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sicminds
GenIII
7/18/2003
11:38:35
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 Subject: Understanding the TPS, and MAP, anyone?
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I just want to know what the three wires are on these sensors and what they do.
I know 2 of them are +5 volts and Negative
but which wire does the pcm read?
Also, does the pcm read both wires from the IAT?
I am working on a "chip" that modifys the voltage to the max 4.5v read by the pcm from the sensors.
Any help would be apreciated.
thanks!
now you know thats..................
sic
do me a favor and run to my websites and I will hook you up!
sicminds clothing company
Easy Solution Pc
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bry
Dodge Dakota
JOIN HERE
7/18/2003
16:04:07
|  RE: Understanding the TPS, and MAP, anyone?
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I have spent several years working with sensors on various engines from several different sensor manufacturers. I have not worked with these particular ones, but have worked with very similar sensors from the same manufacturer.
These sensors take an analog input convert it to a voltage output. This is normally done by an intigrated circuit located inside the sensor.
The basic principle behind most any three wire sensor is the same. The difference is in what technology is being used for the analog input into the integrated circuit. What is inportant in most cases is the internal resistance of the sensor (circuit) as seen by the power supply in the engine controller. If you do not have the correct resistance you can have power supply problems. The results of using the incorrect resistance varies depending on the internal make-up of the control module and how far off the resistance is. Could have no effect at all, set a fault code, or it could burn up the engine controllers power supply.
To simulate this type sensor all that is needed is a simple resistor bridge(two resistors in series ground on one side, positive on the other, with the output tapped from the middle of them). I have made many of them by simply cutting the connector off an old sensor and soldering the appropriate size resistors to the connector. (I have actually done this to get a test vehicle running when I was on the road so I could get home.) If you design the circuit to give a constant 4.5v, you will most likely cause a fault code because many engine controllers run a calibration at key on and see a constant voltage as a failure. Another option is to use a couple variable resistors to make the bridge and then you can vary the resistance (output). You still stand a good chance of setting fault codes because if you set all these sensors at 4.5v, the engine controller will know something is wrong.
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J and J Auto
Dodge Dakota
JOIN HERE
7/19/2003
01:19:03
| RE: Understanding the TPS, and MAP, anyone?
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Message:
Why do you want to do this what are you trying
to accomplish here.
Larry
J&J Auto
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sicminds
GenIII
7/20/2003
00:20:54
| RE: Understanding the TPS, and MAP, anyone?
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Message:
This is still just an idea thought up at work.
When I am WOT my tps only reads 3.6v, does this mean that the PCM is not seeing that the TB blades are all the way open? Or does it see it as being only 80% open?
If it only sees it as 80% then isn't there really a 20% loss? Wouldn't it just be like if I wasn't pressing the peddle 100% and only pushing it 80%?
I am by far no mechanic; I just can build circuits, lol. Just tell me if my ideas are out of the question, or if it’s even worth a try.
I wouldn't be supplying 4.5v to the pcm all the time, only when the tps voltage gets to 3v or higher then the circuit would output 4.4v to be on the safer side.
now you know thats..................
sic
do me a favor and run to my websites and I will hook you up!
sicminds clothing company
Easy Solution Pc
|
dcxer
Dodge Dakota
JOIN HERE
7/20/2003
00:50:23
| RE: Understanding the TPS, and MAP, anyone?
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Message:
The PCM reads the third wire on the TPS.The difference between 80% and 100% throttle and 80% power is not linear.You need about 93-94% to reach enrichment.The TPS should top out about 3.6-3.9V or so.Very rarely have I seen over 4V on a 5.9L.Never as high as 4.4V.You can do the popular TPS mod(adj voltage @ idle to approx .7V) that will take you into enrichment sooner.I agree with the above post about the fault codes and the possible damage.If you read 3.6V and the blades are fully open then thats WOT.
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J and J Auto
Dodge Dakota
JOIN HERE
7/20/2003
13:03:49
| RE: Understanding the TPS, and MAP, anyone?
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Message:
The computer will learn what the max voltage is
at wot, I have seen them antwhere from 3.3 to 4.2
at wot and they work just fine.
If you adjust the TPS to around .7 .74 closed
it will give you better response and a higher
reading at wot but will not change the wot
performance at all. it will just learn the
new higher voltage and be the same.
Larry
J&J Auto
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js
Dodge Dakota
JOIN HERE
4/08/2004
12:32:33
|  Dead spot @ 65 mph
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Message:
I just rebuilt a 95 Dakota 4 banger 5 spd for my son and I'm going nuts here trying to pin point this dead spot in the rpm range @ 60-75 mph, it sorta acts like it runs out of gas or leans out but if I press the acclerator down a lil it comes out of the spot and runs fine.. everything have been replaced, from the TB, to the fuel pump and this lil booger still is hiding in there somewhere... Anyone have any ideas here? Tonight I'm putting new ignition componets to see where we get... any info you guys might have would be greatly appreciated here :)
cheers JS
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