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V6 Dakotas
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bluegrey
Dodge Dakota
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11/17/2004
17:27:37

Subject: TPS mod necessary?
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I definately have that hesitation when I hit the gas, but I checked the TPS voltage and it's dead on at 0.7v. Should I just forget about it?



J and J Auto
GenII
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11/17/2004
17:36:27

RE: TPS mod necessary?
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What year truck

92 to 95 obd1 upto 1.2
96 and up up to .88

What this does reading a higher voltage tells the
comp there is more load and an advaced throttle
posision giving you more fuel to respond quicker

A tired o2 or other bad sensor can also cause a
hesitation, low fuel presure can also cause this
bad cap rotor wires or plugs check these things

Vacume leak 18.5 to 18.9 is normal vac
free scan auto zone can find these things

I run 1.02 volts on my TPS obd1

Larry
J&J Auto

bluegrey
Dodge Dakota
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11/17/2004
17:55:52

RE: TPS mod necessary?
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Ok I'll check all other factors, then maybe I'll go ahead with the TPS is everything else is ok. Thanks.



wadak
GenIII
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11/18/2004
20:51:19

RE: TPS mod necessary?
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Larry, Just to let you know I'm running the TPS on 97 v6 at .905 volts, I don't get any codes. For me this seem to be about the best setting I have to run the truck. I gradually moved it, I have thought about going higher, but it's running so good know I think I will leave where its at.



N56629
Dodge Dakota
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11/19/2004
10:39:20

RE: TPS mod necessary?
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Maybe Larry wants to address this-

Answer me this...

When my TPS voltage is at 0.40v, my scan tool says my TB is open "xx%". As soon as the blades start to open, the % goes up.

When my TPS voltage is at 0.75v, my scan tool says my TB is open the same % as when it was at 0.40v. And again, as soon as the blades start to open, the % goes up at the same rate as when it was set at 0.40v initially.

Everytime you you turn on the ignition of your truck, the PCM does a check of all the sensors (basically to check if they are all there). When it reads the TPS voltage, it set's that voltage as it's base voltage. It doesn't matter if it's 0.40v or 0.75v. The PCM sets that as the "closed" voltage. What is there to gain by setting it at a higher voltage? According to what my PCM is telling me via the scantool, it doesn't matter what the initial voltage is.

"If that were the case, you would really mess things up if you started your engine with the throttle plates slightly more open by putting your foot on the gas pedal."

That's what I thought too. In fact, I think I mentioned it last time somebody started a thread about the "TPS mod". But I did some testing with my scan tool, and it appears the computer actually sets it's 0% open voltage based on the lowest voltage it ever gets from the TPS. With the throttle half open, I turned on the ignition and the PCM read it as shut. When my friend opened the throttle, it read as normal, but when he closed it all the way, the computer read it as closed, and acted the same as when we turned on the ignition with the throttle shut. So it seems the computer sets it's "shut voltage" at the lowest voltage it gets.


[url]http://dakotausa.com/vBulletin/showthread.php?t=19457&highlight=tps [/url]



joe
Dodge Dakota
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11/19/2004
11:05:35

RE: TPS mod necessary?
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"92 to 95 obd1 upto 1.2
96 and up up to .88"

hey J & J
i have a 94 with the 3.9
when i checked mine it was at .80

i get the hesitation have since i bought the truck in 2000 then with 56,000

when i asked i was told to leave it,

but after reading your post here
i have to ask again
can i increase it to try an get a bit better throttle response?




J and J Auto
GenII
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11/19/2004
15:26:38

RE: TPS mod necessary?
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Yes you can increase the volts but you will reach
a theshold where it will not idle down than you need
to back off a little

As far a the percentage the comp reads any time
you raise the volts you should start and shut off
the truck 3 times than it will learn the new volts
setting

It don't matter if its .3 or 1.3 once it learns
what it is that will be 0% closed idle

i get the hesitation have since i bought the truck in 2000 then with 56,000

The hesitation may be something else spark plugs
will do this, on my 95 after 3,000 miles I changed
to the splitfire plugs and the hesitation went
away.Or some AP Autolites 3923 if you have more mods
3924 or 5224 closer to stock and gap .040 .045

I did not do any mods to this truck untill it had 36,000
miles and the bumper to bumper was off the
truck, than I pulled the motor and stroked it
as I did with all 3 new daks I bought. I am
waiting for the hemi to come out in the Daks than
I will be first in line to buy another, have the
cash just sitting in my check book collecting
intrest and waiting for that great day to come

The hemi in a Dak has been a dream of mine since
my first Dak

This you may not beleave but I bought 3 new Daks
in 1 1/2 years time I liked them so much just a
great little pickup truck

94 Black 3.9 5 speed oct 93 $11,000
94 Green 3.9 Auto sept 94 $16,000
95 green Dak 4X4 Auto dec 94 $19,500

And everyone said I was nuts, even my insurance
company questioned why I bought 3 new trucks so
close togather

Love these Daks my oldlady says I am certifiable
when it comes to my cars and trucks but thats just
the way I am, its my life and has been for over
30 years now, I just enjoy working on the things
some days I just sit and think about what I can
do next to 1 of my vehicles

Some people are into drinking
some people are into smoking wacky tabacky
I am into playing with my cars and trucks

Larry
J&J Auto

N56629
Dodge Dakota
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11/19/2004
18:34:18

RE: TPS mod necessary?
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"What this does reading a higher voltage tells the comp there is more load and an advaced throttle posision giving you more fuel to respond quicker." --Larry

"As far a the percentage the comp reads any time you raise the volts you should start and shut off the truck 3 times than it will learn the new volts setting.

