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Accelerator Switch


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#1 Major Burkenshaw

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Posted 05 February 2007 - 10:25 PM

Have been sorting out the jumble of wires for my engine conversion to Spi. Have worked out what most of the wires are for, but the Haynes bible mentions a switch on the accelerator pedal. Does anyone know what the function is for this switch? :(

#2 Sprocket

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Posted 06 February 2007 - 12:10 AM

Do you have a one or two plug ECU and wiring loom??

#3 fikus01

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Posted 06 February 2007 - 01:23 AM

it lets the ecu know when the pedal is all the way up!! my 1991 metro spi had one but i've seen minis without! as sprocket said depends on the ecu and loom

#4 Major Burkenshaw

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Posted 06 February 2007 - 07:23 PM

Do you have a one or two plug ECU and wiring loom??


Erm... 2 and a vacuum pipe, I think :(

#5 Sprocket

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Posted 07 February 2007 - 12:42 AM

Then you need the switch on the accelerator pedal. I personaly have never seen one. It tells the ECU when the throttle pedal is un pressed. As to what it does within the logic of the ECU, i am a little confused. This system is the Rover MEMS 1.6. The later cars with one plug ECU and loom is MEMS 1.9 so the software has been changed and does away with this switch.

#6 The Matt

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Posted 07 February 2007 - 08:35 AM

Is it the same as a TPS then, only mounted on the pedal rather than the linkage at the throttle.

#7 Sprocket

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Posted 07 February 2007 - 08:04 PM

No its purely a digital switch.

Normaly when something is described as a 'switch' its function is on or off (digital). When something is described as a 'sensor' its function is variable (analogue) :wub:

#8 Major Burkenshaw

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Posted 07 February 2007 - 11:11 PM

So if i just rig up a micro switch to the throtle pedal, it will do the same job :wub:

#9 Bounce

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Posted 07 February 2007 - 11:18 PM

depends if it was 'push-to-make' or 'push-to-break.' And you have to figure out if it puts a live or ground onto or away from the ecu.

#10 fikus01

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Posted 08 February 2007 - 12:47 AM

yeah microswitch shud do it, u get NO and NC terminals usually on them! no idea what it is as std! i jsut know if it revs up without the swithch (from the body) it ran like a bucket of spuds!

#11 Bulldog

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Posted 26 May 2007 - 09:02 PM

I think I know what the accelerator switch at the pedal is for.
You might have noticed that with the engine running, if you press the accelerator lever at the throttle body, the revs go up, then down, then up, etc...
Well, only this week I got up and before driving to work, I thought I'd top up the oil. So I started on my way, and suddenly, driving on the motorway, the car just went full throttle!!!
So I let go of the pedal and the revs went up-down-up-down. I made it to a safe spot off the motorway, opened the hood, and there was the oil filler cap stuck behind the accelerator lever on the throttle body. Last time I'm doing anything to my Mini at 6am :blink:

So I guess it's a kind of safety feature, so the engine doesn't keep over-revving when something happens to that lever.

#12 AlexM

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Posted 26 May 2007 - 09:08 PM

The switch lets the ECU know the position of the throttle pedal so it has some idea of the performance your looking for. If you index the throttle from under the bonnet the revs go up and down, but this is because you are moving the throttle without input from the switch and the engine doesn't know where it is as the revs go wild it reverts to overrun or so im told and runs leans.
If you do it quickly it will stutter quite badly. This is only a feature of later spi's possibly from 93on or so (mine has the switch and mines a early 93car). I wouldnt recommend indexing the throttle from under the bonnet, just use the pedal.

#13 daz-lee

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Posted 26 May 2007 - 10:13 PM

i have the switch on my 1992 spi and i have have unpluged it as it runs better with out it

#14 Sprocket

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Posted 26 May 2007 - 10:29 PM

The switch lets the ECU know the position of the throttle pedal so it has some idea of the performance your looking for. If you index the throttle from under the bonnet the revs go up and down, but this is because you are moving the throttle without input from the switch and the engine doesn't know where it is as the revs go wild it reverts to overrun or so im told and runs leans.
If you do it quickly it will stutter quite badly. This is only a feature of later spi's possibly from 93on or so (mine has the switch and mines a early 93car). I wouldnt recommend indexing the throttle from under the bonnet, just use the pedal.


I think you are confused

The switch on the pedal is an on off switch, it only tells the ecu that the engine is in an idle condition. It is omitted from late 93 onwards cars runnng the MEMS 1.9 ECUs

Indexing the throttle cannot be done on MEMs 1.6 two plug ECUs by pressing the pedal as this causes the switch to open. You have to hold the pedal up with a bungee cord and activate the throttle linkage under the bonnet. Also note that you index the throttle with the engine switched off.

Acceleration enrichment uses the throttle position sensor on the throttle body. Load is determined by the MAP sensor and RPM.

Edited by Mini Sprocket, 26 May 2007 - 10:40 PM.


#15 Sprocket

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Posted 26 May 2007 - 10:30 PM

Moved




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