DarrenW
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| posted on 13/9/07 at 09:16 PM |
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TPS Calibration - negative value
Ive tried searching but cant find the answer.
Just fitted TPS tonight to the bike carbs. Checked the readings in MJLJ config software then discovered its running the wrong way round - ie from high
to low instead of low to high. Is this a problem for the latest version of config software?
I cant think of an easy way to get the readings to run the correct way round.
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oadamo
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| posted on 13/9/07 at 09:18 PM |
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cant you just swap the wires around.
adam
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givemethebighammer
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| posted on 13/9/07 at 09:20 PM |
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This might be a stupid suggestion but could you reverse the wires in some way ?
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bigrich
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| posted on 13/9/07 at 09:22 PM |
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thats 3 thinking the same thoughts
.JPG)
A pint for the gent and a white wine/fruit based drink for the lady. Those are the rules
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DarrenW
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| posted on 13/9/07 at 09:28 PM |
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TPS is pre-wired to loom and connector. Dont want to rip it apart if there is a way to get round it in the software. i seem to recall it is a 3 wire
pot - not sure which 2 to swap.
Ill change wires if i have to, just exploring alternatives first.
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bigrich
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| posted on 13/9/07 at 09:34 PM |
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outer 2 normally are + and - and centre is signal out IIRC
A pint for the gent and a white wine/fruit based drink for the lady. Those are the rules
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DarrenW
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| posted on 14/9/07 at 08:35 AM |
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Brent has confirmed that the sensor must read the correct way round and that there isnt a software fiddle.
From the pic am i right in thinking i just need to swap the red and white leads over? or is there a bigger problem in that the sensor is rotating the
wrong direction and swapping the leads wont make a difference?
I have a bigger problem to solve now as well as i possibly didnt aligh the sensor correctly yesterday and have managed to snap the plastic
'pin' off close the the sensor body!! Its a 10K LinA pot, not sure where i can get one of those locally. Will try to repair first.
[Edited on 14/9/07 by DarrenW]
 
Rescued attachment 14092007228.jpg
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DarrenW
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| posted on 14/9/07 at 08:43 AM |
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Here is my pot.
http://www.maplin.co.uk/module.aspx?TabID=1&criteria=usb&ModuleNo=2205&doy=search&C=SO&U=Strat15
Im wondering if i can get a more robust type with steel shaft.
Ive also noticed i only get a range of no more than 60 when i read the scale on MJLJ software last night (10K pot) . Am i right in thinking that a
swap to 4K7 pot will almost double my range?
Thanks again,
Darren.
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David Jenkins
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| posted on 14/9/07 at 08:46 AM |
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Darren,
I think you will have to swap the 2 outer wires - red and silver(?) - the centre white one is the wiper that tracks around the resistance.
As for the Maplins pot - you will find that it's too fragile for fastening to the side of the carb, and also it's not
'weather-proof' so it'll soon get mucked up with engine fumes etc.
Proper TPS pots are sealed units - but don't ask me where you'd get one from!
[Edited on 14/9/07 by David Jenkins]
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DarrenW
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| posted on 14/9/07 at 08:57 AM |
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Thanks David. Ive just seen that RS do metal shaft pots but again dont look sealed. I have a zetec TPS but dont know how to connect it to the bike
carbs.
The plastic shafted pot snapped off even without engine running - i was actuating pedal to test repeatability of the readings, obviously not
repeatable!
Car is running 2D OK so not exactly urgent, but you know how it is when you have a puzzler and are on a mission to resolve it
The sliver wire is connected to the screening of the cable.
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David Jenkins
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| posted on 14/9/07 at 09:10 AM |
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quote:
Originally posted by DarrenW
The sliver wire is connected to the screening of the cable.
That's OK - just swap it with the other one. I'd guess that 'screen' is the chassis earth, the red wire is whatever voltage
is sent by the MJ (5v probably) and the white wire is the 'signal' that sweeps between 5v and 0v/chassis.
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02GF74
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| posted on 14/9/07 at 09:39 AM |
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numpty guide to pots - this should allo you to work out how to wirte it.
B _
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A _|
imagine hte pot as a staircase. Once end, A is connected to one voltage, other end B to another voltage that is higher than A so staircase goes up
from A to B.
You - the slider - walk up the staircase; as you trun the slider towards A, you wlakd down toward A eventually reaching A. Likewise with B.
so you get the range of volts that is between A and B.
Seeing that maplin pot made me t hink it ain;t gonna last no time - as indded you have found out.
RS should do more robust ones but you should be able to make use of the Ford TPS - it may be different resistcance but you should be able to allow for
that in the software.
I'll find out what my frined used for his TPS.
added; quick search on RS shows that you probalby want to be looking at servo pots;
e.g. 164-2677 approx £ 12.
460-1821 approx £ 11
460-2048 approx £ 9
[Edited on 14/9/07 by 02GF74]
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DaveFJ
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| posted on 14/9/07 at 10:00 AM |
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The TPS on a Pinto Efi is very easy to remove and should becompatible - I beleive. get yerself down to the breakers... or alternatively I have one
floating around the garage somewhere... 
Dave
"In Support of Help the Heroes" - Always
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DarrenW
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| posted on 14/9/07 at 10:05 AM |
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Ive managed to glue the snapped plastic shaft together. Also shortened it a touch and found some close fitting softer rubber tube. Also glued this to
the shaft. The plan being that the glued rubber tube should strengthen the join and stabilise the joint. Ive also managed to swap the silver and red
leads over so will give that a try.
My last connecting tubed was larger stiffer rubber tube held in place with jubilee clips. Now having a bit more compliance between the throttle shaft
and pot im hoping it acts as a kind of universal joint in case there is a modicum of misalignment.
Ill also set the pot this time so that it operates between its mid point and allow the software to calibrate it in. This should hopefully get me away
and have a go at mapping. If it fails before i get hold of more robust pot i can disconnect it easily and revert back to 2D mode. I just want to
convince myself that a rotary pot can work for now.
Fingers crossed
Well that the TPS fitted. Its lasted double the pedal presses so far. Ive loaded Tangomans 3D bike carb map in and reset the TPS values to suit my
calibration. Time to see what its loke on the road!
[Edited on 14/9/07 by DarrenW]
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DarrenW
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| posted on 17/9/07 at 08:28 AM |
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Just to report back and finish the thread off for future prosperity. TPS has held up now on a decent blat at the weekend but remains a weak point.
Later ill source a steel shaft pot or try and fit the zetec TPS i have in garage to make it more robust.
Swapping the outer 2 wires changed the polarity very well, quick calibration on software and it runs great. Close enough for minor fine tuning later.
Im now running with Tangomans 3D map and my TPS settings.
Many thanks to all those that helped.
Darren.
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