robt964

Every thing is back in, have oil pressure and checked the fuel system by jumping the relay - all good. What's not good is that I'm not getting a peep out of the DME. Checked the relay, checked pin 37 of the big DME plug for power, all good. Suspicions were raised when cranking the fuel pump is not powering up. This is not a fuse or DME relay issue. I have the T-OBD but it won't connect either.
Suggestions?

HiWind

glad its back in Rob - any minute now ... I was exactly here a week ago
and I could see my lights/plugs weren't sparking as I have a piggy backed system and it has lights...
I can tell you all the clever stuff I did then and for the next 12 hours ...
...
...
...
but what worked was ...
check that the 3 plugs on the back left - especially the crank pos sensor one - are connected!
I hope that works - then you're as dumb as me

ras62

Sounds like the crank position sensor is not reading if the second coil in the DME is not operating. Has it been removed as the distance must be correct.

robt964

Yes, the crank sensor has been removed and refitted to the correct 1mm gap. Is it possible for the stock immobiliser to cause this? How can I rule that out?
As the T-OBD won't connect (first time i've used it) i'm concerned it's something more sinister.

Andy Roe

Are you sure that you have the switch on the T-OBD set to DME and the ignition on? This was a mistake I made when I couldn't get it to connect.

robt964

Yep, followed Tore's instructions to the letter. Going to try the OBD on a working 964 tomorrow to check that it does all work properly and setup right.

Zingari

I've never managed to get my T-OBD to work not in my 993 nor now my 964. The LED comes on in the device but nada in terms of connections..................I just gave up wit it

robt964

Oh... that's rather disappointing. I hope that doesn't turn out to be the case here as I'm kind of reliant on getting this connected to save me many hours chasing the issue.

robt964

Prior to starting, should the fuel pump run for a few seconds once the ignition is switched on?

crg53

The fuel pump should run until the system is pressurized.

gristle101

mine audibly hums for 3-5 seconds (Babying my car, I let it run until it cuts out before ignition)

robt964

Hmm mine doesn't which leads me to think that something more fundamental is amiss.

robt964

Just to rule out big ticket items, would my C2 ECU work in a C4 car?

ras62

Rob, the fuel pump only runs once the engine crank position sensor tells the DME it is moving. At this point the second coil inside the DME relay closes and starts the fuel pump.
If you take the plastic top off the DME relay you should be able to watch one relay operate when the ignition is switched on then when cranking the second relay should operate starting the fuel pump. If it does not, its because the DME is not seeing a crank position signal. Or the DME relay is duff...

jevvy964

Id either jump the relay or hot wire the fuel pump to see if it will start to narrow down the potential problems. Have you only got a c4 ecu? Got a spare c2 one here if you need to borrow it.

Good luck dude