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Misfire Cylinder 2 - Please Help

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Misfire Cylinder 2 - Please Help

 
Old 05-15-2019, 05:53 PM
  #51  
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Originally Posted by bspurloc View Post
It really doesnít need to be see thru. The average tired engine seems to only collect a few ounces of oil over 5000 miles.
Tired meaning some bad blow by.
So you are not likely to collect a whole quart over 5000 miles. If u do u have much more serious issues to resolve lol.
I have to reread this whole thread as I seemed to have missed a lot of replies due to using cellphone lol.
Just spoke to my mechanic and he said adding a catch can to a 4.2 isnít going to do much. To quote him directly he said ,ĒItís like putting a bandaid on your elbow when you scrape your kneeĒ. Interesting feedback. He stated that the only ones heís seen with catch cans are the VWís with the 2.0 TSI motors and even then they arenít exceptionally effective because so much still bypasses the catch can than the OP never sees.
He further stated that, ďmany of the early FSI Turbo motors had a block off plate you could get to reroute the hard vacuum that the pcv normally used and made it less damaging to the vehicleĒ. He said he hasnít seen one for the V8 4.2 but suggested I look around and see if such a plate exists.
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Old 05-16-2019, 01:38 AM
  #52  
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Haha mate I would suggest your mechanice has a double look at the PCV hose routing into the throttle valve again and realise there is no way you can block this off unless you had and old skool walking stick pumping out the crankcase fumes onto the ground but once again lots will then need to be blocked of to stop the vacuum leak.

The catch can will still be placed in between the rocker cover outlet hose and the PCV valve. It will then pass and drop off heavy oil vapours into the can and only then the remainder of oil vapour gases will be then seperated by the favtory PCV then will it pass back into your throttle valve manifold. Yes as I mentioned 2.0TSI kits are available, thats because the 4.2fsi is obsolete, outdated and not worth putting kits into production.
If the factory PCV was so good from Audi, then why do all FSI owners have issuses with carbon buildup on the valves. It clearly shows the PCV was never working at its best. Also the 4.2fsi is not turboíd. Just TSI engines.
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Old 05-16-2019, 01:43 AM
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Originally Posted by Up-it View Post
Haha mate I would suggest your mechanice has a double look at the PCV hose routing into the throttle valve again and realise there is no way you can block this off unless you had and old skool walking stick pumping out the crankcase fumes onto the ground but once again lots will then need to be blocked of to stop the vacuum leak.

The catch can will still be placed in between the rocker cover outlet hose and the PCV valve. It will then pass and drop off heavy oil vapours into the can and only then the remainder of oil vapour gases will be then seperated by the favtory PCV then will it pass back into your throttle valve manifold. Yes as I mentioned 2.0TSI kits are available, thats because the 4.2fsi is obsolete, outdated and not worth putting kits into production.
If the factory PCV was so good from Audi, then why do all FSI owners have issuses with carbon buildup on the valves. It clearly shows the PCV was never working at its best. Also the 4.2fsi is not turboíd. Just TSI engines.
Agree with everything you said. He did say that using such a block method was something he saw a LONG time ago and heís never seen something like that attempted on a 4.2FSI. He still claims that a catch can setup isnít going to do a ton but I still wonder if it would hurt anything to add a catch can, if I installed it properly. Doesnít seem like it could make anything worse.

Unrelated here but im still trying to find a good scan tool that will give me more accurate information vs a generic obd scanner. I canít afford the super expensive tools but what do you think about this one:

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Old 05-16-2019, 04:25 AM
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Originally Posted by Up-it View Post
Hey mate, I cant show you a picture of mine at the moment as I am away at work but I did find a link for a DIY kit also for the v8. I pretty much did the same. Sourced the catch can and connected the can in between the rocker cover and the PCV. Quite simple with some hosing and fittings from you local hardware store also.
attached Is something you will need to follow.
cheers.
https://www.audizine.com/forum/showt...atch-can-setup
Check this out. Just doing some google searching and I came across this setup:

https://www.repairmanuals.co/product...QQAvD_BwE&kwd=
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Old 05-16-2019, 06:37 AM
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Originally Posted by Willgatlin25 View Post
Agree with everything you said. He did say that using such a block method was something he saw a LONG time ago and heís never seen something like that attempted on a 4.2FSI. He still claims that a catch can setup isnít going to do a ton but I still wonder if it would hurt anything to add a catch can, if I installed it properly. Doesnít seem like it could make anything worse.

