Prefered TPS Voltage.

darkstar_one

Registered User
Hey, what is the prefered voltage for the TPS at idle while warm? I have used the search but dont come up with a specific range.
 
Im probably off a little but I believe its going to be .99volts at wot and 5volts at idle.
I mat have it backwards but Im sure it is close

S
 
i think u have it backwards, that would mean, that at idle it would be reved out of its mine and at wot it would be closed
 
kool, thanks, for the help, wasnt trying to be an ~~~ earlier, i know u didnt take it like that but just trying to clear things up. thanks for the info dude.
 
No problem , I didnt take it that way. I had an idea that i was bass ackwards on it and just wanted to cover myself b4 someone else jumped me for it.:p
Even though its not sc specific its still a blue oval and set up the same way.

S
 
TPS from Yahoo EECTuner

The below is from EECTuner forum at Yahoo Groups

http://autos.groups.yahoo.com/group/EECTuner/message/31529

RE: [EEC Tuning] Erratic Idle and Jumpy timing


Marcello,

I mainly lurk here as I don't own any sort of twEECing equipment, but love
the FORD way of doing things when it comes to electronics. I had my own
repair shop for 27 years (till 2001) and specialized in diagnostics and
performance tuning. Tuning EFI is no different than tuning carbs. It's just
that IFR's, PVCR's, ECR's, power valves, PMJ's, SMJ's have been replaced by
silicon and electrons.

I find the conversation on this forum stimulating. Unfortunately I have
found that, on occasion, some posts regarding "driveability" are slightly
flawed. There are many knowledgeable people here with vast information and
respect them, their input, their views and wish I had the opportunity to
work with some of this community and equipment. Where I see the flaws is
when contributors start saying "try this" or "try that". The correct
response IMO should be "What does the system run like in a default mode, or
using the old FORD vernacular, "FMEM"".

Regarding any ECU controlled function (and idling conditions in
particular), before any strategy based adjustment can be made by a computer
controlled system, it must first run somewhat normally in a default and OL
mode. To do this with a FORD you must first follow a few rules.

You must keep the TPS input above the deadband area and below the "tip in"
area. On a FORD this equates to below approximately 0.9V and above 0.45.
Anything above 0.90V the ECU thinks the throttle is starting to open. This
brings into affect possible dashpot and fuel cut strategies which can turn
one grey real fast. Below approx 0.40-0.45V the system suspects an incorrect
input and substitutes a default figure. So first off, the TPS should be set
to around 0.55-0.75V.

The second step is to deactivate the ISC-BPA solenoid. This sets the
pressure balanced control plunger to its default mode.

The third step is to pull the SPOUT plug. This locks the timing to what
ever base you set with the timing light. Many will use the FORD default
figure of 10 degrees. This is great "IF" you have not got a heavily modded
engine. Base timing for a modded engine will always be more that 10 degrees.
Setting a base of up to 16 and sometimes more is not out of reality. Base
timing has the biggest influence on idle quality.

The last step is to disable feed back fuel control, just unplug the O2's.

Minimum idle RPM is then only influenced mechanically by the airflow of
the base opening of the throttle plates. This is an area where I find many
fellas get lost. Many assume the throttle screw is there to adjust engine
idle when you can't get things to work properly. It is not, it is soley for
setting a default idle mode when one or more idle control inputs are missing
and the ECU cannot form a valid control strategy. Some applications have the
min idle adjustment screw broken off at the factory just to keep those who
know too much from getting involved in trying to "fix it".

With these base settings, you should be able to start the engine and see
if it will idle. Get the engine to run at an RPM about 50-100 RPM lower than
what your curb idle will be. Adjust the minimum idle speed screw to attain
this. Shut down the rig, turn the "key on" and measure the TPS voltage. If
it is less than 0.90V (preferably <0.80V) then you are in the ball park. If
it won't idle you have to figure out whether it is fuel mix or air volume
related. Fuel wise, you can do this without using your "twEECing" equipment.
The simplest way is to restart and introduce a small amount of propane into
the intake. If it makes things better or worse you will have to
increase/decrease your fueling to attain the correct desired result.

In a heavily modded engine you may have to increase base timing to as much
as 16-18 degrees to maintain stability. I don't like going much past this
point as it can create hot start problems.

If you cannot attain a min idle RPM without going over a TPS value of
0.90V or adding a lot of timing, you will have to alter or make a bypass
hole in the throttle blades. Make this hole around 0.060-0.090 to start or
if one is already there increase it by 0.010-0.030. If making a new hole, it
is best to drill the section of plate that moves towards the intake manifold
as the throttle is opened.

