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Discussion Starter #1
Ive been using this forum for the past 2 years since I picked up my problem child of a Passat Wagon. Love the car, just has a few issues here and there. Since I bought the car, I have performed all the basic maintenance, as in changed all the fluids (all of them even the power steering fluid) spark plugs, etc..... it really is in amazing shape, super clean, looks nice, drives nice, whomever had it before me took pretty good care of it for the most part. if I can sort this problem out, ill probably replace the suspension on it this fall, and keep it until it dies, hopefully after another 100K or so

I have also read every post regarding bad coils, multiple misfires, rough idles, etc... Sometimes a new coil fixes the problem, sometimes its the spark plugs, most of the time its the fuel injectors. But nothing quite like this issue. so I don't think I am re posting here.

This post was the most complete that I found, but at the end there seems to be no resolution in the end.

http://www.passatworld.com/forums/42-volkswagen-passat-b5-discussion/301079-my-v-6-eats-coils-why-all-these-codes.html

First off, My car:

2003 Passat Wagon
GLX 4Motion
2.8LV6
137,000 miles

So far in the last 2 years, I have put 5 new coils in the car. The first time, I didn't think much of it, the coil I replace was the original with 120K on it. worked great for about 6 months, then the same slew of codes, (random misfire, Cylinder X misfire, Ignition coil code). So for the second coil after reading this forum on what to do, I changed the plugs, and wires (which I should have done earlier). Once again all was good for about 6 months, then came the misfiring and same codes, so I figured I bought a bad coil replacement. I put another one in, and all was good until about 6 months later, bad luck right. So I put in a third, then a 4th. Right before the 4th one went bad, I thought I had it figured out, I saw oil in the spark plug wells of the motor, so after some research here, I replaced the gaskets on the valve covers, soon thereafter I had the timing belt changed, along with a new water pump. Now that one has gone bad as well, for my 5th at latest, I replaced the wiring harness, also something I learned from here. I have dumped lots of bottles of fuel injector cleaner in this car as well, I bet it has the cleanest fuel system ever.

To replace the harness, which sucks, there is no commercially available repair harness, there is for the 1.8 and the W8. Here are the part numbers you have to buy to make one from scratch. 80ish bucks later and you have a new harness, don't forget the weather proof crimping wiring connectors too. When splicing it in, be very careful, the original wiring is brittle, and the insulation is difficult to get off.

4D0-973-725 - Housing
NAPA AUTO PARTS | PART DETAILS
000-979-225-E Wire set
Home Page > ES#1009140 WIRE SET - 000979225E
000-979-021-E Wire Set
Volkswagen Golf IV 1.8T > ES#515449 Repair Wire - Priced Each - 000979021E
357-972-741-A Seal
Home Page > ES#261009 Red Waterproof Grommet - 1.5mm Wire - 357972741A

With the 5th coil in, and hopes that I finally have it figured out, I magically get 3 new codes I have yet to see at the same time, P0351, 352, and 353. The car seems to run fine, but I'm guessing the coil is not producing the correct voltage for the spark plugs. and I don't think its a good idea to drive the car when I am throwing codes.

so at the end of all of this I have 3 questions:

*Is there anything else I can do to prevent my car from eating coils?

*Are the codes P0351, 352, and 353 indicative of just another bad coil? could I really be that unlucky? its a cheap Evan-Fisher brand, only 70 bucks
Evan-Fischer EVA13872034107 Ignition Coil Standard Type pack 1 per engine 12 volts Blade 5-prong male terminal : Amazon.com : Automotive

*Next to the wiring harness, and spliced int one of the wires, there is a wire that I am assuming is some kind of ground. It has a small black box on it, and it is attached to one of the corners of the coil. I noticed that the wires was cracked a bit, it has part number 0310000064 on it. What does this thing do? does it need to be there, my mechanic says no.

things I have not done, but still need to:

*need to get a multimeter and start checking resistance readings

*open to suggestions on anything else.


I love this forum, hopefully someone has had a similar experiences I have and I can get this worked out.

Thanks!
 

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It could be your alternator overcharging (Voltage too high).

To check your alternator for correct output voltage, connect voltmeter to battery terminals and run engine at idle, voltage should be between
13.8 & 14.8 Volts, increase engine revs. to 2000 RPM, voltage may go a little higher but settle back to between 13.8 & 14.8 Volts.

Switch on high beam lights, A/C, and radio, again increase engine revs. to 2000 RPM, voltage may go a little higher but settle back to between 13.8 & 14.8 Volts.
 

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*Next to the wiring harness, and spliced int one of the wires, there is a wire that I am assuming is some kind of ground. It has a small black box on it, and it is attached to one of the corners of the coil. I noticed that the wires was cracked a bit, it has part number 0310000064 on it. What does this thing do? does it need to be there, my mechanic says no.
The black box is for noise suppression. The wiring diagram just lists it as "suppressor".

Ignition Coil/Power Output Stage ground - 98 A4 30V (AHA) - Page 2 - AudiWorld Forums
 

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Do you know that the replaced coils were actually faulty? The fact that the ran OK after replacement doesn't necessarily mean the coils are faulty.

Have you checked your voltage regulator, as described in my earlier post?

Also you should check all connections in the charging system. This includes all connections from negative battery post to engine block and connections
from positive battery post to alternator large terminal. (All these are heavy wires.)

The suppressor (Black box) would not cause this problem.

