fuel system depressurization w/o running engine

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

bryan - 22 Oct 2006 16:37 GMT

if my car won't start, doesn't that make it impossible to depressurize
the fuel system? besides the flammability of gasoline, what's so
important about depressurizing it anyways?

-bryan

Reply to this Message

Alec - 23 Oct 2006 20:33 GMT

Fuel injection systems hold fuel at high pressure in the injector fuel
lines. If you work on the engine with fuel at high pressure in the lines and
disturb a joint, fuel may spray out

This is why cars having fuel injection systems have 'impact' detectors to
turn off the fuel pump in the event of a crash.

There can be fuel in the lines when your car will not start. For example if
the computer which actuates the injectors is faulty

Alec

> if my car won't start, doesn't that make it impossible to depressurize
> the fuel system? besides the flammability of gasoline, what's so
> important about depressurizing it anyways?
>
> -bryan

Reply to this Message

David Matkin - 19 Dec 2006 23:46 GMT

Alec is right The fuel will hold pressure for a while after the engine
is shut off but cranking the engine with the fuel pump fuse removed will
allow the residual pressure to be removed as the fuel is allowed into
the cylinders if the problem lies with the ignition system. It does not
need to spark to do this. Other wise try to remove a hose into a
container with the engine COLD.

I once removed a fuel pipe on a stopped bmw engine without relieving the
pressure and fuel squirted hosepipe style all over my clothes and face.
I was stood 12 inches from a hot exhaust manifold ( headers ). Fuel
ignition would have probably killed me. I only realised my stupidity
later on when I sat back and thought about it.

PLEASE DON'T TAKE CHANCES WITH GASOLINE.

With concern for your safety

Dave.

> Fuel injection systems hold fuel at high pressure in the injector fuel
> lines. If you work on the engine with fuel at high pressure in the lines and
[quoted text clipped - 13 lines]
>>
>> -bryan

Reply to this Message