I called JET about this awhile back, they said exactly what you detail
below about modifying the incoming fuel and timing curves (from 1500 RPM
to WOT) to the PCM, and this should not promote the MIL...they suggested
going back to the 195 T-Stat as the stage II only recommends a 185 T-Stat,
not that it is required....I'm toying with doing this as I felt a nice
little improvement with the chip and would like to keep it -vs- no chip
and running a 185 T-Stat.
BTW, JET says they are working on a new chip that will remove the top
speed limiter, they have had many requests for this...no ETA
On Tue, 11 Dec 2001, Will Coughlin wrote:
> I think thermostats in general are not too reliable or consistent, not just
> the Robert Shaw's. As for the computer, have you considered that the Jet
> chip "modifies" the input signals from the sensors to adjust the fuel and
> timing curves(that's how they work)? Maybe it is "modifying" the coolant
> temp sensor input lower to up the fuel curve, and your running cooler than
> stock kind of doubles the effect, therefore causing the PCM to think it is
> too cold and throwing the code?
>
> Will Coughlin willcoughlin@hotmail.com
> '00 Reg. cab 2wd, 4.7L/NV3500HD/9.25" 3.92 sure-grip
>
>
>
> ----Original Message Follows----
> From: Paul Macey <pmacey@ans.net>
> Subject: Re: DML: More 4.7L cooling issues
> Date: Tue, 11 Dec 2001 11:22:59 -0500 (EST)
>
> Ok, how about problems with the RS 180 T-Stats? Who has had to replace
> them, and once again, by looking at a T-Stat, can you physically till if
> it is stuck open?
>
> I'm fighting a 1281 MIL: Engine Coolant Too Cold, though the truck seems
> to warm up and run normal....Jet Chip II issue or the damn computer?
>
> Thanks.
>
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