# Need help diagnosing.



## Evaughn (Oct 4, 2011)

I got a mk5 2.5L rabbit with a swapped 08 motor in it, done by a shop. Running lean. Can't find a leak or anything, shop did a smoke test, found a leak, fixed it, runs a lot better but still running lean. Also found coolant in cylinder 5, they were saying a cracked head gasket but it has never overheated. They did a compression test and it was fine. Any input? Thanks in advance.


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## afawal2012 (Jan 9, 2013)

Is the coolant reservoir clean or is there oil in there. Pull the oil dipstick out. Is there a lot of white"ish" foamy stuff on it?
- Did you change plugs and coils?
- You might also have an issue with fuel injectors.

Are you getting any error codes?

Need more info.


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## Evaughn (Oct 4, 2011)

afawal2012 said:


> Is the coolant reservoir clean or is there oil in there. Pull the oil dipstick out. Is there a lot of white"ish" foamy stuff on it?
> - Did you change plugs and coils?
> - You might also have an issue with fuel injectors.
> 
> ...


Plugs were changed, fuel filter was changed. I don't believe the injectors or coils were. No foam on the dipstick, and the coolant reservoir is clean and did not need to be filled. I've had a bad coil before and those were bad misfires, this is nothing like that. Before the leak was fixed the car would run rough and there would be a high idle, but now it's running better than ever with no high idle. I'll try and get a code tonight for more info. Should I try injector cleaners for the sake of it?


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## afawal2012 (Jan 9, 2013)

The bottle in the fuel tank type injector cleaner is not going to give you instant results, so in the short term you will not see a change if that is the issue.

I'm just curious, how do you know it is running lean? What are the symptoms you are getting?


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## Evaughn (Oct 4, 2011)

That's what the CEL is on for apparently, I haven't gotten the code read recently but last time a I read it, it said it was running lean.


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## zer0hz (Apr 1, 2014)

Logging the Lambda (Actual) sensor in VCDS should tell you whether it's running lean or not. 
<1 = Rich 
>1= Lean 
1= Stoichiometric (14:1 A/F)

It could be a case of one of the sensors in the Lambda calculations that has gone bad.


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## Evaughn (Oct 4, 2011)

I don't have VCDS/Vag-com etc. I just use a regular CEL scanner, thats the best I got access to.


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## watercooledfool (Dec 4, 2012)

A good shop should have a cylinder leakage tester. With this they can confirm is there is an actual cracked head/blown head gasket. This is because when using a leakage tester if you see bubbles in the radiator/coolant reservoir, then you have a cracked head/blown gasket. Good luck:thumbup:


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## Evaughn (Oct 4, 2011)

Update. 
Leak in Air intake system P2279 - 008 - - MIL ON
Fuel Trim; Bank 1 P0171 - 001 - System Too Lean - MIL ON
Idle Control System RPM P0507 - 001 - Higher than expected - Intermittent
Incorrect Immobolizer Key P0513 - 008 0 0 Intermittent

Don't worry about the key part. I'm not sure if these codes were taken after or before the big leak was fixed. Since then the car runs much smoother, no more high idle, but still a CEL for running lean. Previous Owner believed it was something with the SAI. Taking it to the dealer next week to see what they think it is. Of course I'd like to avoid the stealership at all costs, so if anyone can provide insight it will be highly appreciated. Thanks.


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## le0n (Jun 12, 2013)

clear codes.

clamp the n80 valve hose (either side) shut. test drive and wait for subsequent codes.


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## Evaughn (Oct 4, 2011)

What do you mean clamp shut? Like check for leaks?


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## le0n (Jun 12, 2013)

clamp it shut where vapor can not past through it.

if the n80 malfunctions, it can do so in the "open" position, creating an internal vacuum leak scenario.

is the engine ever hard to start after fueling?

edit:

there's a photo of what i'm talking about in this thread: http://forums.vwvortex.com/showthread.php?6925695-Starting-amp-Over-Shifting-Issue-Related


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## Evaughn (Oct 4, 2011)

le0n said:


> clamp it shut where vapor can not past through it.
> 
> if the n80 malfunctions, it can do so in the "open" position, creating an internal vacuum leak scenario.
> 
> ...


I'll let you know the results tomorrow. Does not have trouble starting after filling up.


