I'm looking for any clues as to why the Corolla is hitching and stuttering, It's only happening when the car is first started (and warmed for a few minutes) then driven down the road. It's been serviced (two weeks ago) by a fairly well trusted mechanic and he reackons the auto choke is fine. It does seem to go fine when the engine is at running temp.
Location: North East NSW
Registered: December 2002
Re: Hitching and stuttering 4AC
Thu, 01 July 2004 05:40
it's getting old? does hitching mean bunny hopping and surging? possibly could be running lean like it's got a vacuum leak somewhere? or if it stumbles but builds power perhaps its running rich and your mechanic friend has played with the idle mixture? has the timing been set correctly for the fuel it's running? have a look at the autochoke yourself if you doubt it's working, it should be closed when the coolant is cold, open when it warms up (or do they have electric choke? i don't know)
Thanks Super Jamie - by Hitching its a stuttering and reluctance to move more than a bunny hop.
The mechanic did play with the timing but I have faith that he did it well as it was even crappier before he fixed it (due to a dodgey mechanic previously stuffing around and trying to create business for himself). It did have a problem with an air leak in the fuel line above the charcoal canister that was causing the petrol to drain back to the fuel tank, so there is a good possibility a vacumn leak could be elsewhere also.
I am still curious though as wouldn't these problems still be affecting the engine after it has been warmed? Cause it runs fine after it reached running temp...?
Location: North East NSW
Registered: December 2002
Re: Hitching and stuttering 4AC
Thu, 01 July 2004 11:47
things warm up and expand and close miniscule clearances. not totally unheard of. just giving you ideas of things to check maybe the motor has excessive piston-to-bore clearance and just wants to warm up more before you use it. perhaps the idle is running too rich or lean
without being there or knowing an awful lot about 4ACs (these are just general troubleshooting tips) it's difficult to troubleshoot just on description. good luck!
Thu, 01 July 2004 04:50
does hitching mean bunny hopping and surging? possibly could be running lean like it's got a vacuum leak somewhere? or if it stumbles but builds power perhaps its running rich and your mechanic friend has played with the idle mixture? has the timing been set correctly for the fuel it's running? have a look at the autochoke yourself if you doubt it's working, it should be closed when the coolant is cold, open when it warms up (or do they have electric choke? i don't know)