Rich Posted October 14, 2015 Report Share Posted October 14, 2015 Hello all, After a fill up today i noticed that the fuel gauge only reads half even though the tank is full. Ive never filled the tank to full before so its the first time I've noticed this. All the other gauges and clocks work fine. The car is a MK1 vitesse cabriolet, any help of advice as ever is greatly received Many thanks Rich Link to comment Share on other sites More sharing options...
dogsbody47uk Posted October 14, 2015 Report Share Posted October 14, 2015 What did it read before you filled it up, and how many litres did it take to fill it? The Vitesse tank holds about 40 litres. Subtract what it took to fill up from 40 gives you a rough guide to how much was in the tank beforehand so you know where you are as the tank empties. Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 15, 2015 Report Share Posted October 15, 2015 If you have non stabilised gauges, ie the needles fly up to a reading not slow and damped you may find someone has fitted a stabilised float , this mix and match gives some back to front fuel reading you need to half empy the tank remove the float and check it works out the tank. is this a six hole sender or bayonet fixed ?? pete Link to comment Share on other sites More sharing options...
Mjit Posted October 15, 2015 Report Share Posted October 15, 2015 Just drive it and burn off some fuel to start with (so there's no risk of the level being higher than the sender hole), then pop out the fuel level sender. Chances are you'll find the sender float half full of petrol due to a pin hole leak or maybe a miss-bent arm. If it's a leaking float, replace it. If not get the level down to the point you can empty the petrol in to jerry cans (if you disconnect the fuel pump feed you'll probably find it syphones naturally). Pour a couple of litres back in and then set the arm so it's just lifted off the bottom test (a multi-meter set to resistance should help you judge this from outside the tank). Finally put the fuel back in and fill 'er up. You may not get a full needle when full - but you will know that an empty needle still means a couple of litres to get you to the nearest pertrol station! Link to comment Share on other sites More sharing options...
AidanT Posted October 15, 2015 Report Share Posted October 15, 2015 Hi, Just in case none if the above works and you want the gauge to read correctly: Mine also only reads 3/4 when the tank is full to the brim! I have checked and changed everything as described above apart from changing the gauge itself. I intend to get my gauge re-calibrated over the winter period and will be sending the new sender along with it so they can be matched. Will let you know how it goes ! Aidan Link to comment Share on other sites More sharing options...
Rich Posted October 16, 2015 Author Report Share Posted October 16, 2015 Hi many thanks for all your replies. Pete, its a six hole sender with 2 electrical cables that attach in the centre. The needles move up slowly and seem dampened. Time to burn off some fuel Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 16, 2015 Report Share Posted October 16, 2015 so thats looking stabilised, grey matter was unsure when this was introduced this could be heading for a stabiliser fault , make sure its earthed to the speedo and is right way up they are marked 'top' six hole stabilised sender seems rare , H and V are same sender , its the stroke not the tank width that makes it the same . if you short the sender to earth does she read full ??? if not suspect the stabiliser voltage is low , what the temp gauge doing ??? as they are all fed from the satbilised unit, they give out about 10.5volts as a pulse 0-10-0-10 Pete 1 Link to comment Share on other sites More sharing options...
Rich Posted October 17, 2015 Author Report Share Posted October 17, 2015 Hi Pete temp gauge never goes up by more the. Couple of mm. Just off cold really, when she runs hot it's still just off the cold, never gets quarter to half reading. Regards Rich Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 17, 2015 Report Share Posted October 17, 2015 If they are slow movers and the temp gauge is reading low also think i would change the stabiliser on the back of the speedo it feeds both gauges pete Link to comment Share on other sites More sharing options...
AidanT Posted October 18, 2015 Report Share Posted October 18, 2015 Pete would you still suggest this if when you short out the sender the gauge goes all the way to and past full? Aidan Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 18, 2015 Report Share Posted October 18, 2015 ive got a proper smiths test box that does the calibration settings, full and empty for all types of gauge and sender, not used it for years so need to read the book to get the wires on right. but its a long way to sunny luton I as with ign off they all read empty /cold then a higher voltage reads full or hot, if its over reading the stabiliser could be poking out more than the pulsed 10.5 volts they should run at with the tank sender earthed it should just read Full or a little over as the resistance is 18 ohm full 256 empty earthed is near 0 ohm. thats with the sender having its location notch at the top ( the sender i have is not marked top) so this maybe inverted guess work. my brains forgot about the ohms law and all that but v=IxR so you could have a duff satbiliser or you need the gauge needle given a light 'bend' try to check the green wire feeds from stab to gauges for what volts are being produced the stab must be earthed and 'top 'at the top solid state ( e bay) ones dont have this requirement Pete Link to comment Share on other sites More sharing options...
Rich Posted October 18, 2015 Author Report Share Posted October 18, 2015 Pete many thanks for your advice, once I'm back in the garage I'll do some checks as you've discussed and put the finds on the forum. Regards Rich Link to comment Share on other sites More sharing options...
