My car is the devil!!!!!

[Brotherturtle]

This car has been a nightmare on so many levels. It cuts out like it isn't getting gas. I have a P0171 system lean code, P0300 multiple random misfire, P0302, P0303, P0304 for misfired on 2, 3, and 4. I have replaced the fuel filter, HPFP/cam follower, and LPFP. No change. Any ideas?

2006 A4 Quattro 2.0T - Unmodified

[Brotherturtle]

On a more strange note, when I replaced the LPFP, I pulled fuse 28 for the pump to relieve the fuel pressures. It should have died shortly after, but kept running. I removed the rear seat and cover and unplugged the pump, and it still kept running. I don't understand.

2006 A4 Quattro 2.0T - Unmodified

[Brotherturtle]

My son put new plugs in it a few months ago before I got it from him, but I don't think it's an ignition problem. I had taken the turbo charge hose off to replace the MAP sensor. I didn't clamp it tight enough. So I was going down the road and it blew off the intercooler. When it did, the car went to limp mode where it ran smooth with no misfired at all. But no power at all. It felt like I was towing a bulldozer. But no misfires.

2006 A4 Quattro 2.0T - Unmodified

[Brotherturtle]

I should also add that we checked compression and it's good.

2006 A4 Quattro 2.0T - Unmodified

[timzcat]

Fuel pressure sensor?
Can you view sensor data or are you just able to pull codes?

[dalmation53]

Replace coils and spark plugs report back.

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[StatusQuo]

On a more strange note, when I replaced the LPFP, I pulled fuse 28 for the pump to relieve the fuel pressures. It should have died shortly after, but kept running. I removed the rear seat and cover and unplugged the pump, and it still kept running. I don't understand.

2006 A4 Quattro 2.0T - Unmodified

Hey man. If you pull the fuse, it can take a very long time to die. When I pulled my fuse, my car ran for something like 5 minutes.

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[StatusQuo]

Replace coils and spark plugs report back.

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Yup. Listen to this guy. Many issues solved by doing this.


Also put some BG 44k in the tank. Might clean the injectors a bit.

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[EvolutionArmory]

While it is possible for 3 ignition coils to take a dump at the same time, I’ve just never seen it happen. Usually with multiple cylinder misfires coupled with other codes, it’s safe to say the problem is somewhere else.

On the other hand, since new spark plugs are a recent addition, I would check spark plug gap. Some of these plugs come gapped as high as .044 which is .012 higher than recommended stock gap of .032.

[EvolutionArmory]

And since there is a lean code listed on top of the misfires, I would be looking for boost leaks and MAF readings, not really focusing on the coil packs and plugs. Boost leak test, check DV for rips if you have the old style, check the plastic hoses for breaks, check PCV valve, etc.

And what lead you to believe this was fuel related and made you replace all of those parts?

http://wiki.ross-tech.com/wiki/index...5/P0171/000369

[B7S3wannabi]

That is a lot of money spent on guess work already.

PCV would be my first guess with the P0171.
Second guess is purge valve stuck open.
This is assuming no vacuum leaks are present.
These are just guesses of course. A full scan would be helpful.


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[Brotherturtle]

Fuel pressure sensor?
Can you view sensor data or are you just able to pull codes?

I only have a cheap code reader. I can't see the data.

2006 A4 Quattro 2.0T - Unmodified

[Brotherturtle]

And since there is a lean code listed on top of the misfires, I would be looking for boost leaks and MAF readings, not really focusing on the coil packs and plugs. Boost leak test, check DV for rips if you have the old style, check the plastic hoses for breaks, check PCV valve, etc.

And what lead you to believe this was fuel related and made you replace all of those parts?

http://wiki.ross-tech.com/wiki/index...5/P0171/000369

I thought it was fuel related because in limp mode, it doesn't misfire. A bad coil or plug should misfire all the time. That and the lean code.

2006 A4 Quattro 2.0T - Unmodified

[EvolutionArmory]

I thought it was fuel related because in limp mode, it doesn't misfire. A bad coil or plug should misfire all the time. That and the lean code.