Unrelated here but im still trying to find a good scan tool that will give me more accurate information vs a generic obd scanner. I canít afford the super expensive tools but what do you think about this one:
I have this one and it is great. This can reset maintenance reminders. I pulled a code for my AC pressure switch, tested all the flaps on the HVAC system and tested my O2 Sensors to verify they were bad. I also was able to code so my lack of my TPSM so it didn't display an error. You can purge bleed the brake master cylinder and do much of what RossTech can do. This is stuff I had done and there is a lot more I haven't had a need to do.
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Old 05-16-2019, 07:00 PM
  #56  
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Update regarding the repairs:
The misfire on cylinder 2 is completely gone now. The issue was in fact due to a dying injector that once replaced solved the issue.
However the mechanic told me that when they reassembled everything and did the test drive they got a few random misfires on cylinder 5 but it wasnít concerning. When I went to pick up my car I started it and the vehicle was noticeably shaking, check engine light immediately started flashing, and when I put it in drive it bogged down badly. The mechanic plugged in his computer and it came back as misfire 281 times on cylinder 5. He told me to drive the car home so they could get some additional computer history to try and determine what happened. On the drive home it completely fell on its face. Severe lack of power even when having the throttle pinned there was minimal acceleration. Trying to go up a hill I had to manually shift into 2nd gear to prevent the engine from bogging and stalling out.
Strange thing is that while driving the check engine light does not flash indicating that the massive power loss is due to a continued misfire on cylinder 5. Honestly it feels like a massive vacuum leak or like Iím trying to drive on a dead cylinder.
He told me to come back in the morning and is allowing me to stay with him at the shop while they tear the intake back down and see what happened.
I started with a subtle vibration and misfire codes on cylinder 2 and now I have a vehicle thatís 10 times worse than before the repairs were made. Canít say that Iím pleased at all but the mechanic is taking ownership of this issue and making the repairs on his dime now.

Once again, will report back with updates when the power loss is diagnosed.
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Old 05-18-2019, 12:04 AM
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Oh man... sounds like maybe they screwed up someone on cylinder 5 in the hurry to replaced injector 2.
maybe shorted its wire or something
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Old 05-18-2019, 12:47 AM
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Default UPDATE 5/18/19

And now the moment we have all been waiting for, the resolution to this:

Allow me to back up to when I drove the car home on Thursday. I barely made it home while the engine was bogging down and struggling like crazy. It felt as though I was driving on about 50% power and it sounded like a Subaru. No offense to Subaru but my Audi should not sound like one! It felt like either a massive vacuum leak or like I was driving on a dead cylinder. Ever disconnect a spark plug wire or coil pack and try to drive? Exactly what it felt like...

So through troubleshooting we decided to replace injector 5 as well. If anyone ever takes the upper intake manifold off and follow the fuel lines youíll find that cylinder 2 and 5 are both fed by an independent fuel line which makes absolutely no sense when the HPFPís are separate from each other on either side of the motor. The only thing we could conclude is that possibly a chunk of carbon or some type of contaminates broke loose and flowed through that line and whatever clogged injector 2 now also clogged injector 5.
Using their Autel computer (which by the way was far more effective than VCDS) we replaced injector 5, reassembled, and started it up. As soon as the air bubbles purged themselves through the fuel rails every single little misfire cleared and the engine sounded normal again. Gave it several good revs and zero misfires... the problem was resolved. So the conclusion here is that the cylinder 2 misfire was due to a partially failing injector, but had not yet completely failed. When injector 5 got clogged up it completely failed and it was easy to see on the computer. On cold start the misfire on 5 would happen instantly. It would climb to 182 misfires and then stop completely, but the engine was running like crap. Turns out the reason for the misfires showing that they stopped was because the injector had completely failed so the ECU actually shut down the cylinder itself. Smart move actually or the fuel would just keep trying to pump into a cylinder that wasnít firing and eventually flood it out if there was still a small amount of fuel passing through the injector, or it would cause some type of catastrophic engine failure if that fuel suddenly ignited and blew the cylinder apart.
So when I said that it felt like I was driving on a dead cylinder, itís because I was! The ECU detected the injector failure and shut the cylinder down in basically an auto protect limp mode type action.
Since my car was in the shopís care while it was being worked on and more issues developed we worked out a deal. I paid for the new injector and they covered the labor. I could have been an *** about it and tried to fight them all the way saying it was their fault because ďin a wayĒ it was, considering I paid them to fix my car and they made it worse. But, they do seem like good people and have a good reputation. I didnít really want to burn a bridge with these guys so I was happy to pay for the parts. Iím actually happy to have paid for the part and knowing that we found the issue and it wasnít really a major undertaking to correct the failure.
Honestly now that Iíve seen the process to remove the upper intake itís not as hard as I thought. I definitely would not move as fast as these guys but I could do it in my garage if I had to. Good learning experience.

