I must say as I was only doing 60Mph, I was hoping to achieve a little more than 31. as around the 70mph mark, this would see my fuel consumption worsen more, and was hoping for more like 31 combined, not best!!
take it it was the Main engine ECU relay you changed? Did the main dealer suggest this? I will certianly look into purchasing this part! Do you have the Part no.? Also is it poss. to post a pic with the location of the part?
I think that the rotor arm is the only part out of your list that has not very recenty been changed, will take the dizzy cap off & have a look as I have not done this yet!!!I have noticed on another post that there can be a prob with the engine temp sender, causing the car to overfuel, is this a common or likely thing to cause?>
Cheers!!
Original relay is a small black box of electronics where a small amp circuit controls a larger one - in this case the main ECU. As the original was made in some place the World left behind, the cost cutting exercise behind the rational of manufacturing such a critical component there is not one of VWs best decisions. Frankly I would replace it anyways - No 30 above the fuses (under driver's dashboard) , and you may have to temporarily unplug others to get at it. As for a main dealer recommendation - welll Nurse stitch back my splitting sides - they wouldn't even know what a Mk3 is - it is way too old for them, and would Sir like a brand new GTI instead - a snip at £21 000. No, the information comes from a bit of knowledge about how these things work, 30 odd years of mucking about with cars and of course, this very useful forum.
Ref fault finding, golden rule is to do one thing at a time, replace everything else as was, and see if it cures the fault. Take it slowly and logically. Check any air/vacuum hoses for leaks whilst you're at it. Yes engine temp sender could be another possibility, but stick to the simple and obvious first and see if that cures it.
