[Diy_efi] Gauge/Sensor accuracy?

[EFI Dude]

Gauge/sensor wise, it's got electrical VDO Cockpit Series
gauges.  Oil press, water temp and fuel pressure are elec.,
and vacuum/boost is mechanical, though I have another
accurate vac/boost gauge that I'll hook up for the tests.

[BTW, also have tach, speedo, volts, amps (not hooked up),
and fuel level.]

Vehicle wise, it's a 5.0 in a kitcar.  TFS stage 1 cam,
TFS alum heads, 1-3/4" long-tube primaries into 2.5"
collector.  73mm MAF, 65mm TB, Vortech S-trim w/2.95
pulley, 42lb injectors, MSD6.  (Trying to get 500hp).
Running a 155lph in-tank w/T-rex (which Vortech claims
is more than enough for my combo), but I'm replacing
that with 2 in-tank 255lph high-output pumps (GSS340's).
Stock A9L computer.

Before I get into the problems, I wanted to set it up
to some good/known baseline settings, and gather some data,
hence the gauge questions first.

However, it's good a poor idle, especially cold, then
occassionally stumbles at higher rpms.  I can tune it out
a bit, but after 50-100 miles, it goes back to the problem
stage.  Doing some other work on it right now, so it'll be
a few weeks before I can drive/test it again, but I wanted
to get my gauges in order in the meanwhile.

Thanks,
-Neil.




-----Original Message-----
From: diy_efi-admin at diy-efi.org [mailto:diy_efi-admin at diy-efi.org]On
Behalf Of Perry Harrington
Sent: Saturday, June 29, 2002 7:19 PM
To: diy_efi at diy-efi.org
Subject: Re: [Diy_efi] Gauge/Sensor accuracy?


Neil,

Post as much info as you have, I can probably assist you with
this.  I've got a 5.0 myself, and I've done some tuning to
understand what the motors do when a certain set of values is
applied.

Have a look at the idle PW calculator at my site to get a good
starting point.  The REQ_FUEL value is the most important value,
so getting it right from the start will help tremendously.

The site is http://www.dainst.com/

I'm very interested in your progress.

BTW, stumbling is usually due to a lean spot.  If it only happens
on accel, your pump shot is too small.  If it happens at cruise,
that spot is too lean, fatten it up by increasing the VE value.

--Perry

On Sat, Jun 29, 2002 at 06:39:39PM -0500, EFI Dude wrote:
> Hi,
>
> Have a stumbling problem on my 5.0 EFI, and before I start
> testing and gathering data, I want to make sure my measurement
> tools (VDO aftermarket cockpit-series gauges) are accurate.
>
> The question is, how accurate are these?  Especially the
> temp and fuel-pressure gauges?  I had seen the sender
> output chart (V-out vs. pressure) for a SW pressure sender
> some time ago (can't find it now), and it was really
> non-linear, and all over the place.  My guess is that the
> gauge is not compensated for this, hence my concern.
>
> Anyone have any thoughts on this?
>
> Thanks,
> -Neil.
>
>
>
> _______________________________________________
> Diy_efi mailing list
> Diy_efi at diy-efi.org
> http://www.diy-efi.org/mailman/listinfo/diy_efi

--
Perry Harrington			Data Acquisition & Instrumentation, Inc
perry at dainst dot com					 http://www.dainst.com/

Those who would give up essential liberty to purchase a little temporary
safety
deserve neither liberty or safety. Nor, are they likely to end up with
either.
                             -- Benjamin Franklin

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