[Diy_efi] TPS Specs / PN's

[Scot Sealander]

You don't have to use an op-amp to do what you want to do! 

First, are you sure that the throttle blade is fully opening?  If it is, and
the 3.8 is all the volts it gets, that is OK.  Just change the gain factor
inside the ECM code to reflect that 3.8V is the max value.  If it is set to
0.5 volts at idle, and the max is 3.8V, then you need to change the gain
factor to the value X, where (3.8V - 0.5V)X = 5.0 volts. 5.0/3.3 = 1.5, so
the gain value is 1.5

The stock gain value is 1.65, so it looks like the stock code considers your
3.8 volts WOT no problem.

If you have a scan tool, look at the scaled TPS value, and see if it reaches
100% TPS, I suspect that it already does.

Scot 

-----Original Message-----
From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org] On
Behalf Of Clair Davis
Sent: Friday, December 29, 2006 2:54 PM
To: diy_efi at diy-efi.org
Subject: Re: [Diy_efi] TPS Specs / PN's

I guess at some point, I'd do myself a favor if I learned something about op
amps and other little electronic widgets I could make myself, but I know
squat about them at the moment.  I still have my "Principles & Applications
of Electrical Engineering" text, but only because it was so full of errata
that the bookstore wouldn't buy it back after that semester...

I'd really prefer to have a PN/application that I could ask for at any given
parts store should the thing fail out in BFE.

Clair


----- Original Message ----- 
From: "Mike" <niche at iinet.net.au>
To: <diy_efi at diy-efi.org>
Sent: Thursday, December 28, 2006 12:55 AM
Subject: Re: [Diy_efi] TPS Specs / PN's


> an LM 324 op amp would do it, few app notes on that around the
> web, its a 14 PIN ic with 4 x opamps, select resistors for multiply
> by 5/3.8 and use one as buffer amp at front end for 1:1, that and a
> zener regulator would be all you need... cheers
>
> mike
>
> At 12:50 PM 12/28/06, you wrote:
> >I've run in to an issue with my TPS that may become a problem in the near
> >future.  I'm using a Mopar Performance billet 4V 1000cfm throttle body
that
> >came with Mopar-type sensors (MAP, IAC, TPS) as it is the "off-road"
> >replacement for the Magnum V8 throttle body.  Although the MAP and IAC
seem
> >to be pretty straight forward, the TPS is both non-adjustable, and
doesn't
> >seem to reach full voltage at WOT.  By relocating the mounting holes, I
was
> >able to achieve 0.5V at idle, but I can now only get about 3.8V at WOT.
I'm
> >not sure how the Magnum trucks dealt with this issue, but I don't think
my
> >'7730 is going to be happy as-is.
> >
> >I suspect that I may be able to program around the WOT voltage limit, but
> >I'd prefer not to if at all possible.  This now brings me to my
question...
> >is there a resource out there that discusses the various options for
TPS's?
> >I'd like to see if there is something out there that will give +/- 5.0V
at
> >WOT and still give 0.5V at idle, AND be correctly "handed" for my
> >application.  I would estimate that the throttle shafts turn about 80-85%
of
> >the GM TB I have in the garage when at WOT.  I've got a catalog on TPS
units
> >made by Tomco.com, but it doesn't get in to the guts of the specs, just
PN's
> >and ID photos.
> >
> >Any help greatly appreciated, especially now that the critter is running.
> >Idles OK (needs IAC tweaking), throttle response is nice (not moving
yet),
> >but I want to make sure it KNOWS that it's at WOT when it is.
> >
> >Clair
> >69 Valiant 340/'7730
> >FTWTX
> >
> >
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