how to de-pressurise fuel system ?

[Fatty]

I'm swapping my fuel injectors in the na6. Last time i did this i remember there was a trick to depressurise the fuel rail so that when you disconnect the injectors, fuel doesn't piss out everywhere.

i think you unplug the CAS at the back of the head, and then crank the car over (apparently what happens is that the injectors open, but there is no spark and the fuel pump doesn't work).

Have i got this right?? do i actually crank the car over or do i just put the ignition into "on" ..

memory is very fuzzy about all this stuff ..........

[wun911]

You can un plug a yello cable under the stearing wheel, turn the car on all the fuel in the line will be burnt up, car will stall. (yello plug goes to the fuel pump)

its in miata net how to change the fuel filter...

[NMX516]

You can remove the fuel pump relay while the engine is running... The engine will suck all the avail fuel out of the lines/rail until it can suck no more!

[Guran]

According to my workshop manual, the method described by wun911 is spot on. The fuel circuit opening relay is yellow in most cars, but you might find it's a different colour (apparently that applied to some markets). If you can't find it, just unplug one at a time, let the car run for a minute -- if it doesn't stall, then you've got the wrong plug. Once you've got the right plug and the car has stalled due to fuel starvation, the fuel system is now depressurised and you need to turn off the ignition, plug the relay back into he connector and reinstall the cover on the steering column.

[Fatty]

thanks heaps guys .

[Juffa]

What they said. Also don't forget to remove the fuel cap as this will release pressure in the tank. If you can't find the Circuit Open Relay (COR) another option maybe to unplug the air flow meter as it this what tells the COR that air is flowing and to keep the circuit open to the fuel pump.

J