4eyes2wheels 0 Posted August 27, 2011 (edited) Over the last two years I have been improving my VR6. Suspension, brakes, wheels, tyres, DG Cams and Map etc. I know the cams and maps will have an adverse effect on fuel economy but on a motorway run I would get 28 mpg roughly and around town about 24 mpg, over the last few months. Recently I have noticed the fuel consumption slipping. Having done 190 miles of mostly dual carriageway / motorway and filled up again I have averaged 22. Tyre pressures are right and I was only two up - not heavily loaded. I am wondering why the drop off? Was serviced in March. My exhaust is blowing and will need to be replaced soon - would that be a contributory factor? I have had a couple of engine sensors over the last two years - crank position amd camshaft position - but without VAGCOM it'll be a struggle to work out what's wrong. MAF ? ISV - I get the odd stall when warm. Any ideas or tips for simple diagnostics? Edited September 15, 2011 by 4eyes2wheels Quote Share this post Link to post Share on other sites
dragon green 4 Posted August 27, 2011 How old is your Cat ? When they get near the end of their life, they tend to "smog" the engine and it uses more fuel ! Just an idea Quote Share this post Link to post Share on other sites
4eyes2wheels 0 Posted August 27, 2011 Nothing in the service history to suggest it has been replaced. Mileage is (only) 78,500 so could be on the original? Quote Share this post Link to post Share on other sites
Pat_McCrotch 0 Posted August 27, 2011 I would be horrified if my VR was getting that. My car averages 35mpg on the dash! Perhaps I drive too slow? Quote Share this post Link to post Share on other sites
4eyes2wheels 0 Posted August 27, 2011 I would be horrified if my VR was getting that. My car averages 35mpg on the dash! Perhaps I drive too slow? Even trolling along at 56 doesn't yeild the return it once did. I am especially bothered as I have a 400 mile round trip to Yorkshire on Monday and it's going to cost me a bomb! May sound like a dumb question but does a FULL EXHAUST SYSTEM include a Cat? How full is full? Quote Share this post Link to post Share on other sites
dragon green 4 Posted August 27, 2011 Full doesnt include the Cat ! your milage being so low,i doubt if it is your Cat ! Quote Share this post Link to post Share on other sites
4eyes2wheels 0 Posted August 27, 2011 your milage being so low,i doubt if it is your Cat ! Any ideas? Don't want to hand it over to a local garage and give them free rein as I would with DG Autotech but can't get to see them anytime soon. Quote Share this post Link to post Share on other sites
Pat_McCrotch 0 Posted August 27, 2011 Can the Lambda sensor cause overfuelling? Quote Share this post Link to post Share on other sites
4eyes2wheels 0 Posted August 27, 2011 I guess we really need to get VAGCOM on the case otherwise it is an expensive game of replace parts and cross fingers. Lambda sensor hasn't been changed (as far as I can remember). Quote Share this post Link to post Share on other sites
davidwort 0 Posted August 27, 2011 Be handy if someone local to you with vag-com could help you out, would help diagnose any issues much quicker. A friendly mot station might check your lambda signal for little, but unless you use a vag specialist it's unlikely they can check sensor behaviour and signal ranges etc., having said that, most garages should be able to do an obd1 scan for faults recorded. Quote Share this post Link to post Share on other sites
4eyes2wheels 0 Posted August 27, 2011 Looks like I need to check out the VAG COM thread and work out what combo of leads and licenses I need to shell out for. Quote Share this post Link to post Share on other sites
sime6920 0 Posted August 27, 2011 Get a lead off ebay follow the instrutions to install drivers costs about a tenner, download vagcom lite its free and check your engine any time you like if you don't have a laptop borrow one sorted mine easy was o2 sensor ! did about five miles more to the gallon once done Quote Share this post Link to post Share on other sites
4eyes2wheels 0 Posted August 27, 2011 Get a lead off ebay follow the instrutions to install drivers costs about a tenner, download vagcom lite its free and check your engine any time you like if you don't have a laptop borrow one sorted mine easy was o2 sensor ! did about five miles more to the gallon once done I guess I need to just man up and do what you suggest. But there are SO MANY different options from a fiver to over 300 quid. There are also the handheld scanners for £25 ish that require no PC. . Quote Share this post Link to post Share on other sites
buttles 0 Posted August 27, 2011 Or for the cost of petrol drive over to Redhill and I'll do it for free Quote Share this post Link to post Share on other sites
4eyes2wheels 0 Posted August 28, 2011 Or for the cost of petrol drive over to Redhill and I'll do it for freeThanks for the offer. You have PM. Quote Share this post Link to post Share on other sites
n3p 3 Posted August 28, 2011 buttles to the rescue again :D Quote Share this post Link to post Share on other sites
davidwort 0 Posted August 28, 2011 Best thing about the forum, always nice to see offers to help each other out like that :) Quote Share this post Link to post Share on other sites
buttles 0 Posted August 28, 2011 Sadly failed dismally!! Not got a 2x2 connector. Quote Share this post Link to post Share on other sites
4eyes2wheels 0 Posted August 28, 2011 I am going to purchase cables and see what codes (if any) appear. I think we could be ploughing some more cash into the old girl. Just watched the Top Gear feature on the Mk5 Golf GTI so trying to resist buying on of them instead! Quote Share this post Link to post Share on other sites
buttles 0 Posted August 28, 2011 http://www.lonelec.co.uk/index.php?main_page=product_info&cPath=2&products_id=28 It's only £6. Then gives you full access to my vag-com? Neil Quote Share this post Link to post Share on other sites
4eyes2wheels 0 Posted August 28, 2011 http://www.lonelec.co.uk/index.php?main_page=product_info&cPath=2&products_id=28 It's only £6. Then gives you full access to my vag-com? Neil I'll probably get the other cable as well which comes with the shareware version of VAG COM so I can be independant - thanks for the offer though! Quote Share this post Link to post Share on other sites
4eyes2wheels 0 Posted August 29, 2011 So today was a day of motorway driving - M25, M1, M18 and A1 for 190 miles and the good news is that the mpg gradually crept up from 25 on the M25 all the way up to 28.2 mpg overall. A lot better than I was expecting. The way back down was marred by an accident on the M1 which meant crawling along for about an hour and so mpg on the way back was 26.3. I suppose the old girl just needed a good long run! Quote Share this post Link to post Share on other sites
Pat_McCrotch 0 Posted August 29, 2011 Still lower than i'd personally be happy with. Have you tried fuel additive followed by an Octane booster? I don't mean the stuff you see on the Petrol Forecourts. Google for you nearest Wurth Stockist, get your fuel filter changed (if you haven't already done so), run a tank of fuel additive then the Octane Booster. Think how much carb and crap buildup an 18 year old fuel system has in it! My original green VR struggled to get over 30mpg on trip 1. A few hundred miles of rotated fuel and octane booster saw it getting anything up to 37mpg :) It's a long shot but for £15 worth a go! Or you could just be heavier on the right foot. Which isn't a criticism by the way ;) Quote Share this post Link to post Share on other sites
4eyes2wheels 0 Posted August 29, 2011 I've never tried any fuel additives as I have always thought they must be "snake oil" or "unicorn horn" but there must be something to be said for the more reputable ones (like Wurth). My right foot is not VERY heavy really. Quote Share this post Link to post Share on other sites
