79 Spider won`t start, just in time for summer!!

[pluktv]

Well, so far, the spider was running great - until now.
This happened around a month ago, and while I was playing around and replacing the ignition coil with another used one it started working for no apparent reason. Then it`s been running great until now. Maybe this is irrelevent but it`s only happened both times after being stood for a week.
This is the story so far and what I have ascertained.
There is no spark from the top of the coil at all.
I have 11.9 volts to the + and 9.4 volts to the - on the coil with the ignition on. These drop to 9.6 and 7.4 respectively with the engine cranking.
I bought and fitted a new icm and it made no difference at all.
The mag pick up in the distributor looks to be brand new by the p.o.
I changed the coil the previous time, but it also did not produce a spark. The coil was checked resistance wise and looks to be roughly in spec, certainly the same resistance as the last one. I DO know how to use a dmm, but can`t vouch for 100% accuracy.
I fitted a bulb to the -ve of the coil, and when cranking the engine it does not pulse, only goes like a headlight would when cranking it over. It`s like the icm is not doing, or can`t do it`s job.
I`ve checked as many wires resistance/ground wise as I can. They all seem ok.
I think that`s about it as far I can go. I`ve been messing with this all day now it`s roasting hot and am out of ideas.
Sorry for the long windedness of this post, I was just hoping to give you guys as much info as I can.

Anyone have any ideas apart from throwing a few hundred bucks in parts at it?

Phil

[nelsonj]

Did you double check the connection between the magnetic pickup lead and the igniter/icm? Mine came loose and I had to push one tab out, one tab in on my ICM to get the cable to make a good solid contact.

Take off the distributor cap and make sure that all the wiring from the dizzy to the ICM looks solid, and that the magnetic pickup on the distributor is still in goo shape and spinning as the engine cranks. It sounds like the problem is between the magnetic pickup/wiring to the ICM/ICM/wiring from ICM to the coil. Are you sure the ICM is good?

[digitech]

I have just gone through a similar issue on my '79. I found my coil/heatsink ass'y was not probably grounded even though it was bolted tightly to the car - I re-worked the mounting to improve the contact but also installed a ground wire. Also, I found I needed at least 12.5v at the B+ of the coil for it to run, and the - side should ohm to ground when installed. My ign control module became damaged by operating without being fully grounded and I had to put in yet another new one - luckily, you can get them anywhere for about $20.

[pluktv]

Ok, the story so far...

There WAS a bad connection to the icm from the magnetic pick up lead. I took off the nasty black connector and made a good connection to the icm.
I`ve charged the battery, cleaned up all the grounds and I now get a healthy 12.5v to the + and - of the coil with the ignition on.
The pick up in the distributor is definately spinning round.

Couple of things. Could someone confirm that the pink and red wire goes to the +ve on the coil, and the brown and black wire goes to the -ve? I`ve had this thing apart so many times now that I just can`t remember...
Also, does the coil itself have to be grounded?

Unless anyone else has any ideas, It`s looking like I need another icm, it could be already damaged according to digitech. If I don`t fix this this weekend, then I`m going to order a new mag pick up, coil and icm from AIP and start from there. It`s the cheapest place for parts, This is Nova Scotia and I paid $38 just for the icm, but unfortunately it`s gonna be a couple of weeks off the road.
It doesn`t help when a friend comes round last night just as I was working on it and says"Well, I did wonder about you buying an old car like that" . They just don`t get it do they?

Phil

[digitech]

Pink/red to +, Black/Brown to -. The coil is grounded thru icm, make sure you read ground from heatsink to chassis.

[pluktv]

Thanks digitech

Check, check and check.

Am going to order some stuff tomorrow, hopefully with a new pick up, coil and icm I will have something to go on. The only good thing about this is that it`s forecast wet weather for the next week or so. I miss driving it, I really do.

Ho hum, at least I have my kz650 to fool around on in the meantime.
Watch this space...

Phil

[pluktv]

Fixed!!

It was the magnetic pickup in the distributor that was the problem. Spoke the the guy at IAP and he told me how to check it, a good one should read around 700 ohms between the connections. Mine was completely open circuit.

So, parts arrived in record time, replaced the rotor and another icm as well as I don`t know if I damaged the others. Everything is grounded nice and clean. Starts better than ever before now.

Thanks everyone for all your help!! (No thanks to the Canadian government who charged me a $42 "brokerage fee" - on top of tax- to bring these parts into the country)

Phil

[dmwhiteoak]

"It doesn`t help when a friend comes round last night just as I was working on it and says"Well, I did wonder about you buying an old car like that" . They just don`t get it do they"



Most of them don't. But they will spend 30+ grand on a car and complain about driving 50 miles to work. I will drive to work in 100 deg temps just for the ride home in the lower 70's with the top down and enjoy every second of it.

[nelsonj]

That is great news - that it is up and running, not that your government robbed you of of $C42.
If your magnetic pickup was bad, most likely your previous ICM is still good. I would put it in a safe place for future use. I might even put it in a zip-lock bag and throw it in with the spare tie. If your new ICM ever goes out you will have an emergency ICM with you on the road.

Enjoy the ride.