I prefer to increase the bypass hole to the point where I can reduce the
min idle speed screw setting to get a TPS value of 0.55-0.60V. The reason I
prefer a lower TPS value is that it makes for crisper throttle response and
allows for a wider TPS tuning signal input ranger.

With these base adjustments YOU WILL eventually have an engine that will
idle at a "default" low RPM. This default should be, as mentioned earlier,
around 50-100 RPM lower than the normal curb idle. With a lightly modded
engine you can use the min idle spec in the FORD manuals. Since you have
access to a gas analyzer you should be able to set things so idle mix will
be no higher than 2% CO. I absolutely love these pieces of equipment for
doing any type of tuning. There is no wide band or computer controlled piece
of equipment that can tell you what is going on better than a gas bench.
It's too bad most people think it is just for measuring emissions. It's
their loss.

Another post mentioned that the ISC-BPA just sets idle speed and does not
control it. This is not 100% true. It controls idle speeds for varying load
and driving conditions. In later ECU's the ignition "timing" is used to TRIM
idle speed. This is why timing moves around. Since the ISC-BPA is a
mechanical monster it is slow to react due to air transport times in the
engine and from friction, both air and mechanical within the ISC-BPA. Its
control resolution is thus large and slow. Timing "trim" on the other hand
is real fast.

There was mention of someone seeing 25 or so degress at idle and thinking
it was to much. This is not so, because most systems that run CL at idle
require additional timing to stabilize idle. You can see this affect in
older carb'd rigs. Lean down the idle mix and the idle gets unstable. Apply
some vacuum to the advance pot and things smarten up nicely. At idle there
is no high cylinder pressure, so thinking that this excessive timing will
wreak havoc with your engine couldn't be further from the truth.

Once you have made these "base" twEEC's, you can get on with the fun
twEECing. FYI, up to 65% of todays ECU strategies are concerned with idle
conditions. Idle is the hardest area for an ECU to handle.

Remember to adjust your timing tables to compensate for any additional
base timing you add.

BTW, some will say that the MAF will control idle. This is only true as it
relates to fuel control. If the MAF is cal'd correctly you should be able to
disconnect it with the system in FMEM (and for that matter when running CL)
and there should not be a big noticeable change. If there is, you gotta get
it squared away and start all over again. A good working set up will be
capable of running an engine at idle with only an RPM reference. Racers have
used alpha-N set ups for years and they only use RPM and TPS inputs.

Trying to "tune" out problems with the ECU running offence (or defence
depending on your point of view) is beating your head against a wall.

Tom
*********************************************************
Robert,

I have not spent much time on the strategies of the newer gen boxes. I
gave up the search when I lost the desire to twist wrenches. Extrapolating
theories would dictate that many of the basic stuff would apply to the newer
stuff. Sort of goes with the "If it ain't broke, don't fix it.".

The narrower the voltage of TPS range, the less resolution the ECU has to
work with. Therefore, if the TPS range is from 0.45 to 4.5V, this gives a
4.05 operational range. If the idle set point is moved to 0.95V this gives a
3.55V range (87% of the 4.05V range). In round figures the TPS signal has
10% less resolution. As with idle RPM strategies, the lower part of the
range is looked at more carefully when ECU control is concerned. Case in
point would be how much air flow increase is there from 0.5V to 1.0V of
throttle opening conpared to 4.0V to 4.5V? Since the throttle angle changes
more from the off idle position than it does as it approaches the WOT arena,
the signal resolution must be a lot finer resolution. The TPS is the first
order feed forward input, the MAF/MAP second. Better resolution = better
response.

I live in Canada land and have paid as much as $15,000 for a stand alone
5-gas. I started using a gas bench in 1976 for tuning. The $nap-On boys were
by the other day and showed me there new hand held 4-gas that goes for
around $3K these days. I woulf question the asperation level, response time
and O2 cell longevity on something that small. I have seen used ones go for
$800-1500. Be forwarned however, any gas bench has to be cal'd on a regular
basis, the filters changed regularly and the O2 depletion cell has a life of
about 2 years.

The wide band is great for doing WOT and loaded runs. They fall down when
it comes to low speed accuracy however because they can be lied to. With a
4-gas one has to know the intra-relationship of the 4 gases in order to
conclude what is happening but the 4-gas can never be lied to. It tells the
truth no matter what the conditions are. A fellow I know in Alberta found
that the wide bands are good to get one in the ball park on the dyno, but
the final dial is best done looking at all the gases, not just oxygen.

As far as brand is concerned, it's more personal preference. I like units
that have 120V pumps in them, for fast response and longevity. Unfortunately
those setups can get bulky and need a little thought to get them to stay on
the seat of a car.

Tom
 
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