faulty ect sensor?

R

RGM1800

Member +
the car park overnight, woke up this morning and pulled of the ect sensor to check the resistance.
after hooking it up on the multimeter the reading it shows 1500 ohms.
what do you guys think? its overfueling? time to replace?
 
Texx

Texx

Super Moderator
The resistance does sound a little low for a cold engine. 1.5KΩ would be indicating a coolant temperature of around 30-35°C. If the resistance doesn't drop any lower when the engine is up to temperature, then yes it could cause a rich mixture. I'd check it's resistance again once the engine has warmed up before spending money on a new sensor.

Is the engine difficult to start from cold?
 
R

RGM1800

Member +
i pulled the sensor when the engine is dead cold. car doesnt have difficulties starting during cold.
ill try to upload pics of the sensor later
 
Texx

Texx

Super Moderator
The stock ECU will probably run with cold start enrichment up until coolant temperature reaches about 45°C or a THW resistance of approx 1KΩ or less, so the resistance reading you've got possibly wouldn't cause a poor cold start issue anyway.

Get the engine warmed up to the point the cooling fan has kicked in at least twice and then test the sensors resistance again. You'll want to see a resistance of 0.5KΩ or less to confirm if it's reading correctly.
 
R

RGM1800

Member +
so the reading normal engien temp would be not more than 500 ohms right? ill give it a try tomorow. so my reading during i pulled off the sensor is quite low? does it indicate overfueling? throwed a rep
 
Texx

Texx

Super Moderator
At normal running temperature you'd expect the coolant to be around 85°C and so the sensor should give a resistance of less than approx 0.5KΩ. If the sensor still maintains a resistance of 1.5KΩ or it's resistance doesn't drop sufficiently when the engine is up to temperature, then it will cause a rich mixture.

This graph should give you a better understanding of what you need to look for.


ectgraph.png
 
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Texx

Texx

Super Moderator
Ideally at running temperature you'll want to see a resistance of 250-350Ω, but certainly no more than 500Ω.
 
Texx

Texx

Super Moderator
I've not measured the resistance of one straight out the packet, however the ambient air temperature can still have an affect on the sensors resistance. To test the sensors integrity throughout it's operating range, you'd need an accurate thermometer and some way of gradually heating water like a saucepan on a stove.


ecttest.png
 
H

hapster

Fresh Recruit
hey texx i have now the resistance. measured after 20kms of driving.
i measured it whiel the sensor was bolted on the thermohousing. and water is also drained. its 274 ohms. is that ok?

and also measured the intake temp sensor its 537 ohms.
 
Texx

Texx

Super Moderator
hapster said:
hey texx i have now the resistance. measured after 20kms of driving.
i measured it whiel the sensor was bolted on the thermohousing. and water is also drained. its 274 ohms. is that ok?

and also measured the intake temp sensor its 537 ohms.
Click to expand...


If the engine was still hot when you measured the resistance of both sensors, then yes I'd say they were OK.
 
R

RGM1800

Member +
Texx said:
I'm not 100% sure which sensor your referring to, but it's probably the sender for the temperature gauge in the dash.
Click to expand...

when facing the engine, the temp sender is "after" the ect.

im referring to the sensor "before" the ect.
 
Texx

Texx

Super Moderator
TBH without looking I couldn't say for certain, but it's possibly a coolant temperature sensor for the A/C amplifier.
 
R

RGM1800

Member +
Texx said:
TBH without looking I couldn't say for certain, but it's possibly a coolant temperature sensor for the A/C amplifier.
Click to expand...

ah ok. its a single wire like the temp sender but bigger than the temp sender. what does it do? can i plug it off?
 
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