Date: Wed, 5 Jul 2000 18:35:47 EDT
From: Hemikota@aol.com
Subject: Re: DML: Very poor MPG
First, change out your thermostat back to a 195 then reset your
computer. Its controversial here on the list, but I think in some
climates and
maybe altitudes, the 180 stat lets the truck stay in open loop. Its
like
having a stuck shoke on a carb. Normally, the truck runs rich at start
up but
once it hits 170-175 deg. it leans out and reads off the O2 and other
sensors.
If your stat is opening at 180 or maybe even sooner, then the truck may
be
cooling down enough to trick the computer into thinking its cold and
goes to open loop and runs rich to heat up the engine.
Also tune it up. Cap, rotor and maybe wires if they are worn and
arcing and
check the plugs for proper gap. And try for at least a tank or so, to
keep the foot out of it.
I know, thats the hardest part for me!
Hope this helps.
Boog
Thanks for all the feedback everyone, and at least it sounds like I'm
not alone in my problem. The mileage went down before I did any mods,
including the 180 stat and inch larger tires, so I don't think it's
either of those. I'll try a new cap, rotor, plugs, and possibly wires.
Any recommendations on brand and part #s for the cap and rotor? What
should I gap the 3923 plugs at for a 318, auto, stock ignition, 180 ts?
And how do I go about reseting the computer? I've got the overhead
console so I'll keep a constant eye on the mpg during warm-up and at
temp, before and after I do the tune, see if they vary at all.
Also, on the instrument panel, below the fuel gauge is apparently an
indicator for the "fuel door". It has a triangle shaped arrowhead in
front of the words "fuel door" that points to the left. I've never seen
this light up, doesn't matter what postion the door or cap is in or
whether the truck is running or not. Does this actually do anything?
Should I look for a blown fuse?
Thanks for all the input,
Chris
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