Okay so this is my story. I bought my car second hand, and it did not have much power, especially when going up a hill. There was no engine light on or anything. I left it like that for about a year and then read on the forum that it could be my MAF sensor. I unplugged the MAF sensor and it ran like a dream. I then left the MAF disconnected for about 5 months, when I finally bought a new one. At the end of the 5 months the engine fault light would start coming on for short periods especially while over taking on the highway.

Once I fitted in the new MAF it did not have the power it used to have, and once I took it on the highway the engine light came on and it had even less power and would not rev passed 3100 rpms and the engine fault light never went out.

I took it to a Fiat garage which connected the diagnostic computer to it, which said EGR or Turbo fault. The guy said he would advice me to drive it like that for a week or so to see if it cleans the egr.

I drove it for about a week and the engine fault light did go out for some time, but then always came back on again. With the last time the engine light coming on but not going out again, but the car was able to rev passed 3100 rpms, but it did seem to hesitate once it hit 3100 rpms.

I then cleaned the egr myself, which was very very very stuck. It can be moved by hand now, but it did not solve the lack of power or the engine light. But the car does not hesitate anymore at 3100 rpms. I then proceeded to clean the MAP sensor, which was very dirty, and it did give a small performance increase but still left the engine light on and the car with a loss of power. I struggle to 120 km/h on the highway.

Does anyone have any idea what it could be?

Check the air filter is clean. Check the turbo wastegate is not jammed open. Disconnect the battery for a half hour then reconnect. (make sure you have radio codes first). There is an air pipe goes into a box on the right hand side of the engine (between battery tray and engine) on my car this pipe split and gave low power. Let us know how you get on.

Just some feedback. I took my car to a fiat dealership. A mistake I will never do again. Like three weeks and lots of money spent later the car came back without being fixed and with all my wiring striped and covers taken off and not replaced. They had replaced the electronic component of the EGR and it had a slight performance increase. I then noticed a hole in a black box under my car that is connected to my airflow pipe right after the Mass Airflow Sensor. I am not sure of the purpose of the box? But I removed it and cabled tied a bag over the hole to close the hole. This resulted in a massive performance increase and the car driving as I believe a 1.9 diesel should

The black box connected to the MAF sensor.. is that the airbox?

Or do you mean the little box glued underneath the airbox?

My beast has similar symptoms.. It's fine until I rev it to 3100rpm, then the Engine Management light comes on.. and the beast runs "lethargic".

It clears up after a few days... but every time I rev past 3100, the EML comes on and it does it all over again.


Would I change the MAF or the EGR valve as first thing to try? I will try disconnecting the MAF this weekend, so see if that gives me a hint.

Ralf S.

Ralf S. said:

The black box connected to the MAF sensor.. is that the airbox?

Or do you mean the little box glued underneath the airbox?

My beast has similar symptoms.. It's fine until I rev it to 3100rpm, then the Engine Management light comes on.. and the beast runs "lethargic".

It clears up after a few days... but every time I rev past 3100, the EML comes on and it does it all over again.


Would I change the MAF or the EGR valve as first thing to try? I will try disconnecting the MAF this weekend, so see if that gives me a hint.

Ralf S.

Click to expand...

Do you have any diagnostic codes.

No.. I don't have the OBD doodah yet (but I can see I'm going to have to buy one.. )

Car is "not bad"... (I'll check the turbo solenoid too) but I feel it lacks a bit of poke.

I can get the EML to come on "on demand" just by revving it past 3100rpm. It goes rather lethargic afterwards, so I think it's a real fault... but after a few days the light goes out and car drives better.

The car has been like this since I've had it (a couple of months) so I have no experience of it running properly... My impression about it feeling a bit flat are just subjective.

The MAF looked clean (had the airbox off to change the clutch not long ago) and the EGR was "lightly sooted".. though it felt stiff to open and close by hand. Nothing obviously knackered.. but I'm sure the beast has something not quite right.


Ralf S.

I just had similar fault after clutch replacement.

Things you can check..

map sensor/all pipe work from air cleaner to turbo and inter cooler + oil trap under air cleaner.

My code was P0235 turbo boost..

and the cause of this fault was brake switch that i recently fitted.

Overboost valve is notorious for exposed, low positioning. Gets water in it. Remove, check the piping & clips, clean it out and remount it somewhere higher. Several topics here -
https://www.fiatforum.com/stilo/118850-overboost-again-sorry-dealer-move-free.html
https://www.fiatforum.com/stilo/159553-egr-valve-overboost-valve.html
https://www.fiatforum.com/stilo/160230-overboost-valve.html

bri1232 said:

I just had similar fault after clutch replacement.

Things you can check..

map sensor/all pipe work from air cleaner to turbo and inter cooler + oil trap under air cleaner.

My code was P0235 turbo boost..

and the cause of this fault was brake switch that i recently fitted.

Click to expand...

Correction it was turbo boost valve just so happens brake switch was playing up at same time..

I've got exactly the same problem with my JTD , Thanks for above info, I'm working on it

When people say you should clean your overboost valve what do they mean? How do you clean it? Is it just opening it up, removing the little circular sponge. Spraying that with WD40 and replacing it?

Hey Ralf S. The little black box I was referring to is not the air filter. It is the oil trap underneath the air filter box

vodka said:

Hey Ralf S. The little black box I was referring to is not the air filter. It is the oil trap underneath the air filter box

Click to expand...

I think it's going to be the turbo boost valve/solenoid switch under the battery box.

My EGR wasn't too bad when I looked.. and the MAF doesn't seem very likely since the EML comes on at 3100rpm.. and to me that means something isn't activating.

I'd speculate that a MAF fault would just be giving screwy readings to the ECU - the ECU wouldn't know if those are right or wrong... but it would know whether the EGR or the turbo valve are supposed to have done something but haven't engaged.

My hoses look tight and connected okay.. but I have a service coming up soon so I'll have another look. I'll clean/free up the EGR (I want to blank it off anyway) and maybe replace that solenoid thing just to see what difference it makes. I have a spare MAF.. but as above, that seems the least likely thing of the three.


Ralf S.

Afternoon

I had the same problem on my old MW, turned out to be a dead MAP, its boost related by the sounds of things.

check your vacuum pipes to the boost valve in case on had come off, and move it onto the side of your battery box (guide some where on here

If you have MES you could check the readings/Voltages from the MAP/MAF check the EGR is working correct (get it blanked!)

Paul

Hmmm..... I have a new turbo switch to go on.. and a MAP sensor is not too dear.

I'll give that a go too. 120,000m service is coming up.

Ralf S.