3.0 - Random 4, 5, 6 Mis-Fires

[SJorge3442]

Hey everyone,

Yesterday I was driving home after a mini ice/rain storm we had and when I was accelerating from a stop getting ready to shift from 3-4, I felt that terrible feeling of some misfires. I looked down and the CEL was flashing. Whipped out the handy Torque Android App and quickly learned that the misfires were all on the drivers side bank; Cylinders 4, 5, & 6. This went on for a while (2 miles ish) until I pulled into a parking lot to do some diagnostics.

Idle was searching while sitting there, so to get a clean state, I cleared the CEL and the idle was still rough. I turned the car off, then back on and it was idling great. I threw some STFT and LTFT icons on my Torque app and monitored fueling for the drive home (30miles all highway). At the end, my LTFT's were both locked in a +2.3%. There was also not one misfire the whole trip and I was sure to get on it a few times to see if I could get them to show up again.

Since the drivers side bank is the far bank from the fuel pump, could this be a dying fuel pump? What about the fuel pressure regulator? Fuel filter gets changed every ~12 months. Ever since running a k0mpresd ECU (which blew out most of my coils), I've been having all these small issues. Never did I have any issues before hand. I've been back on the stock ECU for some time now.

[SlickFix]

Could be a dying fuel pump. Does it make any noise when you put the key in the on position? How about the coil harness on the driver's side? Is it plugged in all the way? Are there any bare wires in the harness that could have been exposed to moisture?

If you change the fuel filter ever 12 months, and you don't drive it much, it should be ok. But then again, it's a $10 part so it might be worth replacing it to see if the misfires come back.

[SJorge3442]

Could be a dying fuel pump. Does it make any noise when you put the key in the on position? How about the coil harness on the driver's side? Is it plugged in all the way? Are there any bare wires in the harness that could have been exposed to moisture?

If you change the fuel filter ever 12 months, and you don't drive it much, it should be ok. But then again, it's a $10 part so it might be worth replacing it to see if the misfires come back.

Its funny, my passenger side harness needs some attention (waiting for the warmth) as the plastic covering is brittle and broken, but the drivers side is great. I can eyeball the drivers side again, but visually, I believe they are fine. I mean, I have 136K on what I believe is the stock pump, so thats the first place my mind is heading, but before I drop $200 and an afternoon to replace it, I wanted to see what others think. It sounds fine when I prime the engine before I start it (I always wait 2-3 seconds with the key on On before cranking), but now that you mention it, it did seem to make a lower pitched groan a few weeks ago, a few times, but since then its sounded fine. I also ran the tank pretty low this past weekend (20 miles remaining per the DIS), so maybe something got into the filter. I could swap that out first, but if I don't it will surely be swapped when/if I do a pump.

I read another thread where someone had this issue caused by his timing being off, but I find it hard to believe that I would have problem again, but its totally a possibility.

[cschuster]

There is the ground harness for each bank. Check out the connector on that side. I've also read somewhere that the VVT can cause random misfires on that side and can happen even if its working just fine. Cannot confirm that one though.

[SJorge3442]

There is the ground harness for each bank. Check out the connector on that side. I've also read somewhere that the VVT can cause random misfires on that side and can happen even if its working just fine. Cannot confirm that one though.

hmm, interesting. Do you know where I might find the ground connector? I don't think I've ever come across any of our grounds, other than the one of the firewall on the passenger side.

[deyrag]

If I remember correctly from my engine swap it is on the back of the head up against the firewall.

[SJorge3442]

If I remember correctly from my engine swap it is on the back of the head up against the firewall.

Cshuster pointed me to the connector that attached to the VVT at the front of the head. I'm not sure which is right. Are you saying the connection is on the firewall? I feel thats the most likely place for it to be, as the engine and electrical should all be grounding to the chassis, whether or not that connector has the ground contained within it or not is beyond me.

[deyrag]

Cshuster pointed me to the connector that attached to the VVT at the front of the head. I'm not sure which is right. Are you saying the connection is on the firewall? I feel thats the most likely place for it to be, as the engine and electrical should all be grounding to the chassis, whether or not that connector has the ground contained within it or not is beyond me.

I thought there was a short section of single wire with a ring terminal that was part of the harness and was attached to a stud on the back of the head. Will see if i can find some pictures.

