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Scorpio · Posted: Thu Sep 16, 2010 7:22 pm Post subject: TPS on megatune dilema

Bench testing my TPS with megatune when i calibrate TPS i get:

Throttle shut ADC count = 38
WOT ADC count = 230

After i recalibrate my throttle position in megatune it starts on 10 % (with closed throttle) and opens to 92 %

Shouldnt after recalibrating it start on 0% and reach 100 % on WOT??

what am i missing? flood clear or physically adjust TPS??

_________________
1979 NA
MS1..EFI..
GARRETT T25 TURBO
BILSTEIN SHOCKS
GT BASED CUSTOM BODYKIT

Brisbane , Australia
Think mean think fast
all youll see is
my Porsches Arse!!!

Arvidw · Posted: Thu Sep 16, 2010 8:07 pm Post subject:

It should say 0 to 100% after calibration.

I find your ADC counts quit low, mine where around 120 to 1400.

Are you sure that connected the TPS correctly?
_________________
Porsche 924 2.0 Kompressor 136.1wHp @ 5650rpm / 201.9wNm @ 3900rpm (dyno @ dp-engineering.nl)

Scorpio · Posted: Thu Sep 16, 2010 8:18 pm Post subject:

The mega manual says I'm within range , I'm quite certain I've wired it properly as it increases open percent in megatune as throttle is opened . Even when I type in different values into the adc count I press ok and it's still starts at 10% mystery
_________________
1979 NA
MS1..EFI..
GARRETT T25 TURBO
BILSTEIN SHOCKS
GT BASED CUSTOM BODYKIT

Brisbane , Australia
Think mean think fast
all youll see is
my Porsches Arse!!!

Min · Posted: Thu Sep 16, 2010 11:57 pm Post subject:

I'm not entirely certain why this is occurring, however it won't make any difference to your car's operation. Set your floodclear to 75percent, and off you go.

Min
_________________
Custom means it didn't come from a box.
1980 n/a with EDIS and Megasquirt II Injection. 7 different colors and counting.

Martijnus · Joined: 29 Dec 2006 Posts: 2019 Location: Netherlands

I'm sure it has nothing to do with it, but my MS started to flip out when I tried to calibrate the tps on a running engine. So since you're benchtesting it, be sure you don't have a crank signal.

But i'm probably confused... because you don't have a seperate TPS and megastim at the same time... and without the stim you probably haven't got a crank signal.

Weird problem though.
Have you tried turning it off and on again?

(I mean flashing the firmware).
_________________
"Rule: Turbo's make torque, and torque makes fun." (C. Bell)

924 "50-jahre", 1981.
MSII/extra, LPG, ITB's, 5lug.
To be turbo'ed in a while.
Killed her at the Nurburgring, Porscheless at the moment

RC · Joined: 25 Mar 2007 Posts: 2637 Location: Australia

Have you sussed this out during your 12 hr sess?

One way or another, it is not right.
Assume correct communication, code, .ini file for MT, wiring, etc for MS1. Low ADC @ WOT indicates low voltage. Caused by high resistance TPS, very poor earth, low angular deflection of TPS or limited butterfly movement; should be around 80 - 90* with TPS at say 100 - 120* for full coverage.

What TB?
What TPS?
Voltage readings of all 3 connections @ TPS on idle/closed throttle and also at WOT?

Hint - one should be 0 - 0.2V and earthed at same physical location as all other MS earths, and another at 4.8 - 5V. The sweeper terminal should vary between 0 and 5V but in your case will likely only be around 0 - 2V?

Scorpio · Posted: Thu Sep 23, 2010 2:32 pm Post subject:

Ok will check it out rc the engine is on a stand and in earthily everything straight back to the battery negative. I'm wondering if something is wrong with my megasquirt as throttle on megatune originally would climb to about fifty percent with no tps plugged in but now with no tps it goes to 100% open what specifically could be making it act all hormonal like this ?
_________________
1979 NA
MS1..EFI..
GARRETT T25 TURBO
BILSTEIN SHOCKS
GT BASED CUSTOM BODYKIT

Brisbane , Australia
Think mean think fast
all youll see is
my Porsches Arse!!!

