Technical 500 poor mpg and possible egr fault?

[Baron Von Konig]

Hi there wonder if anyone can help/

I recently bought a 500 lounge 95 multijet. The car suffers from mpg in the 50-55 mpg. The car has been returned to the main dealer for investigation with no fault found and ' within specifications'

The car does not pull as well nor does it sound as it should, with por=or torque, poor mpg, very rough from cold and a somewhat alarming 6.4 instantaneous mpg sometimes!!

Doing some test reveals that the onboard computer is acurate enough for using on mpg tests being only out by a computed 1.1 mpg difference over a tankfull of diesel.

A diesel specialist has also had a look at the car - his findings were the same as the main dealer- but did note a lack of oomph, and general rough sounding engine.

Using FiatEcuscan, some more tests were done, looking in depth at the egr valve.

Findings:

On open %age the valve never closes but stays open by 9%- tho it can go below this on gear changes but soon resumes a position of 9%.

Showing a graph of actual position- desired position- egr opening% and engine speed, reveals negative values from the acutal egr position, with no correspondence between actual and desired position.

Questions:

Does examiner show as much detail as Ecuscan about the egr?

A valve closing and show a negative value, possible? or in reality a daft question as that would mean the sensor showing closed with having a 'false' zero - am I answering my own problem?

Anyone come across this before?
Many thanks.

 

[OrangeSport]

I can't answer the techy questions I'm afraid, but the average MPG you are seeing seems on par with what I've heard from others.

 

[Most Easterly Pandas]

:yeahthat:

It's cold also ATM which will kill it. What sort of journeys are you doing?

 

[Baron Von Konig]

The journeys are almost solely on dual carriageways and motorways, the fiat panda multijet would average high 60's doing the same runs.

I know the government figures are laughable, but it does seem a bit off compared to teh identical and less poweful panda.

The egr on the panda will show 0% on the egr position, the 500 shows this as 9% and 'bounces' below this, and is very rough sounding doing it.

 

[jrkitching]

What kind of cruising speed are you using?

 

[306maxi]

The journeys are almost solely on dual carriageways and motorways, the fiat panda multijet would average high 60's doing the same runs.

I know the government figures are laughable, but it does seem a bit off compared to teh identical and less poweful panda.

The egr on the panda will show 0% on the egr position, the 500 shows this as 9% and 'bounces' below this, and is very rough sounding doing it.

Remember that the Panda and 500 have different engines. The panda will also run skinnier tyres too. How long are your journeys?

 

[Baron Von Konig]

thx for the replys. both cars are used on the exact same journeys, same conditions, same times of the day yet the Panda will easily be 10%+ better.

The point of the post is the egr seems to have the wrong readings and both the main dealer and an independent and well respected diesel specialist cannot 'see' a fault yet one is there.

The egr shows a consistent 9% opening (on boost and under load) yet shows essentially a 'closed' position.

If this is the case then many cars could have a fault, yet they only look for the closed position/value but it is actually still open. This goes back to the first post:

Can Examiner show the %age opening or just a open or closed position?

I know to prove the problem is going to be to replace the egr valve, but a) to prove the fault exists, and b) pass this info onto others so they can try and get there cars closer to the comical government figures should they have a similar reading.

To try and get this car to near the panda consumption figures involves a consistent effort to not use the throttle and also to try everything to not use fuel.

 

[jrkitching]

Just a thought, but is the 500 mjet engine built to tighter emissions standards? Maybe it's configured to run with a minimum egr opening?

 

[306maxi]

Also, a 500 will have wider tyres and be heavier too......

 

[Baron Von Konig]

The wider tyres and increased rolling resistance are taken care of by running the tyres at 40 psi, not recommended tbh, but purely in the interests of science.

Not dismissing the slightly open therory, but under boost would the boosted air not be going past the egr the 'wrong' way, ie boosting into the previously burnt gases?

Would anyone if they have the time, use Ecuscan to see if they get a slightly open egr at all times when in gear, please? just as a comparision.

The spec is a 1.3 multijet 95 lounge 2010.

 

[badboy20cm]

Hy,

Anyone know were is EGR valve on engine 1.4 petrol ?

 

[306maxi]

Hy,

Anyone know were is EGR valve on engine 1.4 petrol ?

Petrol 1.4 won’t have one.