johnpbransfield Posted October 8, 2018 Share Posted October 8, 2018 2009 Sigma....car has never registered full, only 3/4 when brimmed so I use a dip stick to check. At the Anglesey club sprint this weekend and it has now started registering past the Full mark all the time. Does this mean I shall never have to buy any more petrol or does the fault lie with the sender or the gauge ? Any help much appreciated. Well this morning decided to check the wiring...well the earths. At the guage end I spliced a wire into one of the negs and a new earth ....same result needle goes quickly to full. Did the same for the other earth same result, then earthed them together (they both go into the same part of the plug behind the guage).... Started smoking so quickly turned off. Decided to attack the pump!! which had completely fallen apart...just held together by wires. The top was attached to the tank the main bit and float were rolling around at the bottom of the tank so that was why the float was registering FULL with only 1/4 tank of fuel. Managed to get it back together and it seems quite secure as I can't pull it apart.Wired the guage back in (no smoke) and tested the pump out of the tank by moving the float.....and hey presto it works.....all the way to full.So question, how has it come apart as when it is in the tank it is screwed down and a spring compresses between the two parts, there is about 4cm of compression between the two parts so no room to separate when in situ. So I know the float will give a full value, but when in situ it only gives 3/4 when full. Which way do I slightly bend the float....down or up?......I am completely brain dead after today. Thanks for your advice so far. Any more input will be much appreciated. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 8, 2018 Member Share Posted October 8, 2018 Any recent work or has anything else changed recently?All other instruments working normally?Do you have a multimeter and the *appropriate wiring diagram?Jonathan* Let me know if you'd like one. Link to comment Share on other sites More sharing options...
SM25T Posted October 9, 2018 Share Posted October 9, 2018 If it operates in the same way as the temperature gauge ... and has now gone to full scale deflection, it may be the wire from the sender has gone to earth ... ie been chafed through or crushed ? Maybe by boot floor it it contacts the cable? Link to comment Share on other sites More sharing options...
SM25T Posted October 9, 2018 Share Posted October 9, 2018 Or as it happened at a track with high cornering and braking forces ... perhaps the sender float has got jammed against whatever it was previously contacting in the tank ? Is it integral with the fuel pump in the Sigma tank ... Or a separate float ? Link to comment Share on other sites More sharing options...
johnpbransfield Posted October 9, 2018 Author Share Posted October 9, 2018 Jonathan....yes all other dials working fine.SM25T yes integral with the fuel pump...will take the floor out and check the wiring. Had the pump out last year to try and sort the gauge reading but the float was registering with the top of the metal strip so all ok...just under reads true level. Lost power at one stage of the sprint.... Fuel starvation? But tank was nearly half full....I think chaffed wire may be the one to look at. Maybe worth investing in a multi meter? Thanks both for the advice. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 9, 2018 Member Share Posted October 9, 2018 Currently recommended multimeter. And treat yourself to an additional pair of leads with croc clips.Jonathan Link to comment Share on other sites More sharing options...
SpeedPete Posted October 9, 2018 Share Posted October 9, 2018 If you can take out the fuel pump, you could change the angle of the float by hand while checking if the gauge follows your input. However, that would probably not be enough resulting info to identify the exact location of the issue without additional further steps like the ones suggested by the others, I guess. Link to comment Share on other sites More sharing options...
johnpbransfield Posted October 9, 2018 Author Share Posted October 9, 2018 Boot floor out but can't see any chaffing / bare wire. Wire dissapears over diff holder...very tight there but not sure where the wires go after that? So JK a wiring diagram would be useful please. I don't think the float is stuck as the tank was never more than half full....but registering on the red which is normal for my gauge, even when overfilled it still only registered 3/4 full and that would be with the float at the top touching the tank. Not very electrically minded so how does a multimeter work and what should I look for when using one. Many thanks in advance. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 9, 2018 Member Share Posted October 9, 2018 Please send me a Private Mail with your email address and details of the Seven. ThanksJonathan Link to comment Share on other sites More sharing options...
SM25T Posted October 9, 2018 Share Posted October 9, 2018 Whatever you try.... no sparks anywhere near open fuel tank please .... it's the vapour that is most dangerous. Link to comment Share on other sites More sharing options...
John Vine Posted October 9, 2018 Share Posted October 9, 2018 Have you seen this thread re altering the float position?https://www.lotus7.club/forum/techtalk/recalibrating-fuel-gauge-using-spiyda-gauge-wizard(Sorry, can't do a linky from my Windows phone. ETA: Now fixed.)I think your fuel pump is the same as my R400 one. If so, you should be able to get more sensible gauge readings.JV Link to comment Share on other sites More sharing options...
johnpbransfield Posted October 10, 2018 Author Share Posted October 10, 2018 Thanks JV. JK email sent Link to comment Share on other sites More sharing options...
Area Representative Golf Juliet Tango Posted October 10, 2018 Area Representative Share Posted October 10, 2018 I can only comment on my experience with a fuel tank in my Crossflow. Mine started registering full at all times but this was an incorrectly mounted float. A similar issue affects the 21. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 10, 2018 Member Share Posted October 10, 2018 So I know the float will give a full value, but when in situ it only gives 3/4 when full. Which way do I slightly bend the float....down or up?Sounds like progress.I'd now read John's discoveries from post #11 above.Jonathan Link to comment Share on other sites More sharing options...
John Vine Posted October 10, 2018 Share Posted October 10, 2018 So question, how has it come apart as when it is in the tank it is screwed down and a spring compresses between the two parts, there is about 4cm of compression between the two parts so no room to separate when in situ. Bizarre indeed. I can't suggest why it came apart, except to suggest it wasn't assembled properly when last removed/installed.So I know the float will give a full value, but when in situ it only gives 3/4 when full. Which way do I slightly bend the float....down or up?..Down (as illustrated in my thread linked in post #11above -- see post #23 in that thread). This is what you want to achieve:Bend the arm so that the float sits level with the base of the pump.JV Link to comment Share on other sites More sharing options...
johnpbransfield Posted October 11, 2018 Author Share Posted October 11, 2018 Thanks JV will try that. Just been in touch with someone who has had the same problem with the separating pump! Ended up having to buy a new one.CC said it was quite common! Link to comment Share on other sites More sharing options...
ChrisC Posted October 12, 2018 Share Posted October 12, 2018 Can the pump/sender unit be fitted in a different orientations to the tank, i.e. if the sender arm isn't pointing towards the front of the car, then it would be effected by the angled shape of the tank bottom. In the pointing forward direction it would get the most movement potential in the tank. Obviously this would only applied if the pump/sender can rotate as the securing ring is tightened. Link to comment Share on other sites More sharing options...
John Vine Posted October 12, 2018 Share Posted October 12, 2018 Yes, the pump can be rotated in its mounting plate. The difficulty will be that the fuel hose may not reach the pump unless the connector points pretty much to the left-hand edge of the tank (its normal position).But even with a wider range of movement for the float arm, rotating the pump won't solve the problem of how to pick up the 5-6L of inaccessible fuel.JV Link to comment Share on other sites More sharing options...
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