Rpmayne 0 Posted March 15, 2004 Does anyone know where the main earth is taken for the montronic ECU on a VR6? Having problems with the injectors, fuel pump and idle stabilisation valve, so thinking they all aren't being grounded properly through the ECU. I can also hear the ECU power supply relay 'flickering' on and off, again controlled by the ECU. Checked the relay operation across the battery and its fine. Tried to run the car once with some nasty misfiring. Any help would be much appreciated! Thanks. Quote Share this post Link to post Share on other sites
Kevin Bacon 5 Posted March 15, 2004 I think the ECU is grounded at the back of the head, under the plastic cowling. There's a bunch of 4 or 5 earths there and VW traditionally earth the ECU to the engine for some strange reason. I would run an additional 4 guage earth strap from the engine to the back of the head to give some extra grounding. Might also be an idea to find the ECU's earth pin out and run a wire from there straight the battery negative aswell. K Quote Share this post Link to post Share on other sites
Rpmayne 0 Posted March 15, 2004 Thanks for the reply. Just removed all those earth connections, filed the mating faces clean and retightened using copper grease. Re-checked the resistance to the -ve on the battery and its under an ohm. Using the bentley wiring diagrams I checked all pins for resistance to earth. All the pins which should be earthed are, and the battery and ignition supplies are fine. A few others also have low resistance but these are some of the sensors and the coil pack which I guess is right. Any other ideas? Thanks. Quote Share this post Link to post Share on other sites
Kevin Bacon 5 Posted March 15, 2004 Sorry, in my last post I meant run an additional earth strap from the battery to the head, not from the engine to the head, duh! I've found that always helps in the past with strange ECU gremlins. Have you scanned the car on VAG-COM? Mike Edwards had a problem with the injectors on his VR and it turned out to be a duff ECU :? Hope that isn't the case with you. Might be worth seeing if your local breakers have a spare ECU to try? K Quote Share this post Link to post Share on other sites
stormseeker 0 Posted March 16, 2004 ... and VW traditionally earth the ECU to the engine for some strange reason. K Maybe cos most of the sensors/valves/injectors live round the engine? Quote Share this post Link to post Share on other sites
Rpmayne 0 Posted March 18, 2004 I can't get the car anywhere to get the VAGCOM test so I sent the ECU away to ATP electronics ( http://www.atpelectronics.co.uk/ ) for a bench test. Apparently the ECU is faulty, and has been chipped which is a suprise to me. They are sending an exchange unit which should be here today so fingers crossed it will just plug in and work tonight, rather than plug in a blow the new ECU up. Quote Share this post Link to post Share on other sites
Kevin Bacon 5 Posted March 18, 2004 How much do ATP charge for a bench test and also for an exchange ECU? Just need some figures really in case I have to go down that road if I can't isolate my engine issues. Cheers K Quote Share this post Link to post Share on other sites
Rpmayne 0 Posted March 25, 2004 The bench test was about £40.00 including the return delivery. My bill including the bench test, exchange unit (looks brand new, fitted with the chip from the old ECU), delivery and VAT came to £340.00. Quick turn-around. I sent it special delivery and it arrived to them the next day. They tested it that day, found it was faulty and I recieved the new one the day after that. Quote Share this post Link to post Share on other sites
