thanks bob i dont know much as far as messing with the pcm or map or tps but
i will definately try to learn. thanks for the info and if you figure this
out let me know.
thanks arnold
----- Original Message -----
From: "Bob Tom" <tigers@bserv.com>
To: <dakota-truck@buffnet.net>
Sent: Thursday, March 01, 2001 9:43 AM
Subject: Re: DML: hello everybody (throttle) ques. for 4.7 daks
> At 06:33 AM 3/1/01 -0600, you wrote:
>
> >Arnoldo Silva wrote:
> > > thanks shane considering what you just said how can i fix the problem.
and
> > > get more power at full throttle diff t-stat or what.
>
>
> >Man I wish I knew the answer to that. I really would like to continue
this
> >thread. A redneck method might be to limit the travel of your TPS to
just
> >under
> >what the PCM considers WOT. Thats one of the things I want to try at the
> >dragstrip.
> >
> >Bob (from Canada) - didn't you do some testing at the dragstrip re: this
very
> >phenomenon? Did you come to any conclusions or have any interesting
> >results/tricks/ideas? Thanks in advance, Shane
>
>
> Hi Shane, Arnoldo.
>
> I was thinking of the 'redneck' method but for different reasons. One
> was that scanner readouts done on track runs (strictly WOT) showed that
> I was running extremely rich. Not have wide band O2s setup (very
expensive)
> nor a dyno with that type of diagnosing capability up here, I suspected
that it
> was richer than the approx. 12.5 range at which max. power is produced.
> A phone call to Zimmer in CA kind of confirmed this suspicion but even he
> could not give me an approx. afr from the pulse width voltages that I gave
him.
> He just said that it was pretty rich. As far as I can tell from my web
> searches,
> my afr is probably around 12.0:1 at WOT.
>
> As far as the phenomenon with the throttle, I think that it is because,
> when the PCM senses a quick/sudden full throttle condition from a sudden,
> drastic
> change in TPS signal, it makes a momentary enrichment in the afr as a safe
ty
> precaution and, possibly, retards the timing a bit as well. Once the PCM
> figures what's going on, the MAP signal plays a larger part and the TPS
> signal plays a lesser in the pulse width adjustments. At least from what
> I've read, that seems to be the common strategy that is adopted. I know
> from my dyno runs, no matter which PCM I used, a blip (drop) in rwhp and
> torque for a split sec. happened at 4300 rpm.
>
> As far as solutions, I think that you either have to have the PCM
reprogrammed
> or test and tune, if you have the necessary equipment and some knowledge,
> by manipulating the TPS and the MAP signals.
>
> As for reprogramming, all delays would have to be removed and timing
> advanced a bit with enrichment lowered a bit in the WOT tables. There
goes
> the safety factor:-) Question for me was: would I spend the $500 U.S.
> (currently over $750 CDN) without knowing what the approx. gain, if any,
would
> be in the 1/4. For a retiree, the answer was obvious.
>
> Hope this enlightens or provides food for thought. Keep the threads
coming.
>
> Reading with interest.
> Bob
>
>
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