ignition help

[tops911]

I am in need of some help on an issue. Up front I've done many searches but I'm just looking for any other info I could get.
My car is a new to me '82 930. It ran fine when I dropped it off at the port to have it shipped to Germany. They called when it arived and said the battery was dead, no biggie I kind of expected that. When i go to pick up the car it wont start.
it would catch a little. It did get running for a few moments, running very ruff and back firing, it did a big back fire and then it died. it never seemed like it wanted "hit". I took the battery home to recharge and then ended up buying a new battery. After a trouble shooting session it is clear it is not getting any spark. I can smell fuel if the car is cranked on for long, so the fuel pumps seem to be working fine.
I checked to see if power is getting to the coil and it does not seem to be getting a signal, there is continuity between the ends of the wires to the coil and the "green" coax cable (I unplugged the CDI box and tested from the connector there to the other end of the wire).
The CDI box is whinning. I've removed the box and I'm looking on how to verify it is in good working order
Is there a way to test the distributor to see if a signal is going from the dizzy to the CDI box? anyone know what that value should be?
What does the brain trust reccomend for further checks. I have to drive about 40 miles from where I live to where the car is and they are only open on week days, so my ability to run out and check things is rather limited.
Thanks for the help.

[snbush67]

Have you removed the distributor cap and checked the rotor? , sometimes they get too much juice and melt.

The CDI send a signal to the distributor, check the pigtail (Green wire) and ensure it is serviceable.

Or, go to the nearest service station and look for Dieter, he will be wearing blue overalls, tell him you are returning one of the flock to the motherland and need some help.

[WPOZZZ]

I had a very similar problem and found one of the wires in my harness burned.

[tops911]

I did a visual check of the rotor, it is a rev limiting rotor and the spring seemed fine. I do have another rotor to take with me. However it does not look like power is getting to the coil from the CDI box.
I guess next I'll crank the engine and look for current at the "green" coax wire to see if there is a signal comming from the dizzy to the CDI box.
I also checked the relay connectors and cleaned them, but short of that I dont know how else to check the relays.
Thanks

[HFR_Racer]

You should obtain a copy of the 930 service manual that covers ignition troubleshooting.

Search 911 service manuals...

You should confirm that you don't have spark first. Remove a spark plug and lay it on the engine block ( ensure that it is grounded). Crank the engine. You should see spark. If not then I'd check to see if you have 600 ohms resistance across the shielding and the core of the GREEN wire. If not then the pulse coil within the dizzy is bad or your GREEN wire is bad. Next, check you ignition coil. You need to check the

[HFR_Racer]

Primary and secondary sides of the ignition coil. If your CDI whines then your getting power from you keyed switch to the box. I find it unlikely that your car was driven into the boat and your CDI failed during transport. If you've been playing around then you may have shorted out your ignition coil. Maybe a bad ground due to travel over salt water?? Was your car properly shipped? Check your grounds...

[Ken911]

And wiggle the green wire while checking it mine was shorting out after it had been moved but when i originally tested it looked ok.

[Ronnie's.930]

Originally Posted by HFR_Racer

You should obtain a copy of the 930 service manual that covers ignition troubleshooting.

The manual is available here: Manuals

You should confirm that you don't have spark first. Remove a spark plug and lay it on the engine block ( ensure that it is grounded). Crank the engine. You should see spark. If not then I'd check to see if you have 600 ohms resistance across the shielding and the core of the GREEN wire. If not then the pulse coil within the dizzy is bad or your GREEN wire is bad. Next, check you ignition coil. You need to check the

I'm not trying to be your daddy or anything, but I'm fairly certain that posting links to Porsche manuals is forbidden by this website (based on reading past threads regarding this subject) . . . people typicaly send the links to one another via email.

[tops911]

Thanks for the help. There is no spark at the plug, I've taken out a plug grounded it and no spark and just to be sure my eyes were not failing me I held the plug while cranking.... no shock. I just have no clue what the guys on the boat (in addition to the truck transport guys)did to the car. I was shipped thru the Army (civilian company). They were the ones who jump started the car and told me they drove it off the transporter, 2 days later when I arrive to pick it up it does not run. I was wondering if they hooked up the battery wrong could it have killed something in the ignition system (i just dont know if anyone has experanced that). I need to do a better check of the green coax, coil and the relays. It just sucks that I have limited hours to deal with the car and that it's 45 miles away. I wont sign for it until it's running because if the issue was from the shipper they should be liable for the damages.

[HFR_Racer]

I would assume that's it's going to be hard to prove that the shipper damaged your car since you've been tinkering with it. Get it to your home where you can diagnose the issue.

