swindon_alan Posted May 23, 2016 Report Share Posted May 23, 2016 INFO Lotus description: "Relay, low fuel delay module"/"Low fuel warning lamp delay module" Lotus part number: *089M6330F Manufacturer: BMI BMI part number: 01212E Cross references: None, specific to the Esprit Status: Obsolete, SJ Sportscars, the Elise Shop, etc. may have stock PHYSICAL BOARD LAYOUT COMPONENTS CIRCUIT DIAGRAM FUNCTIONAL DESCRIPTION"Low Fuel Level Tell Tale: This lamp is calibrated to light up amber when the level of fuel in the combined tanks falls to approximately 10 litres (2.2 imp. gal; 2.6 US gal). Note that the fuel gauge will be reading zero at this time. The level sensor is combined with the fuel gauge sender in the LH tank." The module smooths out any temporary movement of fuel in the tanks to provide a stable tell tale illumination. COMMENTS This feels like a lot of electronics and probably overkill to provide some hysteresis around preventing the tell tale coming on when temporarily accelerating/decelerating/climbing/descending/pulling Gs around corners (and conversely to latch on when "properly" triggered). But then this is a Lotus :-) WORKAROUND Jumper wire: LOW FUEL WARNING LAMP TEST Jumper wire: 2 Quote I tempted fate...now my Esprit V8 IS in bits...(sob) Link to comment Share on other sites More sharing options...
Erikl Posted April 13, 2019 Report Share Posted April 13, 2019 I was installing the ABS delete kit on my 94 and I hit this with module with my elbow and broke it 😞 JAE here in the states does not have one - S&J show one but I have not confirmed. Thanks for posting the work around - going to give this a try and see how it goes. 1 Quote Link to comment Share on other sites More sharing options...
march Posted May 29, 2019 Report Share Posted May 29, 2019 Has anyone thought of wiring one of these into the old relay body. Seems to do the same thing. https://www.ebay.co.uk/itm/Low-Fuel-Warning-Delay-Switch-Relay-Fits-Triumph-TR7-TR8-BDS1003-00-/352502185452 Quote Link to comment Share on other sites More sharing options...
swindon_alan Posted May 30, 2019 Author Report Share Posted May 30, 2019 Interesting @march. It has four terminals, T, L, B and E. Presumably Tank, Light, Battery and Earth? That's the same arrangement as the BMI module. So possibly... However, we would need to see it in the context of the wiring diagram. The Lotus uses a separate switch in the tank to signal that one, whereas this one might use the variable voltage off of the fuel level sender. The part number, BDS1003 also covers BDS1004 by the look of it and the description on an ad reads: This is a NOS Smiths thermal delay switch, or low fuel warning relay for Triumph TR7 and TR8 . Smiths Part number BDS 1004/00. That tends to suggest that it is switched. Quote I tempted fate...now my Esprit V8 IS in bits...(sob) Link to comment Share on other sites More sharing options...
march Posted May 30, 2019 Report Share Posted May 30, 2019 1 hour ago, swindon_alan said: we would need to see it in the context of the wiring diagram Will scan the manual tonight. The tank line comes from a switch on the fuel sender if I remember correctly. I assume being an old Leyland part it is going to be pretty dumb. Quote Link to comment Share on other sites More sharing options...
march Posted May 30, 2019 Report Share Posted May 30, 2019 @swindon_alanThe scan shows 99 being the low fuel delay relay, 98 is the tank sender unit. LGR feeds the low fuel light via relay switch. I may even have one of these lying around should anyone wish to prove this. Quote Link to comment Share on other sites More sharing options...
Erikl Posted May 30, 2019 Report Share Posted May 30, 2019 Hmm Maybe I will buy it and have it shipped to Alan so he can take it apart. Odd, I have my module unplugged and out of the car. I was surprised my gauge worked at all. The gauge moves a bit when going around a corner but its barely noticeable. I have to put the bypass wire in and see how it acts. Quote Link to comment Share on other sites More sharing options...
march Posted May 30, 2019 Report Share Posted May 30, 2019 This module does not affect the gauge at all, just the low fuel light. Quote Link to comment Share on other sites More sharing options...
Erikl Posted May 31, 2019 Report Share Posted May 31, 2019 Ohh wow - that is a lot of extra just for the light. Sometimes I am amazed at the hoops auto makers have to jump through to deliver something like a low fuel light that you never think about or take for granted. Quote Link to comment Share on other sites More sharing options...
ekwan Posted May 31, 2019 Report Share Posted May 31, 2019 (edited) If the Lotus fuel sender has a separate switch for "low fuel", a simple delay circuit using the NE555 timer could provide say, T=3s (more or less) damping for the fuel light. Cheap and uses the minimum of components. Edited May 31, 2019 by ekwan Quote Link to comment Share on other sites More sharing options...
Erikl Posted May 31, 2019 Report Share Posted May 31, 2019 The NE555 is less than $2. Can you get a socket that it fits in that allows easy attachments with short leads? https://www.frys.com/product/8052424?store=38&source=google&gclid=Cj0KCQjw_r3nBRDxARIsAJljleFDxTz-vTv92ydjhuQvJpPaDO7JntSK546-5-tzYv7MVpfGWsUdd74aAv_2EALw_wcB Quote Link to comment Share on other sites More sharing options...
