cold start problem

[ceedub]

When I start my car in the morning to go to work or when finishing work in the afternoon - the engine seems to be slugish.

What I mean is that as I accelarate up to 80kmh or so the engine seems to be missing. I have noticed that this keeps happening until the thermostat kicks in and after that it is fine.

Someone has told me it could be a faulty temp sensor.

Anyone experienced this before?

Where can I find this temp sensor?

Please help !

CW

R32- GTR

[Jimbo2000]

you are driving it gently till it gets up to operating temp right?

[Messiah]

good point zoidberg... YAY your helping

if you are warming it up, how long does it take, does it warm up quick or take ages.

A dodgy thermostat will either not open at the desired temp (causing over heat)

or be stuck open all the time (making warming up take ages)

I wouldnt assume its the thermostat as this should only affect warm up times and engine temperature... AFAIK

a way of checking yr thermostat is working tho is to take of the rad cap, swtick in a thermometre and turn on the engine. iff all is well then the car should idle for a while with the radiater fluid temp staying steady, then it should heat up as the thermostat opens and starts letting coolant into the engine.

[Jimbo2000]

HOORAY I"M HELPING

[BHDave]

Mine does something similar. It feels like the timing is jumping around while the car is still warming up. Only does it when maintaining a speed or accelerating slowly. Idles fine or when under a bit of load. Then it will just suddenly be fine, like the computer switches from cold run mode to normal temp mode or something.

Definately either sensor or ecu related, not thermostat i think.

[ceedub]

Mine does something similar. It feels like the timing is jumping around while the car is still warming up. Only does it when maintaining a speed or accelerating slowly. Idles fine or when under a bit of load. Then it will just suddenly be fine, like the computer switches from cold run mode to normal temp mode or something.

Definately either sensor or ecu related, not thermostat i think.

Definatelly not the thermostat - that is working correctly - Warming up doesn't take long. BHDave seems to have the identical problem as me.

I have checked spark plugs etc but the only thing left is the temp sensors if only I knew where to look.

[avalonea]

From memory cold start program on the ecu relys heavely on the o2 sensor

that would be my first port of call

`josh

[Penfold]

how do you test what the reading is on the 02 sensor?

[ceedub]

where is this O2 sensor is there only one? or are there many?

[Cubes]

Mine has always done the same.

When cold (especially in winter) the car develops what feels like a flat spot when cruising on a set speed or accelerating lightly.

Some times it starts to drive fine then it feels like some thing engages and the flat spot develops.

It only lasts for around 1km then dissapears.

Warm the car up for a couple of minutes and you won't notice it.

I'm suspecting it could possibly be some thing to do with the O2 sensors pre-heat function, as an O2 sensor doesn't work until it has reached a certian operating temp.

[avalonea]

yeah . also a o2 sensor doesnt last for long. about 20,000k's they tend to die and get cloged

`josh

[R31Heaven]

This effect can be caused buy several things.

1. air regulator Valve stuck closed

2. ECU temp sensor (this sits on your radiator inlet pipe the one with two contacts)

3. bad earthing on your motor

4. leaking vacuum hose

just a couple to look at