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techfox Newbie
Joined: 18 Dec 2016 Posts: 5 Location: BA14
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Posted: Sun Dec 18, 2016 22:03 Post subject: EGR Valve - Electrically Actuated - Shogun 3.2 DID - Queries |
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The EGR valve on my Shogun appears to be electrically actuated i.e. no vacuum pipes involved.
My valve has been stuck open so today I removed it and cleaned it. Although there was soot etc in the main part of the valve, the problem seemed to be that the solenoid was holding it open (even with power removed). I have removed the solenoid and found the armature very stiff to move in or out. I have tried lubricating it but this makes little difference. The mechanical part of the valve appears to work satisfactorily and requires reasonable force to operate it.
So my questions are:-
a) The solenoid has a 5 pin connector. Does anyone know what these are for and even better have a circuit diagram showing where they connect to?
b) Should the solenoid be stiff to operate? It is behaving like it has a damper built in. Of course it may even be a stepper motor.
c) Is the solenoid deliberately stiff and require driving in or out by application of the appropriate voltage on the appropriate terminals?
I hope this hasn't been covered before. I have searched the forums and Google with no success.
Hoping someone can help.
Ray |
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Posted: Sun Dec 18, 2016 22:03 Post subject: Google Ads keep the POCUK free to join! |
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peteinchad LifeTime Member
Joined: 07 Jan 2013 Posts: 15079 Location: UK
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Posted: Mon Dec 19, 2016 5:53 Post subject: |
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Hi - welcome to the club.
The MkIII is not my area of expertise but there are some online manuals for that model HERE
If you follow the link then the wiring diagrams can be downloaded. |
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techfox Newbie
Joined: 18 Dec 2016 Posts: 5 Location: BA14
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Posted: Mon Dec 19, 2016 18:51 Post subject: |
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Thank you for such a quick reply. You have provided an excellent link which enables me to answer my question "a" and hopefully give me a clue on my question "c" once I have worked my way through the multipage circuit diagram. And all so early in the morning.
Thank you again.
Ray |
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peteinchad LifeTime Member
Joined: 07 Jan 2013 Posts: 15079 Location: UK
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Posted: Mon Dec 19, 2016 20:58 Post subject: |
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There is also the complete workshop manual in downloadable pdf form on there.
If you can't find it let me know as I have put it on my Google Drive. |
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techfox Newbie
Joined: 18 Dec 2016 Posts: 5 Location: BA14
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Posted: Thu Dec 22, 2016 20:48 Post subject: |
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Thanks for the tip on the Workshop manual. I have been ploughing through it but there appears to be nothing very useful for the Mk III EGR valve.
Having done some research on the Internet I think my valve is a linear EGR valve and driven by pulsed 12volt supply. I have tested it with a very brief 12volt supply and it opens very effectively, however it does not close by itself. The solenoid is holding it open even when not powered. So I am in a quandary. Does the varying mark to space ratio of the pulsed 12volt supply have a cunning effect and help the valve to close (back EMF etc!) or is there a return spring in the solenoid that has failed?
I suppose now I know it is not coked up I could put it back onto the car and see if it sticks open again. At least I now know what the connections do and what they should measure.
Thanks again.
Ray |
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peteinchad LifeTime Member
Joined: 07 Jan 2013 Posts: 15079 Location: UK
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Posted: Fri Dec 23, 2016 5:59 Post subject: |
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I looked at a photo of it on eBay and it looks like a motor (but I maybe wrong).
If it is a motor then it will stay open until the polarity of the feed is reversed - possibly the ECU inverts the feed.
I would assume that there is a relay controlling it - but that is just guesswork on my part. |
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techfox Newbie
Joined: 18 Dec 2016 Posts: 5 Location: BA14
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Posted: Fri Dec 23, 2016 12:29 Post subject: |
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Before I had the circuit diagram, I thought the polarity would be reversed. However the circuit diagram is quite clear in that one motor connection is solidly fixed to the 12 volt and the other is directly connected to the Engine ECU. Interestingly the circuit shows the solenoid as a motor so perhaps I should stop calling it a solenoid. Having scoured the Internet I found references to GM EGR's using a similar wiring configuration (2 pins for motor and 3 pins for the position sensor) and this is where I got the idea that it could be what they call a linear EGR. The linear EGR is driven by a pulsed 12 volt supply where they vary the Mark to Space ratio of pulses to provide a continuously variable valve position control - i.e. it is not just on or off but can be positioned anywhere between.
I think I will have to put it back on the engine and monitor with an oscilloscope to see what happens. I quickly connected it back on the engine yesterday (just lying lose) and turned the ignition on (but not started the engine) to see if the ECU would sense the valve was open and drive it close but nothing happened. It is possible I have an ECU fault but I think I can only determine that if I fully re-install the EGR and run the engine.
Interestingly a youtube Video shows the GM EGR being energised by 12 volts like I did and it returned to closed position when the 12 volts was removed suggesting it was sprung loaded.
Of course after all this it could be the circuit diagram is wrong! I hope not. |
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peteinchad LifeTime Member
Joined: 07 Jan 2013 Posts: 15079 Location: UK
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Posted: Fri Dec 23, 2016 12:44 Post subject: |
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It makes sense that it is a pulse driven "stepper" type motor - but I am not at all sure how it would reverse - unless the position sensor somehow switches the polarity. If it is a motor then I can't get my head around how a spring would make it close.
I'm not good on stepper motors !
You will need to look at the ECU output with the oscilloscope - as you say, without knowing what signal it is getting i is difficult to know what it is supposed to do. |
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techfox Newbie
Joined: 18 Dec 2016 Posts: 5 Location: BA14
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Posted: Fri Dec 23, 2016 13:10 Post subject: |
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Oh well. A job for after Xmas.
Thanks for your input. When I figure it out I will document it here for future reference.
Merry Xmas. |
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peteinchad LifeTime Member
Joined: 07 Jan 2013 Posts: 15079 Location: UK
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Posted: Fri Dec 23, 2016 13:31 Post subject: |
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I'm just glad mine only has the vacuum operated version!
Have a good Christmas. |
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redfantasea **
Age: 76 Zodiac: Joined: 25 Nov 2006 Posts: 75 Location: Dorset UK
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Posted: Mon May 08, 2017 12:14 Post subject: |
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Did you ever solve your problem? I have a similar problem (see topic: http://www.pocuk.com/forums/viewtopic.php?p=1444433#1444433 ). Like yours, the motor on my EGR valve has a 5 pin connector but all the manuals show 6 pins. Did you find a circuit or other that enabled you to test the motor? Mine runs out OK undwer 12V supply and I assume that the spring in the EGR valve returns it. I get about 25 Ohms between pins 1 and 3 (pin 2 is missing) which are the pins that drive the motor. Other readings on pins 4, 5 and 6 are between 1k Ohms and 5.5k Ohms. Could you send me a link to the manual that you used, please? I have looked at the ones on this web site and they all show the 6 pin connector. I guess that, as the motor is running, the fault is either in the ECU, the wiring loom or the position sensing system in the motor. Cheers. |
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