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Hello everyone. I found this great forum while looking for help. I've been tasked with repairing my in-laws 84 Veloce. Here is what they told me:
They were driving it with no issues and stopped to fill up with gas. Shortly after it went dead and could not be restarted. It was towed home, and sat there for 7 months untill I began diagnosing it.
I have gotten it to start, but it will immeaditely go dead. It has good fuel pressure while starting, but as soon as it starts the fuel pump stops pumping. Any ideas?
 

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I've been tasked with repairing my in-laws 84 Veloce.
Does your success/failure affect any inheritance? If we prove helpful do we get a percentage? :D

I have gotten it to start, but it will immeaditely go dead. It has good fuel pressure while starting, but as soon as it starts the fuel pump stops pumping. Any ideas?
The fuel pumps get power in one of two ways. During starting (key turned all the way to 'start') they are powered directly via the ignition switch. Once started (key released to the 'run' position) the drive relay receives a "tachymetric" signal from a coil sense wire and (should) then supply power to the fuel pumps (there are two - the main pump underneath the car and an in-tank pump in the tank). If the tachymetric signal is lacking the fuel pumps do not get power. (this also functions as a safety device as the pumps will not remain on in the event of an accident/engine stall)

The tachymetric signal can go missing for a couple of reasons - no ignition or sense wire fault. Since it will start briefly we can assume the ignition system is functioning. Check the wires at the coil (I suggest you remove & clean them - don't assume good connections). If the connections are good then the next possibilty is a faulty drive relay. Check all connections first as the drive relay is not inexpensive and it is not likely to be found on the shelf at your local auto parts store.

The drive relay is located under the parcel shelf behind the seats - next to the FI computer. More info in the L-jetronic Spider diagnosis page.
 
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