idle hunting

[123andieh]

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my 2001 seat arosa failed its MOT on emissions. It was 5.03%. when idle at traffic lights the engine hunts. I took it to the garage yesterday and had a new LAMBDA probe fitted. I had a new emissions test done and it was perfect. There is still dirty sulfur smelling smoke coming from the back and the engine is still hunting. This has been happening for about a year. I have had a diagnostic test done 4 times and there is nothing wrong. At night when it is hunting the lights dip. The problem is intermittent from one set of traffic lights to another. If I turn the engine off and back on really quick then the engine dose not hunt. It also dose not hunt for the first 2 miles in the morning.

PLEASE can anyone help????

Regards,
123andieh

 

[lunalupi]

It probably has a dirty throttle body - its a very common problem, but also very easy to fix.

Get yourself a can of carb cleaner.
Take off the airbox and you'll be able to see into the throttle body - it will probably be all gunky and oily.
Get someone to rev the car while you spray carb cleaner into the throttle body to clean it out.

Simple as that, it should stop doing it

 

[123andieh]

i am going to have another co test in the morning. if i can get it to pass the mot i will then sort the hunting out. thanks for the responce and i will try what you said

regards
123andieh

 

[allallyouyou]

Try a bottle of 'REDEX' , that cleans fuel injectors / bits of the engine etc. Worth a try?

 

[Boo]

My Arosa was the same at my last MOT. The garage put some Redex through the system and kept trying until it finally was low enough to pass. How did it go today ?

 

[123andieh]

the car passed the MOT. it was the lambda probe that made it F the MOT. but the hunting was because it had a dirty throttle body.

thanks LUNALUPI. the garage didnt even charge for doing it. which was good.

he also said that you shouldnt put REDEX in the car because it dose more damage than good.

regards 123andieh

 

[lunalupi]

I hoped it would work - it usually does!

 

[allallyouyou]

Yeah some people dont recommend 'Redex' but I dont see what the problem is personally / nor have the people that say it causes damage ever actually seen or proven it do damage. Afterall if it was a cause for concern it wouldn't be sold.

Glad the garage sorted the MOT for ya

 

[TDI_luver]

I have been having a similar problem with my 1.0 litre 1999 Arosa for some time now (AER engine).
It has just passed an MOT emissions test fine (CO <0.5% at idle 850 rpm), throttle body and throttle valve clean and shiny as a new pin with Carb cleaner, new fuel and air filters fitted, just serviced, everything spot-on (Only 50,000 genuine miles). New plugs 5000 miles ago (OEM spec), new HT leads also.

However, when warm it hunts at traffic lights, in very wet or cold weather it may even stall. This can be prevented by retarding the static ignition advance, put that destroys the engine's acceleration capacity. When the static timing is advanced just to the point where its won't pink on full acceleration (Optimum setting for power), I get the idle hunting back again. So its a catch 22 situation.

Any suggestions ? Diagnostic check throws up nothing wrong.

I was tempted to change the coil, but as there is no misfiring, I dont see what improvement that could make.

As as there are no fault codes (or actual emission problems) I cant see the issue being a bad lambda probe either.

Any ideas anyone ? I dont fancy running on retarded ignition timing for evermore just to avoid idle hunting and traffic light stalls !

 

[allallyouyou]

Its strange as my Arosa did this off and on before i replaced the fuel pump. It seems ok now though. Cleaning the throttle body does improve running I must say