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## le0n (Jun 12, 2013)

then it's probably not the n80. however, it doesn't hurt to test.

are you using a stock air box assembly or aftermarket intake?


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## Evaughn (Oct 4, 2011)

le0n said:


> then it's probably not the n80. however, it doesn't hurt to test.
> 
> are you using a stock air box assembly or aftermarket intake?


Stock airbox. Motor is completely stock but it does have a 93oct tune and a res delete in the exhaust. Those are the only "performance" mods.

Edit: This couldn't be an ECU issue could it?


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## chc-rado (Nov 20, 2008)

If you smoke test it and no leaks found. N80 valve(purge valve) can easily tested with vacuum gauge. Apply vacuum to purge valve on either end, it should hold vacuum and bleed very slowly. If it doesn't hold vacuum at all. Stuck open purge valve. They are cheap. High failure rate. Also when car is running. Check the secondary air hoses going to intake boot. No cracks and also clipped in all the way. There two hoses that clip into the intake boot. Also check air box if not damaged. Check the breather on the valve cover too. Those tend to leak causing a vacuum leak and higher than idle than norm. If the breather is bad, you new valve cover. Also if you replace valve cover make sure you didn't pinch the valve cover gasket too. That will cause false air too. Using brake cleaner is an other way look for vacuum leaks. Just be careful. Avoid using carb cleaner (very flammable compare to brake cleaner)


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## Evaughn (Oct 4, 2011)

Any of you think it could be the PCV valve?


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## watercooledfool (Dec 4, 2012)

We had a Beetle in a few months back with a p0171 code, ended up being intake manifold gasket leak.


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## Evaughn (Oct 4, 2011)

watercooledfool said:


> We had a Beetle in a few months back with a p0171 code, ended up being intake manifold gasket leak.


I think I might change it if it doesn't turn out to be n80 valve, is there any way to check for a failing gasket?


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## Evaughn (Oct 4, 2011)

Got another update.
Still have the P2279 and P0171 codes. I plugged the n80 and nothing feeling around though I noticed the idle jump around when I would move the hoses to the Secondary Air Intake. I believe that there is a leak with one of the hoses, or on the pump itself. That would make sense because the leak would be post Mass Air Flow so the motor would get more air then expected causing it to run lean. Has anyone else had problems with the Secondary Air Intake before? Let me know. Thanks.


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## le0n (Jun 12, 2013)

in regards to the PCV valve, try to remove the oil filler cap while the engine is idling. if it is difficult to remove (hard vacuum) then your pcv is faulty.

if you get an idle change when you move the hoses, then i believe you've found the culprit. remove those hoses.

there was a warranty extension on the sai sensors for the mkv rabbits/jettas. i got a letter in the mail last year.


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## chc-rado (Nov 20, 2008)

le0n said:


> in regards to the PCV valve, try to remove the oil filler cap while the engine is idling. if it is difficult to remove (hard vacuum) then your pcv is faulty.
> 
> if you get an idle change when you move the hoses, then i believe you've found the culprit. remove those hoses.
> 
> there was a warranty extension on the sai sensors for the mkv rabbits/jettas. i got a letter in the mail last year.


That for map (manifold absolute sensor) not for maf (mass air-meter) cars. 2010 model years and up.


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## le0n (Jun 12, 2013)

^^ true. i just didn't know if it was physically possible for that sensor to crack 'leak'.

from what he described last, the sai hose is probably cracked.


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## Evaughn (Oct 4, 2011)

Checked the SAI hoses and even put a new gasket on and still threw a code? Could the SAI not just be working at all? Do you guys think it could be the intake manifold gasket? The code was P2279. Thanks.


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## le0n (Jun 12, 2013)

Evaughn said:


> Any of you think it could be the PCV valve?





chc-rado said:


> Check the breather on the valve cover too. Those tend to leak causing a vacuum leak and higher than idle than norm. If the breather is bad, you new valve cover. Also if you replace valve cover make sure you didn't pinch the valve cover gasket too. That will cause false air too.





le0n said:


> in regards to the PCV valve, try to remove the oil filler cap while the engine is idling. if it is difficult to remove (hard vacuum) then your pcv is faulty.


the PCV (breather valve) is integrated into the valve cover. you can test it with the method mentioned above.

check out this thread that gives detail as to what happens when the pcv diaphragm fails: http://forums.vwvortex.com/showthread.php?4876767-2006-2-5L-Idle-Problems-P2279-and-P0507

some people have luck with just replacing the torn diaphragm, others don't.


