hey all,

was driving earlier today, and put my foot down to do an overtake, but the stilo decided it didn't want to budge, can get up to about 60-65mph but after that I just have no power.

Its a 1.9 diesel JTD so normally an overtake would throw you back into the seat.

Any ideas what could be wrong?

No visible smoke (i dont think) and no warning lights on, it's just lost its higher speed and building up power if that makes sense?

oh should say, to get up to 60-65mph it has to really built up, no real torque at all.

hmmmm, go out, find the MAF sensor and disconnect it, then go for a spin and see if it has most of its power back, if it does, either leave it unplugged or buy a new one, a new one is preferred as leaving it unplugged means it runs in a base MAP on the ECU and uses a little more fuel, but i'm still getting 44mpg average out of mine and 64mpg on a run. I just keep forgetting to buy a new one lol

interesting ill give that a try , wouldnt the MAF turn on the managment light?

I was thinking EGR, When I gave it home I gave it a blast on the driveway, got the a point the whole car juddered and black soot flew out the exhaust.

Did this a couple of times, same thing every time.

Disconnect the EGR valve, it will give the engine warning signal but it will not do any damage, if your car runs fine then you know what it is.

the MAF does NOT put the light on, its worth a check for the sake of unplugging it and then take it for a quick spin around the block.


as above, EGR is another possibility but I believe Smoke from the exhaust is another sign of this.

thanks for that , what is difference between MAP and MAF and how do I find each one?

dont wanna unplug wrong trhing by accident

Ok when i disconnect egr valve i get a slight boost in performance but still nowhere near normam

Next try is maf sensor i think

Ok something else to report , it smells a bit burny when i take it for a spin round the block trying to make it accelerate - a faint burny smell coming from it .... Hellpp lol

MAF is the Mass Air Flow sensor on the intake pipe, try unplugging it.


MAP is Manifold Air Pressure Sensor, these aren't fitted to the JTD I believe.


The MAP I was on about the fueling map in the ECU, its the software that tells what bits of the engine to do what.


unplugging the EGR wont do anything much to tell you if its working or not as when it fails it fails either open or closed and sticks there so unplugging it wont make the slightest bit of difference.


Seriously, unplug the MAF and see if its that.

Im really struggling to find this maf sensor.

Ive attached 2 pics of what I thought were right,

The one at the top of the engine that plug I think is the MAF?

The other one shows a plug in the middle Ive unplugged which looks like a MAP.

when unplugging both of them to car can't rev over 3000 revs regardless of how hard I hit the pedal.

Am I unpugging the right things or the wrong thing?

I do have a engine light on now, which Ill reset later

Ah ha - ok so its just the MAF (The one lower down one)

If I disconnect that, yay I get a fair chunk of power back
(although she isn't what she used to be, faster but not as fast as it was - I take it if I replace the MAF I should get full power back)

Thanks for the help so far

mariocinq said:

unplugging the EGR wont do anything much to tell you if its working or not as when it fails it fails either open or closed and sticks there so unplugging it wont make the slightest bit of difference.

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I beg to disagree, mine is clogged up and the car failed to start. Unplugged the power cable and the car runs just fine until I can block it, which will be sunday.

Is yours blanked off stealth

XB23 said:

Is yours blanked off stealth

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Not yet, 2 months ago it would not start and I unplugged it. No problems since just the engine management warning. I have the plate to blank it. Sunday, clean it out and blank it, new spring, drivers side and replace both headlamp units.

Yeah its the bottom one lol, I couldn't take a pic of mine to show you what I meant as mine has been relocated due to induction kit lol.


yeah you should be back to full power, like I said, with it disconnected its running about 75% power.


Blanking off the EGR is always a good plan, not really sure exactly how they work, I just normally blank them off with-in a few weeks of getting the car.

Ok stilo is back to power again. cleaned the MAP sensor and replaced the MAF (£90!!) mind you that is a genuine bosch one.

When I plugged my laptop into the car I noticed these readings on the Injectors, why are 3 on minus numbers and 1 positive?

Is that normal??

yes think of it as ecu trying to balance the rpm via injector flow.
so to get a smooth as possible crank speed, its plus on inj 1(maybe suggesting slight blockage, delivering less than required)
so to keep a smooth crank speed its also requesting less on the other 3.
usual is to see 2 minus 2 positive all even values is ideal, close to zero ideal.
I would run a tank of good injector cleaner and keep an eye on them to see if it reduces number 1 down a bit.
also I would recheck at different revs and engine temps like cold start, and hot start, and vary the revs like the sort of logs I did in this thread
https://www.fiatforum.com/stilo/419933-diesel-injector-cleaner-ar6400-cr.html
I would recommend something like forte injector cleaner, bg244 , or the recent ar6400-cr, over the likes of petrol station redex or carlube stuff not that I don't use them just I don't think theyre strong enough to waste time when you need a cleaner id use them as a maintenance keep it clean now and again.
also try removing the injector plugs and use contact cleaner to clean connections and plug unplug a few times to ensure good connection.
if you go for the ar6400-cr look for the ones who give away a free £5 worth sample of 20ml ar6200 fuel treatment
like this one
http://www.ebay.co.uk/itm/Archoil-A...620?pt=LH_DefaultDomain_3&hash=item2ed1650e8c
and I wouldn't use it same tank or tanks(looks strong enough to split into 2 tanks) as the injector cleaner use it after when its nice and clean.

Cheers for that ill try that stuff and give the injectors a good clean