Stalling and rough Idle after car is warm.

[greenbeen]

 

OK so here goes trying to describe the issue.

 

After some decent driving ie going over a decent hill or some motorway driving and then coming to a set of lights or parking, the car will have a really rough sounding and feeling idle. Oftern doing this it will eventually stall.

 

The problem seems to be happening more frequently.

 

At first when the problem happened and it stalled, I could re-start the car and it would come right, but now it will sound rough and likely stall putting it in gear, unless I apply throttle to up the revs.

 

I have recently managed to capture sound and video of it happening, video is after driving over a "formidable" hill and parking, the car stalled while parking, Video starts after re-starting the car.

 

Hoping someone with a keen ear can help, as my mechanic is at a loss...

 

 

Car is a 06, JDM, 5 speed auto, turbo 130 k's, it also has a shifting issue, which is unrelated as this happens even while in park..

[MilesA]

Youtube says video is unavailable. Sorry about that, etc.

[greenbeen]

Youtube says video is unavailable. Sorry about that, etc.

 

Hopefully fixed that now?

[MilesA]

Ok, your video is working fine. Feeling like a quiz show participant right now, so let me ask you a few questions. There are a number of possibilities, so it might help to try to narrow the field a bit.

 

Are you running the A/C in your video (turn it off if so)? Do you have any Check Engine Lights showing? Do you have any driveability issues other than the rough idle and strange noises? Hesitation, stumbling, lack of power, worse fuel consumption than usual? Any unusual smells under the hood or from the exhaust pipes (petrol or coolant smell)? Is your radiator filled to the level or running low? Have you had any work done to the car recently? Did you do the timing belt service on schedule? Does everything appear to be in order under the hood (bonnet)?

 

Something else you could do is to try and work out where the sound is coming from. You can use a mechanics's stethoscope, or use a piece of pipe and listen to several spots on the engine. Listen to the front timing belt cover, each cylinder head, etc., see if you can find where that clattering sound is coming from. Then, maybe we can help you more.

[greenbeen]

Ok, your video is working fine. Feeling like a quiz show participant right now, so let me ask you a few questions. There are a number of possibilities, so it might help to try to narrow the field a bit.

 

Are you running the A/C in your video (turn it off if so)? Do you have any Check Engine Lights showing? Do you have any driveability issues other than the rough idle and strange noises? Hesitation, stumbling, lack of power, worse fuel consumption than usual? Any unusual smells under the hood or from the exhaust pipes (petrol or coolant smell)? Is your radiator filled to the level or running low? Have you had any work done to the car recently? Did you do the timing belt service on schedule? Does everything appear to be in order under the hood (bonnet)?

 

Something else you could do is to try and work out where the sound is coming from. You can use a mechanics's stethoscope, or use a piece of pipe and listen to several spots on the engine. Listen to the front timing belt cover, each cylinder head, etc., see if you can find where that clattering sound is coming from. Then, maybe we can help you more.

 

Cheers MilesA, Soo many questions!!!

 

A/C was off

 

No CE lights when this happens, however I get a plethora of lights at separate times, diags sugest this is due to the steering angle sensor, so unrelated to this problem(sigh)

 

There is another issue with the car when manually shifting from 2nd to 3rd under acceleration it will "clunk" but this is obviously a gear box issue and not related to this due to this problem happening in park(this is with insurance company pos replacement of valve body).

 

It feels if there is lack of power, at low revs, but power is returned when putting the pedal down(hope that makes sense)

 

Fluids all been checked.

 

I have noticed a smell at times, but I think thats related to the gearbox issue? Not a petrol smell, not sure on how to describe.

 

Mechanic has never seen the problem happen(although he now has the vid), so haven't been able to do the mechanics's stethoscope job.

 

Its very frustrating as it only happens after a fair bit of driving!!!

 

Thanks

[MilesA]

There's a fairly long list of things that can cause poor idle. But, in your case that clattering noise leads one to suspect something in the valvetrain. Consider doing some testing to rule out valvetrain issues and vacuum leaks. NOTE quotes below are from the USDM 2.5 DOHC Turbo factory service manual, you may need to revise for your motor.

- stethoscope to pinpoint the source of the noise

- vacuum gauge on the inlet at idle should show ~18 inches Hg with a steady needle

 

Intake Manifold Vacuum

A: INSPECTION

1) Remove the collector cover.

2) Idle the engine.

3) Disconnect the brake vacuum hose from intake

manifold, and then install the vacuum gauge.

4) Keep the engine at idle speed and read the vacuum

gauge indication.

By observing the gauge needle movement, internal

condition of the engine can be diagnosed as described

below.

Vacuum pressure (at idling, A/C “OFF”):

􀀐60.0 kPa (􀀐450 mmHg, 􀀐17.72 inHg) or less

 

Diagnosis of engine condition by measurement of intake manifold vacuum

Vacuum gauge indication Possible engine condition

1. Needle motion is steady but lower than normal position. This

tendency becomes more evident as engine temperature rises.

