Black Arrow

How does this work?

My car rpm itself up to about 1800rpm and then falls down to 1000rpm and does this repeatily when idling. (on cold engine it stays at 1400rpm until it gets warm)
Thought it was a vacum leak, but I cant find any hoses thats bad or have fallen off where they should be.

What can this be? And does anyone know how I can check the idle regulator / idle control valve for fault?

J Chen

Looks alone can be deceiving. Perform
a pressure test & you'll be surprise.

Black Arrow

I`ll do. But, does anyone know how the idle control valve work? Should I be able to blow right trought it when its out of the car?

hosrom_951

The ISV works or 'switches on' when the car is cold and when the a/c is turned on.

If you are getting bad idles ONLY when cold, try waiting or driving untill the car is warm. Then, turn on the a/c, if it acts the same when it's cold, the ISV is bad. Cleaning it usually helps, but the intake manifold has to come off if you want to access it.

Another reason for strange idle WOULD be from teh TPS, correcting/adjusting it takes 10mins or so, this link may help: http://www.clarks-garage.com/shop-manual/fuel-06.htm

Now, who was it that ALWAYS commented me on either vacuum or TPS

Black Arrow

Thanx hosrom. It wasn`t me that commented you, but I bet the one that did shakes in his trousers

As said earlier it doesnt have bad idle on cold engine. Then its just stabile at 1400rpm. When its hot, the idle problem starts to show. And are bumping between 1800rpm - 1000rpm.

And whats the ISV? Idle Control Valve? Idle sensor valve or something?

I would very much like to know how thats working! cant really understand that it should be right that I can blow right trough it..? Isnt this a valve? When and how does it close? When does it open?
My intake manifold is of the car anyway

hosrom_951

Since the intake manifold it out of the car, take off the valve and clean it out. It's probably filled and contaminated with oil.

The ISV is electronically controlled, but since you say that it SITS at a specific idle when cold, and bounces when it's warm. Then that is the TPS, or the TPS may nee an adjustment.

Check the link i posted for clarks garage, i had a similar problem, idle bounces between 1,000~1,200 when warm only. Replaced and adjusted the TPS and problem solved.

No, it wasn't you who commented me it is someone else........

Black Arrow

Oh, thank God it wasn`t me that commented you hosrom... my memorie isnt that good! hehe

Then a question; if the tps is bad. Wouldnt this affect the car when giving trottle also? When I give trottle the car does run ok. Accept a little bad a/f-ratio.. The idling problem occurs ONLY at varm enginge with no trottle.

I`m going on a track day in a week so need to sort this out very soon!

hosrom_951

tma951: No, it wasn't you, i know who but not saying

Anyway, i would replace/update the vacuum line (all of them) while 'your in there'. A safety and $$$/time saving job.

Black Arrow

its already done.. the vacum line
Just need to sort out the other problem now.. I think I`ll order both the tps and idle control valve from paragon and see if thats help.. Do they deliver quick to europa? I know pelicanparts does... but want to trie paragon the compare

hosrom_951

In MY experience, USPS Global Express was the fastest (5 days here in Duba) and cheapest option.

Paragon would gladly use the frieght method of your choice (Jason is a great guy!).