Assuming the replaced coils were all faulty, the most likely cause would be the voltage regulator (This could be an intermittent fault), the next most
likely would be the charging system.

There may be other possibilities but they would be unlikely.
 

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Discussion Starter #5
Thanks for the words of wisdom.

I have a multimeter on the way and some free time this weekend to start checking things such as grounding issues.

I never did check and see if the coils were actually bad. I guess I just assumed they were bad because once I put a new one in, the car worked again, for a few months anyway. Is there a good way to test a coil? I have heard of water technique in the dark, but never tried it. Is there a better way?

I will look into changing out the voltage regulator as well.

Thanks, and i'll put up an update on this soon.
 

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I have heard of water technique in the dark, but never tried it. Is there a better way?
Check out this article & other info on this site, there seems to be a lot of good info on this site including coil pack testing.

Part 1 -Ignition Misfire Case Study (Carbon Tracks).

If you have a carbon track problem on your plugs & in the boots, and you replace the coil leads and run the engine at some time in the near future it will start to arc again and form a carbon track in your new boots, if you then replace the plugs it will probably run ok for a while and then start arcing again through the carbon track in the boots, this will again create a carbon track on the plugs, this could go on forever.

When you have a carbon track problem, you must replace plugs and coil wires at EXACTLY the same time.

If you have VCDS (VAG-COM) you can use it to check the voltage for the alternator/regulator test.
 

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Discussion Starter #8
Update

Tested the battery and the voltage regulator, seems to be charging fine with nothing out of the ordinary to report. Everything seems grounded as well, and all the wires look good.

Still waiting on my new coil, should be here tomorrow or monday. Took a look for the carbon tracking and didn't see anything odd, my mechanic told me to change the spark plugs too,as bad gapping or the wiring ones can cause all kinds of odd problems as I didn't remember what kind I put in last go around. (put new NGK's in). When I took them out they reeked of gas, not sure what this means, but it further making me think the coil that is in the car isn't working very well an the spark is not igniting all the fuel in the cylinder. I removed the old coil as well and boxed it up to send back, hopefully i'll get a refund.

Still banking on the new coil and wiring harness to solve my problem, nothing else seems to make sense. we will see when I get the next one in. If anything this thread tells people what is needed to replace the wiring harness.

Chris
 

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As mentioned in the link posted by 2002GLXV6, that guy had a grounding problem with his coil pack, the car was working ok at time of
his last post but don't know if his problem is solved long term. (He has also replaced 5 coil packs).

The coil pack is mounted on rubber mounts and these should insulate it from ground, make sure yours is not grounding and check there
plenty of clearance between your coil pack and any ground. I don't know if grounding it could cause it to break down, but that certainly is a possibility.

My car is a 2000 B5 V6 with the same coil pack, I checked it and found that with engine idling I get a varying voltage between the coil pack and Ground.
with ign. off & meter on Meg Ohms range, with leads on one way I got a reading of about 1.6 Meg Ohms, with leads reversed it read infinity.

Therefore I deduce that grounding might cause coil damage, but could not say for sure. (Best to make sure it is not).

The black box (Suppressor) should be in the circuit, it is there to protect other electronics in and near the car, but make sure it is connected to ground
and not to the coil pack.

Just to clear a point: The suppressor (Short for "Interference suppressor") referred to above, is a capacitor (Often incorrectly called a condenser).
There are other types of suppressors.

If I had your problems with coils, I would get one of those HEI Coil Testers, only 10 to 20 USD.

Which wiring harness are you replacing?
 

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hi there have you ever thought of your car computer if u had another one off another car it would have to be same year and have the same motor... i would try that... just saying
 

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Discussion Starter #12
well the coil I just got in the mail had one of the spark plug receptacles broken off, so I won't know until this weekend, when another one gets sent to me if it will all work. This car has a curse on coils I think.
 

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Discussion Starter #13
well, the new coil is in, and the car seems to be running again. I also put new spark plugs in. Just in case the the musical coil game possibly affected the old ones. its been a few days and so far no codes. We will see how long this lasts. if for some reason it misfires again, I will update this thread. I think if someone is having issues like mine, splicing in a new harness may be a good idea.

Chris
 

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I am having the SAME exact issue with my 2001 Passat Wagon GLX V6. New coil on the way. It's crazy. It has to be a ground somewhere causing this stuff. Car runs fine and then out of nowhere, misfires --- p0303, p0305, p0353, p0300.

Have you figured anything out on this? My wife is now starting to target deer on the roads. She wants this car gone badly.

Thanks!
 

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How many coil packs have you replaced ?
I don't believe that there have been multiple OE/OEM coil pack failures, if you use cheap coil packs, they are likely to fail.
If OE/OEM coil packs are being used, I believe the fault is in the wiring, probably the plug that connects to the coil pack,
possibly one of Pins T121/94, T121/103, T121/102, in the ECU connector, could also be in the wiring between.
The heat sync on the coil pack must NOT be grounded, it should be insulated from ground.
 

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Hello I am having this issue as well 04, 2.8 wagon. Has anyone tried using the dielectric grease? if so does the problem continue? I need to check and see if that black box is connected to coils or to ground. Thank you for all the info.
 

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You need to provide details of your specific symptoms, and what has been done to try to solve the issue.
Dielectric grease is used keep moisture out to help prevent arcing or corrosion, it won't fix a bad connection.
 
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