STILL hard to start - getting interesting

[Guest E.Murray]

I am now on week 4 of the hard starting problem in my Z. Nearly every time I hop in I have to crank and crank and crank to get the thing to fire up. It ran fine and fired up instantly until a month ago when I had a fuel filter sitting on the valve cover and was boiling the fuel when flat out on the highway. When I was trying to restart it after boiling the gas, the fusible link blew. I fixed the fuel line routing and put a new fusible link in. After that incident, I now have to crank until I'm afraid to run out of battery before it will fire up. It doesn't matter whether the engine is hot or cold. I've chased this through fuel (fresh carb rebuild, filters, etc.) and ignition (new MSD 6AL box, plugs, etc.).

Now, though, I've noticed an interesting thing. The usual procedure is that I have to crank away 3-4 times to get it to start. The first 2-3 times, I'll crank for a while and get nothing. The 3rd or 4th time, it will fire up pretty easily. Yesterday, I was letting it sit a minute with the key on between cranking and I noticed that the first 2 times that the radio went off when I started cranking. The third time I turned it over the radio stayed on the whole time and it fired up instantly. I thought that was strange, so I paid attention the next few times I started it and it's the same thing every time. No matter how many times I try to start it, if the radio and other electrical stuff doesn't stay on when I turn the key to start, I will have to crank and crank. Sometimes if I hold the key over long enough it will go ahead and start, but even then the electrical stuff (radio, lights, whatever) comes on just before it fires up. If the electrical stuff stays on when I turn the key from Run to Start, the car will start right up. I thought the electrical always went off when you tried to start the car... This is weird and really irritating(although I still wouldn't trade for some boring reliable new car...) Any ideas?

[Mike kZ]

Sounds like when you have the key on the start position, you aren't always making contact. Try replacing the keyed ignition.

[Guest E.Murray]

The ignition switch must be working, because the starter cranks just fine.

[Pop N Wood]

You need to see what your spark is like when the problem occurs. Pull a plug wire to check. Sure sounds like not enough juice to the ignition.

 

I will bet money you still have electrical gremlins. Bad ground or dirty contact with your power wire. Could also be a chaffed wire shorting to ground. Did you ever figure out what caused your fusible link to blow?

 

Hard to trouble shoot over the internet. But you said you have an MSD box. So I assume the ballast resistor is bypassed/removed and the ignition is powered off normal run power only. This is important because with a standard points ignition, the coil gets power straight from the starter solenoid when cranking, but through the ballast resistor when running. So there is still a chance one of the other contacts in the ignition switch is bad, allowing the starter to turn over but not power the ignition.

 

About the best advice I can give is first do a full visual inspection looking for dirty or loose electrical connections. Check your fusible link and grounds again. Check the power wire from the battery. Look for any wire shorting to ground. Pay special attention to where wiring harnesses contact sheet metal.

 

If all good, then hook a voltmeter up to the power of the MSD box and try to recreate the problem. If you see low voltage at the box, then start working your way backward till you see good voltage. That should isolate the back contact/short.

 

Another test would be to hook a jumper wire straight from the battery to the MSD box. See if that makes any difference.

 

Good luck.

[Guest E.Murray]

Pop N Wood,

Thanks for all the advice. I've pulled a plug wire on 4 separate occasions to check for spark and 3 times it fired right up (figures...). The fourth time, there was spark, but it wasn't there for the first few crank revolutions and when it did appear it was a pathetic little yellow thing (this is with a new MSD box, coil, cap, rotor, wires, and Pertronix). I'll try again tonight and see what happens.

The ballast resistor thing is interesting. I don't have points any more (Pertronix Ignitor II) so I took the ballast out. Should be OK, right? Does the extra ignition contact come into play, then? Also, all this ignition stuff was in for about 3 months before the incident and worked like a dream for hundreds of starts.

I hadn't traced the wiring yet since it runs great once it starts and I couldn't see any reason for wiring weirdness to just appear when starting then operate exactly right the rest of the time. I will chase things as you suggested.

BTW, no I don't know what caused the fusible link to blow. I was just trying to get it started alongside the highway after the gas boiled and it popped. I haven't been able to find the monster-sized female blade-type connectors anywhere (anyone else know where to get these?), so the fusible link wire is just twisted on the male part, but seems to be fine.