RC · Joined: 25 Mar 2007 Posts: 2637 Location: Australia

MS should be Ok as a FLOATING input like that will result in anything. Leaves it vulnerable to picking up static too. NEEDS between 0 and 5V to it to make it function rationally, even earthing out for 0V. A basic test is connecting both earth (simulating closed throttle) for ADC count and then 5V for a WOT reading.

Min · Posted: Fri Sep 24, 2010 12:23 am Post subject:

Don't expect rational results when you don't have a TPS plugged in. This actually caused me some headaches, install a resistor or plug in a TPS. I have a resistor installed in mine. It does wonky things if you leave it as a floating input. And MS will do things based on that wonky input, BTDT.

Min
_________________
Custom means it didn't come from a box.
1980 n/a with EDIS and Megasquirt II Injection. 7 different colors and counting.

Scorpio · Posted: Fri Sep 24, 2010 9:51 am Post subject:

It was doing strange things with it plugged in ie 10-92% after calibration . With it not plugged in I was curious why it was the only real time gauge input doing strange things. I'll move the tps around and see if starting a closed throttle with different original tps orientation does anything
_________________
1979 NA
MS1..EFI..
GARRETT T25 TURBO
BILSTEIN SHOCKS
GT BASED CUSTOM BODYKIT

Brisbane , Australia
Think mean think fast
all youll see is
my Porsches Arse!!!

Min · Posted: Fri Sep 24, 2010 11:10 am Post subject:

Scorpio · Posted: Tue Oct 12, 2010 10:01 pm Post subject:

ok Jim stim finally arrived...and confirms that there is something wrong with TPS on my megasquirt

calibrating jimstim i get adc=0 and adc =254

BUT

when i slowly rotate the TPS knob on the stimulator it doesnt slowly rise or fall it jumps from 0-33-66-100 but mainly straight from 0 to 100% open

dont know why this is??
_________________
1979 NA
MS1..EFI..
GARRETT T25 TURBO
BILSTEIN SHOCKS
GT BASED CUSTOM BODYKIT

Brisbane , Australia
Think mean think fast
all youll see is
my Porsches Arse!!!

Rich H · Posted: Tue Oct 12, 2010 10:48 pm Post subject:

Easy, don't use TPS just wire a resistor in it's palce and run on MAP.

Mine ran just fine like that, read an article on MSEFI.com about the lag between MAP and TPS and it was rediculously tiny like milisecs.
_________________
1994 Lotus Esprit S4 - Work in progress...
1980 Porsche 924 S2 DITC Turbo - Original spec
1978 Homo-Sapiens - Tired spec
1953 Landrover S1 - Pensioner Spec

Scorpio · Posted: Tue Oct 12, 2010 10:59 pm Post subject:

good point Rich! will keep trying with this and if i cant get it to work then resistor it is

EDIT

OK after some playing its working now?..strange thing is i can remove throttlefactor.inc file from mtcfg folder and it still works?? why so tempremental?..seems like its working now but wasnt 10 min ago

im using megatune 2.25 p3 without the extra code (think its original B and G code) where exactly do i check which code im running? ..i tried loading extra code but when shorting the boot load pins it didnt want to work...Im determined to get this sorted
_________________
1979 NA
MS1..EFI..
GARRETT T25 TURBO
BILSTEIN SHOCKS
GT BASED CUSTOM BODYKIT

Brisbane , Australia
Think mean think fast
all youll see is
my Porsches Arse!!!

Scorpio · Posted: Tue Oct 12, 2010 11:30 pm Post subject:

turns out its not working!??...

i thought it was but whenever ide calibrate it at say 50% throttle to be fully closed it wouldnt hold the calibration value....its only going 0 adc to 254 adc because the resistance on the jim stim is made that way..NOT because the calibration is working......very frustrating
_________________
1979 NA
MS1..EFI..
GARRETT T25 TURBO
BILSTEIN SHOCKS
GT BASED CUSTOM BODYKIT

Brisbane , Australia
Think mean think fast
all youll see is
my Porsches Arse!!!