Car died. Bad coil?

[tirwin]

Hey guys -

Need a little advice again. The main question: What coil can I get at a local part store to test?

Here's what happened and what I've done so far... I'm worn out right now so I might've overlooked something.

After being 5°F on Monday and some bad storms last night, today the weather was 61°F and sunny. I had to coach my son's basketball game today so it was a perfect day to drive the 911.

Drive to the game was great. Went to leave a couple of hours later and the car wouldn't start. Battery seemed fine but it wouldn't start. Pulled off the air filter and with the key on I lifted the pressure plate arm. Injectors squealed so it as getting fuel. A friendly guy in the parking lot came over and we tried jumping it just in case. No dice. Then I thought fuel pump relay. I had bought a spare.... And then left it in my parts box at home.

But then I remembered that some of the relays are the same so I swapped the horn relay with the fuel pump relay and the car fired right up!!! Started driving home and then I got about half a mile from my house and when I pushed in the clutch approaching a right hand turn, the engine died and it wouldn't start again with the same symptoms. A couple of kind people stopped and helped me push it into a gas station.

Called AAA for a tow and on a funny side note when the agent asked me what kind of car I told her '83 911. She asked what color. I said black. Then she said, "As it should be, sir!" A little bright spot that gave me a laugh.

While I was waiting on the tow truck a former Porsche mechanic saw me and stopped. He tried to ground a plug while I cranked. No spark. We looked at everything we could without tools and couldn't find anything. Checked all the plugs wires and hunted for loose connections.

Got the car home. I pulled the fuel pump relay and jumped pins 87 and 30 and the fuel pump runs. I hooked up the timing light to check for spark. The car started, ran rough for a few seconds and died again. Timing light fired at first and then flickered with the engine until it died. Battery read 12.2V but that may be because I had tried starting it so many times.

I do have a Permadoom instead of Bosch CDI. I'm thinking coil is the most likely suspect but if someone else has a bright idea of something I'm missing, please let me know.

[McLaren-TAG]

No crank with a known good battery doesn't seem alike a coil issue to me, I'd start with the engine ground strap. Anyway, I wasn't able to concentrate much after the 61 and sunny bit of your post.

[tirwin]

Originally Posted by McLaren-TAG

No crank with a known good battery doesn't seem alike a coil issue to me, I'd start with the engine ground strap. Anyway, I wasn't able to concentrate much after the 61 and sunny bit of your post.

Trust me, I'm moving to Key West one day. That 5°F is for the birds!

I will edit the post. I said it didn't crank but I meant to say it didn't catch and start. My brain is fried...

[LEAKYSEALS951]

Originally Posted by tirwin

Hey guys -

I pulled the fuel pump relay and jumped pins 87 and 30 and the fuel pump runs. I hooked up the timing light to check for spark. The car started, ran rough for a few seconds and died again. Timing light fired at first and then flickered with the engine until it died. .

Was this with the horn relay in the fuel pump relay, you shorting between 87 and 30, or were you using the new fuel pump relay you bought but left at home?

Similar symptoms with my car a couple of weeks ago. Mine had blown the fuel pump fuse, but it would start..run rough... then die... I had just replaced my ignition with a MSD so I immediately thought my MSD had gone bad, but that wasn't the case. If you keep trying to start your car... go try it... and there is a fuel delivery problem, the "initial start.. rough run.. stall..." will degrade to "no start whatsoever." (At least mine did). Switch between a red relay and a straight jump to see if that makes a difference. The reason is that if you want to go buy a new coil, (and i could be wrong on this....), you have to either commit to a new bosch coil (or permatune coil) for the permatune, or decide to abandon permatune altogether and go for something like msd. Backing up to my "new" MSD story (the problem before the fuel pump fuse blew-which I dont think is your problem-you should check for good continuity in the fuse anyway)...that the MSD was an install to rid myself of a prematune several weeks prior... Like you, I couldnt figure out if my coil was bad or the permatune was frying... so I ordered an MSD blaster high vibration coil to rule out the coil. Car ran like a scalded dog (good) for about 20 minutes, then permatune fried completely. Some people have hadgood success with permatune and MSD coil, and others will preach why its a bad idea. I did it as an experiment and that was the end of that.... That's why I'd try fuel delivery thingees first, and then make new coil choice dependent on what you would ultimately replace the ignition with if the ignition is infact the problem. good luck!
Ron

[john walker's workshop]

bosch silver coils are a known issue. so is a permatoon.