2006 A4 Quattro 2.0T - Unmodified

Limp mode happens when actual boost varies from requested boost by like 3% or if other set parameters are outside of their set operating range by a set margin. It isn’t just fuel related. In fact, it’s usually boost related on these cars.

Do a boost pressure test. If there are no obvious boost leaks, check your DV for rips if you have the old style diaphragm DV and check your wastegate for play/rattle. If that all checks out, start looking into your MAF and PCV valve.

[dalmation53]

Buy obdeleven. Best $60 i have ever spent
Just do some cheap maintenance. I have a n80 valve and diverter valve new for $80 OEM. If interested. Will ship today if you need it.

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[EvolutionArmory]

Buy obdeleven. Best $60 i have ever spent
Just do some cheap maintenance. I have a n80 valve and diverter valve new for $80 OEM. If interested. Will ship today if you need it.

Sent from my G3313 using Audizine mobile app

That’s the biggest problem right there^^^.

Throwing parts at problem instead of actually diagnosing the problem. No offense but so far you have just suggested in this thread that he replace all 4 coil packs, 4 spark plugs, a DV and the N80 valve without even recommending that ANY tests be performed. Throwing parts at a problem is the worst advice you can give.

[dalmation53]

That’s the biggest problem right there^^^.

Throwing parts at problem instead of actually diagnosing the problem. No offense but so far you have just suggested in this thread that he replace all 4 coil packs, 4 spark plugs, a DV and the N80 valve without even recommending that ANY tests be performed. Throwing parts at a problem is the worst advice you can give.

It needs to be done anyways. If it hasn't been done thats why i said "maintenance" did you not read? All the things i said fail on this cars or tell me i'm actually wrong?

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[EvolutionArmory]

It needs to be done anyways. If it hasn't been done thats why i said "maintenance" did you not read? All the things i said fail on this cars or tell me i'm actually wrong?

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While you are right, all of these mainenence parts are a great idea on a car that runs right, it probably won’t do anything to FIX his problem. What’s the point of a throwing preventative maintence parts on a car that doesn’t run right unless it is directly related to the fault? Do you not see that it’s just like telling someone to replace their coil packs because their transmission is slipping? Or it’s like this, what’s the point of throwing in a new air filter if he needs a new clutch?

Don’t be so quick to spend other people’s money when they are asking for help is all I’m saying. He’s already probably spent a grand and he’s nowhere near solving the problem. Diagnosis is a process. You have to work the steps before you start replacing parts and all the new coil packs in the world aren’t going to fix a lean code.

He doesn’t need preventative maintenance right now. He needs a specific solution. And in case you haven’t noticed, I can read and communicate words pretty well actually.

[dalmation53]

Well you missed my first post on solving his issue.. If you had read you wouldnt be saying this.

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[vce1232000]

While it is possible for 3 ignition coils to take a dump at the same time, I’ve just never seen it happen. Usually with multiple cylinder misfires coupled with other codes, it’s safe to say the problem is somewhere else.

On the other hand, since new spark plugs are a recent addition, I would check spark plug gap. Some of these plugs come gapped as high as .044 which is .012 higher than recommended stock gap of .032.

And since there is a lean code listed on top of the misfires, I would be looking for boost leaks and MAF readings, not really focusing on the coil packs and plugs. Boost leak test, check DV for rips if you have the old style, check the plastic hoses for breaks, check PCV valve, etc.

And what lead you to believe this was fuel related and made you replace all of those parts?

http://wiki.ross-tech.com/wiki/index...5/P0171/000369

Limp mode happens when actual boost varies from requested boost by like 3% or if other set parameters are outside of their set operating range by a set margin. It isn’t just fuel related. In fact, it’s usually boost related on these cars.

Do a boost pressure test. If there are no obvious boost leaks, check your DV for rips if you have the old style diaphragm DV and check your wastegate for play/rattle. If that all checks out, start looking into your MAF and PCV valve.

