2.0 misfire mystery. Guru's please help..

[JETBLK]

Agz 2.0 I got recently has random misfire, cylinder 3 and cylinder 4 misfires.

What I've done so far:

Sprayed ignition coil with salt water mix and no jumping sparks.

Changed ignition coil with known good, and exact same part number, with no benefit.

Changed spark plugs and gapped. Used multiple brands and Ngk bkr5e in it currently with no help.

Changed spark plug wires, after seeing that even the original wires have acceptable resistance of above 6.0 ohms.

I believe I may have a short, ground loop or other electrical issue because reading across the battery I get 12v and higher, but when going from the negative terminal to chasis ground, I get ghost voltages instead of the normal .1v or 0.0v.

If anyone has the knowledge to help me get this thing running on all four properly again, I would sure appreciate it. Thanks for your time and any assistance you can give.

[Anony00GT]

Compression test. All plugs removed, injectors unplugged, 5 puffs on each hole @ WOT. Post the results.

[ryanj]

Agz 2.0 I got recently has random misfire, cylinder 3 and cylinder 4 misfires.

What I've done so far:

Sprayed ignition coil with salt water mix and no jumping sparks.

Changed ignition coil with known good, and exact same part number, with no benefit.

Changed spark plugs and gapped. Used multiple brands and Ngk bkr5e in it currently with no help.

Changed spark plug wires, after seeing that even the original wires have acceptable resistance of above 6.0 ohms.

I believe I may have a short, ground loop or other electrical issue because reading across the battery I get 12v and higher, but when going from the negative terminal to chasis ground, I get ghost voltages instead of the normal .1v or 0.0v.

If anyone has the knowledge to help me get this thing running on all four properly again, I would sure appreciate it. Thanks for your time and any assistance you can give.

It sounds like you could have a ground problem to the coil pack. Although most of the time I see this you have a problem on all 4 cylinders. This is a common enough problem on the AZG I would give it a try anyways. You can try 2 things. Clean the ground connections under the battery tray or find the ground connector right at the ignition coil cut the wire and run a new ground wire to the ground connectors under the battery tray.

[JETBLK]

Thanks guys. I'll give those suggestions a try.

I sure appreciate it.

If anyone else has any further suggestions, please feel free. Thanks again!

[JETBLK]

i did the tsb on the coil ground, and to no help...

what should the stock compression be on the agz?

i got 125 psi on 3 and 4.. i have "nothing" wrong with cylinder number 1 and it read 125 psi as well.

i did not, however disconnect the injectors or have the car at operating temperature when i took the

readings.


any help with stock and healthy numbers for compression on this engine would be great. i did a

quick google search a couldn't 't find the stock numbers. i also don't have a bentley on this car

just a chilton. thanks again for all of the help everyone!

[WakusPakus]

have you changed your cap and rotor?

[JETBLK]

Wakus, it is a waste spark system. All electronic. Mk4 2.0. Not an Aba. Thanks for the suggestion however.

[ryanj]

I just saw that you are using ngk bkr5e plugs. I would throw those away anything but factory plugs only cause problems. I believe NGK PZFR5D-11 are the factory plugs.

[Jay-Bee]

I just saw that you are using ngk bkr5e plugs. I would throw those away anything but factory plugs only cause problems. I believe NGK PZFR5D-11 are the factory plugs.

Try this^ even though what you are using is a very common plug, i have't seen it crossed with any VW 2.0s

And also my AEG compression checked in at 180-190psi across the board, an AZG should be no different.

I would maybe try to get a leakdown (valvetrain) test.

[JETBLK]

Thanks fella's!! I'll post my findings.

[JETBLK]

Pushed to WOT compression readings are much higher at 175. Good rings and valve train assumingly. I'm going to see if the local shops have those other ngk's tomorrow. Thank you all for the help mates!

[JETBLK]

Does Anyone know the locations of ground locations other than under the battery box on a mk4 2.0? i.e. ground straps, etc? The voltage variance between battery negative and chasis, aka ghost voltage instead of 0.0v.

I just want to make sure that this car isn't missing any that it should have first and foremost. Thanks again for any help everyone.

[Anony00GT]

Does Anyone know the locations of ground locations other than under the battery box on a mk4 2.0? i.e. ground straps, etc? The voltage variance between battery negative and chasis, aka ghost voltage instead of 0.0v.

I just want to make sure that this car isn't missing any that it should have first and foremost. Thanks again for any help everyone.

Ground locations and wiring diagrams can be found in the service manual.

You should have no more than 0.1-0.2v or so on a voltage drop test between B- and chassis ground.

[JETBLK]

I don't have a Bentley, but I have a Chilton. Couldn't find it, may have been looking in the wrong place.

I definitely have higher voltages that those you mention on my drop.. Milli volts, but not what it should be. Thank you for the response. I feel like I'm making some headway with everyone's help here.

[Anony00GT]

How bad is this car misfiring? Is it a dead miss, or does it seem to drive OK and just throw the codes?

Have you tried swapping in the correct plugs, as suggested above?