Edit. if you look directly up from the rear cylinder you can see a short brown/yellow wire
[IMG][/IMG]

[imnuts]

Did you get a chance to view the AFR while it was misfiring? Another thing to do would be to log the requested v actual AFR broken down for bank 1 and bank 2 to see if one side is running more lean than the other. Sounds a lot like what mine was doing before I changed the fuel pump.

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[SJorge3442]

I thought there was a short section of single wire with a ring terminal that was part of the harness and was attached to a stud on the back of the head. Will see if i can find some pictures.

Edit. if you look directly up from the rear cylinder you can see a short brown/yellow wire
[IMG][/IMG]

Thanks for the picutre. In relation to where that wire is in the picture, where does it mount on the head? It is easily findable by reaching and looking back? I won't have time till next weekend to check it out, but the car stays parked all week.

[SJorge3442]

Did you get a chance to view the AFR while it was misfiring? Another thing to do would be to log the requested v actual AFR broken down for bank 1 and bank 2 to see if one side is running more lean than the other. Sounds a lot like what mine was doing before I changed the fuel pump.

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I wasnt able to check AFR while it was occuring. I did keep an eye on that when driving home and even that was hovering around 14.5 the whole time. I was unaware of the ability to log AFR vs the different banks. Thats possible? We you actually getting flashing CEL misfires on 4,5,6 when your pump needed replacing?

[imnuts]

You need VCDS or ME7Logger to see the individual bank AFRs, Torque only gets the overall. When I got misfires, the CEL would flash. Typically it was only one or two cylinders though that would misfire, but sometimes it was 3 (4, 5, & 6) or 4 (3, 4, 5, & 6). Most of the time, I never had a problem but every once and a while, it'd act up for a little bit, then usually go away after stopping the engine and restarting, or just letting it go for a minute.

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[SJorge3442]

You need VCDS or ME7Logger to see the individual bank AFRs, Torque only gets the overall. When I got misfires, the CEL would flash. Typically it was only one or two cylinders though that would misfire, but sometimes it was 3 (4, 5, & 6) or 4 (3, 4, 5, & 6). Most of the time, I never had a problem but every once and a while, it'd act up for a little bit, then usually go away after stopping the engine and restarting, or just letting it go for a minute.

Sent from my DROID Turbo 2

Alright. That sounds exactly like my issues. Like I said, after sitting, then restarting the engine, it was fine. I'm gonna check my grounds firstly, then go from there, but I feel like this almost has to be a fuel pump issue. I need to upgrade my VCDS as I switched laptops too many times now and I need to cash in my lite credit for a full cable, but just havent done it yet. Might have to read up on ME7 just to get some data.

[imnuts]

Also, misfires would go away for me if I tried to bring the RPMs up. It was worse at idle than at higher RPMs. It didn't make sense to me, as I'd think that if it were fuel pump related, increasing engine speed would only cause more problems, but things typically smoothed out if I brought the RPMs up somewhere between 1500-2000, and sometimes they'd go away after that, sometimes they'd be right back as soon as the RPMs dropped.

[SJorge3442]

Also, misfires would go away for me if I tried to bring the RPMs up. It was worse at idle than at higher RPMs. It didn't make sense to me, as I'd think that if it were fuel pump related, increasing engine speed would only cause more problems, but things typically smoothed out if I brought the RPMs up somewhere between 1500-2000, and sometimes they'd go away after that, sometimes they'd be right back as soon as the RPMs dropped.

Yeah, once I got past like 2400 ish it would smooth out. After shifting and dropping engine speed down below 2k again, the misfires would come back. Sounds like a new fuel pump is in order. Hell, with 136K on the engine, its time for a new one anyway. Thanks again. I should also mention, in this feisty cold we are experiencing, the car is running great. Now I just need to get the transmission fluid changed too. I grabbed that from you a few months ago at this point.

[deyrag]

Might get it done for free, worth a check.


"Safety Recall JL 2003 year Audi A4 quattro with 1.8L Turbo or 3.0L engine and 2003 Model year Audi A6 with 3.0L engine"
The fuel pump on some affected vehicles may contain a carbon brush set that is susceptible to premature wear.

[deyrag]

Any updates for us fellow 3.0 owners?

[SJorge3442]

Nah not yet. I live in the city so I walk to work during the week, plus I have no where to wrench, not to mention this upcoming monster of snow storm (lets hope). I am gonna check out the wiring for obvious issues, then probably order a fuel pump and do that. Its funny, a fuel pump and radiator were both on my preventative maintenance list for the spring. Looks like one with get done sooner than that.

