2016 VW Jetta

Chris Diagnostician Bryans Road, Maryland Posted   Latest   Edited  
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2016 Volkswagen Jetta S 1.4L (CZTA) 6-spd (09G) — 3VW267AJ8GM212737
P0300 — Random/Multiple Cylinder Misfire Detected
P0302 — Cylinder 2 Misfire Detected
P0303 — Cylinder 3 Misfire Detected
P0171 — System Too Lean Bank 1
P2177 — System Too Lean Off Idle Bank 1

Good evening I have a 2016 vw Jetta with a 1.4t in for a check engine light. Im am wondering if anyone has had any luck doing some sort of relative balance test on the injectors. It is running lean and misfires on start up. I would like to rule out the injectors. I tried modis and autel and they don’t have any tests for the injectors. So I pulled out the Vag-com and it has a test for fuel Injection deviation. I ran the test and it says system test finshed system not ok. So I’m not sure if that means there is a issue with the injectors. I couldn’t find any data worth watching during the test that would help me agree with the tests outcome. There was also a test for (trying to remember what it was called) fuel rail pressure release and it also said system not ok. If anyone needs a vin I can get it tomorrow.

Thanks for any help

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Craig Technical Support Specialist
Chicago, Illinois
Craig Default
 

Good evening Chris, how many miles are on this vehicle, depending on use and maintenance it's possible you have carbon build up on the intake valves. Depending on the deposits composition it can cause many symptoms. Craig

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Chris Diagnostician
Bryans Road, Maryland
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It has around 92k new customer to me so I don’t have much history. I know carbon issues can cause some random misfires. Would carbon build up cause the engine to run lean?

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Richard Technician
Stony Brook, New York
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I would first check for vacuum leaks. Especially internal types caused by ruptured crankcase valves. On most of the VW I see, they are built into the valve cover some can be replaced separate from the valve cover. Just run the car at idle and see how hard it is to remove the oil cap. If it is pretty tough the valve is bad. I wonder if it is running to lean to complete those tests on the scanner.

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Chris Diagnostician
Bryans Road, Maryland
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It says the test are completing but I guess it sees something t doesnt like bad instead of saying it fails the test it says system not ok. i will look into crankcase thanks

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Hans Technician
Salt Lake City, Utah
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It’s probably going to be high on this engine, I’m betting normal pressure is -35ish in/h20. It has to be measured with a manometer to know what’s really going on.

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John Technician
Cape May Courthouse , New Jersey
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The misfires on start up are usually a sign of carbon buildup. I haven’t seen carbon cause a lean condition personally, but maybe it’s possible. Have you checked fuel pressures?

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Chris Diagnostician
Bryans Road, Maryland
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Yea I agree with the misfire on start up can be carbon. Yes low and high actual matches desired. Also forgot to mention once the lean codes set there is no longer a misfire on start up. The car ran great until I ended up clear the codes and that’s when the misfires appeared at start up until the lean codes set again.

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Sadel Owner/Technician
Fairfield, Ohio
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Hey Chris, if I were you I'd start with chasing the lean code condition first, only because depending on how bad of a condition it is it will most certainly cause misfires to occur. As stated above, check the crank case vent valve, very common issue, but depending on the type of leak it is having (internal/external) the "pull the oil cap test" might not show you correctly. Yes , I'd go ahead and…

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JB Owner/Technician
Minneapolis, Minnesota
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You can always look at the duty cycle on the low side pump at idle (usually below 80pct). Then take it for a hard drive. Shouldn’t get much higher than high 80s low 90s. If your duty cycle is high at idle or under heavy load you will want to investigate the fuel system further (low pressure side pump/control unit). Verify the command duty going into the control unit matches the duty going to the…

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Bill Owner/Technician
Jackson, Michigan
Bill Default
 

The VIN# and Engine Code would be helpful for all of us... Measure crankcase pressure at dipstick tube using manometer with engine running at idle. Report the finding Smoke test all air induction, crankcase and turbo system hoses Using Vag-Com you can view actual and specified fuel pressure data for your high side. The fuel pressure release function is only to depressurize the HP system for…

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Chris Diagnostician
Bryans Road, Maryland
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Unfortunately I don’t have a manometer looked into getting one and didn’t know which one to buy. Is there one you would recommend ?