That’s the biggest problem right there^^^.

Throwing parts at problem instead of actually diagnosing the problem. No offense but so far you have just suggested in this thread that he replace all 4 coil packs, 4 spark plugs, a DV and the N80 valve without even recommending that ANY tests be performed. Throwing parts at a problem is the worst advice you can give.

While you are right, all of these mainenence parts are a great idea on a car that runs right, it probably won’t do anything to FIX his problem. What’s the point of a throwing preventative maintence parts on a car that doesn’t run right unless it is directly related to the fault? Do you not see that it’s just like telling someone to replace their coil packs because their transmission is slipping? Or it’s like this, what’s the point of throwing in a new air filter if he needs a new clutch?

Don’t be so quick to spend other people’s money when they are asking for help is all I’m saying. He’s already probably spent a grand and he’s nowhere near solving the problem. Diagnosis is a process. You have to work the steps before you start replacing parts and all the new coil packs in the world aren’t going to fix a lean code.

He doesn’t need preventative maintenance right now. He needs a specific solution. And in case you haven’t noticed, I can read and communicate words pretty well actually.

^^^^^^^^^ some advise here OP

[Brotherturtle]

Limp mode happens when actual boost varies from requested boost by like 3% or if other set parameters are outside of their set operating range by a set margin. It isn’t just fuel related. In fact, it’s usually boost related on these cars.

Do a boost pressure test. If there are no obvious boost leaks, check your DV for rips if you have the old style diaphragm DV and check your wastegate for play/rattle. If that all checks out, start looking into your MAF and PCV valve.

I understand limp mode. I was just saying that when the boost hose came off and the car went into limp mode, it didn't misfire, so it can't be any of the ignition parts.

But in response to comments about the DV and boost leaks etc, would those air flow problems cause misfires, or just cause it to be sluggish? This is my first turbo car, so i still have lots to learn about that.

2006 A4 Quattro 2.0T - Unmodified

[EvolutionArmory]

Well you missed my first post on solving his issue.. If you had read you wouldnt be saying this.

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Your first post on solving this issue was you recommending he spend 100 bucks or more on new plugs and coils and “reporting back”. “Reporting back” is not a diagnostic procedure.

I’m going to give you some wisdom right now. Do you know the difference between being wise and being clever? A clever man can always find the last word in a discussion. A wise man knows when it’s time to listen. Be a wise man.

[dalmation53]

Your first post on solving this issue was you recommending he spend 100 bucks or more on new plugs and coils and “reporting back”. “Reporting back” is not a diagnostic procedure.

I’m going to give you some wisdom right now. Do you know the difference between being wise and being clever? A clever man can always find the last word in a discussion. A wise man knows when it’s time to listen. Be a wise man.

No..

[EvolutionArmory]

I understand limp mode. I was just saying that when the boost hose came off and the car went into limp mode, it didn't misfire, so it can't be any of the ignition parts.

But in response to comments about the DV and boost leaks etc, would those air flow problems cause misfires, or just cause it to be sluggish? This is my first turbo car, so i still have lots to learn about that.

2006 A4 Quattro 2.0T - Unmodified

Yes. Combustion is only a combination of air, fuel and spark. If any of those 3 are absent or less than ideal, you’ll get misfires.

[vce1232000]

Your first post on solving this issue was you recommending he spend 100 bucks or more on new plugs and coils and “reporting back”. “Reporting back” is not a diagnostic procedure.

I’m going to give you some wisdom right now. Do you know the difference between being wise and being clever? A clever man can always find the last word in a discussion. A wise man knows when it’s time to listen. Be a wise man.

.................

[Brillo]

If you are running too lean it can result in misfires.
Can't remember if it's been said but check to make sure your PCV valve isn't stuck open. It will act like a boost leak under boost conditions but I'm not sure it would give you a lean condition. Easy enough to check though.

[Theiceman]

good troubleshooting techniques start with a good interview ... before having anyone do anything . The trick is getting themto tell you what they are seeing , not what they or you think the answer is.