Leakage around intake manifold gasket, or disconnected or

damaged vacuum hose

2. Needle intermittently drops to the lower position than normal. Leakage around cylinder

3. Needle drops suddenly and intermittently from normal position.

Sticky valve

4. When engine speed is gradually increased, needle begins to

vibrate rapidly at certain speed, and then vibration increases as

engine speed increases.

Weak or broken valve springs

5. Needle vibrates above and below normal position in narrow

range.

Defective ignition system or throttle chamber idle adjustment

 

- compression test

 

Compression

A: INSPECTION

CAUTION:

After warming-up, engine becomes very hot. Be

careful not to burn yourself during measurement.

1) Remove the collector cover.

2) After warming-up the engine, turn the ignition

switch to OFF.

3) Make sure that the battery is fully charged.

4) Release the fuel pressure. <Ref. to

FU(H4DOTC)-44, RELEASING OF FUEL PRESSURE,

PROCEDURE, Fuel.>

5) Remove all the spark plugs.

<Ref. to IG(H4DOTC)-4, REMOVAL, Spark Plug.>

6) Fully open the throttle valve.

7) Check the starter motor for satisfactory performance

and operation.

8) Hold the compression gauge tight against the

spark plug hole.

NOTE:

When using a screw-in type compression gauge,

the screw (put into cylinder head spark plug hole)

should be less than 18 mm (0.71 in) long.

9) Crank the engine by means of the starter motor,

and read the maximum value on the gauge when

the pointer is steady.

10) Perform at least two measurements per cylinder,

and make sure that the values are correct.

Compression pressure (350 rpm and Throttle

fully open):

Standard:

981 — 1,177 kPa (10 — 12 kg/cm2, 142 —

171 psi)

Difference between cylinders:

49 kPa (0.5 kgf/cm2, 7 psi) or less

 

You didn't answer about your most recent timing belt service. When was the tensioner last replaced?

[MilesA]

How's it going, OP?

 

I know you posted about stalling/rough idle but that rattling sound at low revs is not normal and should be checked out.

 

It sounds like you could have a bad timing belt tensioner, which is why I suggested trying to locate the source of the noise. Also, why I asked when the tensioner was last replaced. If that tensioner goes, you will have expensive engine damage.

 

Still a tensioner alone would not likely cause low idle. Low idle can be caused by many things, which is why I suggested the vacuum gauge test and, if that does not reveal the cause, the compression test. These are standard diagnostics.

 

Potential causes include vacuum leak, dirty/bad idle air control valve, dirty throttle body, dirty/bad MAF sensor, dirty/bad fuel injectors, low fuel pressure, etc. So, quite a long list as you can see, and you say there are no CELs. If there were, it would be easier to narrow down. It helps to be systematic and diagnose, rather than guess, at the cause.

[greenbeen]

How's it going, OP?

 

I know you posted about stalling/rough idle but that rattling sound at low revs is not normal and should be checked out.

 

It sounds like you could have a bad timing belt tensioner, which is why I suggested trying to locate the source of the noise. Also, why I asked when the tensioner was last replaced. If that tensioner goes, you will have expensive engine damage.

 

Still a tensioner alone would not likely cause low idle. Low idle can be caused by many things, which is why I suggested the vacuum gauge test and, if that does not reveal the cause, the compression test. These are standard diagnostics.

 

Potential causes include vacuum leak, dirty/bad idle air control valve, dirty throttle body, dirty/bad MAF sensor, dirty/bad fuel injectors, low fuel pressure, etc. So, quite a long list as you can see, and you say there are no CELs. If there were, it would be easier to narrow down. It helps to be systematic and diagnose, rather than guess, at the cause.

 

Thanks MilesA, car was with the mech yesterday, but said there was not much he could do and there are no error codes related to the engine.

 

Not sure about the tensioner, I know the fan belt was done.

 

Im not sure if it comes across in the vid, but I dont think its a "low" idle problem, its very rough and stalls when put into gear.

 

Ive seen some other threads regarding the throttle body, but the mech said its alot of work to check that out with the turbo, is that correct or are there any tips on doing so?

 

He has tried a new air flow thingie(sorry suck at cars!) problem remained, does that rule out the MAF sensor?

 

Problem is, it only happens after the car has had a fair amout of driving, so mech has only seen the video...

 

Mechanic said to get the gearbox fixed first

[MilesA]

Mechanic said to get the gearbox fixed first...

I can see where he is coming from. One thing at a time and fix the problems you already know about, etc.

 

Saying he cannot diagnose anything without codes is lame, though. There are problems that don't trigger any codes. A vacuum test is really easy and only takes a few minutes, no need to take things apart.

 

The timing belt is behind a black plastic cover at the front of the engine. This is completely different from the drive belts for alternator, power steering or A/C. See diagram. It's important to know when this was last serviced.

 

Maybe you can post again when you find out more.

[hadvw]

Get VAG-COM and romraider log, or btssm + cable and log.

 

I had similar issue when switching from cold->warm, and managed to see misfires on a particular cylinder when mine would idle badly (and eventually stall). Swapped coil packs, found the misfire moved, and found that coil pack wasn't OEM. New coilpack, all better..

 

Without SOME kind of logging, you're really in the dark here..