High Idling speed

Martron

My car has been sitting up for about 9 weeks. ((toyota avensis) . i had to jump start it this morning. anyway it now idles at 1500rpm. instead of just below 1000rpm. The da says it might be that the automatic choke is stuck. Is this possible? nad if so is there a remedy or another possible reason?

omb0wyn5ehpij9

Have you driven it much since you jump started it?

Martron

drove around all day in it and no change.

AugustusMaximus

Maybe its the lambda sensor.

I know this can cause cars to idle too low.

E92

Martron wrote: »

My car has been sitting up for about 9 weeks. ((toyota avensis) . i had to jump start it this morning. anyway it now idles at 1500rpm. instead of just below 1000rpm. The da says it might be that the automatic choke is stuck. Is this possible? nad if so is there a remedy or another possible reason?

Your dad is wrong:)!

Modern fuel injection cars don't have chokes! It's all electronic these days, and probably some sort of sensor giving the ECU, or the brains of the engine the wrong information and then the ECU is telling the engine to idle at a higher speed based on incorrect information.

VH

what year is it?

E92 wrote:

Modern fuel injection cars don't have chokes!

people still use that terminology to describe intake air bypass valves etc - just like they still talk about fanbelts

co-incidentally many such valves on modern cars are wax filled and not connected to any sensor or even the ecu

Mr.Diagnostic

In general, anyone who talks about an automatic choke on a modern car has no idea what they are talking about. Waxstats etc went out with button boots. Cold running enrichment is controlled by a map rather than external actuators.

E92 is pretty much spot on with his comments above.

Aside from a stuck throttle cable or butterfly valve or a vac leak the car really needs to be looked at.

VH

a quick google for wax idle valve shows the mx-5, rx-7, various hondas, all have them - we have a '00 car that has one

automatic choke is a general term, like fanbelt is

unkel

Mr.Diagnostic wrote: »

Aside from a stuck throttle cable or butterfly valve or a vac leak the car really needs to be looked at.

And mabye a dirty throttle body?

Martron

its a 2000. it idles high after maybe an hour of driving.

i have checked the throttle cable and the rest and there seems to be no leakages.

i know before the 9 weeks it did rev slighlty faster when i started it but did drop down after 30 minutes or so.

i take it that the is no quick fix then?

Mr.Diagnostic

Leaving aside the issue of trying to prove this fault could be caused by a faulty component that is not actually fitted to this car, the OP’s latest info throws a new light on this.

I have done a few Toyota idle control issues. Most of them have been down to faulty idle control motors. The motors can be either faulty or clogged up with carbon. It would be worth while removing it to clean it. Mark its position if you do this.

Does this have a MAP or MAF sensor? I have seen a few newer ones with a faulty MAF cause a high idle. I think yours will have a MAF. When it is playing up try unplugging the MAF. Also try tapping it gently with the handle of a screwdriver while it is running.

Martron

where abouts would i find the MAF? whats it look like?

Mr.Diagnostic

It will be on the air intake between the air filter and the manifold. A quick google image search should get you an pic of it.

VH

Mr.Diagnostic wrote: »

Leaving aside the issue of trying to prove this fault could be caused by a faulty component that is not actually fitted to this car, .

nobody is trying to prove anything, except you - no-one said anything was fitted to this car - and all you are trying to prove is you know more than anyone else - which frankly is off-putting

op - what model engine is this - it should be written in big lettering somewhere and should start with a 3 or a 4 - eg 4AFE

Mr.Diagnostic

Strangely enough only one of us has even attempted to help the OP.
Your version of helping so far has been to talk about a component that is not even fitted to the car so as to back up what you incorrectly posted earlier.
I imagine the OP would rather have some relevant advice.

Me stating quite clearly that I have done a few of these and I don’t know if this one has a MAF or not is not exactly me claiming any great knowledge on this particular system now is it? You appear to have a reasonable grasp of the English language so I imagine the opinion you posted is based more on you wanting to have a go than your actual interpretation of my post.

It sounds to me like you have a chip on your shoulder for some reason. Either way, lets see if the ignore button works.

VH

i have asked the OP for the year and engine model number - more information is needed before making a judgment

i have not jumped in with an authoritarian attitude and looking to rubbish other peoples views without even looking for the most basic of information - youre offering solutions without even asking if its petrol or diesel!

at the same time you come out with things that are clearly wrong - and in a very condescending way i might add - like that no modern car has a wax idle valve

i have also come across high idle problems on toyota engines - particularly a 4AFE after being in storage for 3 months - but i will not offer advice until i find out what engine the OP has

Martron

the engine is 4afe.

VH

if you start the car from cold and leave it idle what happens?

also was it stored out doors?

also have you used all the electrical things in the car since it came out of storage, like heater, window demister etc?

Martron

it was stored outside. and if i leave it idle it will just stay at the 1500rpm mark. where as before it would idle just below 1000 rpm. as for the heaters and stuff i have not tried them but lights and radio seem to work fine. electric windowes sunroof etc

VH

have you checked the idle adjustmet screw?

is the check engine light working?

you should use all your electrical things to make sure none are faulty

Martron

ok just went out to the car. fired it up. was still idling high. followed the air intake pipe to the mainfold and there was a little round box. gave that a bit of a tap and the revs dropped instantly. but now what happens is that the revs drop below 800 then goes back up to 1100. then drops slowly to 800 then goes back up to 1100. is this normal?

Martron

VH wrote: »

have you checked the idle adjustmet screw?

is the check engine light working?

you should use all your electrical things to make sure none are faulty

there is no warning lights on and everything seems to be working fine. Electrnics wise

Mr.Diagnostic

Martron wrote: »

ok just went out to the car. fired it up. was still idling high. followed the air intake pipe to the mainfold and there was a little round box. gave that a bit of a tap and the revs dropped instantly. but now what happens is that the revs drop below 800 then goes back up to 1100. then drops slowly to 800 then goes back up to 1100. is this normal?

Can you describe the round box? colour. size, number of wires going to it etc

Martron

about same size as a match box with rounded edges on it. its connected straight to the side of the manifold where the air intake joins it. it has 3 wires connected to it. red blue and black

Mr.Diagnostic

Since tapping it gave you a change in idle speed you have probably found the correct area of the fault. What you need to do now is identify what that component is. I will have a look later and see if I can ID it from the wiring colours or maybe show you a few images.

Darragh29

AugustusMaximus wrote: »

Maybe its the lambda sensor.

I know this can cause cars to idle too low.

Bring it out for a good long drive and make sure it gets really warm. Drive down a motorway for at last 40 minutes... let me know how you get on...

Mr.Diagnostic

does this look like your engine layout? Where is the item in question?

Untitled.jpg

Martron

yeah thats it. 2nd generation 4a-fe. the piece i am talking about looks like it is lower and behind point 22

Mr.Diagnostic

That was a quick reply. Hope you weren’t waiting all afternoon for me to come back. I was having a beer out in the sun

What you indicate is the throttle position sensor. It is possible you have faulty sensor but I doubt it. More than likely the butterfly valve is stuck. You will need carb cleaner (available from any motor factor) to clean it.
It is also possible that your tapping effected the idle control motor (15 on the diagram). They are prone to sticking. That can be removed and cleaned as I said earlier.

In order of easiness I suppose you should clean the throttle body/butterfly first. Then the idle motor, then check the idle switch.

Martron

nah not waiting all afternoon. watching top gear. ok i will look into that. thanks for your time