I just recently fixed a problem with my boost control system. Turns out one of the ECM fuses was missing from the fuse panel. Why this was missing I haven't a clue, perhaps it was the result of one of my many drunken automotive explorations. The world may never know. Anywho, replacing this fuse cured the problem entirely along with correcting several related fault codes. The car seems to pull harder than ever before....well it did until the CEL started flashing at me as the engine shuddered violently. Now every time I give the car more than slight throttle it does this. It only happens while in gear and it's not within a specific RPM range, just with higher throttle, I'm guessing this is defined as "under load".

Some things to rule out: I just replaced my spark plugs 200 miles ago so I'm sure that's not it, I checked the compression on all four cylinders 3200 miles ago which was fine, so I doubt that's a problem either. I even pulled out the multimeter and checked the voltage on the electrical connectors for the fuel injectors, all four were very consistent with the engine turning, I also checked the connectors for the coil packs, they were all consistent with the key turned on, but with the engine turning the infamous #4 cylinder had a slightly lower voltage going to it. I did a little research and understand the problem a little better but still have yet to pinpoint the cause. I keep hearing everyone say, "oh it's a coil pack" but what about the decreased voltage going to the #4 coil pack, does anyone know what would cause this? Does anyone know how to check a coil pack to see if it's defective? I'd rather know that a part is broken before I go ahead and buy a new one.

Luckily I have VAGCOM and am able to supply this to aid in the diagnosis:

 

I just got done testing a few other things plus some of the same things again.

The second test for the coil packs were not consistent with one another at all, it wasn't just #4 this time. The readings were all over the place for all the coil packs, from .11 volts to .91 volts. Now I'm thinking the first test had similar results, seeing how my roommate was the one watching the multimeter then.

The fuel injector readings however, were identical for all four of them at 6.9 volts each while the engine was turning.

Another thing I tested was the resistance of all the connections on the coil packs themselves. They only connections I found were between prongs 2 and 3 with consistent resistance on all the coil packs and between prong 4 and the outside grounding part of the coil pack with no resistance at all.

I swapped coil packs #3 and #4, cleared the fault codes, and am going to test drive it and see if I still get a #4 cylinder misfire. Wish me luck!

 

Just got back from the test drive and sure enough the misfire was still there with all the same symptoms. When I got back, I pulled up my fault codes and found that it was cylinder #3 this time (the one with #4's old coil pack). So this means that it is, without a doubt, the coil pack, right?

Oh, I forgot to mention before, that I checked the resistance of all four wires leading to the coil pack electrical connector. I checked the wire to the fuse - no resistance, the wires to the grounds - no resistance, and the wire to the ECM ground - which fluctuated a lot.

Also forgot to mention. Upon initial start up after replacing the missing ECM fuse, I heard a horrible loud very high pitch noise coming from the turbo, sounded just like a jet engine at close range. It's intermittent, and has become less frequent throughout the day. Anyone know what it could be? the car has 126,220 miles on it.

 

Seems so... prolly was going, but the added load of having your turbo actually doing its job prolly killed it.


No idea about the screeching

 

Cool, thanks.

I'm thinking the screeching is the sound of the turbo working properly for the first time in months, lol. Anyone, please correct me if I'm wrong.

 

Could also be restricted oil.. as in the lines are clogged up.

 

I've considered that possibility as well. I'll probably check them tomorrow.

Is it likely that the turbo has reached it's life expectancy? How long does a KO3s usually last?

 

That I couldnt tell ya.. dont have one

If you can find the oil lines going in and out, pull them and check. You can run a piano wire or similer through them to clear them out. Look in the turbo too.

Now might be a good time to upgrade to a K04

edit: dont know if this is the cheapest, but here's one. Turbo only for the same price as thier k03:
http://www.volkswaparts.com/18T20VK0...FSQMDQodeEoGew


or, just a rebuild kit for the k03:
http://www.volkswaparts.com/K03Rebuild.htm

 

Thanks for the advice. I'll have to try that. As for upgrading to a KO4, I don't think I'll do it. Only reason being that I want to upgrade to a GT3076r once I have the money and all the supporting mods completed. If worst comes to worst I'll probably end up buying another used KO3s or getting the rebuild kit. Didn't realize you had an A6, that would explain why you don't have a turbo, lol.

 

let us know.