B5.5 2005 Chronic problem

My Passat was nearly totaled in 2008. Rebuilt etc.

Since then the car never ran like it used to. It was a rocket with great mileage.

It’s been looked at, troubleshot, parts replaced but to no avail. I eventually just accepted what I have.

Until today when I met a man with the same car. We shared our experiences, performance, challenges etc.

It turns out his wasn’t nearly destroyed like mine AND run very well with great mileage etc.

My car tends to go into limp mode when it starts to get cool outside (like now). I have to idle for ~30-60 seconds before it will engage and accelerate as I’d warmed up. The colder it gets the longer the idle (upwards of 2 minutes when really cold).

Anyway, his TDI doesn’t do this.

Talking to him has dredged up old frustrations, and questions.

For starters since the accident I’ve:

Unchained the Balance Shaft
Rechippedto Rocket (3 year’s ago)
Replace the glowplugs
Upgraded to injectors
Cleaned again last month The whole intake system. ERG valve and pipes
Checked and rechecked the vacuum, boost (good)
Had the Pacific Northwest VW engineer rep give up on this.
I’ve had “experts” r2 various expensive parts with NO difference.
No mentionable or consistent codes.
This is a sore area for me, especially now knowing that my car indeed has problems still compared to its twin.

If anyone has a clue for me please share!

I miss my old car and it’s abilities.

If the car is going into limp mode, then there will be a code set which can be scanned.

Find someone with VCDS to pull the code for you and determine if it is a common boost deviation code.

If that's the case, then VCDS can plot boost requested vs actual and help determine where the fault lies.

Not really all that difficult, but requires the right diagnostic steps, and the right tool.

How long does the VCDS code stay flagged?

After a short time the car recovers and the issue doesn’t come back again unil the next morning.

I’ll work on get the VCDS read.

Thanks

Further, I can put into neutral and the engine will rev up. But in reverse or drive, no to slow response.

Your transmission is probably low on fluid or it's on the way out. Why did you spend all this time, money and energy into the engine when obviously the transmission has a problem?

Log the actual and requested MAF and MAP (boost) at idle and while driving under consistent moderate load.

It you had front end damage you could have damage to the charge air pipes or a cracked intercooler. These can be hard to locate. It may require removing each and inspecting thoroughly. I have had a few of these pipes fool me when inspecting and missed a small split. This in turn causes poor performance and the occasional CEL.

imo000 said:

Your transmission is probably low on fluid or it's on the way out. Why did you spend all this time, money and energy into the engine when obviously the transmission has a problem?

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Dealer style troubleshooting maybe. Just keep throwing parts at it until something sticks.

Expand on what you did to check the vacuum and or boost. How do you know it actually went into Limp Mode?

Troubleshooting 101. Go back to the last thing that was done to the car and work from there. Since it was damaged in the front end, there might still be damage to the I/C or C/A pipes as pointed out by vztips. As imo000 stated, your tranny probably has issues as well.

I don't think you are describing a limp mode.

Are you saying when you start the car and put it in gear, it wont move. Eventually, if you let it idle, it will go?

My car started doing this a couple of years ago. Doesn't really bother me, since I just let it warm up for a minute. I can rev in neutral but there is no throttle response in drive, or reverse. I have not investigated what's going on, but it never throws a code. There was at least one other person, unless it was you, who had this issue, that I am aware of. I don't think they found a solution. Drivability and fuel economy are not affected at all.

oilhammer said:

Log the actual and requested MAF and MAP (boost) at idle and while driving under consistent moderate load.

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Have you done this?

Me? No, I haven't looked at it at all. At some point when I have free time, I'll look into it.

Johnboy, that sounds like the problem I have.

How is m transmission a possible problem? I’m not disagreeing just unclear.

How do we log the actual MAF and MAP while driving?

If my I/C or C/A are even slightly damaged will my boost still work? Everyone who looks at it says the boost is working...

My head hurts...

Your boost will still "work" with a damaged intercooler, however, you may have a boost leak from the damage.

