Smog pump and Gas Mileage and E.G.R. valve

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Rybo1199@gmail.com - 20 Feb 2006 22:03 GMT

I have an 87 dodge dakota 3.9L V6.
I just got the E.G.R. valve changed and need to get the smog pump
replaced because of a horrible noise that it's making. If I take out
the smog pump will that have an effect on the gas mileage? I ran it
for a while without the smog pump and the gas mileage went to hell.
That was also with a bad EGR. With a new EGR could I run it without
the smog pump and get the same gas mileage I had before? Thanks for
your help.

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Steve - 20 Feb 2006 23:52 GMT

> I have an 87 dodge dakota 3.9L V6.
> I just got the E.G.R. valve changed and need to get the smog pump
[quoted text clipped - 4 lines]
> the smog pump and get the same gas mileage I had before? Thanks for
> your help.

Not for long. The smog pump provides enough air in the exhaust stream
for the catalyst to do its job. Without air, the catalyst can't
completely burn the HC and CO, so it runs too cold, carbons itself up
and eventually plugs solid.

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Rybo1199@gmail.com - 21 Feb 2006 17:24 GMT

Thanks Steve. Do you mean the E.G.R. valve plugs solid without the
smog pump? Again, thanks for your help.

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Steve - 21 Feb 2006 18:55 GMT

> Thanks Steve. Do you mean the E.G.R. valve plugs solid without the
> smog pump? Again, thanks for your help.

No, the catalytic converter itself is likely to fill up with carbon and
cause an exhaust restriction.

EGR valves plug with carbon no matter what you do :-/

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Rybo1199@gmail.com - 21 Feb 2006 19:23 GMT

Steve,
You have been a tremendous help thank you. Would it be safe
to leave the smog pump off for another 2 weeks of light driving?

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Steve - 22 Feb 2006 18:21 GMT

> Steve,
> You have been a tremendous help thank you. Would it be safe
> to leave the smog pump off for another 2 weeks of light driving?

That's hard to say. It would *probably* be OK. Who knows what condition
the catcon is already in, though?

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