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Discussion Starter · #1 ·
Ok, so here's the situation. 2002 beetle 2.0 gas. We replaced the head and gasket with a rebuilt head and new gasket also while into it replaced connecting rods and bearings, pistons and rings. Now it fires up and CEL flashes. I found a loose plug wire on the coil and snugged it down still the CEL flashes. Timing is spot on. Took to get codes scanned and all that came up was 4 for missfire on cylinder #2 and (cant remember the wording exactly but) mass air low input. But the car had this same code for a while with no effect on the motor. So i think the cylinder 2 missfire codes were stored before i fixed the loose plug wire ( i did unhook the battery for a while to clear the engine light but assume codes are stored until cleared out) so i changed the plug in cylinder 2 but no change in flashing engine light and rough idle. Plug wire looks ok. I checked the vacuume lines and even sprayed some starting fluid (vey lightly) on the vacuume lines no change in idle so i dont think there is a vacuume leak. So should i replace the MAF? already took it out and cleaned with MAF cleaner. Bout to pull my hair out. I read that only a misfire will cause the engine light to flash/blink.
Thanks!!!
 

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Discussion Starter · #3 ·
So i lightly misted the coil pack with water and it sputtered worse and died..sprayed wd-40 on the coil pack and it picked up a little bit. Still rough idle and blinking CEL....sorry but what is a hard reset? i didnt get the exact codes, the guy at advance just read them to me.
 

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Based upon the troubleshooting you just did with the water; it sounds like your coil is cracked and/or bad? Make sure you buy a high-quality coil; only high-quality OEM Bremi/STI or one from the VW dealer; do us and yourself a favor and don't buy junk ignition parts from a local auto parts store!.

Genuine Volkswagen OEM part number Part #: 06A-905-097

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Discussion Starter · #7 · (Edited)
Thanks a bunch! I followed the steps, all i have to take the measurements is a standard multimeter. But i was getting 12.4V between pins 1&6 on the plug and i put the leads in (1+2) (1+3) (1+4) (1+5) i had my wife crank each time i moved the leads to the different pin combinations and each showed nearly the same voltage readings when she cranked...so the assumption is; the firing input signals are making it to the input on the coil pack correctly, but the coil pack isn't reacting to the input for cylinder 2. So seems coil pack is bad. Thanks again!! Just to be sure, and to rule out a bad plug wire, I measured the resistance on the plug wires and they all read the same.
 

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Cool, keep us informed as your troubleshooting and parts replacements progresses; definitely let us know if replacing the coil fixes the problem! :) Be sure to get a good brand name, quality OEM replacement part and don't get cheap junk, that won't last and just give you more problems in the future! :)


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Discussion Starter · #9 ·
Ok, still no joy. Replaced the coil pack with a quality OEM replacement and the missfire continues!! So i pulled each plug wire one at a time, inserted a new plug and grounded the plug while the motor was cranked. Each wire provided a good spark...so while it was idling i pushed on the 6 pin coil pack connector and the car stalled and at one point, for a very brief second the idle smoothed out while i wiggled individual wires on the 6 pin plug but could not get it to replicate again..so i pulled the connector and following a DIY removed the wires from the plug with the connecting tabs in place. I didnt find any wires loose/ broken from their connecting tabs. But im going to try and find a replacement connector anyway. Afraid to drive it to get the codes scanned again. It will barely pull out of its own tracks in the driveway.
 

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Hmm, you should be able to get a new connector online or at the vw dealer; if you look on the connector, it will have the volkswagen part # on it. I am currently working on a 2003 vw jetta with a 2.0L; the customer was having misfires, especially at high speeds. So far; we have diagnosed it to be the ecu; we shipped it out to have it repaired. We will see what happens; in our case at first we got codes for grounding out of the coil in two cylinders; then we stopped getting any voltage to the coils and got error codes about no communication from the ecu. I would replace the connector and I will keep you updated; if in our case, the ecu was damaged/defective.

Are there any new or different codes; that came up, after the coil pack replacement? If you still don't have a vw type scanner, I strongly recommend you get one (for less then $50 you can get one on amazon.com look at vag405 or the newer version vs450). The VW scanners; can give you codes that are more specific to the Volkswagen diagnostic trouble code system and can help you diagnose things, more intelligently. If you keep this VW; for any amount of time, the CEL light, will come on and you will have to be trying to diagnose things, without a VW type scanner, in many ways you are flying blind, get a cheap vw scanner at a bare minimum or go for VCDS.
 

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Discussion Starter · #11 ·
I will certainly get a scanner for VW . No new codes and i got a plug from the salvage yard for $5.00 to test and it didnt help. Still missfire cylinder 2 according to generic scanner...so ive ruled out spark and fuel issues and it seems if it were an injector there would be a code for that...so im gonna test the injectors to rule them out but the gears in my head are spinning and now im wondering if the rebuilt head has a stuck exhaust valve?? A compression test is in order...the new coil solved the no spark issue but could the 15-20 minutes it ran without spark damaged the valve? BTW, thanks so much for all the information!! It has been a great help.
 

