78 Spider w/spica miss firing

Stonewall13 · #1 (**permalink**) 07-31-2008, 05:03 PM

My engine seems to run out of gas when I push on the gas but only at times. Sometimes it runs great. I have a new dizzy, coil, wires, intank and main pump, gap set at 19mm. I looked at the wiring diagram and saw that the coil wire goes to the ignition switch. Is it possible that I am getting a short from the ignition switch? I am going nuts trying to figure this out. It sometimes runs great then bucks and misses. Pleas help with some ideas to check!! Thanks

**radamm** · #2 (**permalink**) 07-31-2008, 05:09 PM

Mine had very similar symptoms which were caused by deteriorated wires at the pick-up in the distributor..... that is until the day I had to push it into my driveway!

**Britalia** · #3 (**permalink**) 07-31-2008, 05:27 PM

I bought a new coil, which turned out to give the same symptoms you are having when it got hot. You might try putting in the old coil and see if the problem persists.
Also, you could temporarily bypass the ignition switch by running a jumper wire directly from the battery to the coil. (don't leave this hooked up for long)
Chuck

Stonewall13 · #4 (**permalink**) 07-31-2008, 08:23 PM

I will try the wire from the battery to the coil. That will eliminate the switch. I also had to rewire the hot wire from the starter to the fuse box so maybe it is electrical prob. Thanks!

**Roadtrip** · #5 (**permalink**) 07-31-2008, 08:25 PM

Slim possibility that it could be a fuel cutoff solenoid cutoff switch going bad. If that switch activates/shorts it'll cutoff fuel. Try temporarily disconnecting and taping the electrical lead to the fuel cutoff solenoid and see if that makes any difference.

Stonewall13 · #6 (**permalink**) 08-01-2008, 06:57 AM

John, I'll try that this morning. I do believe that it is something electrical because when it runs well it really runs smooth then starts cutting out. I'll post the results. Thanks

**Roadtrip** · #7 (**permalink**) 08-01-2008, 07:54 AM

Sometimes the two wires that go to the FCS microswitch underneath the injection pump are twisted together. Vibration can eventually rub the insulation off and the two wires complete the circuit before the microswitch . . and it can happen intermittently as vibration or even enertia (cornering) is placed on the car.

billboard · #8 (**permalink**) 08-02-2008, 07:27 PM

Does the fuel pressure warning light work? This would be a good way to figure out if it is fuel or ignition.