sparkz 0 Posted January 24, 2008 Report Share Posted January 24, 2008 My missus' 8v gti decided to blow a head gasket (not my fault ) so i dropped a vr6 lump into it with the fuel tank and full running gear. Now the problem im having is that it is overfuelling badly. At first i thought that it was a dodgy set of clocks so i changed them to a set that i knew were perfect. Same problem, ive removed the fuel level sender, cleaned it and put it back......same problem. I put the 8v sender in it and guess what....same problem. So that side of things has been elimanated. What else would cause this overfuelling malarky? Im going to vag com it on saturday, but would like some input before then to ponder over. As an example, i filled the car up today. £52.00!!!! drove for 20 miles or so and the needle is now on the 2nd notch from full and im talking traffic driving not motorway driving!! Link to post Share on other sites
6potmkII 0 Posted January 25, 2008 Report Share Posted January 25, 2008 patrick so your saying its consuming alot yeh seen as youve checked the sender side of things?? take the plugs out and see what condition there in that might give you a rough indication of what its running like if there black as hell youl kno its overfueling that much, check if theres any air leaks into the system after the maf by sprayin some thing like brake cleaner along the air system, cos that will be unmetered air, lambda will tell ecu its running lean and chuck more fuel in so even tho your in traffic this is happening all the time and consumption will be high... if not check or try a mates maf or something... at work on the bm's this causes high consumption and all sorts probs like rough idle etc, might be the same on the vr too just something to try Link to post Share on other sites
amazak 3 Posted January 25, 2008 Report Share Posted January 25, 2008 patrick so your saying its consuming alot yeh seen as youve checked the sender side of things?? take the plugs out and see what condition there in that might give you a rough indication of what its running like if there black as hell youl kno its overfueling that much' date=' check if theres any air leaks into the system after the maf by sprayin some thing like brake cleaner along the air system, cos that will be unmetered air, lambda will tell ecu its running lean and chuck more fuel in so even tho your in traffic this is happening all the time and consumption will be high... if not check or try a mates maf or something... at work on the bm's this causes high consumption and all sorts probs like rough idle etc, might be the same on the vr too just something to try[/quote']Komi, could you please explain further about the brake cleaner bit as mine is a bit juicy as well, not as bad as Patrick's though. I have had mine on a diagnostic machine but did not find any issues so I did not bother to touch the temp sensors. I probably get around 120 to 140 miles max on a tank. My friend says that cone filters sometimes causes issues with the MAF hence the fuel consumption. Don't know what to do........car was serviced recently and old plugs looked good. ThanksYaseen Link to post Share on other sites
crish72 0 Posted January 26, 2008 Report Share Posted January 26, 2008 Faulty Lambda sensor can also cause overfueling... Link to post Share on other sites
amazak 3 Posted January 26, 2008 Report Share Posted January 26, 2008 Faulty Lambda sensor can also cause overfueling...Where is the lambda sensor located?Thanks Link to post Share on other sites
james4287 1 Posted January 26, 2008 Report Share Posted January 26, 2008 sounds about normal to me? Link to post Share on other sites
sparkz 0 Posted January 26, 2008 Author Report Share Posted January 26, 2008 Faulty Lambda sensor can also cause overfueling...Where is the lambda sensor located?ThanksOn top of the cat. Link to post Share on other sites
VR6Pete 1,455 Posted January 26, 2008 Report Share Posted January 26, 2008 I thought the lambda sensor only made minor adjustments to the fueling? I had mine disconnected for months before I noticed, as i had no overfueling ...pete Link to post Share on other sites
UnitedMotorsport 55 Posted January 26, 2008 Report Share Posted January 26, 2008 Is it a OBD1 or OBD2 setup?If there are any discrepencies on the lambda input on a OBD1 setup, the ECU will dial in MAXIMUM fuel addition (roughy ~25%) so if its OBD1 check your lambda readings. The same is also true if there is no lambda probe present, no probe = ~25% extra fueingIf its OBD2 this doesnt happen, the ecus sees inplausible readings, ignores the probe, throws a code, and just runs with no lambda correction atall. (no addtional fuel is added). Link to post Share on other sites
amazak 3 Posted January 26, 2008 Report Share Posted January 26, 2008 Is it a OBD1 or OBD2 setup?If there are any discrepencies on the lambda input on a OBD1 setup, the ECU will dial in MAXIMUM fuel addition (roughy ~25%) so if its OBD1 check your lambda readings. The same is also true if there is no lambda probe present, no probe = ~25% extra fueingSorry to sound dumb, but how can one check their lambda readings? as mine is OBD1. Link to post Share on other sites
craggsy 91 Posted January 26, 2008 Report Share Posted January 26, 2008 VAGCOM will show lambda readings Link to post Share on other sites
amazak 3 Posted January 26, 2008 Report Share Posted January 26, 2008 Ok, anyone in London with a Vagcom and willing to help me out? Thanks Link to post Share on other sites
craggsy 91 Posted January 26, 2008 Report Share Posted January 26, 2008 There is a list somewhere Link to post Share on other sites
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