preport Posted January 5, 2007 Report Share Posted January 5, 2007 Hi there, As a newbie and new owner of a TR6, it is very good to have found this forum. Before I picked up my TR6 2 weeks ago the noisy Lucas fuel pump was replaced with a Bosch one. It runs perfectly, but on the second time out in it the power supply disappeared from the pump (it is currently running off the tail light). There is power before the wiring harness goes through the bulkhead and the inertia switch is in tact, but by the time it gets to the boot it has disappeared. Is there an inline fuse or something under the dash, and if so, where because I can't see anything, or is there something else I haven't spotted? Any advice would be very gratefully received. Quote Link to post Share on other sites
john.r.davies Posted January 5, 2007 Report Share Posted January 5, 2007 preport, It's running "off the tail light"?! Did you turn off the lights?? Seriously, you would be well advised to run a seperate cable, preferably a heavy duty one, directly from a switched (ie goes off when you turn the ignition off) 12V supply to the pump, AND a serious earth cable back to the battery. The Bosch takes a lot of current, (mine takes 8.3amps) and either way a lighting circuit isn't enough. John Quote Link to post Share on other sites
badshead Posted January 5, 2007 Report Share Posted January 5, 2007 Preport I concur with John - you urgently need to install a heavy gauge dedicated power supply to the pump before you get meltdown! If the original switched power supply to the old Lucas pump at the bulkhead is OK, you can use that to power a relay to switch the new power supply to the Bosch pump - direct from the battery with a 35a in-line fuse will work fine. Quote Link to post Share on other sites
Jersey Royal Posted January 5, 2007 Report Share Posted January 5, 2007 Preport I concur with John - you urgently need to install a heavy gauge dedicated power supply to the pump before you get meltdown! If the original switched power supply to the old Lucas pump at the bulkhead is OK, you can use that to power a relay to switch the new power supply to the Bosch pump - direct from the battery with a 35a in-line fuse will work fine. Welcome to the forum Preport. Something like this. Regards Guy Quote Link to post Share on other sites
ianhoward Posted January 5, 2007 Report Share Posted January 5, 2007 Preport I can recommend fitting a relay and using the exisiting pump wiring to powere the relay. 'Jonlar' may be able to supply a ready made kit as he did for my TR5 (Sorry Jonlar if speaking out of turn!) - now just need one for my recently acquired '6'!!! Easy to fit - honest! Brgds Quote Link to post Share on other sites
robgeev Posted January 6, 2007 Report Share Posted January 6, 2007 Have you checked there's power in and out of the inertia switch? A mobile auto electrician shouldn't charge more than about £30 plus a relay (about £4) to do a nice rewire job for you if you're not very confident. Rob. Quote Link to post Share on other sites
preport Posted January 6, 2007 Author Report Share Posted January 6, 2007 Thanks for the advice. Wiring it up to the tail light was a 'get me home measure' which I intend to change as soon as possible. The inertia switch is ok. My problem is that I loose the wiring once it gets under the dash board and I can't find where it leaves to go to the back of the car. Any ideas? Thanks Quote Link to post Share on other sites
Jersey Royal Posted January 6, 2007 Report Share Posted January 6, 2007 Thanks for the advice. Wiring it up to the tail light was a 'get me home measure' which I intend to change as soon as possible. The inertia switch is ok. My problem is that I loose the wiring once it gets under the dash board and I can't find where it leaves to go to the back of the car. Any ideas? Thanks Preport The wiring loom drops down the bulkhead and runs down the left hand side of the car under the carpet by the sill, the up and over . Guy Quote Link to post Share on other sites
wheeler Posted January 6, 2007 Report Share Posted January 6, 2007 Preport The wiring loom drops down the bulkhead and runs down the left hand side of the car under the carpet by the sill, the up and over . Guy Quote Link to post Share on other sites
wheeler Posted January 6, 2007 Report Share Posted January 6, 2007 Hi Preport To add to Guy's reply this picture may help. Main harness goes through the engine bulkhead/LHS passenger footwell and joins the rear harness via a multway plug , pump supply is the white wire. Rear harness can be seen running along the floor below the door sill. Please disregard previous post - my mistake Regards Bill Quote Link to post Share on other sites
preport Posted January 6, 2007 Author Report Share Posted January 6, 2007 Hi Bill, Thanks for your help. Problem is now fixed. It was the inertia switch which was showing a resistance of a few ohms. All I need to do now is find a replacement switch. Nick Quote Link to post Share on other sites
wheeler Posted January 6, 2007 Report Share Posted January 6, 2007 Nick Before you buy a new one check it. Disconnect and remove the switch. At the bottom of the body of the switch there is a small hole with a small plastic 'pip' inside, push it down and the cover can be pulled off the base, you may have to remove two small screws at the back, do not touch the two screws at the bottom they hold the terminals/spring contacts. Clean the brass ring, it may have to be stuck back on to the plunger with filler or araldite (heat resulting from the resistance causes plastic plunger to melt). Clean brass contacts and the steel ball and reassemble. Test by giving the switch a sharp tap and ensure plunger pops up. This advice was given to me several years ago on the forum by 'Jonlar' and no doubt has saved many inertia switches. If your switch is beyond repair I have a spare you can have. Hope this helps Bill PS Welcome to the Forum! Quote Link to post Share on other sites
badshead Posted January 6, 2007 Report Share Posted January 6, 2007 Hi Preport, The inertia switch is very easy to disassemble with only a few parts. Basically it consists of a large magnetic ball bearing that is held in its seat by another magnet, then unseated by unusually high G-forces, such as in an accident. When it is unseated it breaks the contacts it the upper part of the switch - see exploded view below. If yours is beyond repair, they're no longer available, but identical switch was fitted to Stags, Alfa Spiders (1980's vintage) and apparently some 1970/80s Jags - and probably many other cars of this period. Quote Link to post Share on other sites
stuart Posted January 8, 2007 Report Share Posted January 8, 2007 This switch was fitted to XJ6 Series 2 and 3 and XJS and they are plentiful in scrap yards. Fitted in passenger side behind footwell kick panel. I believe there is also a similar item fitted to Sierras in the spare wheel well. Stuart. Quote Link to post Share on other sites
wheeler Posted January 10, 2007 Report Share Posted January 10, 2007 Hi Preport How did you get on? Inertia switch on ebay if required see http://cgi.ebay.co.uk/justriumph-TRIUMPH-S...1QQcmdZViewItem Best regards Bill Quote Link to post Share on other sites
preport Posted January 12, 2007 Author Report Share Posted January 12, 2007 Many thanks for your help and the offers of replacement switches etc which has been great. The switch is functioning again. Sorry to be so long in replying. My PC died last Sunday, I my spare time has gone on fixing that; and, of course, I couldn't get on the net! Nick Quote Link to post Share on other sites
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