Oh and I called Audi, my vin isn't one of the effected models for the fuel pump recall.

[SJorge3442]

Drove around a bit last night. First 25 minute drive, no issues. Second 25 minute drive, issues when the temp gauge was around 1/3. Sputtered a bit, but I kept the RPMs up and it went away after a few minutes. I would say i had issues for like 7 minutes of that 25 minute drive. Turned car off, then immediatly went on a 40 minute drive with 0 issues. I even tried lugging the engine around a few times to get the misfires to surface.

[SJorge3442]

About to pull the trigger on a fuel pump, seal and cap (do I need the cap?). These misfires are so strangely timed that I feel it HAS to be the pump. They come and go like a ghost. Wiring "looks" good. I havent taken a multimeter to anything though.

[imnuts]

When I ordered it (from EuropaParts), I got the seal (1J0919133B), pump (8E0906087P or 8E0906087N), and cap (8E0201263G). The cap is to cover an extra port on the fuel pump assembly, I'm assuming for a return line in a different model/application.

[SJorge3442]

When I ordered it (from EuropaParts), I got the seal (1J0919133B), pump (8E0906087P or 8E0906087N), and cap (8E0201263G). The cap is to cover an extra port on the fuel pump assembly, I'm assuming for a return line in a different model/application.

Yeah those were the 3 parts I was going to order. I just had no idea what the cap was for. That makes sense though. I too am gonna grab it from Europa and I'll probably just throw a new fuel filter on for the sake of doing so. Why not, right? Have your misfires stayed away since swapping pumps?

[imnuts]

Yeah, still no misfires since swapping pumps, and things seem to be working just fine. I did also change the fuel filter a few times, as well as when I changed the pump, and that didn't make any difference prior to the pump change. For $10, it was another "why not change it?" part when I replaced everything in the fuel system minus the hard and flex lines. It was a problem that I had basically since I got my car, so probably close to 150k miles with the issue, though it was at its worst just before I got the JHM tune, and then about a year afterward. The dealership looked into it twice in my first few years of ownership and had no idea what was causing it. I didn't want to spend the money back then for them to keep it long enough to figure out what was causing it, though I doubt they ever would have. It sucks that the fuel system doesn't have a place to hook up a pressure gauge, as that would make diagnosing the pump a lot easier than logging the bank 1 and bank 2 lambda and guessing at what may cause a difference.

[SJorge3442]

Yeah, still no misfires since swapping pumps, and things seem to be working just fine. I did also change the fuel filter a few times, as well as when I changed the pump, and that didn't make any difference prior to the pump change. For $10, it was another "why not change it?" part when I replaced everything in the fuel system minus the hard and flex lines. It was a problem that I had basically since I got my car, so probably close to 150k miles with the issue, though it was at its worst just before I got the JHM tune, and then about a year afterward. The dealership looked into it twice in my first few years of ownership and had no idea what was causing it. I didn't want to spend the money back then for them to keep it long enough to figure out what was causing it, though I doubt they ever would have. It sucks that the fuel system doesn't have a place to hook up a pressure gauge, as that would make diagnosing the pump a lot easier than logging the bank 1 and bank 2 lambda and guessing at what may cause a difference.

Its good to hear that the pump fixed your issues and has kept them away. I submitted the order through Europa a few hours ago and already received shipping confirmation. I will for sure be swapping the pump this weekend. Maybe I'll finally change my tranny and rear fluid too.

[cschuster]

Its good to hear that the pump fixed your issues and has kept them away. I submitted the order through Europa a few hours ago and already received shipping confirmation. I will for sure be swapping the pump this weekend. Maybe I'll finally change my tranny and rear fluid too.

Hope that's the fix! Use this stuff for your trans. Advance Automotion or from RMEuro. Get 3L

[SJorge3442]

Hope that's the fix! Use this stuff for your trans. Advance Automotion or from RMEuro. Get 3L

Yuppp. Already got 4L sitting on my work bench. Gonna pick up a home depot drill pump to do the transfer for me too. Shouldn't take long at all.

