E46 330D Maf trouble
Discussion
Just browsing comments on Maf problems. I had all the symptons, no power on motorway and miss firing (rev limiting) over 3000 rpm and more noticable at 4500. My friendly indi mechanic replaced maf and zeroed ecu and also changed engine breather. Driving home the fault was still present. However that evening when I went out fault gone! (16 minute drive cycle interesting, thanks blackspider)
The next day took it up the motorway, fault present during whole trip. Yesterday I took it back to the indi mechanic, fault gone again and nice indi mechanic can find no fault codes or replicate the problem.
I have used stp fuel cleaner to flush out any water or dirty jets. 67K miles.
Any ideas anyone, when this car runs it flies, when it doesn't I look like a plum trying to take on kids in there TTs!!
The next day took it up the motorway, fault present during whole trip. Yesterday I took it back to the indi mechanic, fault gone again and nice indi mechanic can find no fault codes or replicate the problem.
I have used stp fuel cleaner to flush out any water or dirty jets. 67K miles.
Any ideas anyone, when this car runs it flies, when it doesn't I look like a plum trying to take on kids in there TTs!!
It sounds like a restriction in the turbo-the variable vains/geometry arent moving.
The most common fault I see with these is the Vacuum pipe that runs from the turbo to the accumilator and from there up and over the top of the engine to a pipe under the manifold.What tends to happen is this braided pipe perishes,either down by the turbo or as it comes across the top of the engine.It becomes weak and sucks in restricting the vacuum,it will also have pin hles in it.This then basically kills the engine above 3500rpm.It doesnt log a fault ever time...But when it does it tends to be boost pressure not met,and air mass meter.
The next one is pre supply pump failure.If the pump in the tank fails the second inline pump cant supply enough fuel on demand,then the engine dies/missfires at higher rpm.As you slow down or take your foot off the gas it picks back up.If this is the case the first port of call is the fuel pump relay(green) located behind the glove box(second from the right)..We have been replacing these as if they are going out of fasion,the contacts burn out due to the loads on this relay-No faults will be stored and more often than not its an intermittent fault.
Other faults not uncommon are injectors,but they tend to give symptons through the range,and will log faults such as rail pressure during start up not met,or smooth running faults.
When you say the engine breather was replaced,do you mean the black housing that sits on top of the engine next to the injectors?If so thats good,because they have now become a service item as they block up and cause oil to enter the turbo inlet pipes.
We also used to have a rail pressure sensor fault where the connector was making a bad contact.What this did was during over taking or 4000 rpm the engine would die as the fuel pressure dropped.This was only M57 engines upto '01.Quite rare now.
There are more faults I can think of but they are more in depth and rare..have a go at the relay first and the pipe.
The most common fault I see with these is the Vacuum pipe that runs from the turbo to the accumilator and from there up and over the top of the engine to a pipe under the manifold.What tends to happen is this braided pipe perishes,either down by the turbo or as it comes across the top of the engine.It becomes weak and sucks in restricting the vacuum,it will also have pin hles in it.This then basically kills the engine above 3500rpm.It doesnt log a fault ever time...But when it does it tends to be boost pressure not met,and air mass meter.
The next one is pre supply pump failure.If the pump in the tank fails the second inline pump cant supply enough fuel on demand,then the engine dies/missfires at higher rpm.As you slow down or take your foot off the gas it picks back up.If this is the case the first port of call is the fuel pump relay(green) located behind the glove box(second from the right)..We have been replacing these as if they are going out of fasion,the contacts burn out due to the loads on this relay-No faults will be stored and more often than not its an intermittent fault.
Other faults not uncommon are injectors,but they tend to give symptons through the range,and will log faults such as rail pressure during start up not met,or smooth running faults.
When you say the engine breather was replaced,do you mean the black housing that sits on top of the engine next to the injectors?If so thats good,because they have now become a service item as they block up and cause oil to enter the turbo inlet pipes.
We also used to have a rail pressure sensor fault where the connector was making a bad contact.What this did was during over taking or 4000 rpm the engine would die as the fuel pressure dropped.This was only M57 engines upto '01.Quite rare now.
