[aussiepage]

Toyota Seca 1992 - 4AFE engine.
The Problem - when car is hot it sometimes stalls when stopping at traffic light.

Seems to happen more at night when headlights are on (probably more load on engine).

Is intermittent - some days car runs fine with no idle issue.

The car always starts again and no issues driving. No issues starting when cold and never stalls when cold.

I have:-

a) Inspected all vacuum lines.

Tested idle air control valve - air passes valave when cold and valave shuts off when engine hot.

c) Replaced air filter.



My questions are:-
1) What are the likely causes? Is it likely that the manifold pressure sensor is faulty.
2) When checking the idle up line for power steering I noticed that even without turing wheel air was passing through the control valve. So air is being sucked directly from air intake, through power steering idle up control switch and being delivered to inlet manifold - when nobody is turning steering. Is this normal? If I blocked this air path then the engine stalls so suspect it is. If I turn wheel the engine idles up correctly so valve must be opening more.

3) Is it wise to spray carb cleaner in throttle assembly while installed? If I open butterfly I can see a buidup of grease/tar - as expected for a car this old.

4) Could a faulty temperature sensor cause these issues?

Am a bit stuck really. Any air leak would increse idle speed, idle air control valve seems ok, idle speed when engine hot seems OK but just this intermittent stall when stopping.


All ideas gratefully received.



Many thanks

Bruce

[Dascal101]

You seemed to of covered everything I would of recommended, as for carb cleaner, I wouldn't, take it off and do a real thorough job of it, even sonic (I think it's called) cleaned. I want to get mine done soon if I don't find a 4age

[wel]

check your car for overheating issues... radiator fan, radiator cap, thermostat, thermoswitch, temp gauge... also check intake air valve, i believe there is a sensor that measures intake air temperature

[A Good's 4A-GE]

My 4age does the same, I just replaced the thermostat so it runs warm instead of cold now but it stalls going up to lights when the temperature is half on the gauge. - It has always stalled like this when it warms up during town driving...

[choicesx]

Adjust your TPS.

[A Good's 4A-GE]

Anyway, I got my 4age running better today by turning the idle adjustment screw to 900 rpm.

[aussiepage]

A Good, on 18 July 2011 - 03:11 PM, said:

Anyway, I got my 4age running better today by turning the idle adjustment screw to 900 rpm.

Thanks to everybody for your help. Has not stalled again this week. Very strange - this is the third time that I have had car stalling - then looked for problem without doing any major work and then it is fixed. I do notice that the temperature guage is always showing cold when driving in winter but warms up to normal if I idle while stationary until the fan starts.

Will keep looking for issue.

Thanks
Bruce

[A Good's 4A-GE]

aussiepage, on 19 July 2011 - 11:49 PM, said:

Thanks to everybody for your help. Has not stalled again this week. Very strange - this is the third time that I have had car stalling - then looked for problem without doing any major work and then it is fixed. I do notice that the temperature guage is always showing cold when driving in winter but warms up to normal if I idle while stationary until the fan starts.

Will keep looking for issue.

Thanks
Bruce

The reason it is running cold is that your thermostat is jammed open, it's pretty easy to replace.

[Dascal101]

Not true, mine runs on complete cold when driving around town etc but goes half up when at lights, parked etc. It's because the movement of the car has cold air going threw the front of the car cooling everything, that doesn't automatically mean the thermostat needs replacing

[choicesx]

Dascal101, on 20 July 2011 - 09:16 AM, said:

Not true, mine runs on complete cold when driving around town etc but goes half up when at lights, parked etc. It's because the movement of the car has cold air going threw the front of the car cooling everything, that doesn't automatically mean the thermostat needs replacing

OMG! I think you need to google what a thermostat does and reply again.

[Dascal101]

The thermostat allows coolant to cool the engine as the engine gets warmer, yes I know what it does, and yes my answer stays the same. If it was jammed while cold why wouldn't it stall when it's cold?