No Start, Spark or Sound

[Pautpadoo]

Greetings all! I'm a new member to this forum, and a new Porsche owner, 1984 911

I have a no start condition. I'm sure this is a well addressed topic here in this forum. I admit to not having done a thorough search, however I have a basic clue which someone may know the meaning of and cause for right away and help get me to "first base".

I've noticed when I turn the ignition key to on, all the dashboard lights go on... but before energixing the start position, I used to hear an "electronic humming" sound, which I no longer hear. Turning the key further to the start position, the motor turns over but does not start or generate a spark.

I am using Bently manual and it appears to point me to posssibility it could be the DME Relay. but I don't find how to test this.

Thanks in advance for sage advice.

[Joe Bob]

The CDI in the engine bay hums. The DME has a relay (under the driver seat) that clicks. If you know how to check for spark or fuel, do so.

Lot's of threads on 3.2 no start problems. DME relays are cheap and easy to replace. CDI boxes not so much.

Fuel can be tested by shooting ether into the intake on start....

[DRACO A5OG]

Welcome Aboard 3.2!

Okay first thing to do is to get your Digital Volt Meter out and measure the battery voltage prior to start.

After that, pull one of the spark plug boots and put an old spark on it and ground to the engine ( per Bentley) and have a helper crank while you watch for spark.

As Joe Bob stated, reach under the seat, place hand on the DME relay and crank the car, if you do not hear/feel a "click" DME relay is shot. if working, you should smell unburnt fuel at the exhaust tip. Another thing you can do is to spray starter fluid into the air filter to see if it will start.

BTW, on our 3.2s, unless you have placed a "Pump Prime" type DME relay there is no hum to be heard unless your seat belt warning buzzer is still in place.

Please post voltage readings.

JB, will swing by today

[Joe Bob]

I'll be around Jim.....DME relays consider the solid state one available on eBay. Buy NOTHINGmade by URO.

[Pautpadoo]

Well guys...that electronic humming sound I mentioned had dissapeared was actually the seat belt warning...duh...boy did I feel smart...so moving right along...

I do have voltage (12.8) at the coil +15, open between +15 and 1 and resistance between +15 and 4. Not sure how much resistance I should see to know if the coil is good?
Still no spark.

I didn't hear or feel a sound from the DME relay and so replaced it, however even with the new one I still don't feel or hear the energixing DME relay when the ignition key is switched on. Still no spark.

I have voltage at the terminal 30 on the DME connector with the key off. With the key on there is no volage at terminal 86 (and there should be according to Bently). Diagnosis points to a short in the "black" wire from the connector which leads back to +15 of the coil. This is where I went to bed... I previously found 12.8 volts at +15. Still no spark.

I'll have another go at it later and I have'nt even gone throught the trouble shoot process for the fuel pump described by Bently...I'm still stumped on the no spark condition.

Could it be the coil?

Thanks for any comments