swindon_alan Posted May 31, 2019 Author Report Share Posted May 31, 2019 9 hours ago, march said: @swindon_alanThe scan shows 99 being the low fuel delay relay, 98 is the tank sender unit. LGR feeds the low fuel light via relay switch. I may even have one of these lying around should anyone wish to prove this. That will do the job @march. As you note, a separate switch in the tank in the TR, same as the Esprit. I would have to get a meter and a 12V supply on one to confirm the pin outs but yes, very good spot. Depending on the size - you might have to pull it out of the can - it could even fit in the BMI shell with some short jump wires, as you suggested. It would swap electronics for electro-mechanical but as I noted above, "This feels like a lot of electronics and probably overkill". @Erikl indeed you could build a NE555 version of the BMI but you would also need timing capacitors/resistors and a power transistor or a relay to ground the 12V feed from the warning lamp. Quote I tempted fate...now my Esprit V8 IS in bits...(sob) Link to comment Share on other sites More sharing options...
march Posted May 31, 2019 Report Share Posted May 31, 2019 @swindon_alan I have half a dozen old TR7 wiring looms, I will see if one is still attached for you to play with (if it's not practical let me know as these seem to have some value - although I have never heard of one failing), will let you know over the next few days. Quote Link to comment Share on other sites More sharing options...
swindon_alan Posted May 31, 2019 Author Report Share Posted May 31, 2019 Thanks @march, yes let me know if you find one and I will PM you my address. I can send it back to you again after examination. Good stuff! Quote I tempted fate...now my Esprit V8 IS in bits...(sob) Link to comment Share on other sites More sharing options...
ekwan Posted May 31, 2019 Report Share Posted May 31, 2019 (edited) 2 hours ago, swindon_alan said: That will do the job @march. As you note, a separate switch in the tank in the TR, same as the Esprit. I would have to get a meter and a 12V supply on one to confirm the pin outs but yes, very good spot. Depending on the size - you might have to pull it out of the can - it could even fit in the BMI shell with some short jump wires, as you suggested. It would swap electronics for electro-mechanical but as I noted above, "This feels like a lot of electronics and probably overkill". @Erikl indeed you could build a NE555 version of the BMI but you would also need timing capacitors/resistors and a power transistor or a relay to ground the 12V feed from the warning lamp. The wisdom of TLF'ers and op-amps shall conquer all. 😂 Edited May 31, 2019 by ekwan Quote Link to comment Share on other sites More sharing options...
march Posted May 31, 2019 Report Share Posted May 31, 2019 @swindon_alan - I have cheked all my spares and rediculously I cannot find one. I know I have a couple but I need them. I will continue looking tomorrow but I will probably need the unit back that I send. Courtesy of the TR7 community here are the contents of the unit - simple eh!. It is just a bimetallic strip that warms up over time and only releases after the current has stopped and the strip has cooled down. Who needs electronics when hot metal will do 🤪. One good thing - I can now get into the stable with some of the TR parts, tomorrow stable number 2! Quote Link to comment Share on other sites More sharing options...
march Posted June 1, 2019 Report Share Posted June 1, 2019 @swindon_alan Hi - I have found a unit (it's a bit ropy but it should work). I think I have also found an alternative electronic version but I don't know the pin out, I have bought one anyway (only £6.50 inc postage), it's from a Honda Goldwing GL1200 1984-87 which could be a better option and will send it along as well. The Relay is labelled ET-65. The Honda unit is has 4 pins and the sender appears to have 3 pins so logically one should be a low fuel switch. Feel free to destroy the honda unit if need be as they are cheap enough - and to be honest these may be a good replacement for the Triumph ones as well. The Triumph one is from the rally car harness so would prefer to have it back, Thanks. Please message me with your address so I can send them on. Marc As a note Harley Davidson do a unit as well but I don't know if it works from a switched sender. 1 Quote Link to comment Share on other sites More sharing options...
swindon_alan Posted June 23, 2019 Author Report Share Posted June 23, 2019 Smiths BDS100x diagrams: (Drawing says Lucas, duh! It is a Smiths Industries part). BMI pin mappings bottom right. Note that the two pairs of terminals can be connected either way round and the male/female combinations ensure that you shouldn't get them wrong. Well at least on a TR7! I've had a go at the Honda Gold Wing electronic module that Marc sent me but the potting compound appears to be made of reinforced concrete and will take a lot of work with a Dremel to get to the components. When I have a spare afternoon perhaps... So thanks very much @march, your unmolested relay is back in its Jiffy bag and will be on the way to you tomorrow. 1 Quote I tempted fate...now my Esprit V8 IS in bits...(sob) Link to comment Share on other sites More sharing options...
march Posted June 23, 2019 Report Share Posted June 23, 2019 @swindon_alanI had a little bit more of a look into the Honda units, couldn't find much in the way of wiring diagrams but I did discover that they were used on loads of Honda bikes through the 80's, 90's and 2000's. It may be worth an ask on the motorbike section here to see if any one has an old Honda Haynes Manual loafing their garage (unfortunately my 94 Fireblade does not have a low fuel warning). Quote Link to comment Share on other sites More sharing options...
v8GTmac1 Posted May 14, 2021 Report Share Posted May 14, 2021 (edited) i dealt with this low-fuel relay yesterday. traced the issue from the sender to the light and found there was this doohickey under the hood. Took it out and sure enough keeping the light on. It was the craziest coincidence that I was re-calibrating my fuel gauge needle to then have this happen? I was so confused. I opened it, re-soldered everything and working good now. I was about to put the jumper wire but it's now good. On 22/05/2016 at 17:18, swindon_alan said: COMPONENTS CIRCUIT DIAGRAM Jumper wire: you did great work here, you mind doing one for the factory ECU? Edited May 14, 2021 by v8GTmac1 Quote Link to comment Share on other sites More sharing options...
mike_sekinger Posted May 14, 2021 Report Share Posted May 14, 2021 Hi Michael, Sadly Alan passed away last year. He did do an awful lot of great work behind the scenes and is still very much missed amongst us. Mike S Quote 1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear) 1999 S350 #002 Esprit GT1 replica Link to comment Share on other sites More sharing options...
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