Engine Hunt at Idle
 

I gave a 2000 2.7 that hunts at idle. What I mean by that is that the idle speed will drop to about 400rpm and the jump up to about 1500 rpm. It does this constantly. It's not quite as bad one you put the aircon on but it's still annoying.

Any idea's on how I can fix this problem.

Thanks guys.

clean the idle air control valve

Idle Air Control Valve Cleaning
 

Thanks and how do I do that?

it's bolted to the driver's side of the throttle body. remove it (2 screws) and clean it out with carb cleaner. make sure the flap operates easily. re-install it.

while you're there, remove the intake hose from the throttle and look in it for oil. if you see oil, you probably need a new oil separator; this causes a vacuum leak that can cause your unstable idle.

also check for other vacuum leaks while you're in there. do this with propane or carb cleaner. wave / spray it around and see if the RPM's jump. if they do, you have a vacuum leak in that area. any of these can cause your issue without throwing a check engine light.

Thanks
 

Thanks I'll try that

If that doesn't work you may want to smoke test the intake for leaks.

Where the hell is the throttle body?
 

Hi,

It's my 1st time workin on the Boxster. I had a bit of a look but was unable to see the throttle body. Do I need to take off the black induction pipes to get access to it. I got a Mitchells manual on CD and it's absolutely useless

Thanks for your help

The black induction pipes(intake system) should lead up to a shiny metal thing,that's the throttle body. You should only have to loosen up the intake tubing to get the throttle body out. Before you do that and take a couple hours I would suggest just smoke testing which takes only a couple of minutes, if there is a leak then you saved a bunch of time.

Ok Found the Throttle Body
 

Ok I found the throttle body, although it seems different from what you described and the pics I found on the forum. By boxster is the 2.7 with the electric accellorator actuator rather than the cable.

Smoke Test
 

How do I do a smoke test?

Thanks I really appreciate your help

Get that K & N air filter out of the car. When I had one it cost me $240 for a new MAF.

Ok what's a Maf
 

What's a MAF & how do I do a smoke test

How Do I do a Smoke Test
 

Can anyone help me on how to do a smoke test to check for vacume leaks?

Thanks

First you need something that makes smoke but not fire.....I use a thick rope with a smoldering end. You can also use a cigarette or cigar if you can tolerate the smoke. With the engine running, move your smoking instrument near the various pipes and hoses in the intake system (throttle body, vac lines, air-oil seperator, etc.) and see if any of them start sucking up the emitted smoke. If so you've found your leak.

The MAF (mass airflow sensor) is mounted in the intake pipe near the air filter housing. It has an electrical connector and it measures the amount of air entering the engine so the proper amount of fuel can be measured. An over-oiled K&N filter will contaminate the sensor, ruining its readings.

or you can just use propane (seriously). auto shops wave an unlit propane torch around the engine bay. if the idle jumps, you found the leak. the propane is sucked into the engine through the vacuum leak and burned in the motor. it temporarily increases the idle.

Thanks
 

Thanks guys I'll try that.

Thanks
 

Thanks guys I'll try that and see what I can turn up.

No Vacum Leaks
 

Ok I did the smoke test and was unable to find any leaks. Tired both ways with smoke & carb cleaner.

Any other idea's. I really apprecaite your feedback.

Bump
 

I thought I would revive this thread. I still have the same problem. Not really a major issue as the car doesn't cut out & I mostly do country driving so you don't notice it, but I would like to get it resolved.

Any other idea's, I had thought of cleaning the MAF although I did pull out the sensor a while back & clean it with no effect.

Thanks for you input guys.

unplug your MAF to see if the problem goes away. most common causes for a hunting idle are MAF, oil separator bellows, and oil fill tube in that order.

The 2.7 doesn't have an idle air control valve, the e-gas system controls throttle position to maintain idle.

Also, typically, if your MAF were bad, you'd notice it while the car is running under a steady load, not just at idle. You could try disconnecting the cable harness to the MAF to see if the car runs better, but I doubt that's your problem.

How many miles are on this car? You might just need to clean out your throttle body if there are no vacuum leaks.

MAF Connections
 

I have tried to disconnect the MAF wires ie, plug but it is very tight. Is there any special way to disconnect it.

Thanks

It's a latching connector and it is hard to release. You might try to remove the MAF to get a better angle, pull off the connector and screw it back in.

Yeh Thought about that
 

Thanks Blue,

Yeh I Thought about that but seem to have misplaced the correct size tourque bit lol.

I can see the clip but the bugger just won't move. Will try again.

Got it
 

Managed to get the plug off the MAF. Started it up and it ran like a dog, blowing lots of smoke and ideling very rough. repleaced MAF plug and started it up and back to as it was before with engine hunting between 400 & 1100 reves.

Any more idea's?

I have had the same problem for a couple of years now. Mine isnt as bad as yours. Mine hunts from about 700 - 1000 something like that. Porsche centre claim to have no idea what is causing it so there goes that.
If it gets real bad i might have to take it to a conventional mechanic as the guys at porsche here in OZ have no idea
I take my car there for the stamp, thats it

How long has it been since the spark plugs have been changed? That can also cause idle hunting.

Oxygen sensor. That was the same symptom V.W. did when the o2 sensor went bad. Is your c.e.l light on? If not does it work? Before you start the car in the on position when all the lights come on does the c.e.l light come on then disappear once the car is running? If you can get access to a ps2 or durametric plug it in and see if you can get any fault codes.

You might try disconnecting the battery to reset the computer. It won't hurt anything and it is free. You will need to unlock your radio and reset preset stations. Make sure you know your radio code

My car did this, I cleaned the butterfly valve in throttle body and hey presto, no more hunting!

It works
 

I cleaned my throttle body & afer some 10,000K it's still going like a train with no sign of hunting.

I also spoke to the guys at Porsche Centre (Brisbane) and they had no idea.

When u think about it no mechanic is going to love your car like you do, and they have a range of cars to service where we tend to specialise in our own cars.

This & other forums have been a great resource for me as it hooks you up with others as passionate about your car as you are and that's what it's about.