Erratic Idling

[gar]

Hi, I have seen older posts of erratic idling, especially when air-con is on and wondered if, after time, the problem has been pinpointed yet?

My 02 Yaris seems to be doing this now and I am unsure as to the cause.

I am about to replace the auxillary- drivebelt as that seems glazed and a little frayed (a bit like me) and squeals a little (again, like me) , particularly if the air-con is on and I am stopped/pulling away. (Auto gearbox). I beleive the air-con could also benefit from a proper re-gass/service but dont think these things actually cause the problem.

I have seen people blame the maf sensor, particularly if there is an aftermarket filter system fitted. I have had a K&N panel filter on for about two years now.

A definate conclusion to this problem would be most helpful to me and also anyone else suffering from or who may develop this problem in the future.

Any insight/help will be gratefully received.

Many thanks,

Gar. B)

[Hogie]

Your rpm will go up and down if the air con is on. Its the compressor kicking in and out. You should here a click as the compressor kicks in and out. If you pop the bonnet

with the engine on with the air con running you can see and hear this happening.

[RossP]

A definate conclusion to this problem would be most helpful

Turn A/C off (lets be honest, do you really need it?) and put the windows down

[gar]

A definate conclusion to this problem would be most helpful

Turn A/C off (lets be honest, do you really need it?) and put the windows down

I appreciate the responce but what is the point in not turning on the a/c if I want it on, just to mask a problem? That's a bit like Homer Simpson putting a bit of black stickytape over his oil warning light.......No light, no problem!

It is not just a usual compressor idle-change, it is more pronounced then that and it happens at very short intervals of only a few seconds apart (About 30). Ignoring problems just lets them get worse until the whole lot goes wrong.

Please bare in mind, it is an automatic, so changes in rpm mean the car tries to move too as it thinks gas is being applied!

[striderwilson]

There is probably a valve that adjusts the revs when the air con switches on ( so the revs don't drop too low), and its probably vac controlled. My guess would be the valve is sticking or there is a vac hose leak.

James

[gar]

There is probably a valve that adjusts the revs when the air con switches on ( so the revs don't drop too low), and its probably vac controlled. My guess would be the valve is sticking or there is a vac hose leak.

James

Thanks. Not sure about vac, though. I think everything is electronic on these. Anyone else? Anyone know how much an MAF sensor costs, from Mr T? I have also heard that it is often these, not the o2 sensor's that go, despite diagnostics stating it is the o2 gone!

[dustyhog]

Hi, I have 1.4 d4d manual, Not sure if you solved this but I had idle problems + started to be 'jerky' (not related to aircon) and the solution was to clean the 'throttle body - I think thats what its called). Another post on this yaris forum had it spot on and mine had a main air hole completly blocked). Tried recon MAF before solution and made no difference.

Check the other - very helpful post for a full description - only takes about 1.5 hours total - cleaning took me the longest bit. Oh my car had only done 30,000 so amazed this got so blocked.

But all great now - hope you find your solution.

[T V O R]

Turn A/C off (lets be honest, do you really need it?) a

Oh yes! :)

[HowardL]

A definate conclusion to this problem would be most helpful

Turn A/C off (lets be honest, do you really need it?) and put the windows down

I'll never buy a car without A/C

[popsr]

A definate conclusion to this problem would be most helpful

Turn A/C off (lets be honest, do you really need it?) and put the windows down

I'll never buy a car without A/C

me neither! a/c is an absolute essential to me. i don't know how i survived before it. ;)

[gar]

A definate conclusion to this problem would be most helpful

Turn A/C off (lets be honest, do you really need it?) and put the windows down

I'll never buy a car without A/C

me neither! a/c is an absolute essential to me. i don't know how i survived before it. ;)

TRUE!

I have just started using a manual Yaris as a driving instruction vehicle and I boil as it has no a/c!

BTW, it is a Frenchy, compared to my Jap and YES, it is worse build quality!!! Glovebox fails to close properly (On this and another Frenchy I tried) rattles, whistles, gets barely more mpg, despite being a 1L to my 1.3 auto! seats are a pain to move, brakes are not as effective.... etc,etc! Only benefit is cheaper road tax . Stearing is lighter but has no feel, so no benefit, exept parking, maybe. Stereo vibrates a lot so cant play too loud!