My '85 Euro 928 had been sitting for several weeks, when I tried to start it, it turned over but the battery was too weak and it wouldn't start. I pulled the battery and put it on a charger for several hours. After I re-installed the battery, the car fired right up. I let it idle, but after just a few minutes it died. When it died, it didn't surge or sputter, it just stopped, almost like the ignition was turned off. I tried to re-start and it turned over fine, but wouldn't fire. Any suggestions on where I should start?
Thanks,
Dave

 

Spray some ether into the intake see if it fires report what you find.

post a picture of the engine bay please.
This will make our guesses more accurate.

 

Does the tach needle bounce when you're cranking it

 

Thanks for the replies. I bought some starting fluid, but before I tried the starting fluid, I tried one more time, and the car fired right up. The other day, when it wouldn't start, I pulled one of the plug wires, attached a plug and when the engine was cranking, I couldn't see a spark. I'm not sure what happened, but I let it run for about 10 minutes and no issues today.

@Mrmerlin I've attached a picture of the engine bay.

@Petza914 I didn't notice the tack needle bouncing when cranking.

 

OK a few more things to look at.
has the CPS been replaced with a Bosch part?

When was the last belt change done in the distributor?
NOTE Since it runs this isnt your problem,
but you should know the answer.

Look above the CE panel look for signs of water leaking,
you may need to renew the blower box seal,

NOTE disconnect the battery during any cleaning services.

NOTE if you have not done so , spray all the connections on the back of the CE panel with D100.
do the fuses and the relays as well.
Do the grounds above the CE panel,
Clean the ground connections for the fuel injection in the engine bay,
These are small bundles of brown wires connected to the engine.
either on the 1-4 cam tower there are 2,
or at the back of the V .
Do a battery terminal cleaning and recharge the battery with a 6 amp charger.

Do a running relay test.
put your finger on the X bus relay,
turn the key to run you should feel it click.
Also do the same test for the ,
the LH,
the EZK
The fuel pump relay, you may have to crank the engine to get a click
Replace the fuel pump fuse.

NOTE the new air cleaner is upside down,
if its brand new you can safely flip it over,
the hump points to the sky.
You also need a hot post cover
(a hot post threaded stud and threaded stud cap, these from an S4)

 

Thanks for the quick reply and the detailed response, I appreciate it. See below for my answers.
Dave

 

it would be prudent to put in a new crank position sensor the one you have most probably has a crumbled connector