Davidw Posted June 19, 2009 Report Share Posted June 19, 2009 Having previously noticed that my Bosch pump noise would change moentarilty every time the indicators flashed I decided to fit a relay a year ago. This worked brilliantly until last Sunday the relay died so I fitted a new one yesterday. I started the car this morning and it ran for precisely 30 seconds before the new relay (and fuse) blew. I go the relays from an online specialist. they are the usual 4 pin type marked 85.86.87 & 30. Aam doing something wrong? I have definitely wired the relays correctly (because I could hear them being energised. Any thoughts gratefully received. Quote Link to post Share on other sites
Jersey Royal Posted June 19, 2009 Report Share Posted June 19, 2009 Having previously noticed that my Bosch pump noise would change moentarilty every time the indicators flashed I decided to fit a relay a year ago. This worked brilliantly until last Sunday the relay died so I fitted a new one yesterday. I started the car this morning and it ran for precisely 30 seconds before the new relay (and fuse) blew. I go the relays from an online specialist. they are the usual 4 pin type marked 85.86.87 & 30. Aam doing something wrong? I have definitely wired the relays correctly (because I could hear them being energised. Any thoughts gratefully received. David, Could be just another dodgy relay, i have had two go within a short space of time, current 30 am Durite relay no problems. I would check your connections, have a look at this thread http://www.tr-register.co.uk/forums/index....89&hl=relay Hope it helps Guy Quote Link to post Share on other sites
Menno van Rij Posted June 19, 2009 Report Share Posted June 19, 2009 Normally I'm not on this part of the forum. But it was 'heads up' when I read the title of your posting. I've written about faulty relays on the 3A part of the forum. I had two bad Bosch relays in a row. The last one the day before yesterday. I dismantled (took it apart very carefully lifting the cap with a watchmaker's screw driver) the relay earlier today and I found some sort of debri between the two contact points. Just blew it out, recapped the relay and put it back and it works again! This makes me wonder what the problem was with the relay that went down a few weeks back! Menno Quote Link to post Share on other sites
Davidw Posted June 19, 2009 Author Report Share Posted June 19, 2009 David, Could be just another dodgy relay, i have had two go within a short space of time, current 30 am Durite relay no problems. I would check your connections, have a look at this thread http://www.tr-register.co.uk/forums/index....89&hl=relay Hope it helps Guy THanks Guy. Can you point me in the right direction to get a Duriet relay? Quote Link to post Share on other sites
Jersey Royal Posted June 19, 2009 Report Share Posted June 19, 2009 (edited) THanks Guy. Can you point me in the right direction to get a Duriet relay? David, The relay i have is Durite 12v 30 amp 0727-62 I got it from a local Auto Elec shop. I have a quick look on net and havent found a supplier yet. Cheers Guy Ha Ha Found it. http://www.holden.co.uk/displayproduct.asp...p;pCode=080.081 Edited June 19, 2009 by Jersey Royal Quote Link to post Share on other sites
Davidw Posted June 19, 2009 Author Report Share Posted June 19, 2009 Thanks very much, guy. I'll give it a go. Quote Link to post Share on other sites
Davidw Posted June 29, 2009 Author Report Share Posted June 29, 2009 Guy, just a heads up. Did what you suggested and it seems to be fine now(?!?!) Many thanks for the help. Now if I can just get the damn' horn to work on command............................ Quote Link to post Share on other sites
john.r.davies Posted June 29, 2009 Report Share Posted June 29, 2009 David, Originally, you said it was the indicators that made the fuel pump note change. The current they draw would be minimal, IMHO. Did you note a similar change when you used something more current-hungry, like main beam? If it is only the indicators, I'd suggest a deeper look at the electrics. Something is making the indicators draw a great deal of current, dropping the voltage to the pump. I can only presume a short circuit somewhere, a run to earth from one of the indicator wires, perhaps. Such a large current through small wires risks fire! Hope you can sus this, John Quote Link to post Share on other sites
roy53 Posted June 29, 2009 Report Share Posted June 29, 2009 David my indicators have been doing the same to the pump noise for over 20 years, so no problem. After Johns comment i am now a little worried though and will check things through. Quote Link to post Share on other sites