Rich Posted October 20, 2015 Author Report Share Posted October 20, 2015 Ok, so i swapped over the positive with the negative on the sender and the gauge read 3/4! This is whats in the tank. so could this be the cause? Or is this what you mentioned Pete by earthing the sender? I then checked the stabiliser at the back of the speedo and i got 12 volts from the wires going in and a pulsed 0 - 5-6 volts (sometimes a 9-10 volts) on the output wire which runs to the gauges. Im going to get a solid state stabiliser but has anyone fitted one of these and are they worth it? Thanks Rich Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 20, 2015 Report Share Posted October 20, 2015 there 's a lot like them , some have been unreliable no hard and fast info on how good they are I fear its hobsons choice the fact youre getting mixed voltages may indicate a problem , inside is a simple wire wound coil around a bi metal strip, this has a pair of simple contacts which open close all i know is 0-10-0-10 is the normal. Pete Link to comment Share on other sites More sharing options...
Rich Posted October 20, 2015 Author Report Share Posted October 20, 2015 Many thanks Pete, Ill have a look once i get it through the post. In regards to the swapping of wires around on the sender, i put the neg on the pos and visa versa and it read 3/4. Could this be a fix or as you originally stated its just earthed to neg? Many thanks for all your help by the way, you should open a garage Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 21, 2015 Report Share Posted October 21, 2015 the two tags on the sender are one is to eath it to the body , lucar is welded to the float base, the insulated one is the line to gauge. they earth the sender as its mounts and tank mounts are not good earthing points . ( dont want sparks outside the tank) so it will probably will work with the earth lead Off. if you link the sender green wire to earth it should give a more than full reading on the gauge dont leave this on for long or you start to cook the gauge Rich, My mum always wanted me to have a garage she makes the cakes and scones and i scratch me head and get oily in the workshop it never happened 42 yrs in truck manufacture , managed all the Vehicle and Unit Audits, smoke emission, warranty returns, testing and tachograph calibration, so we being the factory ferrets had a good understanding of just about everything from electrophoretic paint tanks to screen wash jets great fun till it was closed down in 93 , I departed in 2003,,, just another lost industry in UK Pete Link to comment Share on other sites More sharing options...
AidanT Posted October 21, 2015 Report Share Posted October 21, 2015 Pete In respect of Rich's query in regard reversal of the wiring, Is it possible that reversing the wiring at the back of the Gauge would have the same impact? Its always possible that previous adjustments ended up with these wires being reversed It's something I have not tried yet (Tried most everything else!) Aidan Link to comment Share on other sites More sharing options...
Rich Posted October 21, 2015 Author Report Share Posted October 21, 2015 Pete many thanks for your reply, ive ordered another 'traditional' stabiliser so hopefully will all be ok, Regards Rich Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 21, 2015 Report Share Posted October 21, 2015 Gauges used to be marked with a b for battery and t for transmitter cant see that bi metal are polarity concious but ...you know that with a classic that when you find the fault it wont cure the problem !!!! Pete Link to comment Share on other sites More sharing options...
dougbgt6 Posted October 22, 2015 Report Share Posted October 22, 2015 My traditional voltage stabilizer failed and I got a replacement which also failed after 3 months. Then I bought a solid state one which has been working fine for 2 years. There are some cheap and nasty solid state ones which contain just a voltage stabiliser. This one has additional components, capacitors, which are necessary for long life! http://www.ebay.co.uk/itm/SOLID-STATE-VOLTAGE-STABILIZER-TR4-Dolomite-GT6-TR5-/131629262735?hash=item1ea5b7278f:g:ajsAAOxyUrZSzEu7 Link to comment Share on other sites More sharing options...
Colin Lindsay Posted October 23, 2015 Report Share Posted October 23, 2015 I bought one of those, seemed quite good spec, but never fitted it as yet as the Herald's still off the road.... Link to comment Share on other sites More sharing options...
Rich Posted October 27, 2015 Author Report Share Posted October 27, 2015 Hello all, Many thanks for all your replies. i managed to get a stabiliser from James P and found that its a solid state one but in the same guise as the original bi-metal one. Anyway fitted it today and both guages are working . I put the multimeter on the B terminal and got a good 12-13v and on the I terminal a good 12v. Kinda suspect that i should be getting 10v on the I terminal going to the guages! Could this be due to it being a solid state device? The broken original only pushed out 6 - 8v? Its fitted anyway so i suppose i should check the output with the engine running and all the earths back on which may drop the out put volts. Regards Rich Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 27, 2015 Report Share Posted October 27, 2015 Rich, If you check the voltage without any working load you can get battery volts on the meter not the reduced Voltage you expect solid state does not pulse like the old smiths units which do switch and at 6v is running low, hence your low readings never played with a solid state so blankety blank ifnthebgauges now read too high , well its not working !!!! ¥££€€_%%/× pete pete Link to comment Share on other sites More sharing options...
Rich Posted October 27, 2015 Author Report Share Posted October 27, 2015 Pete many thanks, hopefully will last slightly longer than the last one. Regards Rich Link to comment Share on other sites More sharing options...
AidanT Posted December 21, 2015 Report Share Posted December 21, 2015 Just wanted to add my findings on this. I have also now replaced my voltage stabaliser. I now get the correct fuel readings, well close enough to get to a petrol station before I run out! Shows full when it is filled to. Link to comment Share on other sites More sharing options...
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