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Bill Owner/Technician
Jackson, Michigan
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I use this one currently ( Pyle # PDMM01) there are many options out there.... If your gonna be doing euro engine performance diag your gonna need one for sure

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Chris Diagnostician
Bryans Road, Maryland
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Yea it was something on my list to buy and just forgot. I will order one today thanks

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JB Owner/Technician
Minneapolis, Minnesota
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Pdmm15 Pyle. Works great, not expensive!

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Chris Diagnostician
Bryans Road, Maryland
Chris Update
   

Updated the VIN. I just got some data this morning unfortunately I don't have a manometer so I cant test that right now. The high fuel pressure matches desired at 14MPa. There is a data pid for Fuel pump specified value I am not sure if that is for the low or high but it is at 51%. Seems a little high but I would assume that is because it is asking for more fuel. Fuel trims were ok this morning…

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Chris Diagnostician
Bryans Road, Maryland
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I smoke tested the system and I am not seeing any smoke. I left the PCV hose off and nothing is coming from that so I would say the diaphragm is ok.

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Brandon Technician
Medina, Minnesota
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Without a manometer, the old test was to try and remove the oil cap with the engine running. A crankcase vent valve failure usually causes excessive vacuum and you'll have to fight to remove the cap. Another sign is whistling as air gets sucked in past the oil seals due to the increase in vacuum. Do you have a borescope you can sneak in the the throttle body/map sensor to look at the intake…

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Chris Diagnostician
Bryans Road, Maryland
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Thanks for the post Brandon. It does suck the oil cap down some but I wouldn't say it was overly excessive. This has a clip in PCV valve that clips into the valve cover as this valve cover on this engine holds the cams down. Was thinking about pulling it out and looking at the diaphragm but was worried the clips would break on it. I did clamp off the hose that goes to it to see if the fuel trims…

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Chris Diagnostician
Bryans Road, Maryland
Chris Update
   

Here are some pictures of the valves. Looks like we will be recommending a Walnut blast and go from there. I would really like to get a pico capture of the before and after intake pulls. Should I do that cranking or running to try to get the best results of seeing a before cleaning and after cleaning (if it gets sold). Looks like the only place I could really put the WPS/FLS is where the MAP…

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Brandon Technician
Medina, Minnesota
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WOW!

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Chris Diagnostician
Bryans Road, Maryland
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Yes I said something very similar once I put the camera in. Could you shed some light on when exactly the fuel is getting soaked up to cause a lean condition. Also it looks like since this is a newer engine there are not any walnut blaster adapters for this cylinder head. Does anyone know where I could find one for the 1.4T? Thanks

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Charles Owner/Technician
Barnstable, Massachusetts
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I’m not familiar with this engine. I assume it’s GDI. If so, fuel is not getting soaked into the carbon, as there is no fuel in the intake manifold. The carbon build up is from oil leaching into the intake from either the PCV system or the turbo. I wonder if this engine has seen the specified oil when changed. Your fuel pump duty cycle at 51% at idle is about right. Your MAP sensor may be oil…

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Chris Diagnostician
Bryans Road, Maryland
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Yes I agree that is why I was trying to get some more clarification. Although i remember reading something about the carbon acting as a sponge but I forget what it was referring to about soaking something up. The map on this is at the top. I got the approve to clean the valves so we will start with that and go from there

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Sadel Owner/Technician
Fairfield, Ohio
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if wanting to get intake pull capture, do it cranking and see if can tap into where the purge goes or on other vw engines I normally go where the pipe for the crankcase vent valve goes