There are more faults I can think of but they are more in depth and rare..have a go at the relay first and the pipe.
You know your BMW's Mr Blackspider, thankyou. Vacuum pipe is in good order. The relays all seem to be fine. I say all as 2nd in from right is orange on mine so pulled them all out and sniffed them for burning smell - also no faults logged whatsoever - My indi mech could still not replicate misfire on numerous test drives and I have just driven it thru London traffic to home with no misfiring or powerloss. The relay sounds a plausible cause given the symptoms but it seems ok. Can you confirm which one it is so I can replace it anyway to rule it out.
Could water in the fuel do the same thing? I am now on the third tank since I noticed the problem and the STP may have cleaned it up.
The breather is the one you describe
cheers to Blackspider, from Zhead
Could water in the fuel do the same thing? I am now on the third tank since I noticed the problem and the STP may have cleaned it up.
The breather is the one you describe
cheers to Blackspider, from Zhead
If you turn the ignition to p2 the pumps will run(you can hear them)pull each relay until they stop.
It should be on the right of the orange one,but the Bm' location says left-but ive never had one on the left.
It is possible to have had water through to give you that fault although I havent seen that since I was a peugeot in '93,also if its had petrol by accident before and drained-perhaps before you bought it-then it may be a sympton of that-a component that is begining to fail.
It should be on the right of the orange one,but the Bm' location says left-but ive never had one on the left.
It is possible to have had water through to give you that fault although I havent seen that since I was a peugeot in '93,also if its had petrol by accident before and drained-perhaps before you bought it-then it may be a sympton of that-a component that is begining to fail.
Thanks again Blackspider. No matter how hard I try it is running fine at the moment.
Here is a brief history of what happened, you may be able to narrow the problem down as I deduced it was the maf from other peoples experience, but that could have been masking something else.
Purchased car in Nov 06. Test drove it, it seemed fine, bought it and kept up with the wife in the M coupe on way home. A few weeks into owner ship started to notice rev limiting at around 4500 and was told by BM Stealer this was normal, hurumph. During a very wet M way drive on new years day noticed loss of power around 3000. Fuel was run quite low, 25 range. Filled up and limiting at 3000 stopped but still there at 4500. Then noticed it started again over 3000. A few weeks ago took a short drive to pick up a takeaway, returned to car and it wouldn't start. AA called, he faffed about a bit using a screw driver to undo the hex nuts on the engine cover, then sprayed carb cleaner up the intake and it fired, sort of. Indicating problem was no fuel. Anyway still wouldn't start so Relay called, 20 mins later, arrived and car actually started and I drove it on to pickup.
Stealers the next day said they couldn't find anything wrong and no codes logged, despite explaining rev limiting they sent me packing with a nice bill for doing nothing, they didn't even test drive it. They wont get my business again and I might ask for my money back.
Maf and breather then changed by indi mech, and now that's up to date. The car will now easily go past 5000 and just shifts up in manual mode. So Maf must have been at fault anyway. My mech says everything seems to be in good nick, the pumps are quiet, turbo doesn't whine. What else could cause an intermittent fault?
I'm baffled, but at least it means M Coupe has been out to play more
Here is a brief history of what happened, you may be able to narrow the problem down as I deduced it was the maf from other peoples experience, but that could have been masking something else.
Purchased car in Nov 06. Test drove it, it seemed fine, bought it and kept up with the wife in the M coupe on way home. A few weeks into owner ship started to notice rev limiting at around 4500 and was told by BM Stealer this was normal, hurumph. During a very wet M way drive on new years day noticed loss of power around 3000. Fuel was run quite low, 25 range. Filled up and limiting at 3000 stopped but still there at 4500. Then noticed it started again over 3000. A few weeks ago took a short drive to pick up a takeaway, returned to car and it wouldn't start. AA called, he faffed about a bit using a screw driver to undo the hex nuts on the engine cover, then sprayed carb cleaner up the intake and it fired, sort of. Indicating problem was no fuel. Anyway still wouldn't start so Relay called, 20 mins later, arrived and car actually started and I drove it on to pickup.
Stealers the next day said they couldn't find anything wrong and no codes logged, despite explaining rev limiting they sent me packing with a nice bill for doing nothing, they didn't even test drive it. They wont get my business again and I might ask for my money back.
