jzr

Hi all,
Couple months ago I bought a '79 SA from its original owner to have as a fun around-town/project car. It's been a kick to own and drive but has lately developed some problems I'm hoping the experienced ones here can help with.

When I bought it, the car ran pretty good - it would pull cleanly to redline, and had no trouble idling. A few weeks ago it developed a "miss". I noticed it on cold startup, the tach would bounce around, and while it would maintain fast idle, it sounded like it wasn't firing quite right. This later developed into a miss when warm and accelerating - rough running below 2000rpm, and severe hesitation above 4500-5000. It wasn't all the time though, but was happening more and more frequently; it also started stalling occasionally at idle.

Replaced the cap and rotor, and things seemed to get better, but for so short a time I don't think that fixed anything. Yesterday I went to replace the plugs and found a couple weird things. First, 3 of the 4 old plugs I could unscrew with my fingers! Only the rear rotor's trailing plug was tight. Upon removal, I found that BOTH trailing plugs were completely fouled beyond belief. Both leading plugs looked okay - a little cooked, but not too bad.

So yesterday after the 4 new plugs were securely installed, I drove out to a friends' house. It was really hot out, over 100 degrees. For a little while the car ran well, but then started running crappy as ever, though it did get me there. Late that night I went out to head home, and the car wouldn't start at all. I figured it was a dead battery, as it wouldn't even engage the starter or begin to turn over, and when I tried, all the lights dimmed. So I got it rolling and bumpstarted it, and made my way home just fine.

I figured the extreme heat (car is black) must've cooked the battery, which is quite old. On my way home, when using the turn signals, the headlights would dim. When I got home and shut it off, the battery barely had enough juice to close the headlights.

So this morning I troubleshoot a little. With the key off, voltage is 12.5 or so, which is okay. When I turn it to "run", the fuel pump starts going a bit, but battery voltage drops to 8 (checked at the battery). I also check voltage across the coil terminals, and the leading coil has 8 volts, but the trailing coil (which looks like it had been replaced recently) has 0! Hmmm..

Car still wouldn't engage starter, so I get a brand-new battery and swap out. Voltage is strong, go to start, and nothing - dash lights go black. Now when the key is in the "run" position, every light on the dash is out, and the buzzer doesn't make any noise.

Checked the fuses under the dash, and they all look okay. Which leads me further into the dark realm of stuff I don't know: fusible links. I have the Haynes manual but frankly don't even know where to begin. I think there are at least two separate issues here, and am more anxious to get the car starting again than I am to look at the trailing half of the ignition.

Sorry this is so long; I'm hoping this will be enough information to go on. Thanks so much for any help you can provide!

BrianHeston

Well I don't know what to say about the starting issue, but the ignition issue sounds pretty cut & dried. It sounds like your trailing ignitor has bailed on you. I know this won't help until it starts again, but when you get to that point try swapping the ignitors. If your trailing ignitor is bad, it won't start AFTER the swap. But it shouldn't (as far as I know) keep it from starting now.

Good Luck,
BrianHeston

FJ

Too much is usually better than too little.

The starting (and voltage) problem is likely just a bad connection, as you suspect. The battery terminals are a common cause of that type of problem, but I imagine you used a terminal brush or sandpaper on the battery terminals when they were disconnected. They do have to be shiny.

Fusible links: Follow the small wire from the positive battery terminal to the small block on the strut tower. It will have a few wire fuses wrapped in cloth. Just grab the connector at the end of the link with pliers and pull. Clean the connections (a can of contact cleaner and maybe some very fine sandpaper should do the trick) on the links and block and replace. I've attached a pic of my fusible link block. Yours may not be the same, but it should look similar.

Also check the ground connections. On the later models, the battery negative cable connects at the strut tower and at the rear of the engine. Following your ground wire, you will find the connections. You would want to remove the bolts and clean those connections.

Regarding the trailing, on the newer models 12v goes directly to the positive of the coils, and the negative is triggered by the igniters. But I imagine yours uses points. I'm sure someone will give you info on what to look for in that system. I don't have a diagram for those. Might be a good time to upgrade the distributor and lose the points. A search should provide a number of threads on the topic.

Oh, and you did use anti-seize compound on the new plug threads, didn't you?

-John.

mar3

iTrader: (8)

This will probably be more recognizable. I apologize for its crappy condition. It's a shot from the distant past when I was just learning how to use the Kodak Digicam.... The green arrow points to the lead going to the battery, it was done for a different thread...

jeremy

iTrader: (1)

ok, the trailing plug isn't going to cause that much grief. my negative wire came loose on mine and i just noticed a slight loss in power and worse gas mileage (didn't know that it could get worse, lol). the miss problem is your stupid points dizzy. trust me, i just switched over to an elec dizzy and mine had been doing what yours was. it was useless to rev past 5.5k. now bam to redline without thinking twice. points suck. you need newer coils and an elec dizzy. the points system uses the ballast resistors to cut the voltage back to 6 volts as to not pit the points. the 79 coils are made to work at this lower voltage. the change will bring a big smile to your face. oh yeah, have a etra ignitor or 2 just in case the dizzy has a bad one. they're the little black boxes with the positive and negative wires on the side of the elec dizzy.

jzr

Wow, thanks for the excellent help guys! By some combination of cleaning and sanding connections, I got her running again, strong as ever. FJ was spot-on.

Now about the anti-seize, what happens if I don't use it? I never have in the past, though this is my first rotary. Should I just check the plugs for tightness more frequently?

The novelty of having a points ignition is wearing thin, so I'll make a trip to the junkyard soon for a newer distributor. Fortunately parts are plentiful in nearby San Ysidro. I've been planning to upgrade the alternator as well, perhaps I can get all the parts in one trip.

Thanks again everyone!

RotorMotorDriver

iTrader: (1)

I think its just because they screw into an alluminum rotor housing...Or something...Now that I think about it, Im not really sure why you would use that stuff...lol

~T.J.

inittab

Trust me, use anti-seize on your plugs! When I got my car two of my spark plugs were "welded" to the aluminum housings! I had to use a heli-coil to repair the damaged threads. Believe me, ya wanna use anti-seize!!! Oh, and you only wanta to install your plugs at "just over" hand tight. Do not put them in too tight or you can damage the aluminum threads.

THC

The reason for the Anti-Seize is to prevent corrosion due to dissimilar metals. Plugs are steel and the housing is aluminum. Another problem is aluminum will easily gall which destroys the threads.

Best regards,
THC