[mark]

so the fusible link wire is just twisted on the male part, but seems to be fine.

 

My money is on this connection. Soldier this and check it again.

 

Mark

[Guest E.Murray]

I tried solder, but you can't solder the wire to the blade terminal. I tried to do it right by getting a female spade but the thing is much larger than anything I could find. I went to the local electronics stores and auto parts stores and nobody had a spade connector this size. I wasn't focused on that since the car runs fine and cranks fine even when it won't start (i.e. no slow cranking or anything). I figure if it's getting power for that, then we should be OK, right? Or is the second fusible link for the starter side of the circuit and the one that blew for the coil, ignition, etc. (there are 2 links right next to each other)? This just occurred to me. Hmmm... Any truth to it? If so, why does it run fine once it starts?

[Tim240z]

Sounds like a fuel pump/pressure problem.....it appears that fuel may be draining back into the tank, then it takes a while for it to pump back to the carb. HAve you tried to see if there is fuel pressure at the engine after the car has been sitting overnight? There should be instant spray of fuel on the first crank.....

[Guest E.Murray]

The accelerator pump still squirts fuel into the carb after it's been sitting. Shouldn't this be a sufficient check? Also, it seems to do the same thing even if it's just been sitting for a minute. I've got a tee plumbed in just before the carb and a gauge I can plug in there, so I'll plug it in tonight and see if I still have anything in the morning.

That still wouldn't explain my original question about why the electrical stuff works without interruption when the car starts and not when it just cranks... Gotta love old cars.

[Pop N Wood]

An intermittent electrical connection will do exactly what you are saying. Work fine some times, but wiggle things a bit and the power goes away. You need to fix your electrical problem first. The hard part about fixing it will be getting to happen long enough to find the source of the problem.

 

You could have a problem anywhere between the MSD box and the battery.

 

I would find a permanent fix for the fusible link problem. If your radio is cutting out also than the link is a prime target. The starter gets it's juice directly from the battery, but the radio and MSD box gets it through the link. Take some sandpaper to the wires to clean it up, and with enough heat it will solder to the connector.

 

You still need to look for chaffed wires shorting to ground. This is not an easy thing to do but it could be why your link blew in the first place and why power keeps going away now. Hope this isn't too simplistic, but think of electricity flowing through a wire like water flowing through a pipe. Get a kink in the pipe and no water will flow. Put a hole in the pipe and the water goes out the whole and not where you want it. Switches and relays are just valves.

 

The ballast resistor is only important because there are two different power sources to the ignition. When you are running it is thought the ballast resistor circuit. When cranking the power comes from a terminal on the starter solenoid. If the wire from the starter is shorted out some how, then it could only bite you while cranking.

[pparaska]

If you can find a spare, try a new ignition switch. And don't let the switch supply power to the ignition, let it do that through a relay that you feed from the battery or alternator output.

[A. G. Olphart]

I believe that Mike KZ nailed it: bad ignition switch.

 

I see your radio as a test light, telling you when the ignition is hot.

 

Just because the start contact connects doesn't establish that the IGN contact is as connecting as well. If IGN is worn (below the level of the 'start' contact?) turning to 'start' could tend to break the ignition circuit.

[Datsun660z]

Spend the $20.00 on a new ignition switch. It WILL fix the problem. I had the SAME thing happen to me. You don't need to replace the whole key switch. Just the electrical part on the rear.

 

 

PS: Just because it still cranks does NOT mean the switch is good. There is in reality more than one electrical switch inside.

[Guest E.Murray]

Thanks guys. I checked last night and there is no spark when it's not starting so somehow the starter is getting power but the ignition is not. I will try again to solder the fusible link wire and replace the ignition switch at the same time. If that doesn't get it, I'll go chasing wires (one of my LEAST favorite pasttimes). Thanks again.

[Guest 305240]

I got to go with a bad Ign switch also. I just changed one out for a friend of mine on his 76. I changet it out to a known good one. No more probs. In case of an emergency, or temp repair, you can always put a push button starter switch in. Just turn your ign switch to on and puish the start button. It should start then.