Yes the lambda box and its relay are under passenger front seat. Tim

A battery that measure 12.5 Volts is at 80% state of charge, 12.2 is 50%

See if there is a spark. The CDI might not have liked having a high voltage on it for so long.

The only useful troubleshooting info of the thread!

I was told I would burn up the CDI if I left the key on that long.

You need fuel and spark for the engine to start. Let's hear from the OP whether he tested for spark (ground a spare plug to the engine and crank) and missing fuel (introduce starter fluid into the intake).

FYI, a coil doesn't burn up with the ignition on and the CDI box should not be affected by that either unless it was on its way out to begin with.

Ingo

Marginal CDI capacitors have been known to fail under that condition.

Same happened to me when I left the ignition on in my 82 while working on my radio. Flooded my engine but finally got it fired up with lots of cranking and pedal floored (clear flood mode).

Spark test.
 

I really wish he would look for that hot blue spark...........

Gerry

I'm not the one who figured it was flooded but it was the tech/owner of the stereo shop who does a lot of installs on 911s, said it was a common problem on 911s when ignition is on for extended periods. He was right!

I will check this week. I ran out of time on the weekend.

I hope it really is just flooded. That would be great.

I'm getting a little frustrated with old cars. I was just getting my 911 into good shape. I spend a month last summer diagnosing a lose wire in the fuse box that created an intermittent starting issue. I conquered the power window motor on the passenger side and figured out how to tighten up the flag mirrors without completely taking them apart. The car was running and starting better than ever. And then, no start. :mad: A 30K mile Cayman in mint condition is looking like a good option right now.


-Anthony

Before anymore testing, unplug your fuel pump relay.

My hunch is CDI box.

I tested. There is no spark.

I put the ohm meter on the coil and it checks out.

I was reading about CDI symptoms and during my last drive I was getting an erratic tach around 3k rpms.

Next you need to verify:
1. The CDI has 12 volts.
2 The CDI has a signal from the distributor (possible bad green wire).

The CDI does whine. That means it is getting power, right? How can I test for sure? Test for 12v at the plug?

How can I test the green wire?

Yes, it's getting power. Use an ohmmeter to measure between 7 & 31 (opposite one another) on the connector
and check for 600 ohms. Then measure for about .5 - 1.0 volts A/C while cranking on those pins.
Then check for continuity from the CDI connector to the coil and verify a good ground
on the coil. If all checks are OK, then the CDI unit is bad.

If the CDI is bad, you can send it to Pelican Parts for rebuilding.

How valid are these tests (first post):

http://forums.pelicanparts.com/porsche-911-technical-forum/649722-how-test-6-pin-cdi.html

When I do them I get:

pins 1-3 flickers between .1 and .3 ohms
pins 1-4 2250 ohms
pins 2-5 1.3 ohms
pins 1-5 my Fluke doesn't measure capacitance

Same issue here.

The coil had overheated.

A new one and all works fine.

To really test the box make 3 small extension wires about a couple of inches long: spades on one side and spade sockets on the other side. Then make two longer wires with spade sockets and leave the other ends open. Connect the CDI box to pin1 (GND) and pin5 (power) and pin4(coil) with the short extensions to the harness connector. Then use the two long wires and connect them to pin3 (GND) and pin4 (signal) of the box.

Use a High-Tension cable and connect it to the center of the coil and the other end to a spare plug that is grounded to the engine body. That's your test setup. Get an AA or AAA battery. Turn the ignition on. The box now should whine.

Touch the wire coming from pin3 to the positive terminal of the AAA battery and the wire coming from pin4 (signal) to the negative wire of the AAA battery. Every time you do this the box should release a spark. If you reverse the connection nothing will happen.

Ingo

Do you have a Pertronix? I just read a thing today about leaving the key on and the Pertronix will burn out the coil.

Pertronix says, in their FAQ section...
What will happen if I leave the ignition switch on when the engine is not running?

Leaving the ignition switch on when the engine is not running, can cause permanent damage to the ignition system, and related components. This does not apply to the accessory position of the ignition switch.