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Craig Technical Support Specialist
Chicago, Illinois
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Chris its possible that the engines volumetric efficiency is down due to the engine being unable to breathe. If possible try to get and intake and exhaust pattern with ignition sync before and after repairs. If you look down in the posting history for two posts mentioning carbon studies you will see 2 posts from me with examples of clean versus dirty FLS patterns, I don't know if this link will…

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Chris Diagnostician
Bryans Road, Maryland
Chris Default
 

Yea that is also a good point. I remember those posts. Thanks for the input

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Chris Diagnostician
Bryans Road, Maryland
Chris Update
 

Well I just finished up cleaning the valves and they were pretty dirty. Got everything back together and still have a lean condition like before. I didn’t really think cleaning the valves would fix that but they had to be done with as bad as they were. Not sure which direction I am going to go now. Maybe I will try to smoke test again and go from there.

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Sadel Owner/Technician
Fairfield, Ohio
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if you don't find any external leaks with smoke test, unbolt the high pressure fuel pump, and physically look at the piston drive and cam lobe, I know you stated you checked scan data and pids and so on related to fuel pressure and trims, but you cant always just rely on this information to be the end all, the only reason why I state this is because I had a 14 vw with lean codes present, and…

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Chris Diagnostician
Bryans Road, Maryland
Chris Default
 

Sadel was that on a 1.8t I would guess? I have done a few of those before so I know what you are talking about. This is a 1.4 so I don't know if these also have the same issues. As far as crankcase pressure I can pinch off the pcv hose and nothing changes so I don't think its a crankcase issue. Am I correct with this? I have seen a few people online had these codes same motor with lower mileage…

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JB Owner/Technician
Minneapolis, Minnesota
JB Default
   

How did the injector tips look when you did the carbon cleaning on the valves? The direct injectors on these do carbon up and they have a microsonic cleaner for cleaning them via the dealer in many cases (or they sell new injectors). Can you graphyouru scan data for fuel pressure on a test drive? Map the desired vs actual for the high side pressure. Also graph the low pressure duty cycle (maybe…

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JB Owner/Technician
Minneapolis, Minnesota
JB Default
 

Low side delivery pressure should be 4.0 to 6.6 bar if you decide to measure it directly. Otherwise you can t-in to the low side then command the pump with the key on engine off. Make sure your rail pressure sensor matches your low side measured value. Rail pressure sensor reads 1 bar (which is atmospheric pressure) when there is no fuel in the rail. So keep this in mind!

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Chris Diagnostician
Bryans Road, Maryland
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So I put a gauge inline for low pressure and I got 55 psi. I don't think this has a FPCM so the spec I got was 43-58psi. I tried to connect with fuel module and it said no comm so that's how I half ass assumed it didn't have one.

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JB Owner/Technician
Minneapolis, Minnesota
JB Default
 

Chris, the wiring for the czta engine (what your vin shows you have) DOES use a J538 Fuel pump control module. So it sounds like your low side pressure looks relatively normal at idle but we need to see what it does under load. Drive it while you're t-d in and watch that pressure. Should climb close to 90-95psi when the vehicle is under wide open full load conditions.

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Chris Diagnostician
Bryans Road, Maryland
Chris Default
 

I should have but I didn't think to pull the injectors while I had the intake off. Stupid me. I can graph that stuff if the lady decides to leave the car. The warranty company pretty much said I would have to known exactly which injector is causing the lean and if its because of carbon its not covered anyways. I can also check the pids for other stuff. Car really does run good so I doubt any…

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Chris Diagnostician
Bryans Road, Maryland
Chris Resolution
 

Good evening everyone. I just wanted to close this one out. It took awhile as I was out with the flu. I double checked everything I could think of that would cause a lean condition. I could never find any issues so I sold all 4 injectors since I did not have one cyl with misfires. I really had no way to check the injectors beside send them out to be checked and cleaned but customer said to just…

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