ignition problems

[PDX04a4]

sorry for the long post, been a very long couple days

a little background: i bought an 04 1.8t tiptronic roughly 2 months ago from a high volume car dealer who buys his cars from fleet auction sales. car checked out from carfax and the dealer records, all checkups/regular maintenance, no major repair other than a bulb problem (audi, duh).

late sunday afternoon im driving home, i pull up to a light, stop completely, then give it some gas when the light turns green, the car craps out. cant start it up, engine turns, but does not fire. so i get a push to the side of the road. pop the hood, pull off the engine cover and what do i see, the connectors for the wiring from the ECM to the coil packs are all f'd, some kind of jerry-rig blue light silicone glue special with electrical tape. 2 of the plastic connectors are broken, the wiring looks real messy and corroded. great

so i figure it must be these, roommates who are mechanical engineers and pretty good car guys agree. something electrical must be f'd.

So my roommate and I have narrowed down the possible culprits of my ignition failure. so the car still turns over, but does not fire. talked to a local professional shop and they said it was probably the fuel pump failing and not any electrical problem, they said its not likely all 4 coil packs have a problem.

so last night we disconnected a fuel line that runs over the top of the intake manifold to the engine block, i turned the ignition, gas came pumping out. so it cant be the fuel pump/fuel filter. i never thought it was, i never heard symptoms of a failing pump, hissing or humming.

so then we decided to get at the electrical problem. tested all the fuses in the fuse box and around the ECM, they are fine. tested the relay's around the ECM, they checked out. then i found this post: http://forums.audiworld.com/a4gen2/msgs/982248.phtml

followed that pdf file to test whether or not the coil packs are getting power. based on their test idea, i am getting NO power to the coil packs. using a multimeter to measure, there should be 12v measuring from the coil pack wiring harness -> ground when turning the ignition. i get 0.

it was late last night and we decided to stop there. we are going to try to test the wire from where relay 219 is and the coil pack connector tonight like it says in that pdf.

anyone have any other ideas? is it possible to borrow a vag-com from an autozone or someplace like that to scan it for codes? if we cant figure it out im going to have to tow it to a shop who can scan it.

[jursch2211]

Sound like my problem. I"m replacing all four coils tonight and see if that helps. Let me know what you find out. Never heard of what you're testing. I might do that just for the hell of it.

[PDX04a4]

ya, electrical problems really suck, so hard to find the culprit. let me know how your coil pack replacement goes. im going to have to redo all the wiring going to the connectors. pain in the ass.

[B6 Dude]

I'd say you're on the right track -- you need to trace backwards to the power source to determine where the loss of power is. Also verify that the engine is properly grounded (you can test the resistance from the block to the battery negative, and test the voltage from the battery positive to the engine).

BTW, silicones (other than the sensor-safe type) generally release acidic fumes when curing, which will corrode wiring. So if the blue stuff is not the sensor-safe type, you may want to replace other wires in that area too.