OVER FUELLING ON COLD START

[blitzracing]

You have completely missed the point - it makes no difference at normal engine temps, only when the engine is stone cold, so no risk to the engine whatever the season. Running engines lean is a bad idea under full load and high temperatures but this is not the case at cold start and the worse case is your engine wont start due to lack of fuel if you make the resistance too low. The relay idea is not a fix, as the over fuel problem is still there when the engine starts and the relay drops out, and you sit there gassing your neighbours with unburnt fuel.

[Penelope Stopit]

spitfire4v8 said:

There's something you can buy (I forget the info) whereby you can alter the apparent output of a thermistor for re-aligning a temperature gauge needle on non-standard engine/car installs .. I don't know if it's for bi-metallic strip style gauges so could be a pwm output though or whether it does provide an output that an ecu can see as true thermistor emulation .. if it did then you could set your effective thermistor curve to whatever you wanted.
Forgive me if it doesn't do what's required, it just popped into my head when reading PS's post ^^

That's it then, this is the ideal fix

The unit that spitfire4v8 commented about and Steve_D posted a link to will solve the problem

https://www.spiyda.com/fuel-gauge-wizard-mk3.html

There is no point in altering the temperature sensor resistance for it to work in warm or warmish weather in the summer only for the adjusted to resistance values to fall over during a cold winter

Anyone thinking that cold starting won't be a problem in the winter needs to think again about what adding a permanent fixed resistance into the circuit achieves

Climate, it's all about climate

spitfire4v8 Gets the Blue Peter Badge

[Zener]

The thing is your only adding enough resistance to correct the slight over-fueling these cars suffer from its not massive otherwise the car wouldn't start full stop, it only floods when stabbing the throttle as this introduces even more fuel to the already fuel heavy mix this will only alter things a tad the temp sender will still have its linear curve after all just with a slight offset still producing the necessary cold start enrichment Blitz knows the show

[blitzracing]

Penelope Stopit said:

That's it then, this is the ideal fix

The unit that spitfire4v8 commented about and Steve_D posted a link to will solve the problem

https://www.spiyda.com/fuel-gauge-wizard-mk3.html

There is no point in altering the temperature sensor resistance for it to work in warm or warmish weather in the summer only for the adjusted to resistance values to fall over during a cold winter

Anyone thinking that cold starting won't be a problem in the winter needs to think again about what adding a permanent fixed resistance into the circuit achieves

Climate, it's all about climate

spitfire4v8 Gets the Blue Peter Badge

Why do you always make simple things so complex? Please as you are the expert, use ohms law to work out the predicted temperate shift the ECU sees for lets say 0, 10, 30, and 80 degrees with a resistor value of 4k. You have the figures, now go and do the maths.

[Penelope Stopit]

Unfortunately Gauge Wizard has its limitations

Due to the temperature sensor being non-linear, the "Wizard" can't be set for chosen temperatures between cold and hot

spitfire4v8 said:

I don't know if it's for bi-metallic strip style gauges so could be a pwm output though or whether it does provide an output that an ecu can see as true thermistor emulation .. if it did then you could set your effective thermistor curve to whatever you wanted.
Forgive me if it doesn't do what's required, it just popped into my head when reading PS's post ^^

Output is PWM and it's fallen over https://www.spiyda.com/pub/media/wysiwyg/pdf/PicWi...

This is a shame, could have been good

Back to the drawing board

[blitzracing]

Done it for you mate :-)

[Loubaruch]

:

[rigga]

Penelope Stopit said:

This is a shame, could have been good

Back to the drawing board

Relays ......the answers always relays.

[Penelope Stopit]

At long last a solution has been discovered

A dirt cheap fix is to use a temperature control switch that can be wired to switch a chosen resistance in and out of the vehicles temperature sensor circuit at a chosen temperature

The above method will overcome over fuelling at start-up and will then allow the system to revert back to factory specification once the engine has begun to warm up

Cost is less than 6 Euros including delivery
https://www.ebay.co.uk/itm/W1209-50-110-C-12V-Digi...

[blitzracing]

Seems ideal to me, not only does it have a relay to fix your fetish, it's got electronics as well to go wrong in a TVR engine bay.

[Penelope Stopit]

blitzracing said:

Seems ideal to me, not only does it have a relay to fix your fetish, it's got electronics as well to go wrong in a TVR engine bay.

Nothing of the sort

Only an idiot would fit the above unit in an engine bay

TVR owners are clever otherwise they wouldn't be able to drive TVRs

[blitzracing]

So, you have to run a wiring loom from your temp sensor into say under the dash somewhere (add the time taken to try and remove it), drilling whatever holes, then fit the unit into a case, and add some additional smoothing circuitry to make sure the 12v supply is clean, then finally spend however long trying to calibrate it? As usual with your posts, you wont have tried this, wont be able to show it working, but yet you recommend someone else goes and does it? I'm sure clever TVR owners wont think this is a good idea when a 5p resistor across the sensor will work perfectly well, and if you read the post its actually been done and works.

[Penelope Stopit]

blitzracing said:

So, you have to run a wiring loom from your temp sensor into say under the dash somewhere (add the time taken to try and remove it), drilling whatever holes, then fit the unit into a case, and add some additional smoothing circuitry to make sure the 12v supply is clean, then finally spend however long trying to calibrate it? As usual with your posts, you wont have tried this, wont be able to show it working, but yet you recommend someone else goes and does it? I'm sure clever TVR owners wont think this is a good idea when a 5p resistor across the sensor will work perfectly well, and if you read the post its actually been done and works.

Thank you very much for your input

Having read through your post several times and split it into 2 parts, one part being useful and the other being useless

Was left with

Useless...

blitzracing said:

So, you have to run a wiring loom from your temp sensor into say under the dash somewhere (add the time taken to try and remove it), drilling whatever holes, then fit the unit into a case, and add some additional smoothing circuitry to make sure the (12v moved to useful) supply is clean, then finally spend however long trying to calibrate it? As usual with your posts, you wont have tried this, wont be able to show it working, but yet you recommend someone else goes and does it? I'm sure clever TVR owners wont think this is a good idea when a 5p resistor across the sensor will work perfectly well, and if you read the post its actually been done and works.

Useful...

blitzracing said:

12v

I had completely overlooked the operating voltages of cheap and nasty Chinese stuff being sold through Ebay

Although your above post doesn't show a comment about the possibility of 14.5 volts being applied to the above unit I have a suspicion that you intended it to show yet it wasn't shown in your post due to a typo or computer keyboard failure

Anyway, whatever the reason for the above is of no great importance at present although it might be worth you looking into it (no, not the unit, your keyboard), what is important is the little bit of usefulness that is to be found in your post (12v)

Your good self having got me delving deeper into operating voltages has been a massive deciding factor in a big change being made to the method used for switching a resistance in and out of the temperature sensor circuit

I can't thank you enough for your input and mature manner used in highlighting 12v

Have decided to suggest the use of a capillary thermostat control, not fitting the capillary into a hose but fastening it to a hose, radiator or cylinder head

The cost of the job has now increased to approximately 11.5 Euros including delivery, more than I had wished it to yet worthwhile for reliability
https://www.ebay.com/itm/Capillary-Thermostat-Car-...