shelf are clean and tight. I haven't tested the CSI but since the engine tries to start and runs for a second or so, I'm assuming that it's fine (and it runs perfectly with the tank fuel pump powered up by an independent power source). The leads on the coil are clean and tight.
Interestingly enough, I found an engine ground that was free. When I connected it, the car started immediately and ran for about 10 minutes. I turned it off and later it refused to start. That's when I started chasing the relays. I don't know how to test the tachymetric relay, but I'm starting to think it is in intermittent failure mode. Also, I can't figure out where the pink and white (or is it black) hot wire for the fuel pumps picks up it's juice. The wiring diagrams in the Alfa factory manual are not a lot of help. They don't even show both relays or the ECU. I'd appreciate any thoughts on this. Thanks in advance