Maf and breather then changed by indi mech, and now that's up to date. The car will now easily go past 5000 and just shifts up in manual mode. So Maf must have been at fault anyway. My mech says everything seems to be in good nick, the pumps are quiet, turbo doesn't whine. What else could cause an intermittent fault?
I'm baffled, but at least it means M Coupe has been out to play more
If it is 02 onward the Maf will need to be coded to the ecu,acording to a buddy who had the same.
Either this or there could be a sporadic siezing of the turbo compressor.My 320d did the same where it wouldnt rev past 3k then would rev normally on occasions,the blower was duffed!
Either this or there could be a sporadic siezing of the turbo compressor.My 320d did the same where it wouldnt rev past 3k then would rev normally on occasions,the blower was duffed!
Edited by Levinson on Friday 2nd February 20:04
Levinson said:
If it is 02 onward the Maf will need to be coded to the ecu,acording to a buddy who had the same.
Either this or there could be a sporadic siezing of the turbo compressor.My 320d did the same where it wouldnt rev past 3k then would rev normally on occasions,the blower was duffed!
Either this or there could be a sporadic siezing of the turbo compressor.My 320d did the same where it wouldnt rev past 3k then would rev normally on occasions,the blower was duffed!
Edited by Levinson on Friday 2nd February 20:04
That depends on the part number of the MAF fitted and the software level of the DDE, once connected to the programmer and software read out the programme numbers can be changed depending on the MAF fitted before updating.
Fuel
Sounds very much like the tank pump is cutting out-all the symptoms there would suggest there is insufficent fuel being supplied on demand.
Both pumps need to push out 4 bar of pressure constantely-The tank pump pushes the fuel to the pre supply pump and the supply pump to the high pressure pump.
If the tank pump fails the pre supply pump can pull the fuel from the tank and supply at 4 bar but this pressure falls sharply when more fuel is demanded.
Again,the none start points straight to fuel supply.
We have had alot of trouble with pre supply pump failures aswell(under nearside floor)
I'd check out this area first/doubl check it.The hardest thing is to replicate the fault at standstill.
Sounds very much like the tank pump is cutting out-all the symptoms there would suggest there is insufficent fuel being supplied on demand.
Both pumps need to push out 4 bar of pressure constantely-The tank pump pushes the fuel to the pre supply pump and the supply pump to the high pressure pump.
If the tank pump fails the pre supply pump can pull the fuel from the tank and supply at 4 bar but this pressure falls sharply when more fuel is demanded.
Again,the none start points straight to fuel supply.
We have had alot of trouble with pre supply pump failures aswell(under nearside floor)
I'd check out this area first/doubl check it.The hardest thing is to replicate the fault at standstill.
Edited by blackspider on Friday 2nd February 23:35
My suspicion all along has been fuel supply, aka pump failure. I don't know this car yet but I know the principles well. As mentioned elsewhere on PH the force is strong with Blackspider.
So there are three pumps to worry about then. Tank, pre supply and hp pumps? I have only heard of tank pumps being troublesome but normally when petrol has been put in by mistake, but I guess this can effect all the pumps if not drained straight away or even with water ingress. You are right in that how can you check if a pump is working under load, a skate board roped to the car on an M way?
I shall monitor the situation and hopefully come to a satisfactory resolution.
The maf has been coded to the ECU and ECU cleared of any information so will now only get it from new maf.
Thanks for all your advice, will keep you posted and hopefully there will be a smiley face here when I can reconnect the chip and unleash the beast again.
So there are three pumps to worry about then. Tank, pre supply and hp pumps? I have only heard of tank pumps being troublesome but normally when petrol has been put in by mistake, but I guess this can effect all the pumps if not drained straight away or even with water ingress. You are right in that how can you check if a pump is working under load, a skate board roped to the car on an M way?
I shall monitor the situation and hopefully come to a satisfactory resolution.
The maf has been coded to the ECU and ECU cleared of any information so will now only get it from new maf.
Thanks for all your advice, will keep you posted and hopefully there will be a smiley face here when I can reconnect the chip and unleash the beast again.
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