ismith 0 Posted March 27, 2007 Economy has dropped by 15% on my VR6 around town. The plugs are black. Compression fine. The O2 sensor is new and I checked for leaks on the inlet manifold and purge solenoid. Idle adaptation still low. If I do an ECU reset, the economy is back to normal for a while. Any ideas what could be making the adaptation value go down so low? Thursday 1 February 2007 16:38:30 021 906 258 B MOTOR PMC 1 O2 Idle Part Throttle Full Throttle Active Adapted Value Adapted Value Adapted Value 1.016 0.789 1 0.953 0.992 0.789 1 0.953 1 0.789 1 0.953 1 0.789 1 0.953 1.016 0.789 1 0.953 0.992 0.789 1 0.953 1 0.789 1 0.953 1.016 0.789 1 0.953 0.992 0.789 1 0.953 1.008 0.789 1 0.953 1.016 0.789 1 0.953 0.992 0.789 1 0.953 0.992 0.789 1 0.953 0.992 0.789 1 0.953 1.016 0.789 1 0.953 1.008 0.789 1 0.953 0.984 0.789 1 0.953 1.008 0.789 1 0.953 1.016 0.789 1 0.953 0.992 0.789 1 0.953 1.008 0.789 1 0.953 0.992 0.789 1 0.953 Quote Share this post Link to post Share on other sites
dr_mat 0 Posted March 27, 2007 The MAF is the other part of the fuelling holy triumvirate.. Quote Share this post Link to post Share on other sites
ismith 0 Posted March 27, 2007 Thanks for your support. There are no ECU errors in the log. What would you recommend I do to test the MAF? Quote Share this post Link to post Share on other sites
dr_mat 0 Posted March 27, 2007 There's not a lot you can do .. other than try another one! If you have a late VR then they are ~ £65 + deposit for exchange from GSF. Quote Share this post Link to post Share on other sites
Roger Blassberg 0 Posted March 28, 2007 The earlier VR uses a hot wire MAF which is about 3 times the price of the hot film MAF used in later models. You need to quote your chassis number to get the right one. Best wishes RB Quote Share this post Link to post Share on other sites
ismith 0 Posted March 28, 2007 I can see inside that it's a hot wire one. Mine is a 93 VR6 with 170k miles. I wonder if it's testable or repairable? Euro Car parts want £200. A scrappy will probably sell one for half that (i.e. still a rip-off). Quote Share this post Link to post Share on other sites
Kevin Bacon 5 Posted March 28, 2007 You can only test MAFs properly on an Oscilliscope and even that's no guarantee they will work properly on the engine. Unfortunately diagnosing MAF sensors on OBD1 usually turns into a suck it and see excercise. OBD2 is best for monitoring air mass as it reports what the mass is in grams/sec via the measuring blocks is, i.e 15 at idle and 170ish at WOT. Unfortunately no Corrado is OBD2 and therefore devoid of this luxury. Brand new MAFs can be had from Bosch dealers for £150+VAT Exchange or £200+VAT outright and I would test it in the carpark before leaving as you often get DOAs. Quote Share this post Link to post Share on other sites
dr_mat 0 Posted March 28, 2007 You should be able to pick one up for less than that off ebay. Worth a go to test it .. They *can* be tested, but you'd need to take it to a Bosch specialist I think .. ** edit - i.e. wot he sed.. ^^ Quote Share this post Link to post Share on other sites
Tekara 0 Posted March 28, 2007 You could try and borrow another VR6 owners MAF, if you know someone with the same type. I did spot a hot wire MAF from a K reg Golf VR in my local scrappy they wanted £60 after a little bartering, but the gamble always will whether it works. Might be worth dropping Bigpantsbaby a PM to see if he has any second hand ones, always seems to have loads of VR bits for sale. Quote Share this post Link to post Share on other sites
ismith 0 Posted March 29, 2007 Thanks for your tips, guys. Strange how the car runs reasonably ok and passed the emissions when it's over-fuelling! Anyways, ideas on the oscilloscope stuff? I am an electronics engineer and have access to a lab full of stuff. Quote Share this post Link to post Share on other sites
