Hairsy Posted August 16, 2009 Share Posted August 16, 2009 My Fiat 2.8 JTD based Burstner has an annoying loud / fast 'ticking' electrical interference noise when listening to the aux input of the radio (I have an iPod connected to the radio via RCA leads). The interference is also affecting the screen for the reversing camera with horizontal bars that change in unison with the interference noise on the radio. The interference is affected by the amount of accelerator being applied. With no accelerator there is very little. It is not simply rpm based - at high rpm, the noise almost goes when taking the foot off the accelerator, even when the rpm remains high. It therefore doesn't seem to be a pure alternator problem. The iPod charges while connected and if I disconnect the charging then there is no interference - the interference does seem to be coming from the power supply. Originally the iPod charging was connected to the vehicle battery. I tried connecting this to the leisure battery instead. That made a small difference but the interference is most definitely still there. Years ago (in the days of points and condensors) I used to have this problem on petrol cars but I haven't previously experienced it on a diesel. Does anyone have any suggestions, other than to get a good auto electrician out? I was wondering about injector pump but I'm clutching at straws. Thank you Dave Link to comment Share on other sites More sharing options...
emmbeedee Posted August 16, 2009 Share Posted August 16, 2009 Does your vehicle have a "fly-by-wire" accelerator? These have no mechanical connection but are purely electrical (rheostat?) My ten year old Seat Alhambra TDi has this system, as I found to my cost when it failed & left me in "limp-home" mode. The signal is sent to the engine control computer which adjusts the injector pump, etc., in accordance with the accelerator position. If it does use this system, you may be able to fit a suppressor of some type to eliminate the noise. Hopefully someone with more detailed knowledge of your system will be along soon to offer advice. Link to comment Share on other sites More sharing options...
Hairsy Posted August 17, 2009 Author Share Posted August 17, 2009 That sounds possible although it isn't changes in throttle but actual throttle position that affects the problem. It is a 2005 model if that helps. Thank you for your thoughts Dave Link to comment Share on other sites More sharing options...
davenewellhome Posted August 17, 2009 Share Posted August 17, 2009 It sounds to me like interference caused by the electrically controlled injectors. Try placing a sheet of aluminium foil over the top of the engine and connecting it to the chassis. D. Link to comment Share on other sites More sharing options...
onecal Posted August 17, 2009 Share Posted August 17, 2009 Hi, Check all earths are sound, You will need to open and remake all earths, Check especially the braiding from exhaust to chassis. Check all connections on your alternator especially connections back to relays. Ensure you dissconnect the battery before carring out above checks. Regards, Brendan Link to comment Share on other sites More sharing options...
spospe Posted August 17, 2009 Share Posted August 17, 2009 Dave Newell sounds about right to me as to source of the interference, but I would suggest shielding the iPod and its leads, as that must be where the 'noise' is getting into the system. To do this you need a shielded lead to connect to the radio unit. It may also be worthwhile relocating the iPod further away from the engine, or maybe wrapping it in silver foil. Link to comment Share on other sites More sharing options...
Brambles Posted August 17, 2009 Share Posted August 17, 2009 Hi, It is interfrence caused by either the throttle sensor or the injectors, I suspect the injectors as they draw a high current. It is an earth loop problem because the gnd from the radio is not the same ground as the aux supply or cig socket. The way round this will be to have you accessories using the same grounding wire as the radio. A better alternative is to fit a large ferrite ring to the supply lead for accessories. Like you see on many computer conection leads. You will need the cable to be wound through it 3 or 4 times. To prove the point take a large bolt and wrap the lead around it a few times, as many as you can, and see if it helps...it will not cure completely but should reduce the interference if I am correct and then you can try and sourcing a ferrite ring. I think maplin may sell them or maybe you can pinch one off and old computer lead. Jon. Link to comment Share on other sites More sharing options...
Hairsy Posted August 17, 2009 Author Share Posted August 17, 2009 Thank you all for your advice. I will have a dabble with the various suggestions as soon as I get the chance and will report back. Dave Link to comment Share on other sites More sharing options...
emmbeedee Posted August 18, 2009 Share Posted August 18, 2009 onecal vw - 2009-08-17 2:25 PM Check especially the braiding from exhaust to chassis. Brendan I think this should read "braiding from ENGINE to chassis" Link to comment Share on other sites More sharing options...
tonyishuk Posted August 18, 2009 Share Posted August 18, 2009 Hairsy - 2009-08-16 8:09 PM The iPod charges while connected and if I disconnect the charging then there is no interference - the interference does seem to be coming from the power supply. Originally the iPod charging was connected to the vehicle battery. I tried connecting this to the leisure battery instead. That made a small difference but the interference is most definitely still there. Dave Have you tried a different Ipod or Ipod charger ? Try Halfords and see if they could try a Belkin charger and see if there is any difference ? Rgds Link to comment Share on other sites More sharing options...
onecal Posted August 18, 2009 Share Posted August 18, 2009 Hi Afraid not, The braiding is flat and is connected from the exhaust to the chassis. The main earth is from the engine to chassis. Regards, Brendan Link to comment Share on other sites More sharing options...
spartan3956 Posted August 18, 2009 Share Posted August 18, 2009 Try fitting a choke in the feed to the radio it can reduce interferance. Link to comment Share on other sites More sharing options...
emmbeedee Posted August 18, 2009 Share Posted August 18, 2009 onecal vw - 2009-08-18 9:56 PM Hi Afraid not, The braiding is flat and is connected from the exhaust to the chassis. The main earth is from the engine to chassis. Regards, Brendan How strange. Why do they feel they need to earth the exhaust? Link to comment Share on other sites More sharing options...
onecal Posted August 20, 2009 Share Posted August 20, 2009 Hi. Have a look here www.eautoworks.com/.../ape-auto~performance-Exhaust~Ground~System.htm - Regards, Brendan Link to comment Share on other sites More sharing options...
