Fordnatics List Archive

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Mail From: (email redacted) (George Chang)

David says....
>I've had a similar problem (with a backpressure EGR), and I was
>wondering if you could explain in a little more detail how to
>determine if the EGR is working once you hook a pump up to it....
>
..................................................................
Hi David,

I'm a shade tree mechanic, so most of what I do is by guess
and by gosh. To test the EGR, I just hook up a vacuum pump and see if
sucking on the hose makes the engine run real bad. With a backpressure
EGR, one should partially obstruct the exhaust pipe(s) and have the
engine going a bit faster than idle when doing this. The FSM says to
sit a heavy socket in the tailpipe to partially obstruct the flow. I
have done this. I have also simply stuffed a big wadded up rag into
one of the dual exhausts of my Crown Vic copcar.
In either case, pumping on the vacuum pump made no difference
with a dead EGR, but a big difference with a good one.
Of course you should also hook up a vacuum gauge to the EGR
vacuum line to be sure that there's vacuum in the line when you gun
the engine.

Good luck!
George

PS: For those who are going in for smog tests for the first time, the
smog mechanics out here in California do the "vacuum pump on the EGR"
test as part of the biannual smog test.