930 wont start

[trapper9]

I am looking for a troubleshooting checklist for my 87 930 turbo. I have verified that I have both fuel pumps operational but it will not start. I checked for 12 volts at the coil and it is not present with the key on. I have not checked it when starting the engine. Any ideas? I am going to check the aftermarket alarm but thats next

[Jeff Alton]

Look at the alarm....

[john walker's workshop]

You won't get 12v at the coil. Check at the CD unit plug. The red wire, key on. Back track to the delayed ignition relay if no power at the CD. Then check the condition of the green coaxial wire where it enters the distributor. Pull the coil high tension wire from the distributor cap and do a visual spark check.

[svcetiquette]

Sticky in the 930 forum that is an invaluable troubleshooting resource.

https://forums.pelicanparts.com/911-930-turbo-super-charging-forum/547032-sticky-common-answers-why-my-car-doesnt-start-new-post.html

[T77911S]

after market car alarms are junk. they cause more problems for the owner than thieves.
"most" car alarms break the circuit to the starter. the smarter guys break the power to the ignition because the circuit for cranking is already stressed and adding another relay just causes more problems.

an easier check is to just check for spark.
you can use a timing light or pull a plug, connect it to the wire and ground the plug, have someone crank it and check for spark.

[trapper9]

Thanks Guys ill keep digging

[trapper9]

Can the DME relay be the culprit?

[Rich76_911s]

Originally Posted by trapper9

Can the DME relay be the culprit?

No, the 930 doesn't have a DME relay like the carrera. The overboost (yellow relay) can be the culperit though, as could a lose wire to the overboost sendor.

What year 930? And what is happening? No start at all or does it sputter and not start?

[john walker's workshop]

You can ground the white wire to the overboost sensor temporarily for test purposes. He did say the fuel pumps were working though.

[Ruf1969]

My 930 would not start because the fuel pressure regulator was bad

[trapper9]

Mine is an 87. I do not have 12 volts at my Bosch CDI box terminal 15. Trying to chase it down to see why. Everything works with the key on and I cannot find a bad fuse anywhere. Dont want to have to load it up and take to the shop.

[john walker's workshop]

Post 3. 12v to the delay relay that doesn't continue to the CDunit? Common problem.

[trapper9]

where is the relay located?

[john walker's workshop]

Small metal relay with 4 terminals and a short vent tube located on the engine electrical panel. Take out the securing screw, pull it out and remove the plug. Make a jumper with 2 spade terminals and bridge the 2 terminals in the plug that were closest to the engine and see if you get 12V to the CD then.

[Sailkane]

Wouldn’t it just be easier to pull the coil wire out of the distributor and crank the engine and see if you have spark to ground?

[trapper9]

I used a timing light no spark Ill try Johns jumper idea next

[trapper9]

fixed it today it was a bad ignition cut off relay

[john walker's workshop]

Thank you...

[trapper9]

Thanks John for the help figuring it out. It took a while to find a replacement relay as the newer style is too big and interferes with another relay. Drove the car yesterday and I almost forgot how much fun it is. Ive had this car since new and will probably never get rid of it. My wife would kill me if I did