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914World.com _ 914World Garage _ Failure Mode

Posted by: J P Stein Jun 7 2003, 07:11 PM

Here's the deal.
It's 85 deg ambient. Oil temp 100c. Last of 10 AX runs. Wide guts in 2nd and.....backfire...black smoke, flames out the exhaust....cool.

No spark.
Sumthin in the ignition went poof. NO warning
Whatcha think?
MSD (it was hot to the touch)
Pertronix (got a spare)
Coil?
Cap & rotor are OK.
Magnetic Pertronix thingy on the dizzy is ok.

I let the thing cool down for 3 hours, but no joy......permanent daid.

Posted by: mskala Jun 7 2003, 07:16 PM

It's always the Permatune. 1/2

Posted by: J P Stein Jun 7 2003, 07:20 PM

That would be the cheepest of bad things...I have a spare.

How does one trouble shoot them. I gots voltmeters & stuff.

Posted by: Porsche Rescue Jun 7 2003, 09:46 PM

JP, wish I knew something about ignition. Only prayer I know is "Now I lay me down to sleep". I'll try that.

Posted by: si2t3m Jun 8 2003, 05:59 AM

Hi JP.

Happened to me during a DE...

Running gud, a second later nothing. Vibrations had broke a connector at the coil (took a while to find).

Where are you taking the +12 volts for the MSD? Is it 'controled' by a relay? Could be that the relay crapped out? Hapened to me also.

Marc-André

Posted by: J P Stein Jun 8 2003, 06:58 AM

Screwing around with electricals makes my haid hurt.
All that magic smoke running around in them wires is all very mysterious.

Good thoughts about the 12v feed, M-A. I can't remember anything about how I wired it....except it is the red wire

The Pertronix is THE likely culprit, tho I have heard that the MSD is heat sensetive.....and it was hot.
100C is the hottest oil temp I have seen on the car so we were in uncharted territory.

Other than this small problem, the car is comming around. It was pushing on the tight stuff....bad enuff to make me hit a cone. I'll soften the sway bar a bit....unless someone has some 200 lb rear springs F/S.
My co-driver Chuck was 14 overall at 52.7 & I was 23rd a half second back. The Chuckster had a good run going when the car puked. He rolled the last 150 yards with no power and still went 52.9. 106 drivers. SCCA is pretty competetive around here.

That Z car whupped us'n for the class....damn, he's quick and he has a Porsche emblem with a slash thru it on the side of his car. To add insult to injury, he gave me a ride home.

Posted by: DNHunt Jun 8 2003, 07:19 AM

JP

I doubt I can help you much but here is my best shot.

I had a Pertronix fail, but the car wasn't running. I had the ignition in the on mode without the engine running. I've heard they don't like that. After leaving it on, the ignition was dead, FI fuel pump ran. I'm not sure if I missed something but I thought you said you had a spare. I suspect you already did this and I just missed it but have you tried the new Pertronix? After my experience it would be my first thing to trouble shoot. Here's Pertronix http://www.pertronix.com/ignition/tech/tech.htm

I think the MSD unit is pretty tough. Just in case here is a link to their troubleshooting page http://www.msdignition.com/1troub1.htm

Dave

Posted by: rhodyguy Jun 8 2003, 07:23 AM

if it started raining our cars would prob start jp.

kevin

Posted by: Lawrence914-6 Jun 8 2003, 08:25 AM

I'm sure it's no surprise what *I* think the problem is...

1. Permatune. It puts the "P" in POS.
2. Pertronix. No personal experience, but they have a reputation of going "poof" without warning. Since you have a spare, that might be easier to check.

Jon Lowe has a couple of my Bosch CD boxes. When(ever) I get them back, you're welcome to try one if you think it might help.

take care,
Lawrence

Posted by: rhodyguy Jun 8 2003, 09:01 AM

rusty, was your p-tune bad out of the box?

kevin

Posted by: Lawrence914-6 Jun 8 2003, 09:59 AM

Yep. Right out of the box.

Posted by: mskala Jun 8 2003, 10:20 AM

Old news, but here's the failure modes on my perm-untunes. First
one came with the car care of PO, but only a couple of years old.
It got heat sensitive, but it didn't kill the car. If car (or unit) was
hot, when you shut it off you wouldn't be able to start it until it
cooled off sufficiently. Of course during the time it's doing it you
check a bunch of other things and then it starts working again,
so it looks like connectors or other problems until you figure it out.

So I got a new one, seeing as I needed a reasonably quick
solution and wasn't going to rebuild the bosch one immediately.
The next summer (not many engine hours later) it does the same
damn thing. I was lucky and found a $60 working Bosch unit in
Pano (one of my few scores) and have been using that for a
couple years no problem. I keep an intermittent perm-untune
handy for a spare if the bosch dies. I will be getting the other
bosch rebuild sometime when I have a job.

Posted by: rhodyguy Jun 8 2003, 11:53 AM

i love the no return policy with regard to installed electrical items some firms have. if the sob is bad before you install how are you supposed to know? ah, sister cleo? quite the conundrum. i've relaxed a bit. letting a stupid car run my life...

sign me " the dope in the jetta", old ax joke.

kevin

Posted by: Bleyseng Jun 8 2003, 12:06 PM

I suspect the effin Pretronix as I have gone thru 3 in the last year and I am done with them. Points right now as they don't go poof on the freeway or track. First unit lasted 2 years and then went thru 2 new units.
Geoff

Posted by: J P Stein Jun 8 2003, 01:07 PM

I got the car home this morning (it spent the night in the PIR in-field, top off....whut, me worry?). Got away with one there
Some quick trouble shooting:

12v to the MSD.
An MSD troubleshooting method shows either the coil or the MSD is bad (it by-passes the Pertronix)...the coil is MSD, also. I gotta call MSD tomorrow and talk at em...make sure I'm doing it right. Also find out from them how to check the coil (it's usually resistance across the terminals).....I gots a spare POS for everything in the world...except an effin' coil.

Also discovered a trunk full of oil.....that sux.
Overflowed the catch can. Sumthin' else to worry about. Compression check showed 150/160 cold.....humm. Usta have 175 warm.....I'm agin' it.

Posted by: J P Stein Jun 10 2003, 11:42 AM

Troubleshooting the ignition leads me to the MDS unit. The coil is per spec (resistancewise).

Bypassing the Pertronix while doing the MSD recommended test produces no spark from the unit. Dug out the reciept and it's out of warantee....rats.

Posted by: J P Stein Jun 15 2003, 12:25 AM

The failed item is just above my shoulders.
I sprung for a new MSD and started to do the install.
I had some adult supervision (old Chuck). He's rootin'
around in the engine room and pulls off the secondary coil leads....I think I've found the problem, says he. Both leads had gotten into the fan and......well, you can guess. Snip, snip...crimp, crimp.....varoom.

So now I have this NIB, MSD 6AL for sale....never even opened it
Works on a 4, 6, or 8....$150 plus shipping. I'd just as soon sell it to one of youz guys as pay a restocking fee to Summit.

Posted by: Bruce Allert Jun 15 2003, 11:42 AM

Da Magic Smoke 'Lectric Guy be smil'n upon yer 'ol bones ta dey Mr. JP...
Good job Chuck
bruce
P.s. bet my camra could'a found dem wires!