Car idles nice then just quits...

[patiodaddyo]

I posted under general maintenance but I think it needs to go here. My 79 spider is a recent aquisition and has a 34 DMSA carb. During the test drive the car quit after about 3 minutes. The owner said that had never happened to him before. I towed it home, took the carb apart, reinstalled and it started up and idled for about 2 minutes and then quit. So, I bought a can of no ethanol gas and re-piped it to run from the can with the line from the tank plugged. Took the carb apart again, blew out all the passages, re-installed and same thing again. Ran for about 2-3 minutes then just died. Can't restart. When it died, I noticed the plugged line from the tank was leaking fuel like it was pressured up. Unscrewed the gas cap and noted slight pressure. Hmmm?? I'm out of ideas here. Time to call the pros???

[kilrwail]

That's a classic symptom of ignition switch failure - unpredictable and random. Test the switch against all accessories to see how it functions. Check all your ground and 12 V connections in the ignition circuit. Does it restart easily or do you have to wait a while before trying? Try to eliminate other elements in the ignition circuit through testing or bypassing. When you're confident the points, plugs, distributor, coil and wiring are good, it's likely the switch.

[patiodaddyo]

Thanks for that suggestion. I was starting to think maybe it was electrical related. I can see fuel going down the primary bore when I move the accelerator rod. I was also wondering about the coil/module but I would never have guessed the ignition switch!! When you say "does it restart easily or..." . After the engine just dies, I am able to immediately turn the key and the engine spins over normally, just won't fire up, starter cranks just fine. Plugs look good, so I will look at the distributor and test the coil. Is the ignition switch repairable or just buy new??

[kilrwail]

Some people have rebuilt their ignition switches, but I just replaced mine with a new LADA switch from AutoRicambi. If you do that I'd suggest installing relays for the headlights and maybe the wipers and the ignition switch, since the LADA switches are not as durable as the original Sepia switches. When you say it turns over easily but won't fire, that reinforces my suspicion.

[patiodaddyo]

The "Saga Continues". Thought I had the answer when my ignition control module failed its test. Put a new one in and same thing happened as before. Coil tests out fine. Then I look under the dash where the ignition switch is and what a rats nest ! Can't believe the car EVER ran. So I cut it all out because everything needs to be redone. I have 2 different wiring diagrams for my year. They both have pink, black, red, brown but one diagram shows an extra Lt. Blue/Blk. My ignition switch has this extra wire. According to the diagram it goes to the fuse box and lighting switch. Also, there is a 2 pin connector that comes off my ignition switch with 2 white wires. These don't show up on either wiring diagram. My ignition switch has the number 90030 on it. Maybe this was a replacement switch at one time. Comments??

[kilrwail]

The white wires are for the seat belt buzzer - not required. Because they are there I'd say you have the original switch. The LADA ones don't have them. You need a wiring diagram to fix it correctly. Do you have one?

[patiodaddyo]

Ok, seat belt buzzer, leave that unplugged! Thought it might have been there to illuminate the switch. I do have a wiring diagram, actually 2 diagrams, where one shows the extra Lt. Blue/Blk. in the diagram (one doesn't). I also stubbled across the Mirafiori site where it advised running a second brown wire to the starter lug and connecting it to the second #30 terminal on the ignition switch. That's what that extra wire on my switch is for, someone has already done that!! The pink and red wire were still left on the original white plastic plug (complete with burn marks) and I suspect those old connections were maybe not all that solid and that's causing my problem. So I'm going to cut those free of the white plug and solder all new connections and see what happens! I'll be away from my baby for 3 weeks so I'm done for now. Thanks for all the help!

[RRoller123]

+1 on that. I eliminated that C31 connector and connected the wires directly across. That white plastic housing loosens over time and causes all sorts of havoc! The Fast-Ons themselves weren't bad, so I cleaned and tightened them and didn't bother soldering, would be a pita under the dashboard anyway. No problems, about a year or so in.

[Shadoobie]

Glad to see you're making some progress. Burned out ignition switches can certainly be a pain. It's also worth mentioning that you should be sure to have a return line for the new carb if it doesn't have one. If you don't, it will cause excess pressure to build up in the tank that will mess with your fuel flow and cause problems with idling and starting.

[patiodaddyo]

There is a fuel return line to the tank, thanks for that suggestion. Kind of weird the car starts and runs fine (for the 2 or so minutes that it does before it dies) with the failed ignition module or new module. I saw them test both modules at autozone too. Next step is to make all wire connections solid with the existing switch and if it still does the same old thing, then the switch is next. Kinda cool article on how to rebuild a switch on one of the sites I was on. Might give that a go!!

[patiodaddyo]

Back to square one. Re-did all the ignition wiring and cleaned up the mess under there. It fired up right away then same ol' thing again. Maybe ran an extra 30 seconds before it died this time, but less than 5 minutes for sure. I tested the coil and the primary resistance is a bit higher (0.9-1.0) than it should be. Not sure if that's an issue or not?? Secondary resistance is is just over 11,000 ohms, so close to specs. I didn't check the control module again (I replaced it) but I noticed the connector isn't all that tight on the terminals when I push it on. Maybe??

Not sure of what to test next??? I will gladly take any suggestions. Thanks.

Neil

[patiodaddyo]

Another update. Pulled the distributor cap and rotor off, then looked at the breakerless points and wiring. The insulation on the wires was hard and broken on a good portion of the wire with bare wires exposed against the metal of the inside of the distributor. I think that could be a problem! Guess I need to send off an order!?! Anyone use pertronix stuff or stick with the stock Fiat brands?? Thanks.

Neil

[bobplyler]

I have always used the stock stuff. It is easy to put the magnet under the pickup upside down,

[Nanonevol]

You need to get electronic ignition. Pertronic, Crane, others.

[patiodaddyo]

Thanks for the replies! I have used Pertronix on other vehicles with good success, just wondered if that was the consensus with others. I could not find a number on the base of the distributor that was even close to the Pertronix look-up table. I think I will go with OE stuff. My car is a 1979 so it already has pointless ignition, but in my case it was so old it might have been original to the car!?!? So, give that a try and report back! Thanks.

Neil