How did they test the boost? If they just Revved it up without a load on the engine, the turbo will not come up on boost. A boost leak will show it's self if you lug the engine some. A boost leak will make a hissing sound.

Your transmission has probable issues because of the symptoms you describe in your 2nd post. What's a C/A?

Your head hurts from this very basic stuff? Maybe an appliance car like a Camry or Corolla would be a better fit for you.

If he is seeing what I see, ( I think he is but he's not explaining it clearly). I'm pretty sure its not a transmission problem, unless the transmission can control the throttle. It is also not a limp mode and no codes are thrown.

My car will not leave idle, in gear, until it has warmed up slightly. It only happens if the outside temp is under 40F and engine is completely cool. throttle response is normal in park or neutral. In gear, there is no throttle response until the car warms slightly. It might need 15 seconds on a 40 degree morning, and always less than a minute. If I rev the engine for 2-10 seconds, its fine.

Seriously, that is a head scratcher. Both cars appear to be DSG's. Coincidence? IDK, but could be.

The B5s are not equipped with DSGs.

Johnboy00

That is exactly what happens. I thought it was normal until I talked to the other TDI Passat owner. His wasn’t wrecked and runs like a top and isn’t affected by colder temps.

Ol’Rattler. C/A I believe is Charge Air- you wrote “C/A” in an earlier post.

The various mechanics drive the car with the windows down and pointed out the sound the boost makes. As per the boost being measured? No idea how or what was tested. I’ve never heard hissing sounds either.

Again, the issue related to the accident appears subjective, I know what the car was like before the accident compaired to after the repairs and troubleshooting by experts. Since this car at the time with the B5.5 engine was new nobody knew what it was supposed to drive/feel like. Most said there isn’t a problem.

I only dredge this up after talking to a fellow TDI Passat owner and the differences between.

The B5.5 tdi uses the front crossmember for boost circuit. If that was damaged, you're probably losing boost. It's a tough find to pressurize and check leakage. Weird boost sound may point to that.

Your head hurts from this very basic stuff? Maybe an appliance car like a Camry or Corolla would be a better fit for you.

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I am still wrapping my mind around the vane action on the turbo, I have been working on engines fort 50 years.

Some of this is not intuitive and it gets hard to follow as the logic has changed and our minds get left behind.

Try explain a reversing pneumatic relay to someone.

The B5.5 tdi uses the front crossmember for boost circuit. If that was damaged, you're probably losing boost. It's a tough find to pressurize and check leakage. Weird boost sound may point to that.

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I have been under mine and followed the tubing.

None of it was integrated into the front cross member.

I may be wrong but I don't think it does.

Last time I saw something goofy like that was my CB700SC used the down tubes for oil transfer. Cute but weird.

Smokerr said:

I have been under mine and followed the tubing.
None of it was integrated into the front cross member.
I may be wrong but I don't think it does.
Last time I saw something goofy like that was my CB700SC used the down tubes for oil transfer. Cute but weird.

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Post pictures of what you saw down there.

The charge air tract does indeed include the cross tube, but that tube is its own part, it is not integral with the rubber hoses attached to it at each end.

The tube is what the bump stop mount on the oil pan fits into.

So the tube IS the cross member support. Non turbo cars just have a brace with no tube going through it.

What does this crossmember tube look like? Where does does it run with respect to the front of the engine be?

Thanks for all the input. The knowledge shared in this forum makes my local experts look lost.

Black painted steel tube with bends on each end, and a little bump in the center that the foam roll stop mount fits on. You cannot easily "see" all of it unless the bumper cover is off. But you can plainly see parts of it under the car.

Do a google image search for "3B0-199-521-G" if you want to see a picture of one loose.

Crossmember..

Thanks oilhammer. That part was likely destroyed during the accident and has been taken off at least once for the balance shaft unchaining too.

I’ve got a good lead...

Good on ya then. Some "Engineering Marvels" such the balance shafts on some of the Passat engines need to be "installed" in the scrap metal bin were they can have a new life that can do no harm..............