car starting badly. getting worse :(

[MARK@CMBAUTOS]

(ect) engine coolant temperature sensor it controls cold start fueling and can be very intermittent iv replaced a few on various starlets and other cars

 

[dac69er]

hmmm. ok. it did have a bad spell in the summer when it started being a bitch too.

i did measure the resistances of the sensors when cold and when warmed up and compared them to my other GT and they were fine.

if i blip the throttle it generally clears and runs fine.

it runs badly for literally 5 seconds max unless it stalls itself or i blip the throttle to clear it. when this happens i restart the car and its perfect!?


i did replace the map sensor last night for the one off my other GT. will see how that goes. if still no joy ill get a coolant sensor and try that

 

[MARK@CMBAUTOS]

hmmm. ok. it did have a bad spell in the summer when it started being a bitch too.

i did measure the resistances of the sensors when cold and when warmed up and compared them to my other GT and they were fine.

if i blip the throttle it generally clears and runs fine.

it runs badly for literally 5 seconds max unless it stalls itself or i blip the throttle to clear it. when this happens i restart the car and its perfect!?


i did replace the map sensor last night for the one off my other GT. will see how that goes. if still no joy ill get a coolant sensor and try that

id say ect it sounds like it its the 2 pin plug on ur thermostat housing i think its green

 

[dac69er]

yes mate, its the green plug one. the cable going into the connector was damaged when i got the car but that has been repaired properly now!

ill wait and see if the map sensor makes any difference, if it doesnt then i will order a new ect sensor

 

[MARK@CMBAUTOS]

yes mate, its the green plug one. the cable going into the connector was damaged when i got the car but that has been repaired properly now!

ill wait and see if the map sensor makes any difference, if it doesnt then i will order a new ect sensor

ok iv got a few u could try cause they are around 70 ish new

 

[CDJS GLANZA]

check the vacum line on the map sensor aswell mine played up a bit like yours and it was the vacum line i'm bein a bit like rick and just throwing ideas out there

 

[dac69er]

check the vacum line on the map sensor aswell mine played up a bit like yours and it was the vacum line i'm bein a bit like rick and just throwing ideas out there

i did check it and it looked ok, blew through it too to make sure it wasnt blocked. when i took the map sensor off my other car i used that vac line too just incase!

 

[dac69er]

wasnt map sensor did it again today.

next up is the coolant sensor!

 

[MARK@CMBAUTOS]

good luck i do think this is your problem

 

[Texx]

next up is the coolant sensor!

Check the resistance of the coolant sensor when the engine is stone cold. I'd check it at the ECU first, between E2 and the THW pin, then at the sensor terminals to see if the readings are the same.

If the resistance is good, around 3-4KΩ or more, then I'd doubt it's the cause of the problem, any less than 2KΩ and you may have found your problem. An open or short circuit should flag code 22, but the sensor could intermittently give a low resistance reading which would account for the starting problem being intermittent.

Also the coolant sensor will be connected in series with a fixed value resistor within the ECU, it's mainly to protect the ECU from a dead short of the THW circuit. I can't really see a condition where a fixed value resistor will give a low resistance reading, but it's worth keeping in mind if you don't find the coolant sensor to be the cause and maybe worth swapping the ECU if you have one spare.

 

[dac69er]

Check the resistance of the coolant sensor when the engine is stone cold. I'd check it at the ECU first, between E2 and the THW pin, then at the sensor terminals to see if the readings are the same.

If the resistance is good, around 3-4KΩ or more, then I'd doubt it's the cause of the problem, any less than 2KΩ and you may have found your problem. An open or short circuit should flag code 22, but the sensor could intermittently give a low resistance reading which would account for the starting problem being intermittent.

Also the coolant sensor will be connected in series with a fixed value resistor within the ECU, it's mainly to protect the ECU from a dead short of the THW circuit. I can't really see a condition where a fixed value resistor will give a low resistance reading, but it's worth keeping in mind if you don't find the coolant sensor to be the cause and maybe worth swapping the ECU if you have one spare.

already tried swapping the ecu mate and it made no difference, i do have one more spare ecu i can try though.

i havnt measured the resistance of the sensor anywhere else but at the sensor itself, ill give that a go and see what it comes up with. these dark evenings are a pain, cant do much fault finding in the dark

 

[dac69er]

just an update:

changed the ecu again and checked all connections etc (used to have a fcd fitted).
now running a stock ecu as apposed to the jam unit. if anything its worse, but that could just be a coincidence!

will hopefully get time to measure the resistance of the sensor if its not raining tomorrow!

 

[Texx]

Does it only happen when starting the engine from cold or will it also play up when the engine is warm?

 

[dac69er]

only when cold. it started off intermittent but now it seems to be almost every time.
seems worse when i leave work rather than in the mornings?

when the engine is warm it never has any trouble. today it took several attempts to get it started, once it picked up it ran fine!?

 

[Texx]

After you've blipped the throttle does the engine idle ok when cold? Even with a heavy electrical load such as the headlamps, blower, brake lights etc... ?

Does the engine also have a fast cold idle? Indicating the ECT sensor is giving a near or correct reading?

 

[dac69er]

it clears too quickly or stalls so i dont get a chance to turn anything on tbh. when i blip the throttle it generally clears it and it will run fine. sometimes it doesnt clear it first time though, but only about once or twice ever!

the car will idle about 1800 rpm when stone cold and will slowly drop the rpm until its warmed up and then sit at about 900ish rpm.

this is what is confusing me!

 

[MARK@CMBAUTOS]

it clears too quickly or stalls so i dont get a chance to turn anything on tbh. when i blip the throttle it generally clears it and it will run fine. sometimes it doesnt clear it first time though, but only about once or twice ever!

the car will idle about 1800 rpm when stone cold and will slowly drop the rpm until its warmed up and then sit at about 900ish rpm.

this is what is confusing me!

change that ect sensor ! :argue::haha::haha:

 

[dac69er]

change that ect sensor ! :argue::haha::haha:

i need to get one first mate i wanted to try all the stuff that i already have first just incase it was one of those, no point spending more money than i need to.

ill get one ordered this weekend from camskill as i also need a waterpump for my other GT. when i have it ill change it and report back!

 

[MARK@CMBAUTOS]

i need to get one first mate i wanted to try all the stuff that i already have first just incase it was one of those, no point spending more money than i need to.

ill get one ordered this weekend from camskill as i also need a waterpump for my other GT. when i have it ill change it and report back!

ace keep me posted

 

[Texx]

i wanted to try all the stuff that i already have first just incase it was one of those, no point spending more money than i need to.

Exactly! If you remove the ECT sensor you can quite easily test it's operation by checking it's resistance.

Put a cup of water in the fridge for an hour or so to cool it down, the fridge should drop the waters temperature to around 4°C or 5°C. Connect the ECT sensor to a ohmmeter and then place the probe end of the ECT sensor into the water. Don't expect the sensors resistance to increase immediately, it may take a couple of minutes, at around 4°C or 5°C you should expect a resistance reading of approx 3-5KΩ, a reading lower than 3KΩ is likely to give the ECU an incorrect voltage reading for that temperature. Then repeat the same process with a cup of boiled water and expect a resistance to drop and give a reading of approx 100-300Ω.

If the sensor is reading incorrectly, particularly if you see a low resistance at a low temperature then replace the sensor.