[edragg4]

So John... What's a good coil to use? Newbie here...

[tirwin]

Originally Posted by LEAKYSEALS951

Was this with the horn relay in the fuel pump relay, you shorting between 87 and 30, or were you using the new fuel pump relay you bought but left at home?

At the gym, the car started and ran fine for about 6 or 7 miles using the horn relay. When I got home I tried the new fuel pump relay and it didn't start. Jumped 87 and 30 just to test fuel pump. Then I put in the new relay and it started briefly and died. Next try no start.

[tirwin]

Originally Posted by LEAKYSEALS951

Like you, I couldnt figure out if my coil was bad or the permatune was frying... so I ordered an MSD blaster high vibration coil to rule out the coil. Car ran like a scalded dog (good) for about 20 minutes, then permatune fried completely. Some people have hadgood success with permatune and MSD coil, and others will preach why its a bad idea. I did it as an experiment and that was the end of that.... That's why I'd try fuel delivery thingees first, and then make new coil choice dependent on what you would ultimately replace the ignition with if the ignition is infact the problem. good luck!
Ron

I've heard I can get an el cheapo VW coil to rule the coil in/out. But I read something by Warren (Early S Man) that the wrong coil can fry the CDI. So that's why I'm kinda wondering what part number I should get?

Is there a troubleshooting procedure for a silver PermaTune? Other than seeing if it will fit in my trashcan?

[boyt911sc]

Originally Posted by tirwin

At the gym, the car started and ran fine for about 6 or 7 miles using the horn relay. When I got home I tried the new fuel pump relay and it didn't start. Jumped 87 and 30 just to test fuel pump. Then I put in the new relay and it started briefly and died. Next try no start.

Tim,

This must be a typo. Terminal #87 is for the starter. Terminal 87a is power from ignition switch. Borrow a known good CDI and try it.

Tony

[LEAKYSEALS951]

Originally Posted by tirwin

At the gym, the car started and ran fine for about 6 or 7 miles using the horn relay. When I got home I tried the new fuel pump relay and it didn't start. Jumped 87 and 30 just to test fuel pump. Then I put in the new relay and it started briefly and died. Next try no start.

Based on this (and i have had two glasses of wine- and I am a relative newbie- so take this for what it is worth)- I would jump the 87a (on my 78 it is 87a-after reading boyt911sc) and 30 again and go try and start it. Sounds dangerous, but if there is a problem, it should only burn the fuel pump fuse. If the car runs (at least in my 78), that would signify you either have a bad air flow meter short or bad rev limiter short. If the car doesnt run, I would still want to rule out a bad fuel pump, but this sounds like you had nothing, the jump primed a good fuel pressure, replacing the relay killed fuel pressure, and the engine ran briefly with whatever fuel pressure your jump provided during the jump. On my 1978, #87 would engage the fuel pump in "full start" mode- meaning the ignition is engaging the starter.

I would love for somebody to chime in on the el cheapo vw part #. I too searched for it but could not find it.

Also, FWIW, my permatune (as it failed) ran good when cold, but fluttered when hot. It never failed, just fluttered badly when hot.

I could be on a totally wrong track with the fuel delivery, but I would want to rule that out before heading into ignition (unless you can find a cheap adequate vw coil), because, ultimately, you might have to address the ignition as a complete setup, not just a coil or cdi. If you can find a friend who is willing to lend a cdi, great, however, there are posters here who will advise against trying out other cdi's until you know the root cause of the failure (at risk of blowing friends cdi).

[tirwin]

Originally Posted by boyt911sc

Tim,

This must be a typo. Terminal #87 is for the starter. Terminal 87a is power from ignition switch. Borrow a known good CDI and try it.

Tony

Yep. Typo. Tired. Thanks for catching it.