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## Evaughn (Oct 4, 2011)

le0n said:


> the PCV (breather valve) is integrated into the valve cover. you can test it with the method mentioned above.
> 
> check out this thread that gives detail as to what happens when the pcv diaphragm fails: http://forums.vwvortex.com/showthread.php?4876767-2006-2-5L-Idle-Problems-P2279-and-P0507
> 
> some people have luck with just replacing the torn diaphragm, others don't.


I've changed that diaphragm and that's what changed the whole feel of the car, it went from high idle and running terribly to running just fine, but still with a CEL. 

Update: After sealing the SAI and putting it back I think I've noticed a pattern with the check engine light coming on. When I first erased the code and tried it after "fixing" the SAI it no longer came on within a minute of driving like before. I drove around for about half an hour, accelerating hard on the highway, city driving as well and it was fine. As soon as I turned the car off and turned it back on, it turned on and the CEL reappeared. This happened twice, it seems to come back on when I turn the car on after the initial drive. Any opinion?


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## Evaughn (Oct 4, 2011)

Can someone please explain to me how to unscrew the bolt on the intake manifold that is in the middle on the bottom side? I can not get to it from any angle and am completely stuck.


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## le0n (Jun 12, 2013)

that happened to me and i had to make a tool. essentially an extra long hex wrench, hah hah...

the tape was just there to keep the socket from falling off:


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## Evaughn (Oct 4, 2011)

Thanks, my problem was I didn't realize those little holes on the front of the manifold lead right to the bolts. Stupid mistake haha. No change when I changed the gasket. I'll update soon with the next attempt.


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## Evaughn (Oct 4, 2011)

Update: Change the PCV diaphragm after realizing the old one had a very small tear in it. The CEL didn't come on after turning off the car and turning it on again, but it came on after the car sat and cooled off and was turned on. The idle still seems a bit high and occasionally get rev hang at around 1500RPM


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## Evaughn (Oct 4, 2011)

Another update. I've always had a high idle around 1000. When I rev it up I get a rev hang around 1500. I disconnected the MAF and the idle would drop about 200 immediately, as well as no rev hang. When I scan the codes I get temp sense signal too high and MAF signal too low. Nothing about too lean or a vacuum leak. You guys think I found the culprit? Maybe it wasn't giving accurate readings causing the computer to think there was a leak.


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## Evaughn (Oct 4, 2011)

Changed the MAF and no change other than when the car starts up it has normal idle, but after its revved it doesn't drop below 1000rpm again. I'm thinking it's the fuel side of things, thinking of switching the fuel pressure regulator. Any advice?


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## le0n (Jun 12, 2013)

you've reset the codes?

are you still triggering the same codes?


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## Evaughn (Oct 4, 2011)

Same codes. I'm tackling the oil filter housing gaskets next. That's what the PCV is connected to. I have all the symptoms of a malfunctioning diaphragm, so it has to be something connected. The only thing left connected to that system would be the oil filter housing, I've tackled everything else. I'm fairly confident that this will finally solve the problem. I'll let you guys know.


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## Evaughn (Oct 4, 2011)

When I put in the new MAF I get a code for throttle body correlation(something like that, I forget exactly) and with the old I get the same 2 codes. I also fixed a small leak and changed the oil filter housing. I'm thinking maybe its the MAF wiring?


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## Evaughn (Oct 4, 2011)

Anything? I think I might give up on this car.


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## Geo (Nov 14, 2000)

what year model is your car? you say you swapped an 08 motor into it. I'm wondering if the shop mix and matched sensors that may not be compatible. Don't even know if that is even possible. Also I'm assuming you made sure all the wires near the SAI hoses are securely fastened on the sensors?

edit: have you had a chance to check your mileage per tank?


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## Evaughn (Oct 4, 2011)

The car is an 07 and the motor is an 08, I haven't been able to check the mileage per tank. I put the old MAF in and I believe I'm getting the same two codes despite fixing a bunch of leaks, but the idle is much better now and no rev hang. I have not double checked the codes though.


