Pelican Parts Forums - Possible DME Unit problem but not sure; DME relay is OK

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Possible DME Unit problem but not sure; DME relay is OK

Hi all, I have a '90 Carrera 2 Coupe. After verifying that both switches inside the DME relay are functional as well as trying another, brand new DME relay, the fuel pump won't run. However, bypassing the DME relay by jumping pins 3, 5, 7 does work. The fuel pump can be heard and the engine starts and runs.

It appears that pin 8 of the DME relay goes to pin 3 of the DME Unit's 55-pin connector. Does the DME Unit set this pin to ground to activate the fuel pump relay? I'm not sure if this is the source of the problem or something else. A voltmeter between pins 5 and 8 (for the fuel pump relay) of the DME Relay socket shows zero volts while cranking whereas there's 12 volts momentarily between pins 1 and 6 (for the other relay) while cranking.

Any help would be greatly appreciated!

Bryan

Try your flywheel sensor. It should read about 3V AC when cranking the starter (DME plug 47 and 48). Without this signal the DME cuts power to the fuel pump - maybe the momentary 12V you are seeing.

Fantastic. Nice to have angels on my side. Will check and keep you posted. Thank you!

Bryan