B16A Brief hunting after decel/coming to a stop

[omgzilla]

Hey guys,

Just took my car for a drive, after a week or so of it sitting there and noticed my idle hunting a couple of times after coming to a complete stop at the lights.

Just as I come to a stop the idle creeps up to around 1300 revs then drops to about 700 revs, creeps up again, drops then it settles down to normal. It only hunts twice then settles out.

Any ideas?

Possibly dirty idle valve/throttle body?

Thanks in advance guys,

Shanon

[bennjamin]

happens when your foot is on the brake pedal right ?

[omgzilla]

Yeh, sounds about right.

Had the same problem?

[bennjamin]

issue might be linked to vacuum , and the brake booster. Could need a rebuild/replacement

[omgzilla]

Bugger! That could be expensive :(

Any further info dudes?

[bennjamin]

jump in your car as it idles , and pump the brake pedal a bunch. It should rise the revs alittle normally , but if the revs raise alot or stay high until you drive off/engage a gear you may need to replace the internal gasket or just replace it.

[omgzilla]

Ok thanks bennjamin.

I've found a couple of diagnostic procedures in the workshop manual regarding the booster and check valve etc.

I'll give them a shot and report back.

Thanks again dude.

[beeza]

Does it constantly do it or just sometimes?

[omgzilla]

It's only just started doing it really. I haven't been driving it much lately but it's done it each time we pulled up at the lights on Saturday (took it for a short drive).

[beeza]

If it does do it all the time when the car is idleing then more than likely it's the 'cold air control valve' sensor on the Throttle Body.I changed that and it fixed my problem.My engine is the d16y4,I'm assuming the b16 has the sensor...

[BlitZ]

Doubt it is a vacum...
But here is how u check it:
When it happens run to the bonnet and spray WD40 on the manifold and if it corrects/changes idle pattern than its a vacume leak..

If not found (more than likily),
Bleed the radiator or air. Check coolant level
Clean idle valve.

All else fails.. it could be the early signs of heak gasket

[omgzilla]

I'll do a vacuum leak check too.

Where's the bleeder on the B16A?

I did just do timing belt, water pump etc - wasn't sure where to bleed the radiator so yeh - hopefully that's the issue.

Does the coolant level affect the idle? Something to do with the FITV?

Blitz: What leads you to thinking of early head gasket warning signs?

[BlitZ]

I'll do a vacuum leak check too.

Where's the bleeder on the B16A?

I did just do timing belt, water pump etc - wasn't sure where to bleed the radiator so yeh - hopefully that's the issue.

Does the coolant level affect the idle? Something to do with the FITV?

Blitz: What leads you to thinking of early head gasket warning signs?

more than likily a coolant issue if you just touched your coolant.. Just open the radiator lid, run the car till the fan comes on (your thermostat should be now open).. you will hopefully see some bubbles:thumbsup:

air pockets in radiator = effecting Idle control valve (theres coolant cooling) = idle hunting
blown head gasket (Also white smoke when driven hard) = coolant pressure leak = effecting Idle control valve (theres coolant cooling) = idle hunting

[beeza]

Hey Blitz,thanks a lot man! I just done this to my car.I had quite a bit of air in there...I know my mechanic done this but there was still quite a few bubbles that came out.I left the car running with the radiator cap for a good 15 minutes since the until the bubbles all but stopped.Car is running a lot smoother now and changing gears (automatic) at the right times,not hesitating/surging.
REPPED!!!

[omgzilla]

Thanks Blitz! I'll give it a shot - with any luck that's the cause of my hunting... I didn't bleed it at all. Never even thought to run the car with the radiator cap off... I'm used to working on European cars :confused:

On another note: I did a vac leak check - no vac leaks.

Will do a coolant bleed and report back.

Thanks for your help guys. Much appreciated :)

[BlitZ]

cool.. good to see beeza's results..

ph and also forgot....turn the heater on fully blast to get it fully circulated while lid of off ;)

[beeza]

Good one Blitz,will do next time forsure.I miss your avaitor pic of your EK cornering :)

[beeza]

For the Vacumn test - "When it happens run to the bonnet and spray WD40 on the manifold and if it corrects/changes idle pattern than its a vacume leak.."

Do U just spray WD-40 on the top of the Intake Manifold or around the seals?

[omgzilla]

Beeza: Here is a post I made about how to check for vacuum leaks:

http://www.ozhonda.com/forum/showpost.php?p=1481657&postcount=15

Enjoy.

[beeza]

Ah Beautiful! Got it!
I need to read why and how it works like U wrote.It's just the way my brain works :)

-"The way this works is that the combustible spray gets sucked in (via the vacuum leaking component) and is 'un-metered' so the idle increases briefly. This gives you an audible/visual sign that there is a vacuum leak present - causing your rough running/hunting issue."