[tirwin]

I just tried starting it again. First time it almost caught. 2nd time it started but ran rough. I will try to source a CDI locally. Are the connections between the Bosch and the PermaTune plug and play? Or do I have to find someone else with a PermaDoom?

[MongooseGA]

Tim,

Maybe a good thing you didn't make it down south today. I may have my old Permatune that the car came with. I can check tomorrow when I'm back in the garage. I don't remember if I brought it with me in the move.

If I have it, you're welcome to try it out.

I hope talking about my car didn't jinx yours!

[Harpor]

I had trouble starting my 81 sc and tried substituting my spare cdi & coil.Still no start,finally started checking the green wire coming out of the distributor.when I moved the wire the car started right away.Might be a good idea to check the green wire coming out of the distributor going to the cdi.Just my 2cents worth.Harryk

[tirwin]

Originally Posted by MongooseGA

Tim,

Maybe a good thing you didn't make it down south today. I may have my old Permatune that the car came with. I can check tomorrow when I'm back in the garage. I don't remember if I brought it with me in the move.

If I have it, you're welcome to try it out.

I hope talking about my car didn't jinx yours!

What are the odds? Maybe I shoulda bought a lottery ticket. If you find it let me know.

[tirwin]

Originally Posted by Harpor

I had trouble starting my 81 sc and tried substituting my spare cdi & coil.Still no start,finally started checking the green wire coming out of the distributor.when I moved the wire the car started right away.Might be a good idea to check the green wire coming out of the distributor going to the cdi.Just my 2cents worth.Harryk

Yep worth checking. It caught last night but didn't run well. Signs are pointing to partial/intermittent failure.

[tirwin]

Just an update...

I installed an MSD Streetfire and MSD Blaster II high vibration coil yesterday. Looks like that did the trick. I took the advice in another thread and built a male harness connector so it was truly plug and play to the existing harness.

I also ordered a new 4-fuse ATO panel from Fred Cook and I'll install that soon.

I have not widened the gap on the plugs. Got an engine drop in my future so I'll wait until then when it's easier. Already had Clewett plug wires in the car.

One time-saving tip if you have an A/C car: the MSD coil is a smidge taller than the original Bosch (or maybe I just had it pushed up more) so when I went to shut the decklid the first time it hit the A/C condenser and stopped the lid from closing.

[LEAKYSEALS951]

Originally Posted by tirwin

Just an update...

I have not widened the gap on the plugs. Got an engine drop in my future so I'll wait until then when it's easier. Already had Clewett plug wires in the car.

Glad you got it running..Hey if you gap the plugs, could you please update as to how much you could get away with using the streetfire, and if it makes noticeable difference? You always hear about people gapping the MSD 6al, but I havent seen anthing on the streetfire yet. Thanks,
Ron

[snbush67]

Don't gap the plugs larger unless you need to, if they are burning clean you are where you want to be. I believe that larger plug gaps put lot of stress on ignition components and cause to premature wear. It is likely you will not increase gas mileage or performance.

[tirwin]

If I remember correctly, the plugs are NGK BP7ES. For some reason I have the number .032 in my head but I just looked and it says those plugs are gapped at .028 out of the box. I remember checking them and I did not have to change them. I'll verify soon. I agree there is probably a sweet spot in there between standard gap and the .050 normally recommended for the MSDs. It's a matter of how much work you're willing to put in. I don't have a factory tool kit so I don't have the awesome plug tool everyone talks about. I used some funky socket configuration I made up and a liberal dose of cuss words when I did the plugs. I'd be a lot more tempted to experiment if it was easier to do in the car.

I want the opposite of the human hoist thing people were posting about. I want something where I can lean/lay forward like Superman! I have a bad back and hunching over is worse that getting up and down.

It has been a journey with this car. The day I drove it home I had to use a screwdriver stuck in the ignition switch to start it. When it cranked it was sputter, backfire and you could hear the pop-off valve. I had to give it a little gas for the first few minutes until it got warmed up. Once it was warmed up it really hunted (surged?). Now it's running like a Porsche should. There is a little surging on a cold start when the weather is really cold. Next up is to check the cold start injector, AAV and AAR.

I just want to get done with all this before the spring so I can do some long weekend drives.