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I would reset and see what codes come back. Old codes can stay for a long time before they are cleared and some codes may never clear by themselves.
 

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Discussion Starter · #22 ·
Ok, I will reset them tomorrow. And after I will try on road. I post result ASAP.
Thanks a lot :)
 

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I would expect the MAF out of those items listed. The Engine speed sensor tends to cause no-starts and stalling. The others should clear with the reset.
 
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Discussion Starter · #24 ·
Ok, I just got back from a run.
Now I have no more fault codes.

But I still have the same problems.
Cold, it no longer exceeds 4200 rpm, it runs out of steam and shakes.
Hot, it even exceeds 2800 rpm.

You have any ideas ?
 

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I would check for a collapsing intake hose, they get softer as they heat up. Are you certain the manifold change-over was put back together properly? I don't know if it's possible, but I've seen it happen with cam timing rings. I would also check fuel pressure at the engine, a dying pump can cause similar issues.
 

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Discussion Starter · #26 ·
Hello all,

I'll see it all.

For the intake hoses, are you talking about the big ones that go from the air box to the throttle body?
I hesitate to change all the vacuum hoses.

For camshaft rings, I don't see what it is. Do you have a reference to help me find it in FR? Can one think that it is the AAC sensor which would be HS?

The collector, it is I who changed it, I fixed everything while respecting the tightening torques. The manifold is particularly annoying to change but I have not detected a leak after my work.
I changed the lambda at the same time.

I was able to take these measurements between 2 meetings, do you see any strange data?
I specify that the car was parked, no gear engaged

Should I try to get some into circulation when the problem arises?
I ll command a cable to try use VCDS too

103025
 

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Yes, the hose from the airbox to the throttle body. It's fairly common on the 1.8T, but it can happen on any engine.
For the chart above, how cold was the engine? You have an air intake temp of 11, but a coolant temp of 21 at cold idle. At hot temps, it should be closer to 87-90 instead of 75-76.
Your fuel trims are not far off and I don't know if they were reset after the hoses were plugged. I don't recall what the O2 values should be.
Can you run the above checks at speed when the problems occur?
 

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Discussion Starter · #29 ·
Hi PZ,

I gave it a try. Here are the results, I was able to make 4 readings.
They were taken when the problem arises: the car continues to take RPMs afterwards, but it vibrates and it is difficult to increase its speed.
Do you see anything ?

The main hose between the airbox and the throttle body looks good. It may be the small hose that is connected ?


103073
 

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Your MAF values are off. They should climb with rpm when the throttle is open. Was the throttle floored on each test? You are only showing 25.5%, 27.8, 5.5, and 38 for the throttle. It should reach 90% or so. The maf values on test 3 only show 10g/s at 4158rpm, which seems very low, even with a closed throttle. The last test shows the MAf at 79.9, which seems about right.
Can you block off the PCV system and see if the car runs better? I don't know how it runs on a VR5. I've never seen one and never worked on a VR6 either.
 

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Discussion Starter · #31 ·
Hi PZ,

I was waiting for your answer: D

I was in the acceleration phase for each test, but as I told you before, the car shakes and cuts / starts its acceleration when it reaches these RPMs.
What do you call the PCV system? Is it the breather that starts from the cylinder head cover and returns to the big hose between the throttle body and the air box?

Moreover, on this breather hose, I have an element that seems disconnected ...
I see this topic, it's exactly this element
VW Passat V5 2.3L rough engine

I had seen this topic already. Maybe I have the same problem as this member ?
 

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Sorry, I have only been checking in late at night here (about 3am).

If that is disconnected and not plugged at the intake, it will cause a huge vacuum leak. The system usually has a check valve that only permits a certain amount of vacuum through it. It may be inside the hose at the valve cover, but it can even be part of the valve cover on some engines (the 2.5 I5 Jetta had that). The larger plastic element is often called a "pressure regulating valve" on the 1.8T.
 

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Discussion Starter · #33 ·
Hello Pz,

To be sure that we are talking about the same elements.
I took pictures.