It don't matter if its .3 or 1.3 once it learns
what it is that will be 0% closed idle "
-- Larry

Now that doesn't make a whole lot of sense. On one hand you say the computer learns what the voltage is at "0% closed idle" and then at the same time you say that this very same "higher voltage tells the comp there is more load."

I don't see how you can have it both ways. You can't have the same voltage telling the computer that the throttle is both closed and under load at the same time.

Maybe it lost something in the translation.




Wadak
GenIII
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11/20/2004
04:36:47

RE: TPS mod necessary?
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All I know is that the my Dak operates fine at the TPS at .905 volts, I like the throttle response and the delayed shifting it brings. It works for me, all Daks are a little different, each has their own personality. Larry just happens to be a "Dakota Psychologist" and knows how to get the best out of the Daks.



N56629
Dodge Dakota
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11/20/2004
06:29:58

RE: TPS mod necessary?
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Some Dak psychologists also insist that tb spacers will cure many of your problems. They can't seem to explain it, they just accept it.

Sometimes things do mask a deeper problem, but that doesn't mean the problem is gone.

I'm just looking for a logical explaination to the two seemingly inconsistant statements. I'm as willing to learn as the next guy.



J and J Auto
GenII
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11/20/2004
11:00:23

RE: TPS mod necessary?
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The idle %0 is the idle learn

The computer will go into more agressive fuel and
timming maps under load reading a higher voltage

Its not the same as the idle also at aprox 2 volts
it will decide wheather or not to drop out of
lockup or O/D depending on the load the map is
telling the comp if you hit the throttle fast and
drop the map it will down shift

Now push the gas slow the same amount and the map
will not drop enough to tell the comp to downshift

Just the way these comps work call detroit and
talk to 1 of there enginers they can explain it
better than I can

Larry
J&J Auto

J and J Auto
GenII
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11/20/2004
17:07:20

RE: TPS mod necessary?
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! thing I forgot to add here is vehicle speed is
also a facter

The higher volts will make the trans more agresive
downshifting with less throttle and delaying the
O/D and Lockup shifts holding them to a higher
rpm with less throttle

The trans keeps up with the motor not shifting
and never giving the motor a chance to rev
same as advancing the TV cable for the first 3
gears

Larry
J&J Auto

N56629
Dodge Dakota
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11/27/2004
13:06:33

RE: TPS mod necessary?
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"Its not the same as the idle also at aprox 2 volts it will decide wheather or not to drop out of lockup or O/D depending on the load the map is
telling the comp if you hit the throttle fast and
drop the map it will down shift "


Isn't load based on the difference between the voltage read at closed throttle position and current throttle position? Doesn't the computer take that reading plus the map reading to determine total load?

"The higher volts will make the trans more agresive downshifting with less throttle and delaying the O/D and Lockup shifts holding them to a higher rpm with less throttle"

Are we talking WOT here? Under normal acceleration, I see no difference in the point it shifts to O/D or when the convertor locks up. It does this at the same "speed" and not at different rpms.



J and J Auto
GenII
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11/28/2004
00:55:10

RE: TPS mod necessary?
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"Are we talking WOT here? Under normal acceleration,
I see no difference in the point it shifts to O/D or
when the convertor locks up. It does this at the same
"speed" and not at different rpms."


Your trans O/D and lockup should begain to rise
on a stock truck around 1/2 throttle and
progresivly go up from there

stock truck
light throttle
3-O/D around 30-35
O/D Lockup around 45mph

1/2 throttle
O/D 40-45
O/D Lockup 50-55mph

3/4 even higher shift points

If your truck is not working this way something is
wrong, solonoid valve not venting shorted or on
all the time, lower valve body problem or a bad
controler (computer) the O/D and Lockup are
both comp controlled 1,2,3 hydrolic that is also
true on the RE elec gove presure trans which
raises the line presure as the throttle is
advanced to firm up the shifts so they dont slip


1995 obd1 my truck
light throttle the same
just advancing the pedal 1/8 will raise these points
5mph at 1/4 it shifts
3-O/D 45
O/D-Lockup 50-55mph

TPS Volts
idle 1.02
WOT 4.08

Just over a 3 volt change threw the range

1-2 40mph
2-3 60 65mph
shifting at 4800-5000rpm
WOT the 3-O/D shift is 90mph

While crusing light throttle if I hit it
1/4 throttle my truck will drop into 3rd or
second if under 40mph instantly but I set the trans
up to be that agresive the higher volts making
the O/D and Lockup also more agresive

I have set up many 42 46 RH RE the same way on
costomers trucks and they love it getting the
power to the groud and not boging the motor

Larry
J&J Auto

N56629
Dodge Dakota
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11/28/2004
09:30:40

RE: TPS mod necessary?
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"stock truck
light throttle
3-O/D around 30-35
O/D Lockup around 45mph

1/2 throttle
O/D 40-45
O/D Lockup 50-55mph

3/4 even higher shift points "


Isn't this difference caused by moving from closed loop to open loop with closed loop being the figures at the top?

Maybe we are talking apples and oranges here. I'm talking about throttle response off-idle and normal acceleration. If we are talking open loop or WOT, I would tend to agree with you. In open loop, the computer may measure total voltage at the tps. I'm not sure.

Right now I have my own set at .72v, up from about .45v. When I get the chance I'm going to set it at around .3v or less and see what differences I can actually feel or see. With winter here, I'm not sure I will get accurate or generally relevant results. One thing I do want to try and that is to set the voltage at .3, start the engine and then reset the voltage to .7.



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