Hairsy Posted August 21, 2009 Author Share Posted August 21, 2009 Well I had a little rummage today. The earth strap from the engine to the battery seems to be very good with a clean connection. I can't find any earth from the exhaust though - but I can't see where there would be one anyway. I didn't have time to try more of the suggestions but will do so as soon as I can. Dave Link to comment Share on other sites More sharing options...
onecal Posted August 21, 2009 Share Posted August 21, 2009 Hi Did You do as brambles suggested first, Available from maplins. You need to break(open) and make (close) a few times while cleaning all connections with something like Aero Kleen 50 also available from above or electrical supplier. Did you check ALL your connections on your alternator ? Regards, Brendan. Link to comment Share on other sites More sharing options...
Hairsy Posted August 21, 2009 Author Share Posted August 21, 2009 Hi Brendan, Very limited time today so, no, just looked for the big earth straps. I hope to be able to find some time soon to investigate further. Regards Dave Link to comment Share on other sites More sharing options...
Brambles Posted August 22, 2009 Share Posted August 22, 2009 http://cgi.ebay.co.uk/TDK-MINI-FERRITE-CLAMP-FOR-CABLES-%2f-LEADS-UP-TO-5.5mm_W0QQitemZ370245498756QQcmdZViewItem http://cgi.ebay.co.uk/10mm-FERRITE-CLAMP-FOR-RG8-%2f-RG213--TVI-RFI-SUPRESSION_W0QQitemZ300338101343QQcmdZViewItem http://cgi.ebay.co.uk/13mm-Ferrite-CLAMP-Choke-Filter-to-Reduce-RFI%2fEMI%2fTVI-_W0QQitemZ220444756817QQcmdZViewItem Above are examples of ferrites you can fit to the cable. Go for a size you can loop the cable round and through a few times. If you find passing through just once works then you can order teh smaller on to go on the cable to keep it neat. Us the larger one out of site somewhere like on your camera feed cable or even on supply to auxillary socket. I would get yourself one anyway and try it as your 1st action, it if anything proves if the noise is passing up the supply cable or not when you complete the ground loop by having the RCA leads going to the radio and the supply from the aux socket. Jon. Link to comment Share on other sites More sharing options...
Hairsy Posted September 2, 2009 Author Share Posted September 2, 2009 Next thing tried - I've tried ferrite cores on the 12v feed to the iPod, the RCA leads running from iPod to stereo and the 12v feed to the stereo. It made no difference at all. I tried up to 3 loops through the core. I've temporarily 'fixed' the problem but disconnecting the 12v feed to the iPod. This allows me to play the iPod without charging it and the sound is as clean as a whistle. I will continue to try the various suggestions above and report back. Dave Link to comment Share on other sites More sharing options...
Brambles Posted September 2, 2009 Share Posted September 2, 2009 Hi, I am taken by surprise it has not worked. Maybe your noise is not the normal source in the Ducato but something else is faulty generating it. Putting a core on teh 12 volt lead should have worked. You did put a single core on and feed both supply and earth through to together didn't you?. May not work if seperate. Back to the thinking room on this one and sorry it did not work. Have cured a few accesories used in Ducatos with this fix. Jon. Link to comment Share on other sites More sharing options...
Brambles Posted September 2, 2009 Share Posted September 2, 2009 If you insert the cig plug so ONLY the GND makes connection do you have intererence. If not then unlikely to be the GND so might just be in teh 12 volt supply only. In that case if possible can you modify the plug and lead so just the 12 volts goes through a ferrite core a few times. Might be best tried with using seperate connection wired to extend the 12 volt connection a a temp try out. Whatever if it is only when the Ipod is powered then it is either coming from the supply to it (the cig socket), or is generated in the ipod 12 volt input circuitry itself which could be faulty. Very unlikely to be the ipod itself as it is related to engine speed/power. A supressor capacitor across the cig socket might also improve. Jon. Link to comment Share on other sites More sharing options...
Hairsy Posted September 2, 2009 Author Share Posted September 2, 2009 Thanks Jon - I'll have a dabble. I use the iPod in my car (while charging) with no problem so I doubt the problem is there. I'll play with separating power and ground and report back. I really appreciate your ongoing suggestions. Dave Link to comment Share on other sites More sharing options...
Hairsy Posted September 2, 2009 Author Share Posted September 2, 2009 Thanks Jon - I'll have a dabble. I use the iPod in my car (while charging) with no problem so I doubt the problem is there. I'll play with separating power and ground and report back. I really appreciate your ongoing suggestions. Dave Link to comment Share on other sites More sharing options...
Brambles Posted September 2, 2009 Share Posted September 2, 2009 I have edited my post to make it a bit clearer -- ONLY the Gnd connection. Link to comment Share on other sites More sharing options...
Brambles Posted September 3, 2009 Share Posted September 3, 2009 Hi Dave, I have just had a thought. If yoru gnd connection when plugging in the power lead for Ipod was broken, then you could get a lot of noise even though the ipod will still charge as getting a connection to Gnd via the RCA leads. Check it charges with 12 volt lead but outputs of ipod disconnected from any other equipment, that should highlight if you have a GND connection break. Also check the ipod using headphones when connected to the 12 volts supply. I trust you probably have and it works fine. Jon. Link to comment Share on other sites More sharing options...
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