RT idling problem

[AJR93RT]

I have noticed that my car starts to idle strangly once the engine has warmed up. When i push the clutch down and bring the car to a stop at junctions the car engine starts to idle anywhere between 1500 and 2500 rpms. Is this possibly a sensor problem as it only does this when warm?

 

[Bayliss]

Its funny you say that bcos when mines warm it cuts out when I push the clutch in to stop at traffic lights anyone know what this prob is?

 

[number2301]

Mine does that hot or cold been told its a dodgy sensor cant afford to sort it yet tho...

 

[BenR]

probably vehicle speed information problem, with the sender behind the speedo in teh dash being the problem.

 

[JAY172]

speed sensor for the injection is part of the speedo cable itself.replace the cable as a first step(they are cheap).have a look at the coolant temp sensor as well.

 

[AJR93RT]

Is this likely to be a sensor problem rather than the stepper motor being faulty then?

 

[JAY172]

impossible to say without actually looking at the car.

 

[BRUN]

id go for stepper motor or coolant temp sensor, as these are very common problems on the RT

 

[AJR93RT]

Just taken the car out for a drive, found out that it is only idling strangley once the engine has warmed up. Once the car is then standing it will idle randomly between 700-1100rpm. If i put my foot down on the accelerator with the car in neutral and bring the revs up to around 2000rpm and the lift off, the engine starts to rev randomly around 2000-3000rpm often moving up and down. The only way to bring the revs back down is to put the car into first and bring the clutch up. When i lifted the bonnet while it was idling around 2000-3000rpm i could see the throttle cable moving. Im guessing this is the idle control stepper motor. Not sure if this extra information might help find the problem, any one got any ideas?

After leaving the engine to cool down again and then restarting it, it idles normally around 900rpm again.

 

[JAY172]

it sounds like the idle stepper moter is moving etc so possibly a sensor fault making the ecu operate the stepper moter incorrectly.i would check the coolant temp sensor as the fault appears to be tempurature related.

 

[BenR]

agree

 

[AJR93RT]

ok cheers guys, any clue on the price of the sensor? Also why would the coolant temperature affect the throttle stepper motor position?

 

[AJR93RT]

bump

 

[JAY172]

the ecu is operating the stepper moter as required for the coolant temp it is reading but if this reading is wrong then the stepper moter isnt operating for the actual coolant temp so your idle speed will be wrong.

 

[BenR]

77 00 810 879 SENSOR 3PIN 15.50 ---3 x 1

The coolant temp sensor tells the ECU the engines temp, and, for example, if the CTS is providing cold start temps (sub 20C), then the stepper motor will open the throttle more and inject more fuel, hence a higer idle speed.

 

[AJR93RT]

ok cheers, i understand the problem now just about figured it out myself. Thanks for the part no. Ben ill be getting that sorted in a couple of days.

 

[JAY172]

the last one i did was giving the ecu a temp of minus 112.the outer part of the sensor had complatly corroded away.

 

[AJR93RT]

How easy are they to replace and where abouts is it located?

 

[BenR]

simple unscrew the old and screw in the new and plug up. Its ont he front of the head on the thermo housing.

 

[JAY172]

peice of piss.screws into the head on the gearbox end.its the sensor with the white connector on it.you need a 21m deep socket.the other brown one next to it is for the temp gauge.

 

[AJR93RT]

Just finally replaced the TCS and all seems to be good so far fingers crossed, i also have a spare new TCS if anyone is intrested garage messed up the order so i ended up with two!!!

 

[JAY172]

fingers crossed it stays that way eh.

 

[AJR93RT]

OH JOY ITS BACK!!!! Simple fact that crossing your fingers dont work!! Ok it was fine up until today and i was just slowing down to pull in the driveway and it started reving upto 2000rpm again. This time i also noticed that the temperature gauge wasnt working, i was wondering if the wire connecting the ECU to the TCS might be faulty? If not whats the next thing to change in this long battle for idle control? Stepper motor speed sensor??

[Edited by AJR93RT on 30 April 2004 at 12:45pm]

 

[AJR93RT]

Any ideas people???

 

[AJR93RT]

BUMP

 

[AJR93RT]

BUMP

 

[AJR93RT]

Anyone got a clue what i should get changed next to sort out this annoying problem????

Speed sensor?

Stepper motor?


[Edited by AJR93RT on 05 May 2004 at 8:16pm]