When did the problem start ?
Was it running well then instantly crap out or did it slowly start deteriorating ?
was any work done before this issue started ?
How many miles are on the car ?
When was the last major service or tune up ?
Are there any symptoms you feel may be unrelated that are happening at the same time ?

Try not to tell us what you think , but more of what you see and feel.

Early indications are however that you have a vacuum / boost leak. When the car does go into " limp mode" the mapping is completely different so it is very likely and somewhat normal that you may not see or feel error conditions in this mode ( its designed that way as the car is just running on life support to get you home )
The other possibility is something is fooling the car into thinking It needs to deliver less fuel , , or something is broken causing less fuel delivery.
Whatever it is I is likely a " global issue" affecting all cylinders rather then a particular coil/ plug type scenario. Talk to your son and try to get a bit of history on the car.

cheers.

[vce1232000]

VCDS it and @ the codes. Not use a generic code reader

[EvolutionArmory]

good troubleshooting techniques start with a good interview ... before having anyone do anything . The trick is getting themto tell you what they are seeing , not what they or you think the answer is.

When did the problem start ?
Was it running well then instantly crap out or did it slowly start deteriorating ?
was any work done before this issue started ?
How many miles are on the car ?
When was the last major service or tune up ?
Are there any symptoms you feel may be unrelated that are happening at the same time ?

Try not to tell us what you think , but more of what you see and feel.

Early indications are however that you have a vacuum / boost leak. When the car does go into " limp mode" the mapping is completely different so it is very likely and somewhat normal that you may not see or feel error conditions in this mode ( its designed that way as the car is just running on life support to get you home )
The other possibility is something is fooling the car into thinking It needs to deliver less fuel , , or something is broken causing less fuel delivery.
Whatever it is I is likely a " global issue" affecting all cylinders rather then a particular coil/ plug type scenario. Talk to your son and try to get a bit of history on the car.

cheers.

Exactly!! Good diagnosis usually involves asking more questions than giving answers, which can be very frustrating to the person with the problem but very beneficial in the long run.

[ahotboy15]

listen to damation? WTF

Yup. Listen to this guy. Many issues solved by doing this.


Also put some BG 44k in the tank. Might clean the injectors a bit.

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NOW LISTEN TO THIS GUY. sounds more logical. 3 coils to take a dump. sounds like ur problem exists somewhere else... THANKS EVOARMY

While it is possible for 3 ignition coils to take a dump at the same time, I’ve just never seen it happen. Usually with multiple cylinder misfires coupled with other codes, it’s safe to say the problem is somewhere else.

On the other hand, since new spark plugs are a recent addition, I would check spark plug gap. Some of these plugs come gapped as high as .044 which is .012 higher than recommended stock gap of .032.

[Brotherturtle]

listen to damation? WTF




NOW LISTEN TO THIS GUY. sounds more logical. 3 coils to take a dump. sounds like ur problem exists somewhere else... THANKS EVOARMY

I just don't see how it can be ignition related when the car ran perfectly smooth in limp mode when my turbo hose blew off. It just had no power. But no misfires. When I put the hose back on, misfires came back. I even did it a second time to be sure it wasn't a fluke. Also, ignition problems would not cause a lean fuel mix code. This has to be fuel or air.

2006 A4 Quattro 2.0T - Unmodified

[Brotherturtle]

I don't know anyone with a Vag Com, but I was able to get my son to scan the codes at the shop he works for. But he didn't have time to do anything else. But there are a lot of codes.

2006 A4 Quattro 2.0T - Unmodified

[EvolutionArmory]

Check all the plastic hoses around the intake manifold. Get a boost pressure test done. Check the lines going to the evap purge valve on the manifold. Check your PCV valve.

[B7S3wannabi]

That looks like classic purge valve failure (stuck open).
Causes system lean code, high idle, misfires, and of course the evap leak code.
Remove the purge valve and try to blow through it. You shouldn't be able to.


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