89 Comanche 4.0 inline 6cyl no power to pump and now no spark as well?
I'll try to help you, John.
For spark: If your spark plugs, spark plug wires, dist. cap, and rotor are good, check the coil. Take off the negative battery cable. Use an ohmmeter and check resistance between the coil primary positive terminal and the frame of the coil-ohmmeter should show infinite resistance, if not, replace coil. Put ohmmeter positive lead on coil primary positive terminal, and ohmmeter negative lead on coil primary negative terminal-resistance should be zero or nearly zero, if not, replace coil. Connect ohmmeter negative lead to the negative primary terminal and ohmmeter positive lead to the high voltage terminal of the coil. Ohmmeter should not show infinite resistance, if it does, replace coil.
If coil is good (or has been swapped), check that coil primary has power to it with key on. If it does, and no spark, the problem could be the ignition module or the pickup coil. The ignition module should be mounted with the ignition coil. The pickup coil is inside the distributor-this pickup coil is what tells the computer (ecu) the crankshaft position, so is critical for spark timing.
For the pump: the fuel pump relay is in the power distribution box under the hood. When the ignition switch's run wire energizes the relay's coil, power is sent to the pump. You could check for a signal on the pump wire at the tank, with the engine cranking Should be a steady signal then. If not, pull the relay out to check that the power feed for the pump is still there. The power to the relay comes from Fuse link G, a 20 amp rated green fuse link. It is hot at all times, so check for a power signal on one of the relay terminals with key off. One terminal should have power. If not, check fuse link G. If it does have power, put relay back in and have someone cycle the key-relay should click-may feel or hear it. If nothing, try a different relay. If relay was good, but no power to pump, pull relay and check terminals that relay plugs into: with key held in crank, two terminals at relay should have power-the power feed from fuse link G, and now the ignition switch signal to the relay coil side. If all checks out, probably a bad pump. If you checked for power at the tank with the engine cranking, and did have power, that is for sure a pump that needs replacing.
Sep 06, 2013 |
Cars & Trucks