Davidw Posted June 30, 2009 Author Report Share Posted June 30, 2009 David,Originally, you said it was the indicators that made the fuel pump note change. The current they draw would be minimal, IMHO. Did you note a similar change when you used something more current-hungry, like main beam? If it is only the indicators, I'd suggest a deeper look at the electrics. Something is making the indicators draw a great deal of current, dropping the voltage to the pump. I can only presume a short circuit somewhere, a run to earth from one of the indicator wires, perhaps. Such a large current through small wires risks fire! Hope you can sus this, John John & Roy Thanks for the feedback. The horn is a completely separate issue which is also driving me mad. However, at tickover, the additional loading of ANY electrical circuit would cause the pump note to change. It was just more noticeable with the indicators as the note fluctuated. The ammeter reading didn't bounce around (& still doesn't at tickover) though it will if I just switch on the ignition & indicators. But if there's no charge going in to the battery wouldn't one expect the ammeter to flick up & down in time with the indicators?. If the total wattage is 40 watts ((2x15 front & rear)+(2x5 side repeat)) then the current drawn must be 40/12 which is 3.3 amps - plus the flasher unit. Or have I got something wrong? Chucked out of O'level physics in 1971!! Quote Link to post Share on other sites
john.r.davies Posted June 30, 2009 Report Share Posted June 30, 2009 No, I think you have the physics spot on! And all the lamps do add up, when you all in a group, even indicators. But I still think that the lack of available volts at the pump are the reason for the change in note. If it's any other ircuit that causes that change, then it must be that the alternator can't cope. I don't know what a Lucas Pi pump's wattage is but my Bosch is 150Watts! Suggest you check the volts at the pump while you turn other circuits on and off. Any significant drop, more than half a volt, mens that you need a stronger alternator. Whats the outputy of that, in amps, even the nominal, label output? O/e was 25Amps!! JOhn Quote Link to post Share on other sites
RobinTR6 Posted July 1, 2009 Report Share Posted July 1, 2009 No, I think you have the physics spot on! And all the lamps do add up, when you all in a group, even indicators.But I still think that the lack of available volts at the pump are the reason for the change in note. If it's any other ircuit that causes that change, then it must be that the alternator can't cope. I don't know what a Lucas Pi pump's wattage is but my Bosch is 150Watts! Suggest you check the volts at the pump while you turn other circuits on and off. Any significant drop, more than half a volt, mens that you need a stronger alternator. Whats the outputy of that, in amps, even the nominal, label output? O/e was 25Amps!! JOhn Upgraded to a Bosch pump and had similar issue with indicators. Upgraded toa 45 amp alternator and it was still there. Put in a relay on pump and the ammeter reading jumped from just positive to about a 1/4 of the positive on the gauge. Obviously the pump was starved of power and is now getting all it needs. Just been to southern France (1000+ miles) and all ran perfectly. As a matter of course also upgarded lights dipped and full to relays as well. Quote Link to post Share on other sites
Davidw Posted July 1, 2009 Author Report Share Posted July 1, 2009 Upgraded to a Bosch pump and had similar issue with indicators. Upgraded toa 45 amp alternator and it was still there. Put in a relay on pump and the ammeter reading jumped from just positive to about a 1/4 of the positive on the gauge. Obviously the pump was starved of power and is now getting all it needs. Just been to southern France (1000+ miles) and all ran perfectly. As a matter of course also upgarded lights dipped and full to relays as well. Many thanks, John & Robin for your help. I am unsure of the alternator as it was changed just after I bought the car from OE to (i think!) 16ACR. I have often thought (since reading Roger Williams excellent book - no relation) that I should go upto 45amps. However all the stuff about splitting the brown wires & hooking uo the ammeter so it doesn't blow is pretty intimidating. I'm just glad to know that I'm not apparently in imminent danger of spontaneous combustion. Quote Link to post Share on other sites
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