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D3 - Engine Bay Everything under the bonnet |
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Thread Tools | Display Modes |
#51
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Hi Lee, just checked but can't see any messages - did it send correctly?
Thanks
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- 2005 Audi A8 D3 4.2L Petrol - 2008 Ford Mondeo 2.5T - 2000 Ford Focus 1.6 |
#52
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Re sent
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#53
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Re the "SmokeDaddy"; I've seen (less elegant-looking) testers in that style built on youtube and had considered that option; however I do occasionally smoke cigars and thought this would be a good excuse to have one... except I've had a cold for a couple weeks, and prior to that my times to experiment (smoke) are limited because I don't want my young kids to see me smoking anything... How much pressure do you find necessary to find a leak? I'm guessing 20 PSI couldn't hurt. I can only blow about 2PSI IIRC from elementary school. Still worth a try. What I lack in presssure I make up for in volume (TWSSLN). Sorry, couldn't resist. Thanks again.
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I'm in love with a car. 2004 4.2L Petrol A8L Sage Green/Black (one of only five D3s thus colored sold in the US) |
#54
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Update: I have purposely not reset the engine module since the weekend I replaced the main fuel pump. I checked the figures again today after ~200 miles of driving and the long term fuel trims are now both around +7% and the lean codes haven't come back. MPG still hasn't improved though.
I recently remembered that at my last MOT there was an advisory for brake calipers sticking slightly (both fronts, one rear from what I remember). I was meaning to have a look but completely forgot, until last week that is. I was about to drive home and the electronic handbrake wouldn't disengage - the light was flashing and the motor didn't sound right. The offside rear caliper was seized and wouldn't free. I had to drive it home like this (stopping every couple of minutes so that brakes would cool down - the wheel was smoking and too hot to touch). When I got home I left it overnight and it seemed to work correctly again the next morning - the handbrake now disengages properly and it hasn't happened since. I'm thinking this may turn out to be the cause of my MPG problems. I've never dealt with a sticking caliper before - would it be possible that I've been driving all of this time (sticking enough to cause 13mpg rather than 25mpg) without noticing it? It's never really felt like the brakes were dragging (other than the incident last week) but I'm not sure how much they'd have to be sticking to cause a big drop in MPG. It will roll down a hill in neutral when coming off the brakes. I ordered a new set of discs and pads (front and rear) so I'll try to get them fitted this weekend and see if this improves anything.
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- 2005 Audi A8 D3 4.2L Petrol - 2008 Ford Mondeo 2.5T - 2000 Ford Focus 1.6 |
#55
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Hello Matthew , the fueling trims are much closer to where they want to be now .
I would of thought for the loss of mpg the brakes would have to be sticking a fair bit but any dragging brakes will not help . When you do the job give the brake pad hangers a good fileing get rid of all the rust so the pads fit nice , when you use vcds to open the rear calipers in basic settings the Pistons should be able to be pushed back quite freely ...check for corrosion behind the piston rubbers , same with fronts the Pistons should be able to be pushed back easy enough , sometimes the pads can get really tight in the hanger so as the disc warms up the bind gets more progressive . |
#56
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I did another test with my vacuum gauge last night. It seems to sit at around 17HgIn with a slight fluctuation. (Video attached). Does this give any clues? From what I've read online about interpreting vacuum readings, this could point towards an ignition related problem. (Or possibly bad cam timing but this would seem to cause a much lower drop in vacuum to around 10HgIn). Thanks
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- 2005 Audi A8 D3 4.2L Petrol - 2008 Ford Mondeo 2.5T - 2000 Ford Focus 1.6 |
#57
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Now A8 D3 4.2 40v Supercharged!!! EX: A/S8 D2 4.2, moded done: Manual gearbox, Recaro seats, RNS-E + OEM Bluetooth with working MFSW, S8 converted engine, S8 susspension, Solar roof, RS6 brake setup and bigger servo and pump Future mod: RS 4.2tt engine. |
#58
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If these had failed would it cause a cam timing fault code? Thanks
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- 2005 Audi A8 D3 4.2L Petrol - 2008 Ford Mondeo 2.5T - 2000 Ford Focus 1.6 |
#59
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The vaccum is not as good as it should be Matthew , like i said back there you need to check cam timing first port of call .
If cam timing correct next would be to have a look at variators to see if foot has worn through or fell off .......and the inlet cam timing mark Cambelt drives exhaust cam ........ exhaust cam drives inlet cam with internal chain . Cam / crank correlation codes .......... sometimes you get them .....sometimes you dont .....if the cam that is off does not have a cam sensor the ecm does not know that it is out , it can only reference from the cam that does have the sensor ......does inlet and exhuast have cam sensors ?? . I seen chains stretched to death on vauxhall engines putting cams out loads and still not had cam /crank correlation codes . In some cases the ecm can only see cams that have gone retared (chain stretch) it can not always see cams that are advanced .....as in someone doing cam timing incorrect whilst doing the cambelt job |
#60
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And yes is not have 4 cam sensor, only 2. And no not will give you a fault, but will have rough idle and some time missfire without reason.
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Now A8 D3 4.2 40v Supercharged!!! EX: A/S8 D2 4.2, moded done: Manual gearbox, Recaro seats, RNS-E + OEM Bluetooth with working MFSW, S8 converted engine, S8 susspension, Solar roof, RS6 brake setup and bigger servo and pump Future mod: RS 4.2tt engine. |
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