Disco 2 Surging when changing gear

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Balbas

Active Member
Posts
173
Location
Newton Abbot, Devon
I've noticed when changing up through the gears at low speed, especially when travelling uphill, that when I release the throttle and simultaneously dip the clutch to go for the next gear, that it sounds as though I haven't released the throttle as the revs surge.

This is intermittent.

I'm guessing that there is a clutch switch that kills the throttle when the clutch is depressed (I've never had any joy heel 'n' toeing the old girl, so I'm sure she's fitted with one of these devices), but a quick poke around under the bonnet didn't reveal anything. Am I right, and if so where is it?
 
Normally at the top of the pedal arm. Had this on a corsa *spit* it was the clutch switch.
Screenshot_20171210-185557.png

Have you got rave?

Edit this might not even be right I'm just guessing :D
 
The clutch switch is in the engine bay, as in the pic on pre-facelifts and on facelifts is screwed into the bottom of the clutch master cylinder

clutch switch description.jpg
 
Well. The mystery deepens. Changed the slave cylinder and cross pipe from the master to slave cylinder as it had chafed through. Bled through all fine, clutch is great, but on test drive the engine revs are still flaring.
“Must be the pressure switch” I thought. So the connector was removed and bridged out.
Engine still flares. Puzzled.com
I can only think that it is an electrical issue with no power available
 
Try with the clutch switch unplugged without the connector being bridged... if it's the same you should make somehow to plug in a tester and see if the ECU receives the input from it or not to rule out a wiring issue
 
That’s the next step. Have already run the car with the plus disconnected and unbridged with no change. So i am thinking that there is no voltage to the switch. Anyone know what voltage I should be seeing at the clutch switch connector? Is it a pure 12V input from the ECU?
 
The description of the switch in RAVE might be wrong and the diagram correct cos they are contradictoy... according to the diagram the switch is N/O and closes to earth when the clutch is depressed, you should get earth on the black/green wire of the connector which should reach the ECU black plug pin 35(black/white wire) through the closed switch when the clutch is depressed
 
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Hmmm if the switch is N/O and grounds out during operation, this could suggest a bad earth. Might try an alternate earth wire connection. I also have an issue with the reversing lights not working, seems thee is no power getting to the gearbox switch. Wonder if the 2 are related.....
 
Those are not related cos the reverse switch closes to 12V while the clutch switch closes to earth, get earth with a wire from body and connect it to the switch's pin with the black/white wire and if still the same unplug the battery and see if you get that earth to the ECU black plug pin 35(also black/white wire)
 
The description of the switch in RAVE might be wrong and the diagram correct cos they are contradictoy... according to the diagram the switch is N/O and closes to earth when the clutch is depressed, you should get earth on the black/green wire of the connector which should reach the ECU black plug pin 35(black/white wire) through the closed switch when the clutch is depressed
Going to try to sort this out this weekend. Checked the Rave manual and the earthing point for this circuit appears to be in the centre console. I had all that out to clean the carpets properly. Wonder if I dislodged something.....
 
Well I have to hold up my hands and pin the idiot badge to myself. Got the multimeter out, chased the voltage and found no earth circuit from the pressure switch onwards. Pulled the centre console out to reach the earth point and discovered I had left the multi plug undone where the loom enters the car on top of the gearbox. Plugged back in, just need a test drive now.
 
Well I’m very happy now. Test drive and no engine flaring at all. The whole palava was just down to a missed plug being connected. Wouldn’t have found it but for the Rave manual earth diagram. Every D2 owner should have a copy
 
Well I’m very happy now. Test drive and no engine flaring at all. The whole palava was just down to a missed plug being connected. Wouldn’t have found it but for the Rave manual earth diagram. Every D2 owner should have a copy
Must admit I still haven't had time to investigate, as mine seems intermittent. But when I do investigate, I'll bear your findings in mind, thanks.
 
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