Bouncing idle (again) and iacv gasket

Bludge · Post by **Bludge** » Sun Feb 15, 2015 9:56 pm

My bouncing idle has come back, happens when the engine is warm, drops down to about 300rpm then back up to about 1000 rythmically.

I cleaned the iacv (which cured it when i first got the car) but its still happening. i just looked at a guide for cleaning the iacv and the picture showed a gasket. mine must have totally disintegrated!

Gonna call in to honda to try and get the gasket which im hoping will cure the issue, but is there anything else that could be causing the problem? i have just blanked the egr and from what i have read the fast idle valve causes issues on a cold engine, so shouldnt be the root of my issue, right?

Could it be a vac leak somewhere? or would that effect cold idle too?

Would just like a heads up for other stuff to look for when im under the bonnet doing the iacv gasket!

Post by **Drax** » Sun Feb 15, 2015 10:12 pm

yes, usually a vac line leak. mine was a faulty iacv valve & my spare was faulty lol

Post by **Thebusofwoe** » Mon Feb 16, 2015 12:00 am

Make sure you check all the vac lines. Make sure the EGR vac line is blocked up. Failing that my guess is the IACV has had it. On the older B series engines they are so sensitive as in if you even breathed on it it would jobby itself

Bludge · Post by **Bludge** » Mon Feb 16, 2015 8:13 am

Whats the best way to check the vac lines?

Is the egr vac line the one that runs along the back to the rocker cover?

Post by **Thebusofwoe** » Mon Feb 16, 2015 8:33 am

Just visually check they are all in good nick/connected. Yea that's the one.

Bludge · Post by **Bludge** » Mon Feb 16, 2015 8:57 am

Cool, thanks mate. will block the egr vac line tonight and hopefully the iacv gasket will make an improvement.

Post by **Merlin** » Mon Feb 16, 2015 11:02 am

TBH this doesn't sound like the classical IACV issue. Normally when the IACV is faulty idle RPM increases from base idle (~800 rpm) to 1.5K - 2K rpm and than falls back to base idle level. Falling idle sounds like a different issue IMO.

Post by **Vtecmec** » Mon Feb 16, 2015 11:04 am

Yes, sounds more like a stalling issue, with the IACV doing it's job and pulling the revs back up.

Post by **Drax** » Mon Feb 16, 2015 11:25 am

could it be a coolant issue? low levels, or air in the system maybe?

Bludge · Post by **Bludge** » Mon Feb 16, 2015 12:43 pm

Hmm, it was the same problem i had when i bought the car and cleaning the iacv fixed it until recently. i have just ordered the gasket from honda for about 2 quid so will do that and hope it improves things. will also check the vac hoses thoroughly.

As for the coolant, this is another issue i have had since i bought the car a couple of years ago. i have to top up the resevior every so often, and it goes through a fair bit. the oil is never milky and no matter how hard i rag it (5 hours of redline on the drag strip etc) it has never gone past halfway on the temp guage.

Never been able to find a leak either. im presuming that there is a leak somewhere but its evaporating rather then pooling on the floor.

Its alway run well so its not something i have got round to properly looking into.