Happy New Year everyone. My Alfa developed another problem during the hot summer here in Australia. On a very hot day (over 40c outside), after 40mins driving, car's engine cut out with check engine light on. It was like run out of fuel, but fuel gauge showed 1/4 tank full. I manged to get the car out of traffic, tried few times to restart it, but everytime it stalled after few seconds.
Scanned the error codes in ECU, P0087 fuel rail pressure too low, P2293 fuel pressure regulator 2 performance
Sent the car to a diesel specialist, they think my car may have 1 or 2 leaky injectors which are bad enough to cause the low fuel pressure error. They would like to have them removed and tested. I'm no expert on this but my throey is the injection pump is weak and going to fail.
Has anyone experienced this before? Would a fuel pump be overheating (low fuel level combined with extrem hot weather)? Or the leaky injector could cause this mess?
Have discussed similar issue meanwhile.
When has your diesal fuel- filter been replaced last time ???...
Not sure how it is behaive while extreamly hot.
Cold practise shows that car stop much sooner then you get Clogging message on the dash.
Just make sure it is OK.
Thank you for your quick reply. The diesel fuel filter replaced about 12 months ago, and don't have a clogging message. I believe it should be fine. I've changed it after this breakdown because it is the cheapest fix to start.
Quick update: after the breakdown, I found the car running really rough because EGR valve failed badly, no error message on dash though. It opened 40% at idle...Gave it a good clean and didn't make a difference. I blocked the EGR for now and ordered a new one straight away. Could the bad EGR be the real cause of the low fuel pressure issue?
EGR is closed for majority of working regimes.
My view EGR is open at warm idling with any revs only just to pass MOT test for NOx successfully.
It is a joke of course but very closed to the truth.
Looks like ECU trace warm idling all the time. I do not think it caused by MAF but all sensors responsible for temperature and revs are involved. I would read engine working parameters with MES first.
Here are some images of Multiecuscan data when car is up to operating temp during idle with EGR valve blanked. They look fine except there is no reading on O2 sensor.
When EGR is not blanked, it opens over 45% (sometimes shows 95%) when car is idling, once the MAF sensor unplugged, car runs normal.
Then I tried another MAF sensor, same thing, EGR stays open. So confirmed it is not a faulty MAF sensor. EGR is new, I beliveve it is also fine.
So if I'm following the logic here, what else input will determine ECU to turn EGR valve on? Or maybe I have a bad ECU? Or maybe wiring issue?
Wait... Step back and slowly a bit...
EGR is designed to be opened at idling. It is its task to minimize NOx in exhaust sending some into intake.
EGR may be open partly at idling depend parameters ( like a temperature, etc )... So 40% or 95% open it is not a problem.
Why do you reckon that EGR acts like crazy and stays open all the time ( non- idling for instanse ) ???...
If you want solve raw idling issues only, why do you suspect EGR only ???...
Agree with Buon, it could be anything.. Did you get your injectors replaced? There should be a tolerance value I forget exactly what the bounds are, but I seem to remember anything over +2 / -2 is pretty bad.
I've had the engine sound like a bag of spanners / cut out due to crappy connections to the injectors, I've also had bad injectors which caused the same issue. It could be the fuel pump (I suppose), but your diesel specialists were probably going down the correct path.
Check them out in CUEScan, take a step back and don't jump to conclusions because rough idling can cost you a fortune.
It could be something simple (wiring, injectors, DPF regen needed, glow plugs / GP relay control, MAF sensor, MAP sensor) all the way to pulling the engine out to strip / clean and / or replace the intake manifold.
Thank you for your information. I thought EGR should be closed at cold idle, but I could be wrong.
All my 5 injectors were removed and bench tested by Bosch, they all passed. Although I found the correction of injector #2 could be over 3 at idle.
If the EGR is supposed to be open, I guess I will need to look a different direction for the cause of rough idling. Maybe it has a connection to low fuel pressure issue I just had. Does anyone know how to test the high pressure injection pump?
log egr % and maf airflow for a good few minutes my egr worked on a cycle time at idle so would be off for minute or so the open for a while and so on like this egr 2 cycles.jpg
also you could log rail pressure and regulator opening % to see if its struggling to maintain pressure
Thank you sussexa. I removed the EGR blanking plate, and used your method to logged some data.
When I started the car, I was surprised car was not juddering this time, I cancelled the EGR error message in Multiecuscan, and started recording the data. Found EGR didn't open, but desired air quantity was a lot less than the actual air quantity....Not like your, they are in the same range at all time.
I turned the car off, and restarted it to record again. This time I revved the engine to 2000-2500 rpm to test EGR. EGR opened at 40% and closed a few seconds later. But again, once EGR closed, actual air quantity started to go up and desired stayed the same level.
Rough idle symptoms were not there, I believe it is because EGR stayed close. Why did it stay open at idle before, I don't know. I'm going to drive the car for more testing. But here are some questions,
Is your car also a 2.4 JTD? When you logged your data, was car engine cold or hot? Also is there something wrong with my intake air quantity data as it is very different to yours?
no mines a 1.9 but I think the cylinder volumes are close enough to the same so no egr expect 480-520mg/I(may vary a bit with temps and engine mods) (485mg/I perfect)and egr open 40%+ expect a maf of 200-300mg/I.
your seems to be doing this , just the desired maf is stated as an egr open value even though its not opening egr on 1st pic 2nd pic looks normal function. I think it was warm but cant be sure from several years ago.