Uneven tick-over on choke

[John77]

Hi the car has been sat for a while and now when it starts it has an uneven tick-over until the choke turns off. Any ideas?
2005 Eclass

 

[brandwooddixon]

Some more information might help such as, fuel type and engine.

 

[ajlsl600]

Won't be diesel manual or auto choke .unless op description inaccurate If auto choke maybe its stuck at too lean at start up.

 

[brandwooddixon]

I think the OP is referring to the raised rpm immediately after engine start, controlled by the ECU, used to heat up the catalyst.
The car is 2005 and so will be fuel injected even if its got a petrol engine.
No car with fuel injection has a choke, but there may be other factors involved that are engine specific hence the request on fuel and engine type.

 

[ajlsl600]

On fuel injection there will be a fuelling map that comes into play until temp and press sensors indicate warm up OK and map will change to that of normal operating values again from various sensor inputs maybe one of these is submitting an out of spec value likely pinpointed by reading codes

 

[Botus]

most petrol cars were electronic fuel injection by 1988 - no way a 2005 car left the building with choke

BUT there are a number of things people should be aware of

low / no oil pressure is bad
low cranking speed means the pump is doing pretty much NOTHING - so moving things only on the starter isn't pushing any / or sufficient oil round anyway, don't do it (the light will go out on 2 - 6 PSI when >40 PSI is needed)
the type of damage you get with very slow cranking, means wipe over force on things like cam followers is deadly - that's why the fast 2k RPM process exist for people that know what they are doing
low speed engine running (aka tickover) means the car has to run a very high AF (air fuel ratio) or it just stalls and a high AF is very bad for the engine, and the planet - 1500 RPM or higher starts to allow a piston engine to operate at a less bad fuel mix meaning ring wash / bore wear / polluted oil is lessened - getting to 2K RPM means the wipe force on components is much lower, the oil pump actually pumps well and the oil reaches bits that matter as fast as possible - in addition the CAT warms up and start to function and not just clog

all these points are considered by the manu and hence why they push up the revs up straight away - they are not just total idiots - that preserve is just most owners (through laziness or weak education)

on a cold day crank and get the engine to 2k RPM and allow it to warm through, this should lessen wear, should get the AF better faster, should get the engine running more consistently (AKA safer to drive), should start to get the battery and electrical system to cope with the high loading faster, should allow the CATs and sensors to start adding value, and the vehicle should warm up faster (comfort / getting clearances better before putting under-load) thus the idea is sensible - but the reason the manu say just start it and drive off - is because allowing to idle (ever) especially when cold is so damaging, and the pollution / fuel consumption effect will be vastly reduced. (and their warranty claims / your satisfaction will be higher than most owners will manage trying to help when doing it the wrong way...)

 

[John77]

I think the OP is referring to the raised rpm immediately after engine start, controlled by the ECU, used to heat up the catalyst.
The car is 2005 and so will be fuel injected even if its got a petrol engine.
No car with fuel injection has a choke, but there may be other factors involved that are engine specific hence the request on fuel and engine type.

No uneven erratic. Not smooth.
E200 petrol

 

[John77]

most petrol cars were electronic fuel injection by 1988 - no way a 2005 car left the building with choke

BUT there are a number of things people should be aware of

low / no oil pressure is bad
low cranking speed means the pump is doing pretty much NOTHING - so moving things only on the starter isn't pushing any / or sufficient oil round anyway, don't do it (the light will go out on 2 - 6 PSI when >40 PSI is needed)
the type of damage you get with very slow cranking, means wipe over force on things like cam followers is deadly - that's why the fast 2k RPM process exist for people that know what they are doing
low speed engine running (aka tickover) means the car has to run a very high AF (air fuel ratio) or it just stalls and a high AF is very bad for the engine, and the planet - 1500 RPM or higher starts to allow a piston engine to operate at a less bad fuel mix meaning ring wash / bore wear / polluted oil is lessened - getting to 2K RPM means the wipe force on components is much lower, the oil pump actually pumps well and the oil reaches bits that matter as fast as possible - in addition the CAT warms up and start to function and not just clog