The part I am pointing at is not connected to anything, it looks like a hose must come to connect on it.
partunplug2.jpg partunplug1.jpg

Could it be the vacuum hose that I closed?
MystHose3.jpg

I saw this little leak on the cylinder head cover, could it be the cause of all this?
headcover.jpg

And bonus pic, the (haunted) VR5 :p
theVR5.jpg
 

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I don't see a port for the vacuum line to attach to that pressure regulating valve. I don't know if it needs to be clamped on each side, but I expect it should. The leaking oil is from the valve cover gasket, it's could be caused by a faulty PCV, so I would check what's inside the clamped section of that hose at the valve cover. A large vacuum leak could cause the bad MAF readings. I would remove that valve and plug the section going into the throttle body hose. If the car runs fine, you know it's the issue. If not, I would suspect the MAF.
 

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Discussion Starter · #35 ·
Hello PZ,

Yesterday evening I dismantled the beathe valve.

It looks in good condition, the membrane is complete. But it was full of oil and black dirt.
I cleaned it with brake cleaner.

I saw on PassatWorld.ru, that some guys with had problems with this valve.
I confirm to you that it is supposed to be connected somewhere... At work today, I will investigate tomorrow.

Regarding the small oil leak from the cylinder head cover, do you think I need to fix it? It is very restrictive on this model, I have to deposit lot of parts (intake manifold and all seals...)

When the engine is idling, the oil leak remains calm, no continuous flow or "bubbles".
 

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Discussion Starter · #36 ·
I reconnected all the hoses like diagrams, I think they are correct. I cleaned the breather valve. I put on cable ties. The hose which leaves from the secondary admission, it goes well to the airbox (Hose number 22 - center of image) ?

I have just returned from a new test.

Always the same, but only when the engine is hot.
"Cold" after 10mn on the road, in normal driving, I was able to reach 5000 rpm in 3rd (it started to shake).
On the return, hot engine, shaking again. She raises her RPMs, but painfully.
I reread the specs of my engine, in fact it has problems when it is loaded. All her range where she should have the max of nm, she trembles and can not have it.

Do you think I need a new MAF ?

I would remove that valve and plug the section going into the throttle body hose.
How I can do that ? You mean plug without it ? If I do that, I lose new vaccum line...
But that could mean that she is responsible ... What if I close it?



103126
 

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Yes, plug the intake without the valve. It's one way to test that it's not the issue. If the tests you ran above were all under full throttle and it's not this valve, I would say either your MAF is bad or your throttle body is shot.
 

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Discussion Starter · #38 · (Edited)
Okay, I bypassed the valve. Same symptoms!
I'll put it back.

I believe the MAF had been changed recently before I picked it up. It looks really new :(
Is there a way to test it before buying a new one? Knowing that when I drive unplugged, I always have the same problem.

I looked, for the throttle body, I would have it for 400 euros ... Also way to test it? I thought I saw that if there was a problem there would be unstable idle speed.

I come back to the hose not connected to the vacuum jar, possible that it is the car which does not have enough vacuum in load?
Edit : I plug the hose on vaccum tank, always the same.
 

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Okay, I bypassed the valve. Same symptoms!
I'll put it back.

I believe the MAF had been changed recently before I picked it up. It looks really new :(
Is there a way to test it before buying a new one? Knowing that when I drive unplugged, I always have the same problem.

I looked, for the throttle body, I would have it for 400 euros ... Also way to test it? I thought I saw that if there was a problem there would be unstable idle speed.

I come back to the hose not connected to the vacuum jar, possible that it is the car which does not have enough vacuum in load?
Edit : I plug the hose on vaccum tank, always the same.
There seems to be some language translation problems.

The vac hose with the screw in the end, needs to be connected somewhere.
For the test, you do not bypass the valve, you must disconnect it and block the hole where it connects to the intake.
 

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Discussion Starter · #40 ·
Hello Tomcw,

Sorry for my English, I'm using google trying better to use your technical terms :(

Thanks for your interest in my issues with my VR5.
Do you have a VR5?

Yes, yesterday I connected my "mysterious hose" to the vacuum tank.
The hose that goes to the passenger compartment is disconnected, (the one I show in my photos in my first posts) I don't know what it is connected to, but no diagram mentions it.

When I say I bypassed the valve (PCV valve it seems to me) I had replaced it with a single pipe, wasn't that what I should do? Just plug the little hole that wasn't plugged in?
Or completely "cut" this air flow between the intake and the PCV?
 
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