I'm stumped!!! I have a 02 a6 quattro 2.7t with about 80,000 miles on it. I decided to change the plugs today. I finished up put everything back together as it is supposed to be and now it cranks over but will not fire up. I used NGK PFR6Q as recommended for a replacement so whats the deal? I double checked all the connections but it still won't start up. Any hints to what this might be???

 

Make sure you didn't cross any plug wires, and that the coil packs are in all the way.
Did you gap the plugs properly?
Did you also plug back in every connector you took apart to get to the plugs?

 

*I took each coil pack/plug out one at a time not to accidently put the wrong one in anywhere.
*I did gap the plugs (032)
*I put every connector back that I can see

Note: If I leave the connections off of the airbox the engine tries to start more smoothly, with them on it will cycle and stop. no continuous starting action. did i mess up something with the air sensors by chance?

 

might sound dumb but some plug wires are easily not pushed all the way - the air trapped in works as a cushion that wants to pop the wire off. I would double check that all reboved plug wires are REALLY pushed all the way.

 

nope. that's all good. gonna put it in the garage and think on it for a night. i've double checked everything and still can't figure out what the problem is....

 

Does thecar crank? Did you disconnect anything else besides the wires to the coils? MAF sensor? Check your fuses also.

 

It cranks. I took off both off the 4 connects on the top of the airbox & the MAF sensor along with each of the (6) plugs that go to the coil packs. My friend who drives a VW just told me to check the fuses too. Will do that in the morning, hope its just that simple...

 

have to resort to taking out all the plugs again to make sure there isn't something wrong...

 

So maybe someone with more experience with these things might be able to help me out. Here is what I've diagnosed just by re-installing the plugs...

Looking at the passanger side cylinders all of the plugs looked normal but once I took out the drivers side cylinder plugs they are all caked black and nasty. So my question now is it that I'm having a problem with the drivers side electrical system or harness? What would cause this? Would it have to do with the 4 plugs on my airbox? I really don't want to have to take this in to have the dealer look at it. Thanks in advanced!

 

i dunno what to tell you .... so on the drivers side the fresh plugs are balck just from dropping them in and tightening ??? your gap is fine and as long as your connections are good then you should be fine ... if your pulling out balck soot and crap then thats probably the problem because its junking up the contacts but maybe id try new plugs??? maybe you got a bum one?