Mis-firing when cold

[Johno_c]

Hey guys, got a 172 cup and when it's cold I get about a yard up the road and it misfires like crazy for a couple of seconds then when it's warm it's fine!

Changed crank sensor and cleaned throttle body other day and it's only started happening since then.

Any help or ideas would be much appreciated, had it read and there's no fault codes.

 

[BR33NY]

what did u use to clean ur throttle body?

 

[Johno_c]

Carb cleaner

 

[BR33NY]

its maybe just the excess cleaner clogging up

 

[Johno_c]

I've done 300 miles but only started up about 8 times.

 

[Johno_c]

Any other ideas?

 

[Mark5290]

How many revs are you giving it when cold?, i seem to remember the ecu on 172/182's has a built in inhibitor to stop you over revving the engine when cold and causing any long term damage, after about 10 - 20 secs or so it will run fine, when i first started my 182 up from cold and left home, it felt like you had left the handbrake on slightly, 10 - 20 secs later it was fine, try letting it idle for for 30 secs after first starting up and see what happens.

 

[kevin.s]

How many revs are you giving it when cold?, i seem to remember the ecu on 172/182's has a built in inhibitor to stop you over revving the engine when cold and causing any long term damage, after about 10 - 20 secs or so it will run fine, when i first started my 182 up from cold and left home, it felt like you had left the handbrake on slightly, 10 - 20 secs later it was fine, try letting it idle for for 30 secs after first starting up and see what happens.

i had this problem and found that this does help. mine tends to misfire more when its been pi$$ing it down.

 

[Johno_c]

Thanks I'll try that

 

[Johno_c]

Never made a difference, cut out on first start then ran rough for a little.

 

[Johno_c]

Any body else with an idea?

 

[daddycool]

is it a bad mis-fire? if its just not very smooth, there's a few threads on the subject, lots of people experience it, it's quite common. i get it for about 1-2 mins in the morning. its not a bad mis-fire but its definitely not smooth!

 

[Matt Cup]

Mine does this quite a lot, was told it's common and not to worry about it.

 

[Johno_c]

Mines really bad

 

[Damo_Sport]

mind does it to when cold

 

[imprezaworks]

Does it start first time in the morning?

Dan

 

[Johno_c]

No dan

 

[imprezaworks]

Sorry for the late reply mate. If you look up some of my threads ref the problem i had with my car. Basically first thing in the morning when it was cold the car would start and then cut out. you could keep it going if you kept the revs up but would feel to have a missfire. After a few mins it would be okay. I replaced various things but nothing worked. Bought a new icv off Renault, fitted it over a week ago and touch wood its been absolutly spot on. No cutting out and starts and idles spot on whatever the conditions. Like i say mate have a nose at my threads it might help

Dan

 

[Johno_c]

Will do thanks