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## le0n (Jun 12, 2013)

Evaughn said:


> Anything?


at some point, you're going to have to seek out someone in your area that can properly diagnose this thing with vagcom.

also, provide the odbii code for the throttle body correlation error.


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## Evaughn (Oct 4, 2011)

le0n said:


> at some point, you're going to have to seek out someone in your area that can properly diagnose this thing with vagcom.
> 
> also, provide the odbii code for the throttle body correlation error.


Just scanned it, got the following results, no more running lean, or air leak codes after fixing the leak. Now I think the wiring for the MAF might be messed up, corroded or something.


Address 01: Engine Labels: 06A-906-032-BGP.lbl
Control Module Part Number: 07K 906 032 T HW: 07K 906 032 Q
Component and/or Version: 2.5l R5/4V G U001
Software Coding: 0000001
Work Shop Code: WSC 79413 539 427654
VCID: 3A71434C754486E
3 Faults Found:

000104 - MAP/MAF <-> Throttle Position Correlation 
P0068 - 001 - 
Freeze Frame:
Fault Status: 01100001
Fault Priority: 0
Fault Frequency: 1
Mileage: 137612 km
Time Indication: 0
Date: 2000.00.00
Time: 16:15:36

Freeze Frame:
RPM: 2491 /min
Load: 19.2 %
Speed: 93.0 km/h
Temperature: 84.0°C
Temperature: 21.0°C
Absolute Pres.: 1000.0 mbar
Voltage: 14.351 V

000257 - Mass Air Flow Sensor (G70) 
P0101 - 008 - Implausible Signal - MIL ON
Freeze Frame:
Fault Status: 11101000
Fault Priority: 0
Fault Frequency: 1
Mileage: 137619 km
Time Indication: 0
Date: 2000.00.00
Time: 16:20:22

Freeze Frame:
RPM: 2787 /min
Load: 47.4 %
Speed: 104.0 km/h
Temperature: 87.0°C
Temperature: 21.0°C
Absolute Pres.: 1000.0 mbar
Voltage: 14.224 V

008601 - Intake Air Temperature Sensor 1 / 2 
P2199 - 008 - Implausible Correlation
Freeze Frame:
Fault Status: 01101000
Fault Priority: 0
Fault Frequency: 1
Mileage: 137683 km
Time Indication: 0
Date: 2000.00.00
Time: 04:10:11

Freeze Frame:
RPM: 817 /min
Load: 20.8 %
Speed: 33.0 km/h
Temperature: 81.0°C
Temperature: 45.0°C
Absolute Pres.: 1010.0 mbar
Voltage: 14.097 V


Readiness: 0000 0000


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## le0n (Jun 12, 2013)

i'm guessing that your vehicle is not a 2008. which then leads me to guess that you have a 2006 or 2007 that used a Intake Air Temp sensor on the intake assembly. if so, do you still have this plugged in?

have you cleaned your throttle body yet and checked the range of motion on the butterfly plate?


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## Evaughn (Oct 4, 2011)

le0n said:


> i'm guessing that your vehicle is not a 2008. which then leads me to guess that you have a 2006 or 2007 that used a Intake Air Temp sensor on the intake assembly. if so, do you still have this plugged in?
> 
> have you cleaned your throttle body yet and checked the range of motion on the butterfly plate?


The air temp sensor never came up until we changed the MAF, this is with the old MAF put back in which never gave up this code until recently. We cleaned the throttle body and did an alignment. We also cleaned the connection and that's when it came up. Is it possible I messed up the MAf connection. I was going to spray a bit of brake cleaner which evaporates quickly just to clean the connection, but I sprayed carb cleaner accidentally which didn't evaporate. I'm thinking maybe that messed with it when we plugged it back in?


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## le0n (Jun 12, 2013)

oops. missed the year model info.

i don't see carb cleaner harming any electrical connection. you may have a loose MAF connection.

is the intake air temp sensor still plugged in? do you get a code for it if you disconnect it?


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## Evaughn (Oct 4, 2011)

I'm beginning to think this is a software/computer problem. I took it to the dealership to restore it to stock software (previous owner put a 93 tune) but after two tries they couldn't get original software back on. They recommended getting a new or used ECU. What do you guys think?


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