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Megasquirt coolant temp readings/issues


Off Road Toad
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Have been getting the 90 ready for its MOT tomorrow morning, which has been a nightmare thanks to lots of neglect on my and my strangely absent co-driver :angry: (you know who you are ;) ) since we went to Romania and some other places and bloody slindon a couple of weeks back. LOTS of electric problems mostly sorted now, plus new wolf 110 brakes (calipers and discs) fitted all round etc etc etc blah blah blah.

But i have one more problem. this afternoon the car wouldnt start. It is an RV8 4.6 with megasquirt. yesterday it was fine today it won't play.

Somehow i got it to start after 30 mins of winding over kicking screaming beating and threatening it with a lighter and yet more petrol :ph34r: . I don't know what that was all about but i have noticed on the megasquirt screen that the coolant temperature is fluctuating between 92 and 108 degrees when the engine is cold and not running but with just the ignition on. after it eventually started i took the car out for a sound thrashing up the road to clear the plugs etc ( the 6000 rpm kind of thrashing :ph34r: ) when it gets up to temperature (according to the dash temp gauge which reads a normal 90 degrees ish) it seems to fluctuate between 120 - 138 degrees, so it is reading a rise in temperature but obviously not properly.

My question is why?

any help please will be appreciated greatly. is it a dodgy sender or something more sinister and possibly the cause of the sudden poor starting? also slightly concerned this may upset my emmisions test tomorrow too.

Steve

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In no particular order:

Where did the ECU come from?

Is it set up for the Rover V8 coolant sensor?

What it reading right beforehand?

Is it wired to the correct sensor on the engine?

Is the sensor earth connected back to the ECU plug not just the nearest ground point?

Do you have continuity from the sensor connector to the ECU plug?

Is the sensor resistance correct? (It should be ~235 ohms @ 90degC, ~3000 ohms @10degC)

If you unplug the sensor, what does it read? (should read very cold or default to 77deg)

If you short the sensor connector pins, what does it read? (should read very hot or default to 77deg)

If the coolant reading is p***ed then you'll have a devil of a job starting it from cold and it will run rich/lean depending.

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In no particular order:

Where did the ECU come from? Me :lol:

Is it set up for the Rover V8 coolant sensor? Yes

What it reading right beforehand? Yes

Is it wired to the correct sensor on the engine? Yes

Is the sensor earth connected back to the ECU plug not just the nearest ground point? Yes

Do you have continuity from the sensor connector to the ECU plug? Better to ask Steve to split a atom with a axe - answer = unknown :D

Is the sensor resistance correct? (It should be ~235 ohms @ 90degC, ~3000 ohms @10degC) Yes

If you unplug the sensor, what does it read? (should read very cold or default to 77deg) -40

If you short the sensor connector pins, what does it read? (should read very hot or default to 77deg) Erm asking Steve to "Short" anything electrical normally involves a fire :D

If the coolant reading is p***ed then you'll have a devil of a job starting it from cold and it will run rich/lean depending. Told him this :)

I think its a bad earth or bad connection, his truck has been "Given some stick" in last 10 months, now kicking him back :rofl:

I made the loom, and it had a 1/2 day tuning pre going to Romania to do the weeks event out there, the Lambda stopped working so have been unable to tune more

I think its rich anyway, now with CTS issue gawd knows how much fuel is going in to it

I have a feeling a red 90 will be on my drive shortly :lol:

Nige

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FFS, this is one of the benefits of MS, it won't start because of a wrong sensor reading so just go into the cranking / cold-start tables and move all the values up so it's enriching the right amount for the "wrong" temperatures it's currently reading. Job jobbed. Just remember to save your settings file so you can put it back afterwards.

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FFS, this is one of the benefits of MS,

Mate, quite frankly i couldn't give a flying one about the benefits of MS it just needs to FFS work.

So please leave the 'tone' out.

I do appreciate help but at the moment i am sick to death of this overfueled underpowered sack of RV8 !

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Haul Nige round... He can't be doing anything useful.. (Well nothing that doesn't involve a visit to A&E...)

He will be able to help Steve, even if you feel the need to kick his preverbial while he's bent over the engine bay....

Neil

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:rofl:

I as offerred like

When Mr S calms down from orbit I will sort it I am sure.......

[Michael Winter Advert Mode on]:P

"Calm Down Dear - Its only a lack of F maintenance and extreme abuse on your part

and driving it after 1/2 days logging like a cross between a thawck and a TWOC :P

[/Michael Winter annoying advert voice off]

That should do it :rofl:

Did you hear that ?

That was a "Kin MS Feeeerking blah blah blah grisel grisel Boooooom" from Costa Del Hambledon :P

:D

Nige

P.S Francis

Is this a good moment to mention your warranty has expired like :P

:rofl: :rofl: :rofl:

:P

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