[JETBLK]

My local town doesn't have any of those plugs in stock and I have ordered them. (Small town)

It misses quite frequent and if I run it up and down the road, it gets to about 50 mph and falls on its face as the miss becomes worse off. I feel like a ground strap may be missing or something of that nature so that is the reason I asked about the grounding locations for a mk4 agz 2.0. Thank you for your continued help in directions I should investigate.

[Anony00GT]

I've seen bad MAF's cause this type of symptom before. Unplug the MAF and go for a ride. See if it improves. If it improves, replace the MAF.

DO NOT drive for an extended period of time with the MAF unplugged, do this for diagnostic purposes only.

[JETBLK]

here are my codes. i threw one for the maf trying the above post suggestion, to no benefit.

6 Faults Found:
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-00 -
16688 - Cylinder 4
P0304 - 35-00 - Misfire Detected
18057 - Powertrain Data Bus
P1649 - 35-10 - Missing Message from ABS Controller - Intermittent
16687 - Cylinder 3
P0303 - 35-00 - Misfire Detected
16497 - Intake Air Temp. Sensor (G42)
P0113 - 35-10 - Signal too High - Intermittent
16486 - Mass Air Flow Sensor (G70)
P0102 - 35-10 - Signal too Low - Intermittent
Readiness: 0110 1101



ALSO:

Address 03: ABS Brakes Labels: 1C0-907-37x-ABS.lbl
Part No: 1C0 907 379 C
Component: ABS FRONT MK60 0103
Coding: 0004097
Shop #: WSC 00066 000 00000
VCID: 2A51F16A86964E485F1

1 Fault Found:
00003 - Control Module
014 - Defective - Intermittent

-------------------------------------------------------------------------------
Address 17: Instruments Labels: 1C0-920-x4x.lbl
Part No: 1C0 920 921 CX
Component: KOMBI+WEGFAHRS. M73 V08
Coding: 03232
Shop #: WSC 19404
VCID: 76E9151A52AE5AA80B9
3VWCB21C02M413643 VWZ5Z0Z6191691

2 Faults Found:
01316 - ABS Control Module
49-10 - No Communications - Intermittent
01039 - Coolant Temperature Sensor (G2)
30-10 - Open or Short to Plus - Intermittent

-------------------------------------------------------------------------------
Address 19: CAN Gateway Labels: 6N0-909-901-19.lbl
Part No: 6N0 909 901
Component: Gateway K<->CAN V082
Coding: 00006
Shop #: WSC 19404
VCID: F0E5A302B0CAF498515

1 Fault Found:
01316 - ABS Control Module
49-10 - No Communications - Intermittent




abs and coolant temperture sensor are also throwing addional intermittent codes on vag com.

i went to go view the 1/2 fuel system and it read " no signal"

maybe i have a bad injector? any help would be greatly appreciated. i'd love to get this sorted

sometime soon.

[Anony00GT]

Readings from measuring block 032?

After recording the numbers from MB032, clear codes and run the readiness script. See what the results are, readiness and faults. 16497 and 16486 were created when you unplugged the MAF.

Verify connection at the ABS module, check for corrosion, loose wires, etc. Possibly a bad module.

[JETBLK]

would the aBS have anything to do with it misfiring? the control module is located next to the brake booster, correct?

[Anony00GT]

ABS communication codes would not be related to misfiring.

[JETBLK]

It has got to be injectors.

[Anony00GT]

How do you figure?

[JETBLK]

'Noid probe thanks guys. Part out underway.

[squabeggz]

Changed ignition coil with known good, and exact same part number, with no benefit.

I hope these were both OEM coilpacks. If the "known good one" was a cheap Chineese knock off....it was just a brick with the same part number. OEM coilpacks all day, everyday. No substitutes.

Does Anyone know the locations of ground locations other than under the battery box on a mk4 2.0?

"Engine compartment" Ground locations = under battery tray, main strap to transmission block, and a couple under the rain tray.

Clean 'em up, tighten check wires...blah blah blah.

Check the fuse block on top of the battery. Make sure everything there is perfect. Clean, no cracks or corrosion.

Also, replace that coolant temp sensor. Bad ones do mysterious things...like throw fried ECU codes. (I know from experience and Anony00GT's help...dood knows his stuff)
Cheap part to replace anyway.

[JETBLK]

Ignition coil. Not plural. It isn't the coil on plug set up. I also found a diagram of those ground points as well as various other ones that I did a voltage drop on the b- side to confirm them all.

[Anony00GT]

'Noid probe thanks guys. Part out underway.

Huh? A noid light will only confirm electrical injector pulse.

[JETBLK]

As you well know, the noid tester will show normal and abnormal pulses. the impulse was not as the known good cylinders. Thanks for your help dudes. car sold and gone.

[Anony00GT]

As you well know, the noid tester will show normal and abnormal pulses. the impulse was not as the known good cylinders. Thanks for your help dudes. car sold and gone.

Then it's a bad ECU, not bad injectors

Oh well, someone else's problem now