Mitsi Lancer GS4 Diesel With VW/AUDI engine, (or VAG Diesel owners) need your input!

Solus

New member
Joined
Nov 24, 2011
Location
UK
TDI
Lancer GS4 Diesel DP-F
Mitsi Lancer With VAG Diesel engine problem help/advice needed!

So after 18 years of German and Italian motors I took the dive last month and went Japanese/German and bought an 09 Lancer GS4 saloon Diesel (DPF).

Heres the issues I am having:

1.
On starting from cold the car is usually idle at ~750 rpm. BUT if I turn on the Interior fans the revs suddenly jump to ~1100 rpm and stay there. I have tried adjusting the temps, turning AC off AND adjusting the airflow to floor/windscreen/dash vents etc.
If the vehicle is "coasting" at any speed or the fans are off the revs are at normal idle

No matter what I do the revs sit at ~1100 as soon as the fans are set to on, and it takes aound 15 minutes of driving round town to get the revs to normal idle. Definitely a "phenomenon" triggered by the fans being switched on.

Mitsi have no definite answer why this would happen.


2.
I have noticed some "lumpiness" at idle after a good run during the day. This did clear up eventually, but "tapping" the accelerator briefly caused some "choking" i.e. revs drop to ~500 before bouncing back up.
Also if I hold revs at ~900 - 1000 the engine defo seems to be running rough, yet seems smoother at higher rpms and at idle..

Mitsi have today put the car on to their diagnostics computer and told me:
1.
It's normal for the car to rev high with the fan being switched on,when I asked what, if any purpose this could serve, mitsi were stumped and said


2.
They have not found any error logs in diagnostics in relation to the revs dropping low or bumpy tick over.

However there is definitely something not quite right as I had the same roughness at tick over today after the car had warmed up and the "fan switch idle boost system" had switched off. Maybe the "fan switch idle boost system" is supposed to kick in to prevent the rough tick over at normal idle!
Joking aside though this is really annoying me simply because I am not satisfied with why any car may behave in this manner and because it doesn't help the MPG at all.

If there are any Lancer X GS4 Diesel owners out there who have the VW/AUDI 2.0 engine I would really like to hear from you and see if this something that your car does also.

My first post so I hope I did this right and would really appreciate any advice as to what may be going on here, especially as the car is in warranty till apr 2012 I don't fancy getting fobbed off by mitsi now, only to end up with serious mechanical failure soon after warranty expiry.
 
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DPM

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Mar 16, 2001
Location
Newtownards, N. Ireland
TDI
2019 Rav4 AWD Hybrid, Citroen C4 BlueHDI
The fast idle on startup is likely to compensate for the load of the fan and the (electric) auxiliary heater- most modern diesels have'em. My Subaru does exactly the same until coolant temp gets to 50c, SO's old Corolla lifted the idle anytime the fan was on.

can't help you on the rough idle tho. This is a 140PD 16v engine isn't it?
 

VWBeamer

Veteran Member
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Jan 1, 2009
Location
GA
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2004 Jetta Wagon
Jap is offensive slang here, not trying to be PC, but I also don't want you to unintentionally offend someone either.
 

Solus

New member
Joined
Nov 24, 2011
Location
UK
TDI
Lancer GS4 Diesel DP-F
Jap is offensive slang here, not trying to be PC, but I also don't want you to unintentionally offend someone either.
Sorry mate, was never intending to offend just lazy typing tbh, but if only I'd known............

:cool: edited OP


@JCREWS I believe this is a 2.0 litre Diesel @ 140hp VAG as fittewd in Audi S4 , the only marking i can see is BWC, is that the one?

@DPM I have tried loading the electrics to maximum using windows, electric demister heated seats all light etc but only happens with the fan switch even at lowest setting, weird thing is that if the car is rolling even a 1mph in neutral the revs go back to idle.
 
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