2.0 GDI Idle issue

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dutchpajero
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Hi guys,

First off, i really appreciate you are taking the time to read my post.

I’ve bought a Pajero Pinin about a month ago and having issues with it since then.

The issue started with a check engine light and the first half of the gas pedal wasnt doing anything. To fix that i have just installed a new TPS sensor and adjusted it to spec (0.4-0.6v).

At first i adjusted the TPS to be exact 0.4volt with the result that when the engine is cold it now idles very rough, the whole car shakes at 800rpm. When the engine is warm it wont idle at all without giving it gas. I have then adjusted to be 0.6volt without any improving result.

I’ve checked other threads and other info online regarding the throttle body, i’ve cleaned mine and the valve is opening and closing as it should and doesnt close all the way.

I am kinda at a loss on this, i bought it to have some fun with but has been a nightmare since.

Is there a different way to adjust the idle, other then adjusting the TPS?

Best wishes!

fordem
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Idle speed is not your problem

and no, you cannot adjust the idle speed by fiddling with the throttle position sensor or the accelerator position sensor.

Check under the hood, there should be a label stating the idle speed, I'm not certain what it is on the 2.0 GDI, but on the 1.8 it's around 600 rpm - on most vehicles, idle speed is around 750 +/- 50 rpm, the GDI engines idle at a lower rpm, so if you're at 800 rpm, it's too high - if it's idling at 800 rpm and the idle is rough, the problem is not the idle speed.

Next - one of the things that happens with the GDI engines - again, this is based on the 1.8, not the 2.0 - is that it recalibrates the throttle, if you watch it, it will open & close the throttle plate three or four times - you CAN adjust the idle by moving the TPS, but, the next time you start the engine, you'll be back to square one when the system recalibrates itself.

dutchpajero
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I’ve kept the TPS inside the

I’ve kept the TPS inside the tolorence.

The reason i changed the TPS is because it used to give me a fault code stating the sensor is faulthy.

When the engine is cold the rpms are around 800 and then the car shudders. At operating temp the rpms drop till the point it stalls.

There are no faulth codes at this point...

I’ve already changed the sparkplugs, i’ve got the expensive correct ones.

fordem
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I'm thinking you're not understanding what I'm saying.

You've replaced the throttle position sensor because it was defective and caused a code to be set - with the replacement in place and adjusted to spec, there are no codes, but the engine won't idle smoothly, cold it's idling at 800 rpm and stumbling, hot, the rpms are dropping until the engine stalls.

Assuming that you used the correct replacement TPS, it is unlikely that you will be able to resolve the stumbling/low idle speed problem by fiddling with the adjustment - the electronic throttle servo system will recalibrate itself every time you switch the ignition on - more importantly - there is no mechanical idle speed adjustment, I'm not certain if the idle speed can be adjusted, but, if it can, you're going to need something like the Mitsubishi MUT tool to do it.

To summarise this - I think you're looking in the wrong place, and trying to adjust the wrong thing.

At 800 rpm the engine should be idling smoothly, find out why it's not and fix that.  When the engine is cold, the ECU runs it in open loop mode, fuelling it based on predefined tables, as the engine warms up ECU will switch to closed loop, and fuel based on feedback from the O2 sensor, is it possible that your stalling problems start when it switches into closed loop operation?  Do you have any way to monitor the ECU's operating paramaters?

Apart from idle speed issues, how does the car run, is it driveable?  What was it like before you changed the TPS, apart from having a code?  You say you've changed the plugs and fitted the "expensive correct ones" - what does that mean?  What condition were the coil pack-to-plug connectors in - these can and do develop issues that will cause random misfires, in fact, these coil pack-to-plug connectors have caused me more "drivability related grief" than any other part.

On my car, which has the 1.8 GDI engine, on a cold start the idle speed is around 1500 rpm, dropping rapidly to around 1000, and then more slowly to around 600 rpm as the engine warms - it will reach 800 rpm within about 3 minutes of a cold start if just left to idle (I live in a warm climate, so yours could take longer than this, if the engine is starting from a lower temperature) - at no point during this process does the engine stumble or shudder, and it can be driven immediately after starting, which is what I normally do - get in the car start it, and immediately drive away.

 

dutchpajero
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I have no way to monitor the

I have no way to monitor the ECU.