You should never grab a spark plug to check for spark.

Check your ignition coil next. You can search threads on this site on how to check the primary and secondary sides.

If you dizzy pulse is good and the coil is good then you must have a bad CDI. See if you can borrow a CDI from another Porsche owner to put in your car as a check.
CDI's do fail so it might be wise to have a spare. I had a CDI fail on me just a couple of weeks ago. Glad I have a spare.

[heliolps2]

Your CDI box should be grounded to the body of the car when you do the spark plug test.
or any other test, You should check the harness plug , thats the signal green wire, pin # 6 and 3 should be 600 ohms give or take 100. I agree check all your grounds engine, trans to body and battery , You also might have to adjust you AFR's or CO .

[Porsche2217]

double check the fuel pumps while somebody else open the ig. switch, best way to make sure they are working is under the car but you have to lift the car, you will hear and feel the pumps, if they are not working chances are the two fuel relays aren't working so just interchanged them with the others that you have in the same fuse port; I just have starting issues with my car but finally I was able to get it started my problem was a bad WG diaphragm causing a vacuum leak, to check the spark I just unplug one of the cables and put in a screwdriver while holding it close to my AC compressor you can see the spark jumping to the AC metal case, warning you have to hold the screwdriver plastic handle and don't touch any metallic part on the car, also you can check the distributor rotor to see if it has a proper spinning while cranking the car. One easy way I checked the CDI box is to put it in another 911 that has a 6 pins connector and started, mine started the other car so I knew it wasn't the problem, hope this help.

[tops911]

OK, time for an update....
First it still does not run. Well it did for a few seconds, like 15 seconds. I started like it used to just bumped the key and it started, it did idle a little slow. It then died.
I tried to get the CDI box tested but nether the Porsche dealer nor a Bosch place could test the CDI box. They wanted the whole car...
I tested for power at the wire going to the box (15 I think it was) it has power.
I checked for a pulse from the "green" coax wire while cranking the engine, it seemed to be pulsing, maybe not as fast or as ofter as I thought it would be, but I don't know how ofter the pulse should be.
I tested the coil, tested good, both primary and secondary.
I tested the fuel pump relays and the red relay back in the engine compartment, they all were good.
I tested the other relay with the 4 prongs and the little tube, tested good.
I tested and then replaced the rotor (it was a rev limiting one, put in a non rev limiting one)
I unhooked the green fitting at the fuel distributor, turned on the key and both fuel pumps were running, both sounded the same.
After the car ran for those 15 seconds, it is clear it's not getting spark (again), not out of the coil nor to the plugs.
Any thoughts??? I probably checked more things but after a day of trouble shooting and paying about $450 to get the car towed 50 km, I may be a little distracted and forgot some of the other stuff I checked
Thanks Frank

[wjfk32]

Try another coil. Just becuz the meter says its good it may not. (happened to me) slight leak.
If you have time-chk inside Distrib. coil- .Mine said it was good also(original)..but changed it anyway.

One of my plugs after careful inspection had a hairline crack in it.

Double chk all wires and connections: Get a chair..


Walt

[2porscheguy]

I'm not a 930 owner, nor am I an ignition expert by any means, but any chance that you may have cracked the airbox? My '80 911SC did the very same thing some 7 years ago....it had been parked for awhile and when I started her up, very rough idle for some 20 - 30 seconds, and then a big backfire and then it died....even though I had a pop-off valve, the airbox had been damaged from the backfire.....I had to replace it!

[tops911]

Turbo's have a totally different setup than the SC, I used own a '78. I did check for blown hoses on the intake track. Nothing was loose nor cracked. It did start and idle nice today, just a little slow, and it acted like it needed to run for a few minutes to "clear up". But then died.
I can smell fuel after cranking, if I crank it for a longer time.
Thanks

[heliolps2]

Coil coil

[lucittm]

You have an intermittent ignition problem, probably the most frustrating thing to troubleshoot. It could be anything from a pinched tachometer wire under the chassis (they move some cars with forklifts!) to a corroded connection made worse by the move. I would disconnect one wire at a time (green one to the coil, power to the coil, tach, etc.) and replace it with a known good jumper and when the problem goes away you have found the culprit.

Good Luck,
Mark

[tops911]

well, it's not the coil, (190 Euros later)...... so I'm thinking CDI box, green coax cable, or the distributor. There is clearly no spark. I would be nice if I could swap parts with known good ones; however, I don't know anyone in the area with an "old" Porsche.
I have a new green coax cable on the way. I did have an '81 BMW that the distributor went bad and would not send a signal, this sorta reminds me of that.
This is starting to suck.......

[tops911]

unhooked tach, still no start