need some info guys!!! engine temp sensor...

hainesz

New Member
im still having the problem with the fans not working when temp get hot... my temp gauge will go all the way to the top and nothing no fans will turn on... i have replaced the temp sensor the 2 pin with a red connection on it and also the relay but no joy... if i bridge the terminals in the relay socket i can get them to turn on, so i know that they do work...

when engine is 1st started it will backfire when i get to the top end of the revs before changing gear and wont idle less than 12000 rpm then once it has been run for say 10 mins it will drop the idle down to 1000 rpm but it will then fluctuate between 1000 - 12000 rpm... am i right in saying that this could also be down to the temp sensor? is the ecu not nowing the right temp and throwing in more fuel?

has anyone got a straight forward wire diagram so i could rewire the sensor straight back to the ecu?

i better add that the idle adjust screw is wound all the way in and at its lowest...

cheers guyz
 

danr

Member
could be the sender wires from sensor. have you not got consult or similar you can hook up to obd port and watch temperature, or know someone off here near to check for you?
if you check the manual, there is iirc the resistance at say 93C, so you could bridge connector with that resistance/resistor.
or even clean the contacts on the relays and seats, make sure firmly seated.
or (not checking myself in a rush), the pin out from ecu will go to relay, a +ve feed. so you could hook up an led to the ecu, with other led going to battery earth.
or trace wire etc...
 

hainesz

New Member
could be the sender wires from sensor. have you not got consult or similar you can hook up to obd port and watch temperature, or know someone off here near to check for you?
if you check the manual, there is iirc the resistance at say 93C, so you could bridge connector with that resistance/resistor.
or even clean the contacts on the relays and seats, make sure firmly seated.
or (not checking myself in a rush), the pin out from ecu will go to relay, a +ve feed. so you could hook up an led to the ecu, with other led going to battery earth.
or trace wire etc...
i dont have consult... ill need to know the wires i need to access at the ecu plug to check if there is a fault... anyone know what wires i need?
 

danr

Member


ok,
pin 18 is temp sensor +ve IN (cross reference with canadagtir here)
pin 21 & 29 are -ve EARTH for said sensor & tps
pin 9 is the +ve OUT to switch relay to fans ON

so basically, if the ecu is getting signal from temp sensor on 18 ok, then when hot 9 will go +ve to turn fans.

if you dont have a multimeter, or not sure how to use one then an LED should do the trick (could even use a 5v one as im sure the ECU doesnt operate above this voltage).
you could connect a small 12v LED (long leg is +ve) on pins 18 + 21 and it should be lit by ECU if all is working (whether fans need to be on or not).
then, when you know fans should be on, connect LED to +ve 9 and other leg to a good known earth, any bare metal on shell, floor, cig lighter etc. (or you could use ECU earth, but i'd be safe and go elsewhere), and LED should light.

if all that works ok, then a wire is broken/corroded etc.

usual disclaimer etc.
 
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hainesz

New Member
right im still having trouble, but have narrowed it down now... at the ecu plug pin 18 and 21 for the coolant temp sensor i get voltage and as it gets hotter the voltage drops ( so im taking it that the sensor is working fine) and pin 9 goes to the fan relay now this should turn to ground to switch the relay which in turn should start the fans... if i join a ground to the pin 9 the fans come on... so this means the ecu isnt grounding out this wire once it has reached temperture.... can anyone tell me why or what would cause this??? cheers peeps
 

Gtirchris

Member
Hey buddy, if you have grounded the wire and the fans work then that should mean that the wiring, relay and fans are all working ok, have you tried putting a multimeter on pin9 to check to see if the ecu is sending an earth to the fan relay when it should do i.e engine idling at say 90 degrees c coolant temperature?. if it doesn't then it is probably a fault with the ecu itself mate.
 

hainesz

New Member
ive sorted it now buddy, it turned out to be my gauge on the clocks is out so it looks like it is really hot when it acually isnt... fans are all working now, i just need to adjust the needle on the gauge i must have been put back on slightly out when lockwood dials were fitted... Doh... lol... cheers anyway buddy
 

danr

Member
i should have just said dash sender, but thought it had been mentioned in another post of yours lol
 
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