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Discussion Starter · #13 · (Edited)
ok, so we took it to the garage and compression test showed VERY low compression on cylinders 2 and 4. So a couple things come back to me:

1. When I put the head on it didn't feel "solid" against
the new gasket. Normally after I wiggle it a little it
down good. This time it still kind of rocked a little.
I chalked it up to the gasket just needing compressed
a little by torquing the head bolts.

2. During initial start-up the coolant reservoir was
bubbling quite a bite. But that's pretty normal after
having the head off and air is working it's way out
of the system, UNLESS......

the head gasket is leaking and its exhaust gasses making their way into the cooling system. But no water in oil or oil in the water.

The gasket that came supplied with the rebuilt head was in a plain brown box with no markings other than a part number, so maybe a junk Chinese reproduction. I followed the torque sequence exactly and the head and deck were clean and smooth before I put it on. Just ordered a quality OEM gasket and bolt set. We will see........

So the new coil pack and replacement 6 pin plug has the spark issue taken care of so hopefully a head gasket will be the end of it.
 

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Bummer, I try to stick with the better brands like FELPRO or VICTOR REINZ:

Federal-Mogul Fel-Pro Brand Home

Just seal it! - Sealing Products Victor Reinz Aftermarket

ALL BRAND NEW; head bolts are a must as well. Maybe you could try a leak down test? I guess it really doesn't matter at this point; the head has to come off.. right? Bummer! :mad:

Keep us posted as your repair progresses! :)

PS: we got the ecu back from the rebuilder; found a fuse that was blown and the car starts up fine, found a tech bulletin about adding a new ground wire for the coil plug and now it seems to run fine! Now, its overheating; so, I maybe doing a timing belt/water pump swap next...
 

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Discussion Starter · #15 ·
Good you got that one squared away...Yeah, that was one of the first things I did when I had to replace the coil plug was run a new ground wire...The head gasket I ordered is a Fel-pro Perma-Torque..Same as I put on my silverado heads with zero problems. At any rate, you are correct, the head has to come off to diagnose whether its the gasket, rings, or valve problem. I will know something this afternoon. Parts are supposed to be here by 9:00 this morning.

I guess the lesson here is, when that voice in your head tells you something isn't right, better listen to it! After probably a dozen or so head gaskets in my life, I didn't think the head seated well on the gasket but assumed it was ok to be a little "spongy" before the bolts are tightened.
 

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Discussion Starter · #17 ·
Ok, quick question here. I didnt get a chance to replace the head gasket yet but something i noticed has me wondering. When it first starts up the miss is present but not nearly as bad as it will get. Almost to the mili-second after the secondary air injection pump turns, off the miss gets much worse. The rpm's are the same while the pump is running as after it turns off. Weird?
 

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Well, one thing; in a cold start engine, this:

The engine requires a relatively rich mixture for smooth operation on cold start. For this reason, the ECU operates in open loop mode with a fixed fuel map for the first 20 to 120 seconds of engine operation until the oxygen sensors have heated to operating temperature. Because of this, exhaust gases contain high levels of carbon monoxide and hydrocarbons after cold starts.

More info here:

Secondary Air Injection

Open loop definition:

RUN MODE – OPEN LOOP
In run mode, the ECM operates in two conditions commonly referred to as OPEN and CLOSED LOOP. When the engine is first started and the RPMs go above 400rpm (and is not in clear flood mode), the ECM enters OPEN LOOP fuel control operation. During open loop operation, the ECM ignores the O2 sensor input when making fuel delivery calculations and relies on the other sensors to determine fuel delivery to the engine. There are specific tables stored in the PROM programming that contain the instructions the ECM uses to determine how much fuel to give the engine in this operating mode. Also during this period the ECM still constantly monitors the signal coming from the O2 sensor to see whether or not it is ready (hot enough) for closed loop mode.


http://www.gmtuners.com/tech/modes.htm

So, it makes sense; it would run differently at first, being in a open loop and ecu isn't adjusting things at first? I'm no expert but it would make sense, that the miss would be less pronounced with the fixed fuel map?

Maybe, to confirm everything; you should do a leak down test, to give you more specific info about your compression situation?
 

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Discussion Starter · #19 ·
Still a delay getting the parts in.. Poking around this morning i discoverd that this box that sits behind the coolant resevoir that has several lines and hoses going in to it seems to be coming apart. The lines look like they have pulled loose, you can see what looks like barbed connectors on the hoses exposed.
 

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Discussion Starter · #20 ·
The box is cracked. The 2 main fuel lines from the rail go into it as well as an AC line and a vac hose. The fuel lines are pulled up and wobbly in the box.
 
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