Hi Idle When The Car Is Above 5mph

[solheim]

hi im new to your forum im from the uk have had my car for 3 years now and have got a wierd problem

the car idles fine when standing still fine when below 5mph and fine when the speed sencor is unconected so this elemenates any mecanical elements, pipes off, spilts ect ect so this is something one of the ecus is telling somthing in the engine bay to do the thing is i dont know where to go next any ideas? i have tryed unpluging a few things in the engine bay with the car up on jacks idleing high in second gear to no avail am at a bit of a loss

dan

[mosquitocoils]

Do you mean when you're rolling... and you're in neutral?

Your car idles a bit higher than if you're completely stopped, and in neutral?

[jjman]

Cant make exact sense of the situation you are trying to describe but i think it is 1 of 2 possible things.

1 -and this is normal and not anything to worry about-

R33 skylines will idle higher than the base 650rpm idle speed until the car does in fact come to a dead stop. (possibly to generate enough power in the hydraulic systems to work everything such as brakes n power steering even if you are n neutral and the engine is only using idle speed but you are coasting at 100kmph). So yes, it uses the speed sensor to tell the engine to idle higher (usually between 900-1100rpm) until the car reaches a dead stop.

Also- R33's will idle high due to autochoke remaining on until the the first time you come to a complete stop after the car has reached desired operating temp. Even if this is 30 minutes driving later that you first come to a stop. So again the ecu will monitor the speed sensor and only tell the autochoke to turn off at a time that the car has come to a complete stop.

2-this is a problem, but solved by simple maintenence

the idle/choke mechanism is sticking and isnt working right because it has become dirty due to the age of these cars and can cause a variety of interesting idling characteristics from high idle to overly low idle. Iv had it before that my car would idle at over 1600rpm on autochoke and the autochoke would not turn itself off. I would have to turn the car off once it was warm and then restart it- and because the car was warm it would not engage the autochoke and so it would now idle at the normal rpm.

if it is this you need to have the mechanism removed and cleaned out.

good luck.

[mosquitocoils]

2-this is a problem, but solved by simple maintenence

the idle/choke mechanism is sticking and isnt working right because it has become dirty due to the age of these cars and can cause a variety of interesting idling characteristics from high idle to overly low idle. Iv had it before that my car would idle at over 1600rpm on autochoke and the autochoke would not turn itself off. I would have to turn the car off once it was warm and then restart it- and because the car was warm it would not engage the autochoke and so it would now idle at the normal rpm.

if it is this you need to have the mechanism removed and cleaned out.

good luck.

Are you referring to the AAC valve?

[Kinks]

the ECU will set a higher idle when the car is moving. it's normal.

[3LGODZILA]

how high is the idle?

[solheim]

sorry been at work all day just got it the idle is around 1250 to 1400have cleaned the acc valve and reset my car never yoused to do this because on my way home there is a long down hill to my house and i always coast to my house so the tubby can cool down so this problem has just started i have had the car for three years now

is the cold start valve under the inlet plenum above the oil water cooler? because if it is i disconected this with the electrical plug and still the same thing happens have also disconected the acc valve and the same happens again is there any other way that the ecu can control the idle?

[3LGODZILA]

that not super high, is it really a problem? how often do u just coast with ur clutch depressed anyways, as long as its not idling that high when stationary (warm) i wouldn't worry about it.

but if ur set on trying to locate it, to me it sounds like the acc valve, just coz its clean doesn't mean its not faulty

good luck buddy

[solheim]

that not super high, is it really a problem? how often do u just coast with ur clutch depressed anyways, as long as its not idling that high when stationary (warm) i wouldn't worry about it.

but if ur set on trying to locate it, to me it sounds like the acc valve, just coz its clean doesn't mean its not faulty

good luck buddy

i have disconected the acc electricaly and had the car up on blocks and leaft it idle and put it in 2nd and the revs still rose up so there must be anouther way that the ecu controls idle might get a consolt cable and plug a laptop in and see wat happens there are a lot of cars in the uk with this problem i just want to find out wat it is as it bugs me lol

[BH_SLO32]

i have disconected the acc electricaly and had the car up on blocks and leaft it idle and put it in 2nd and the revs still rose up so there must be anouther way that the ecu controls idle might get a consolt cable and plug a laptop in and see wat happens there are a lot of cars in the uk with this problem i just want to find out wat it is as it bugs me lol

Pin 44 is the neutral signal. The ECU knows when the car is not in neutral.

[solheim]

Pin 44 is the neutral signal. The ECU knows when the car is not in neutral.

it dosent matter if the car is in neutral or not