I have replaced the spark plugs with the $20,- a piece iridium plugs.

the car drives fine, when i push the clutch and let go of the gas pedal it stalls.

the spark plug connector seems in fine condition, and i cant hear a tick that indicated a spark going over to the intake body.

 

Im thinking about pulling the plugs for a visional inspection and find a way to test the fuel injectors.

Also the car has a "green filter" high performance air filter fitted by the previous owner and i'm going back to stock to see what it does.

Also asjusting the TPS back to 0.4volt factory spec.

fordem
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A couple of questions for you ...

First - now that the TPS has been replaced do you still have a check engine light?

Second - do you have owner/service manuals that correspond to the vehicle, how do you know what plugs are the correct ones?  I doubt that this idle problem is caused by the plugs, but, use of the correct plug may be critical to other aspects of engine operation.

If the car runs well under "driving conditions" it's unlikely that the problem is caused by the fuel injectors - they are obviously capable of delivering the larger amounts of fuel required to produce power.

I'm wondering if the EGR valve is possibly stuck in the open position - if it is, it will allow the engine to suck exhaust gases into the intake rather than fresh air through the throttle body, and could account for both the high idle speed and the stumbling.  When the engine is cold and running in open loop, it will hold the throttle plate open to keep the idle speed high and inject fuel as determined by the preset tables, when it goes into closed loop, it will fuel based on "unburned" O2 in the exhaust stream, if it sees unburned O2, it considers the mixture lean & richens it, but if it's actually sucking exhaust gases back into th eintake, there will be less O2, and the system will lean the mixture out.

The EGR system feeds into the throttle body from the firewall side, it should be possible to reach it on the 2.0, as it is accessible on the 1.8 - try making a stainless steel shim to block the passage and insert it in between the pipe & the throttle body.  The EGR valve itself is an electrical stepper motor unit and mounted between the cylinder head and the firewall, I believe the engine may have to be removed from the vehicle to get access to it.

Be aware that this may be considered tampering with the emissions controls and may be an offence in some countries, so I can only suggest it as part of a diagnostic process - it may also set a check engine code, but if the idle improves when it's blocked, you'll have some idea of where the fault lies.

dutchpajero
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Hi,Since the tps is replaced

Hi,

Since the tps is replaced there is no more check engine light.

I went to the local parts store and checked the ngk website to find the correct spark plug. They have plugs at €4,- a piece and plugs at €20,- a piece.

On my other car (vw amarok) i have had the egr programmed shut and it no longer operates. I figure i can have that done to the pajero aswell...

Went searching for fuel injector symptoms and rough idling is listed

fordem
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If the EGR is stuck open

If the EGR valve is stuck open, then "programming" it shut won't change the situation, the valve won't respond to ECU commands - I know of no other way, besides blocking it, to actually be sure it's not open.

fordem
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Thinking along the same lines ...

Consider temporarily venting the crankcase to the air and plugging the PCV line to the intake manifold - you'll find it on the right rear corner of the cam cover - this is a lot easier to do than blanking the EGR so it might be an idea to try it first.

Under normal operating the PCV valve should restrict airflow under high vacuum conditions (such as at idle), but I've seen them break and stick open and cause idle speed issues.

dutchpajero
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Hi guys, Just wanted to let

Hi guys,

Just wanted to let you know i fitted a standard airfilter instead of the “green filter” and the engine runs a lot smoother now. It doesnt stall anymore so thats great.

It still sputters a little bit but the shaking is practically gone!

I think im still gonna replace the injectors and possibly check out the egr or atleast have it shut an never open again...

Thank you all for thinking this over with me

dutchpajero
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how :(

Anyone got any tips on removing the EGR valve?

 

Damn its on a rubbish location, already got scratches up my arm :(

fordem
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I could be wrong ...

but I do not think you can get that EGR valve out with the engine in the car, and if you can, it's going to be a very frustrating job - if what you're planning on is blocking it, it will be easier to do so at the throttle body side of things.

imraojal
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EGR

Removing the EGR is a pain. you have to remove the throttle body, the intake manifold to get a clear access to it. its right behind the engine on your left. you can remove it with the engine on the car. mine has a problem (ran a diagnosis after the check engine light came on) and will be replacing it with one from the salvage yard. having very poor fuel consumption lately

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