MoTeC Global Forum

ok i finally got connected to my m4 ecu now i can go ahead with trying to find my fault,my problem is that the car has started running lean,i have changed all the sensors on the engine including the map sensor and its still not fixed,im new to this motec stuff as its just what came on the car,so far i got into it and got the datalog off it and went to the diagnostics bit and one of the errors that seems to be comeing up a lot is an auxV DP thats happened nearly 26000 times and for over 5000 seconds,what would that be

Aux V DP is actually a status from the ECU even though it is reported as a fault. It simply means that the value from the Aux Volt channel contains a D ecimal P oint. This is not part of your problem.

If the engine is running lean you need to be able to determine whether it is being caused by the ECU or something external. If you dont have a fuel pressure gauge or sensor now - I would install one and make sure the fuel pressure is being maintained during the problem.

The program in the ECU will not "wear out" so if it was right before and its not right anymore - something changed. Usually its something mechanical like a plugged fuel filter. If not then some sensor is probably lying to the ECU causing it to under fuel the engine.

ok well iv checked the fual pump and thats fine,iv ordered a new fuel pressure regulator just incase thats faulty,is there anyway to check the datalogs to see if anything is putting in a bad signal

bit more information is on tickover it runs fine,its mainly on acceleration it goes horrifficly lean

If there are no ECU errors and it is idling ok I would start by testing the fuel delivery rate from the pump.

well there were other errors but they didnt come up as many times,iv put a pic below of the errors page off the datalog,il check the fuel delivery this weekend,

Hi,
You have some throttle position errors there and a few MAP errors. How is the engined tuned? based on throttle position or MAP. If you can attach a log file it will help.

Have you recently changed your fuel pressure regulator ? There are quite a few "copies" appearing on eBay which don't regulate the fuel pressure correctly in line with boost pressure.

datalog is here

http://www.yourfilehost.com/media.php?cat=other&file=DATA.LOG

i changed the fuel pressure regualtor to see if that was the problem and it wasnt as it still does it,im not sure how the engine is tuned,i bought it as a running car then after about 500 miles it started having this fault

It looks like there is some corruption in the file I have downloaded. Can you e-mail your log file and the ECU configuration to me so that I can verify if there is actually a problem with your file? E-mail the files to ross.buckingham@motec.com.au .