In all seriousness, I feel like I can have the pump/filter swapped out in about an hour, pending no issues. Throw another 1.5 hours for the trans+rear diff fill and I should be done in less than 3 hours. Maybe she'll get a wash too

[imnuts]

When you replace the pump, just make sure you get the little tube in the new one in the clip on the housing, otherwise you may have fuel gauge problems. See old guy's thread here. Depending on how easy/hard it is to get the tank cap off and fuel pump out, I'd say it shouldn't take too long to do the pump, just make sure you have less than a half tank of gas, less if you can, otherwise you'll loose a lot of fuel in the process.

[SJorge3442]

When you replace the pump, just make sure you get the little tube in the new one in the clip on the housing, otherwise you may have fuel gauge problems. See old guy's thread here. Depending on how easy/hard it is to get the tank cap off and fuel pump out, I'd say it shouldn't take too long to do the pump, just make sure you have less than a half tank of gas, less if you can, otherwise you'll loose a lot of fuel in the process.

Good tips, thanks! I've been trying to keep the tank under a half since I've been planning on doing this for a few weeks. Probably going to have less than 1/4 when I do it, just because of where my tank is now. I have 30 miles left on this tank and I'll probably put $10 or so in just to get me through the week and to my parents house to do the work.

[imnuts]

Yeah, not thinking, I got gas a few days before I wanted to change my pump initially, still had like 3/4 of a tank when I went to do the swap. Had to put it off another week instead. I had somewhere between 1/8 and 1/4 of a tank when I did change it, and the fuel level was right about even with the top of the pump cage.

[SJorge3442]

Well. New pump is in. DID NOT fix my misfires. I was not too happy, but tbh, the old pump seemed pretty sloppy. I *think* I found the culprit *maybe*

My PCV valved was all gooked up with the egg yolk crap. This is literally 5k miles since replacing the whole PCV system. I cleaned it out with a rag and blew on the PCV to get some more out. Well I started the car and it was making a whale/whirling noise that sounded awful. I pulled the pcv and threw in an OEM one I replaced 2 years ago while trouble shooting and bam. Car sounded better than it has in maybe forever and she ran great. No misfires or CEL after about 1 hour and 40 ish miles.

Fingers crossed that this was it!

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[SJorge3442]

Forgot the pics.



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[SJorge3442]

Can we talk about how a P0150 showed up today...... Damn front o2 sensor. Trying to determine how to attack this repair. Pretty sure it may be worth it to just drop them DP down.

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[imnuts]

The good news is that the bad sensor could be the cause of the misfires. The bad news is that I don't think there is an easy way to replace it. The O2 sensors are probably the last non-routine preventative thing I want to do with my car.

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[Boost_creep]

I threw the p0150 recently as well. Iirc, you can replace it while the dp is in the car.

[SJorge3442]

I threw the p0150 recently as well. Iirc, you can replace it while the dp is in the car.

Haha go figure. You and me are 1:1 on repairs right now. I PM'd Spike as I know he has the documentation of all of the sensors and such. I think it can be gotten to while the DP is in the car, but TBH, the drivers side DP is faily easy to drop. I may just drop it for the sake of simplicity. Of course I'll try to get at it while its in the car, but I'm afraid the angle might be hard to get a good bite on the sensor. But hey, when the DP was out of the car 2 years ago for my clutch job, I put some anti-seize on that sensor. Maybe for once some preventative maintenance will pay off for me. I'd like to just do both front o2's, but I'm gonna be cheap and only do the one. Let's hope that doesn't bite me in the ass.

The sensors are $96 on amazon, which isnt TOO bad, but I still wish they were like $40.

[Boost_creep]

Yep, that's where I got mine.
And with an o2 socket, I was able to get it out from up top.

[SJorge3442]

Yep, that's where I got mine.
And with an o2 socket, I was able to get it out from up top.

You were able to get the drivers side FRONT o2 from the top? I would have never even thought it was accessible from the engine bay. I haven't gone searching for it, but you can bet I'll be adding a spacer to the rear o2 while I'm doing the front sensor.

[imnuts]

I believe that SlickFix has some decent pics in his O2 spacer thread. I think that you can get to both front O2 sensors from the engine bay, just need to move some stuff out of the way to get to them.

[Boost_creep]

Yes, I'm almost positive I did have access to the front sensor. I think the rear is where dropping the dp comes in handy.

[t64030]

I have the same code for the front o2 sensor in bank 2. Would it cause me to not be able to rev above 5k? Sometimes I can after i clear my codes but its really hard to get it to rev that high. Also puts it in epc mode. I feel like I have more torque than I use to though also. Any thoughts? Sorry, don't mean to thread jack.


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