all these points are considered by the manu and hence why they push up the revs up straight away - they are not just total idiots - that preserve is just most owners (through laziness or weak education)

on a cold day crank and get the engine to 2k RPM and allow it to warm through, this should lessen wear, should get the AF better faster, should get the engine running more consistently (AKA safer to drive), should start to get the battery and electrical system to cope with the high loading faster, should allow the CATs and sensors to start adding value, and the vehicle should warm up faster (comfort / getting clearances better before putting under-load) thus the idea is sensible - but the reason the manu say just start it and drive off - is because allowing to idle (ever) especially when cold is so damaging, and the pollution / fuel consumption effect will be vastly reduced. (and their warranty claims / your satisfaction will be higher than most owners will manage trying to help when doing it the wrong way...)

What is a manu ??

 

[Larkone]

What is a manu ??

manufacturer

 

[Botus]

its highly likely you have OLD rotten fuel that is part jelly and or rotting the car - and of course NO car made before 2009 knows how to run correctly on ANY ethanol infected petrol - so E5 or E10 will never run properly and this rubbish new fuel deteriorates rapidly

E5 97 octane from BP with some dipetane may be about as good as it gets - it works wonders in her 57 plate focus that isn't designed to cope the E anything

Dipetane 1ltr Fuel Additive | Halfords UK

Shop the latest Dipetane 1ltr Fuel Additive contains nothing that is not already in the fuel at Halfords UK

www.halfords.com

 

[John77]

its highly likely you have OLD rotten fuel that is part jelly and or rotting the car - and of course NO car made before 2009 knows how to run correctly on ANY ethanol infected petrol - so E5 or E10 will never run properly and this rubbish new fuel deteriorates rapidly

E5 97 octane from BP with some dipetane may be about as good as it gets - it works wonders in her 57 plate focus that isn't designed to cope the E anything

Dipetane 1ltr Fuel Additive | Halfords UK

Shop the latest Dipetane 1ltr Fuel Additive contains nothing that is not already in the fuel at Halfords UK

www.halfords.com

No, fresh petrol put in. Used to run perfectly before left. Runs terrible for about 30 seconds then smooth. I have a video, but not sure how to put it on here.

 

[Wighty]

No, fresh petrol put in. Used to run perfectly before left. Runs terrible for about 30 seconds then smooth. I have a video, but not sure how to put it on here.

Have you taken the car for a decent drive since the car has been sat ?

 

[Blobcat]

No, fresh petrol put in. Used to run perfectly before left. Runs terrible for about 30 seconds then smooth. I have a video, but not sure how to put it on here.

Upload to YouTube and link back here

 

[John77]

Have you taken the car for a decent drive since the car has been sat ?

No the MoT has run out so need to get that done first, but of cause will not pass like this. I have just looked on you tube and it says that this can be the Throttle Valve. I will take a look as it is quite accessible.

Video Link

 

[John77]

CURED!!! Now perfect tick over. Took off the Throttle Valve. Cleaned the Valve and the Sensor, with brake cleaner, as I didn't have any other cleaner. Probably all the same mix, just a different label. Left the ignition on for 2 minutes. Not sure what that does, probably resets everything and then started the car and perfect.

 

[ajlsl600]

Well done

 

[John77]

Well one problem solved, just the airbag to solve now.

 

[Wighty]

CURED!!! Now perfect tick over. Took off the Throttle Valve. Cleaned the Valve and the Sensor, with brake cleaner, as I didn't have any other cleaner. Probably all the same mix, just a different label. Left the ignition on for 2 minutes. Not sure what that does, probably resets everything and then started the car and perfect.

Good job buddy , I’m tempted to do mine now as it’s on 97k

 

[John77]

Good job buddy , I’m tempted to do mine now as it’s on 97k

Very simple. Only 6 bolts, a plug, a jubilee clip and the air intake pipe. I used a toothbrush to clean the Throttle valve and just sprayed cleaner on the sensor and dabbed it with kitchen roll, as it looks very delicate.