unbalanced idle

[clutch]

hey all, i currently have my idle sitting at around 1000rpm, i beleive the normal idle is 700 but at 700 i get a slight unbalance in the engine which doesnt seem to be much of an issue but can get a bit annoying as it baffles the inside of the car. is it normal to be seem a bit unbalanced at 700rpm? if so what could be causing it? and how to fix it?

cheers

[vinnY]

stock motor?

[clutch]

stock motor?

yep stock as a rock bar a pod

d15b engine

[PHM91]

could be low compression in one of the cylinders most likely not
why don't you just simply adjust your idle to about 800-1000
700 seems just abit to low

[PaulsTeg]

750 - 800 RPM imo is actually fairly normal for a 4 cylinder (your ECU will try and maintain this RPM). The manufacturer specification for this should be used. Increasing the idle offers not advantages on multi-point fuel injected cars.

Increasing the idle above spec may cause the on-set of cylinder glazing to occur quicker if there is no adequate airflow.

[clutch]

well its all good and well to have the specified idle rpm, but it wobbles and carries on a bit so im keeping it at around 1000? the mixture should stay correct shouldnt it?

[aaronng]

Have you checked your engine mounts?

[PaulsTeg]

The mixture will be OK. For O2 sensors will be ensuring that. It will just be using more fuel. Checking the engine mounts is a good idea even the spark plug leads and the battery.

Good luck!

[clutch]

The mixture will be OK. For O2 sensors will be ensuring that. It will just be using more fuel. Checking the engine mounts is a good idea even the spark plug leads and the battery.

Good luck!

yea ill check out the mounts when i get home, am i just checking the bolts are all tight?

ive got new leads and plugs so it cant be them... it wouldnt be the dizzy or anything would it? i hear there expencive to replace :S

[jords]

Have you also checked your TB? It could have become dirty and is affecting the sensor at idle.

[aaronng]

yea ill check out the mounts when i get home, am i just checking the bolts are all tight?

ive got new leads and plugs so it cant be them... it wouldnt be the dizzy or anything would it? i hear there expencive to replace :S


Check if the mounts are cracked or if the rubber is deteriorating.

Also remove the dizzy cap to clean out any corrosion on the contacts.

[clutch]

Have you also checked your TB? It could have become dirty and is affecting the sensor at idle.

yea i gave it a clean recently, maybe i should do it again? should i take the tb out completly and do it? i only cleaned it while it was attached

[clutch]

Check if the mounts are cracked or if the rubber is deteriorating.

Also remove the dizzy cap to clean out any corrosion on the contacts.

ok, its a fixed one, the car is efi, same deal? just unbolt and clean?

[aaronng]

ok, its a fixed one, the car is efi, same deal? just unbolt and clean?

Mark the current dizzy cap position (take a pic to show us the position as well). Undo the cap (don't drop the bolts) and then clean as normal. I use sandpaper on the contacts on the cap side.