All Things Mk5 > Mk5 General Area
disappointing performance continued....UPDATED after a day at MRC Tuning
WhiteGTI:
--- Quote from: illyun on April 02, 2009, 10:46:17 am ---
--- Quote from: duncan on March 31, 2009, 09:06:00 pm ---
--- Quote from: RunRabbit on March 31, 2009, 09:02:25 pm ---As above, a sensor is more than likely playing up or you have a boost leak. If it's over-fuelling across the rev range then it could well be a MAF or lambda sensor.
--- End quote ---
it is only running super rich past 3500rpm to the limit
--- End quote ---
Very interesting - sounds like the exact opposite to my issue which is fuel too lean past 4k rpm
--- End quote ---
So does this mean that where MRC tuning have altered the map to counterract the richness past 3500, that it now runs too lean up to 3500?? Just curious that's all!
Also, with regard to what Illyun said above, could it be a problem with the actual injectors then?
duncan:
in terms of the richness
we were only getting problems with the car being too rich when the throttle was wide open and we were over 4500rpm. which was much better than the previous day
this was at the start of the day before the remap went on.
are the injectors faulty? well the ECU is requesting the extra richness so not sure if that rules them out or not.
the car is running fine in the lower rev range - the change made to the richness in the code is that the fuel ration is set on a limit so the ECU does not let the car dip below 11.5afr and bearing in mind this was only happening at pretty high revs.
not sure if ive explained that correctly....
going back to the Richness problem - what else could you have done to see why it was running too rich at high revs? was tricky becuase im guessing it is very difficult to know why the ECU wants more fuel than it should do when you have ruled out the obvious possilbe causes.
one thought was that the latest version of software on the ECU was set to run too rich... not sure if thats a possibility or not
ub7rm:
I havent' fully read your 'other' thread so apologies but I gather there is a question mark over where your car is from?
I'm just thinking aloud here but is it possible that for other countries a different 'stock' map is applied to the ECU to counteract for example higher ambient temperatures (though if anything I would have thought this would result in a leaner mix), the quality of the fuel available in that part of the world etc etc.
Presumably when an update is applied, the correct update is applied depending on the serial number of the ECU. So even if you took it into a UK VW dealer, an update for the UAE map would be applied?
I'm not sure how a map works, does it completely overwrite the stock map or does it just 'add' values to it. I.e for a given set of conditions increase fuel by 5%......
I can see the different stock map for different regions being a possibility, but my theory might be out of the window considering you have the same problem with the performance map....
duncan:
--- Quote from: ub7rm on April 02, 2009, 02:51:30 pm ---I havent' fully read your 'other' thread so apologies but I gather there is a question mark over where your car is from?
I'm just thinking aloud here but is it possible that for other countries a different 'stock' map is applied to the ECU to counteract for example higher ambient temperatures (though if anything I would have thought this would result in a leaner mix), the quality of the fuel available in that part of the world etc etc.
Presumably when an update is applied, the correct update is applied depending on the serial number of the ECU. So even if you took it into a UK VW dealer, an update for the UAE map would be applied?
I'm not sure how a map works, does it completely overwrite the stock map or does it just 'add' values to it. I.e for a given set of conditions increase fuel by 5%......
I can see the different stock map for different regions being a possibility, but my theory might be out of the window considering you have the same problem with the performance map....
--- End quote ---
i think the issue of the car being an import and having a strange country code i dont think is the problem. the car was delivered to the uk without any miles on the clock in september 2006 the date of its first registration. however the car was manufactured late 2005, again i dont think this is the issue.
the stock map seemed to want to run too rich at high revs, i dont think this as an isolated problem is that big a deal. what is strange is that the ECU is requesting to much fuel, after doing alot of diagnostics there was nothing to prove why the ECU was demanding too much fuel at very high revs. replacing the DV / PCV seems to have sorted the power issues and helped with the richness but not entirely. with this remap in its generic form they dont mess too much with the fuel ratio side of the map but in my case they did put a liimit on the fuel mixture which seems to have cured the problem since the car is throwing no error codes under load or after being driven. all the data coming from the car with the latest custom map seems to be looking spot on.
the tuner spent a very long time with the car before he put the map on and then spent a while looking through the data trying to establish if it was a faulty part on the car that was causing the richness issue, since nothing could be found after extensive data logging, all he did was imposed a limit on the cars ECU forcing it not to over fuel, since this has happened the power has been hugely increased, the fuel economy seems to have slightly improved but nothing majorly noticeabe and after driving 100 miles with the new map, the car was data logged and checked for any faults and the only thing that came up was an immobiliser fault which seems to be quite random and is not throwing any numbers up on the dash, this could be due when the ECU was being flashed the flash failed and had to be reapplyed which threw up electrial fault codes but nothing functional going wrong wtih the car.
all in all i would love to say the problem is completley solved.. i dont know for sure and i guess only time will tell; but as mentioned before if the data is looking correct under the new map including the fueling which is now running spot on again along with fuel pressure, boost pressure, MAF, what else could it be?
if there is a problem it cant be to big i guess my point is - if when the car is on load and not throwing up incorrect numbers or fault codes, it is near impossible to see why the over fueling occured in the first place and why it continued to occur during the mapping process
for me i guess it points to the ECU, and possibly when the WALD remap was applied the changed some fundamental Fueling instructions that would usually stay as normal when applying other maps, this would lead to the ECU constantly requesting too much fuel for the simple fact that the data on the ECU was set to do (that could have been the worst explanation ever stated on this forum, but hopefully you know what i mean)
again I agree that getting a remap wtih an undiagnosed problem leading to running rich isnt ideal, but when nothing points to a part failure leading to it then what else can you do apart from tell the ECU to stop making incorrect requests
Thoughts on this?
ub7rm:
"the stock map seemed to want to run too rich at high revs, i dont think this as an isolated problem is that big a deal. what is strange is that the ECU is requesting to much fuel, after doing alot of diagnostics there was nothing to prove why the ECU was demanding too much fuel at very high revs. replacing the DV / PCV seems to have sorted the power issues and helped with the richness but not entirely. with this remap in its generic form they dont mess too much with the fuel ratio side of the map but in my case they did put a liimit on the fuel mixture"
Thats what makes me think that your ECU is behaving exactly as it should. All the sensors and diagnostics are coming up clean. When I say its behaving exactly as it should, its doing what it should be doing say in a country where they sell a lower grade of petrol or where some other constant 'variable' is present. Trouble is no one has told your ECU that its no longer having to deal with that shoddy petrol or whatever and that it doesn't need to throw so much petrol in.
I know your car hasnt' physically been to a different country, but it would have left the factory with the equipment / settings for that country.
As a completely made up example, perhaps in a hot dusty country the fueling paramaters are designed to take into account that the fuel filter may be partially blocked at all times, or that due to expansion of the fuel (due to heat) that for a given number of pump cycles the volume of fuel actually delivered is less than at our ambient temperature. Extreme but this is what I mean.
I realise its an oddball suggestion but you seem to have drawn a blank at the usual suspect.
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