Project79RX7

So....it's been a while since I played with an ignition systems that actually has points! Hell....it's been a while since I played with anything that still had a distributor......so I'm a little rusty here and looking for some help.

The car is a 1979 RX7 with the 12A motor and a standard tranny. I just finished rebuilting the block (and most of the car, for that matter), so everything has been apart....'cept the distributor. Which is why I'm so baffled. Before we tore the motor out, the ignition system was fine. All I've done is unplug the wire. And, I know I have them hooked up correctly.

I've got a good solid spark off the Trailing plugs.......but off the leading plugs, it's intermittant and weak at best (as a result the car don't run). I've set the point(s) gap(s), checked the resistance on the coil(s) and the coil wire(s) and they are in spec. When everything was first assembled the car started right up....it ran for about a minute or so, then the motor started to cut out. It was an obvious ignition problem too....you could tell it was started to miss then it would die out. When I crank it over now, occasionally it sputters to life for a second, then dies out.

Anyone have any ideas or suggestions??

defakto

Bad wire would be my guess and that should be easy to check.

It's possible the unplug and plug of the wire was too much to handle. Start with the simple, obvious things that you think could never be the problem, and work towards the stuff you expect.

nick812

Try to swiching out the ingnition swich.

Project79RX7

The plugs, wires, cap, rotor and points were replaced before I rebuilt the motor. I'm gonna go check that coil wire again (as you suggest) but I'm pretty sure all that stuff is still good.

I've also tried switching the coils...to see if the problem switched to the Trailing plugs....but it didn't...it stayed with the leading plugs. Think I'm gonna go do the same thing with the points and the coil wires too.

Project79RX7

Oddly, I switched the points....move the leading set to the trailing position and the trailing set to the leading position, in the distributor...and it started right up. seems to simple of a fix.

But....that is not uncommon so far....seems if I let it settle for a 15 minutes or so, my ignition problem goes away. But it will only run for a minute or so before it re-appears. The engine is running long enough to gain any tempature...and you can hear it miss occasionally when it runs.

Maybe points and condensors?

trochoid

iTrader: (6)

Condensors can be heat sensitive when they begin to fail. Unless you are set on keeping your car pristine stock, switch over to the later electronic ignition. Link to the 'How To' is in the FAQs.

Project79RX7

if it were my car....I'd have already switched it.

I'm rebuilding this car for a freinds dad and he wanted to keep the things as stock as possible. For example....The header pipe on the things was rotted out (car sat outside in Canada for 16 years without ever being started) and trying to get the guy to go with headers was a bit of a hassle. The deciding factor there was that you can no longer get a stock header pipe.

Anyway.....I'm pretty sure my problem is the points and or condensor. I switched the points.....trailing to leading; leading to trailing. And the car runs....holds an idel and was able to get it up to running temp. BUT, every so often the idle would get a bit rough and the tach would stop working.

My guess is that one of the sets of points is bad, or working intermitently....I've put that set into the trailing position and when they stop working intermittently the engine runs rough. When they were in the leading position, the car would start for only a few seconds. Does my theory sound plausable?

Also....I'm a bit more than inexperienced with this funky dual ignition system....as well as with rotary motors (although, I just rebuilt the block and that seems to be working fine). Can someone give me a quick tutorial on how exactly this ignition system is working. Why the dual systems....leading and trailing?

trochoid

iTrader: (6)

On the 79 ignition, the trailing works part time, not full time. That's why the tach signal comes off the leading, it comes off the trailing on the electronic version.

Project79RX7

The trailing system only works part time.....?????? Which part of the time? and what decides whether it is working and not?

trochoid

iTrader: (6)

I'm not up on the points system that much. In my sig line is a link to the online FSMs. You will find a better explaination there.

Project79RX7

Hey know-it-all-NIMROD.....maybe you should read MY service manual....the one I downloaded month ago.....it doesn't tell how the system is suposed to work...just dis-assembly and assembly instruction.....that, I can already do....and probably becuase I already read the FSM cover to cover. But, you already knew that because your a veteran.....right, CHUMP?

defakto

Yeah, don't disrespect the veterans around here. That's just asking to never get help again whether you agree with their stance or not.

The trouble shooting section of the FSM should allow you to formulate a decent idea of how the ignition system is designed to work.

Kentetsu

What's with the sudden attitude man? Slamming on Trochoid is a sure way to find yourself lonely. See ya...

Project79RX7

I didn't like his snotty attitude...so, I showed my snotty attitude.

I asked what should have been a simple question...."why the dual ingition systems and how do they work together"...for which I've gotten flack....and, by a so-called "veteran". No one needs that attitude. ...especially when his advice was sophemorish at best. I respond to questions on other boards...even the simple ones....because that's how decent people act....they offer their help and knowledge.....not insult people.

And, I'm hardly a newbie...I was bulding engines when I was 12.....restoring cars and working on Super Speedway Race cars when I was 18. And, I'm a engineer....which means I know how to do homework....and did....and so far I haven't been able to find the answer.....which is why I'm posting questions on bulletin boards.

I don't mean to be rude to everyone. There have been a few very helpful people here. And to them....thankyou.

trochoid

iTrader: (6)

Well, Mr. Experience, my sig line is a humorous jab for the newbies, apparently you don't have any sense of one. It's nothing personal, I provide the link for all of the new members. The 79 model is the last year of the points style system, after that, they are all electronic. The purpose of the part time system is for emissions, have you read through that section, i.e. Section 1A?

Since I only have one 79 that comes in the shop. I'm not all that familiar with the hows and whys of the point system being part time, and the owner had me convert it to electronic this summer. As such, I have no pressing need to learn the intricacies of it. Since I am not that familiar with it, and stated such, I provided you with a link to the FSM for your benefit. Not every one knows they are online nor how to find them, it's all part of the 'service' of being a memeber in good standing.

Fwiw, I have an engineering degree also. I also have enough college credit hours that had I decided what I wanted to be when I grew up when I first began my higher educational career and not changed majors several times, I'd have a PHD. What I want to be is still a toss up and my kids are out of school.

I don't know if you are simply having a bad day, or you recieved a lump of coal in your stocking, but your attitude won't get you very far on the forum. We're a pretty decent laid back bunch here in the 1st gen section. We occasionally poke at each other, all in good fun, and you haven't seen my 'attitude' yet. I can be quite acerbic at times.

From my experience, when I get frustrated enough that I feel the need to lash out at someone or some thing, then it's time for me to take a break from the project and regroup.

Kentetsu

Maybe you did not realize that T's signature line is set up for all newcomers, and was not specially built just for you. I suppose that if you had thought that his information (which is set up in a humurous manner) was intended only for you, then I could see you getting a little miffed if your sense of humor was not fully engaged. Still, this would be a misunderstanding on your part, not Trochoid's.