The only strange anger issue I had is while driving home today I got on the throttle a few times to feel the difference. Believe me, itís night and day when youíre not running on a dead cylinder. Funny thing was when I really got on the throttle I could hear a really loud noise that almost sounded like violent spraying and crackling. Like someone just stuck a shop vac into hot coals. Thatís the best way I can think to describe that noise. I did stop at a gas station after I heard that and popped the hood expecting to see a coolant line or a fuel line disconnected but there was nothing. Even when that noise happened there was no check engine light and zero engine hesitation, it didnít feel like anything was mechanically wrong. I even looked under the engine bay, no drips of any kind. After a while of getting on and off the throttle the noise stopped. So..... yeah I have no clue what that was! It sounded horrible but itís just suddenly gone.
I know that they did walnut shell blast all the carbon out of the intakes and that walnut shell crap is everywhere in the engine bay. Given they did try to clean it up as best they could but that crap goes everywhere. Iím kind of wondering if a bunch of that walnut media landed in something and during heavy acceleration it was somehow blowing off and making that crazy noise or maybe even burning on the exhaust and thatís what made the crackling fire sound? All I know is that was some weird noises.

All ive got left now to figure out is consistent warnings about having brake lamps out. I had the entire harness replaced on the left rear side and all new bulbs installed. But even with a new harness and bulbs Iím getting a brake lamp out warning but the brake lamp is working... why the dash is telling me itís not when itís brand new, I have no idea. Itís annoying as hell to start the car and hear the loud ďBEEPĒ with the constant brake lamp light blinking on the screen. Maybe itís just a crappy bulb and it doesnít like the way that bulb is seated or doesnít like the brand of bulb that the mechanic used? It has to be something relatively stupid because Iíve replaced the harness... thereís not much else to replace if the lights are working.

Moral to go this whole thread after weeks of going around in circles: If anyone else gets issues like what Iíve described in this thread, donít rule out your injectors. Itís rare to have injectors die but apparently itís not uncommon on the 4.2 FSI.

Happy Hunting lol.
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Old 05-19-2019, 09:36 PM
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Intakes are usually easy to do, people just instantly declare they are not.
"Smart move actually or the fuel would just keep trying to pump into a cylinder that wasn’t firing and eventually flood it out if there was still a small amount of fuel passing through the injector, or it would cause some type of catastrophic engine failure if that fuel suddenly ignited and blew the cylinder apart."
An injector staying on wont cause a HUGE SCARY explosion, this isn't the movies, I wish movies would stop teaching people this... HOWEVER you would get a catastrophic failure, its called HYDRO LOCK. if the cylinder fills with gas, gas cant be compressed and well that means the piston cant go up. so if somehow that happened while the engine was running BAM, good bye some random part that pushes that piston up. This is why you dont spray stuff down you throttle when the engine is off, cuz that is going to hydro lock a piston and bye bye engine if u get to to crank. usually the crank isnt enough to damage the engine will just halt. but i suppose if the hydro locked piston was the last one in the rotation the engine may be spinning fast enough to bend a rod etc.
Unsure what the noise could be.
Maybe a lower wattage light was put into the brake light?
lift the rear hatch with the driving lights on, do the lights all work in the bumper? put foot on break do they work in the bumper?
lifting the hatch causes brake lights to be used in the bumper instead the hatch
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Old 05-20-2019, 11:28 PM
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Hey there bspurloc:

I didnít imagine the engine would erupt in a giant ball of flames and blast me into the atmosphere lol. I just figured that pumping fuel into a dead cylinder is probably not a good thing. Either hydro lock or leaking past and mixing a bunch of gas with my oil.... neither would be a good scenario.
Good news was that the ECU caught the issue and shut down the cylinder, so completely removed that specific injector from the sequence and saved itself. It was a bit of a pain to track down the misfire (s) because everything was so inconsistent. After I saw the state of the upper and lower intakes my first thought was carbon build up because it was nasty!
Iíve been sick as a dog for the last three days so I havenít even been back out to drive my Q7 since I brought it home. Hopefully the strange noise doesnít return, I have no clue what that was. Iíll be driving it this Tuesday so if something happens Iíll be the first one to know

As far as the tail lights. I havenít checked the lights with the rear hatch open or closed. Iíll try that next and see if there is any intermittent changes.
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