V40 GDI throttle problems - diagnostic help requested? (Long Post)

Hello all,

please excuse the top-posting start - I'm re-invigorating an old
thread.

I have a three year old V40 GDI which exhibits many of the symptoms
described below by Paul Schofield. My comments are interspersed with
his:

I have this problem in spades. When the engine is cold it behaves.
Once warmed up, it is like having 'kangaroo petrol'. It is impossible
to trickle along in a traffic queue, as the car tries to act like a
bucking bronco. This is true in 1st, 2nd and even 3rd gear. The
problem seems to be related to the 'fast idle'. Taking my foot off
the accelerator to use engine braking makes the car surge and almost
stall repeatedly until I brake. This makes it difficult to go over
the speed bumps near my home as well as queue nicely. It feels like I
have a poltergeist tap-dancing on the accelerator.

Yup - once warm, the engine runs at just over 2000 rpm when I am
stopped at traffic lights, occaisionally blipping up and down.
Usually, after 15 seconds or so, the speed drops closer to the
'standard' idle of 650 rpm.

Yes - same problem. What worries me is what it is doing to the seat
belt.

Yes - rear wheels are out of alignment and cannot be adjusted back
fully.

Did anyone come up with a solution for the throttle problems? I'm
about to take thcar into the garage to get it fixed, and I'd like to
make some constructive suggestions.

Remanufactured throttle assemblies are available here:

http://www.bba-reman.com/throttle_body.htm

where they say "Mitsubishi GDi's (also fitted to Volvos) suffering
from poor injector spray patterns, cooked cylinder heads and inlets,
and eventual failure of throttle body. Causes poor idle or poor
acceleration. BBA can supply reman throttle bodies and injectors."
Does anyone have any experience of using this company/these parts and
can give an opinion?

Many thanks,

Sid.

 

In reply to the reported throttle problems, I had a similar problem with my
1.8 GDI (S40). It started after I had serviced the car and had moved the
throttle butterfly valve to clean the area around it. Following this the
engine idle speed was all over the place - anything up to 2000 RPM and very
erratic. The car was also difficult to control in slow moving traffic.
Having thought about it, the throttle pedal and throttle valve are connected
electrically only, i.e no normal throttle cable, and I wondered if the
calibration of the 'feedback signal' to the sender (throttle pedal) had been
lost or corrupted. I therefore disconnected the battery for about 2 or 3
mins, to ensure that the system ahad lost any memory, and then reconnected
the battery ensuring first the the throttle valve was closed and the
throttle pedal not depressed at all. Having done this, the car has been fine
ever since (5000 miles) and hasn't missed a beat at all.

Hope this helps.

Regards

 

Thanks Dave.

please excuse me for moving your comments to the bottom.

I had a look round the bba-reman site and came across a good
messageboard that seems to have relevant information: (long url -
careful of split across lines)

http://cgi.www.bba-reman.com/cgi-bi...s_and_solutions;action=display;num=1068151234

The gist is:

V40 GDI with similar problems - tried:

1) Decoke (at cost of GBP 1000 (!)) (apparently Mitsubishi are using
air-blasted walnut shells to clean the deposits off GDI engines.
2) Replace TPS (whatever that is) GBP 230
3) Replace Idle control motor GBP 400

all which didn't solve the problem. Volvo garage gives up (!).

4) Checked/replaced coolant sensor and Lamda-sond sensor.
didn't solve problem

5) Tried analysing exhaust gas and determined that the exhaust gas
recycling valve (EGR) was not working properly. This solved the
problem.


Other posters say that the throttle bodies are failing, injectors and
heads coking up. It looks like this type of engine (at least in this
version has problems).

To be fair, my car is just over three years old and has done over
100,000 miles, so I would guess the average mileage user won't see
problems.

Anyway, thanks again for your input, and I can go to the garage with a
list of the cheaper things to look at replace first.

Later on on the board it says that Mitsubishi have produced new
software for the ECU that cures/resolves idle problems in earlier
engines - I don't know if this is applicable i.e. do Volvo use a
different ECU/software anyway?

If/when the problem gets sorted on my car I'll post the resolution -
it might help someone else. It needs sorting before a throttle surge
causes an accident for me.

Regards,

Sid