2004 BHW 2.0L TDI Passat: Severe Turbo Lag

CalebHart

Active member
Joined
Jan 12, 2016
Location
Nashville, Tennessee
TDI
2004 VW Passat Wagon - BHW 2.0L TDI
I am the third owner of this Passat. Had it since Jan. 2016.
At 270,000 miles now with original turbo.
I have constantly been experiencing severe lag accelerating from complete and rolling stops until the rpm rises above 2500 rpm or so. It takes 5-7 seconds to really get above 2500rpm from a complete stop, fully warmed up, where the turbo finally kicks in.
I have replaced the large intercooler hoses with bad ends and seals, the N 75 valve solenoid, as well as its vacuum hose to the wastegate actuator.
Still getting nowhere.
No noise from the turbo to indicate the turbine bearing wearing out etc. Just the normal whistle as it spins up.
If it is relevant, nothing on the exhaust has been worked on to my knowledge.
I am at a loss as to the origin of this problem, but it has become a real serious issue, especially when trying to get out in traffic in a pinch.
 
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Windex

Top Post Dawg
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Apr 1, 2006
Location
Cambridge
TDI
05 B5V 01E FRF
Have you plotted requested boost vs actual? Do you have a boost gauge?

have you used a vacuum pump to check that the actuator starts to move at the correct in lbs of vacuum?

Has the car ever had proper boost or power during the time you have owned it?
 

vwztips

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Aug 30, 2009
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2005 Passat GLS Wagon TDI 5 spd manual w/BSM delete 2011 Tiguan TDI/DSG 2005 Audi A4 Avant 6MQ TDI 2011 BMW X5 35d
Also are you getting 25 in/lb or vacuum from the tandem pump?

Have you replaced all the vacuum lines in the turbo system? There are not many and I have had similar experience with frayed ends not sealing off until enough vacuum is pulled.
 

CalebHart

Active member
Joined
Jan 12, 2016
Location
Nashville, Tennessee
TDI
2004 VW Passat Wagon - BHW 2.0L TDI
The car has not had proper boost since I've owned it.
Couple of times got P0299 "Boost Control Range not reached" code. No engine codes for the past few months.
Unfortunately I don't have a boost gauge or vacuum pump. So I'll have to wait a bit till I can purchase such.
There is a vacuum line or two I haven't replaced because the ends looked good.
 
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Windex

Top Post Dawg
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Apr 1, 2006
Location
Cambridge
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05 B5V 01E FRF
1st step would be to really know if you are making the correct amount of boost.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
1st step would be to really know if you are making the correct amount of boost.

Agreed, and the only way to really do that properly (on this car) is with a scan tool.

FWIW, the BHW cars do suffer from much more lag than any of the other 4cyl TDIs sold here. But it is not so bad that it would cause for several seconds of a delay. If you have had a random low boost DTC being flagged, you could have a charge air leak or a vacuum leak in the turbo system. Fortunately, the BHW's vacuum system is the simplest of all the TDIs sold here. So it is pretty easy to troubleshoot. However, the placement of the N75 is a bit fiddly to get to.
 
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thundershorts

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Jul 15, 2010
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west chester pa
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2015 passat tdi sel premium 2015 golf s tdi gls tdi b5.5, 2002 eurovan,Peugeot 505 td,Citroen cx25 prestige
My n75 completely failed and it wasn't too bad to replace it....tight spot to work but very satisfying results after changed...drove like new afterwards. I think it was gradually failing for awhile.
 

Fasteddie10

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Jun 23, 2011
Location
Illinois
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2004 Jetta Wagon TDI, 2-2005 Passat Wagon TDIs, 2-2004 Passat Wagon TDIs
Tools

The car has not had proper boost since I've owned it.
Couple of times got P0299 "Boost Control Range not reached" code. No engine codes for the past few months.
Unfortunately I don't have a boost gauge or vacuum pump. So I'll have to wait a bit till I can purchase such.
There is a vacuum line or two I haven't replaced because the ends looked good.
Hi, you can "rent" the tools for free at many auto parts stores. The hand vacuum pump and gage is available. You buy it and then return it for full price when you are done, usually within 30 days. Then you do not need to invest that money in the seldom used tools. I had two of our turbos rebuilt at Midwest turbo re-builders and I they have been GREAT. Cost is less than half of a new turbo.
 

CalebHart

Active member
Joined
Jan 12, 2016
Location
Nashville, Tennessee
TDI
2004 VW Passat Wagon - BHW 2.0L TDI
My N75 valve is practically new. Replaced a few months ago eliminating possibilities.
I'll look into renting a hand vacuum pump and gauge from a local auto parts store.

NEW NOTE: My A/C hasn't worked properly for many months. I finally had it fixed last month (along with new electric A/C radiator fan because previous one (factory) had burned out).
It cools excellently now. BUT...
When running the A/C I notice a significant added lag when accelerating from complete stops or rolling stops. My guess is the compressor is putting the engine under quite a load but its terrible at take off running the A/C.
During idle, running A/C, I can tell the engine idles unevenly.
*When I turn the A/C off the idle does not even out until I hear the electric radiator fan shut off, making me wonder if the compressor isn't the only thing putting the engine under load then.
If the electric radiator A/C fan is putting a load on it more than the compressor wouldn't that trace back to alternator wearing out?
Thoughts? Insights?
 
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oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
If the engine is not running correctly, putting any extra load on it is not going to help. I can tell you that the BHW engine, when running properly, does not care one bit if the A/C is on. I can feel it for sure in my 1.8t Passat, but not the TDI.

I think you need to get the engine running properly first. And if you do not have a scan tool, you are spinning your wheels at this point. We can guess all day and throw part after part at your car, but that gets tedious, expensive, and unnecessary. For what the one S-shaped boost hose costs, you could buy VCDS.

Also, rereading your post(s), there is no "normal turbo whistle" on that car. That may indicate your problem right there.
 

CalebHart

Active member
Joined
Jan 12, 2016
Location
Nashville, Tennessee
TDI
2004 VW Passat Wagon - BHW 2.0L TDI
If the engine is not running correctly, putting any extra load on it is not going to help. I can tell you that the BHW engine, when running properly, does not care one bit if the A/C is on. I can feel it for sure in my 1.8t Passat, but not the TDI.
I think you need to get the engine running properly first. And if you do not have a scan tool, you are spinning your wheels at this point. We can guess all day and throw part after part at your car, but that gets tedious, expensive, and unnecessary. For what the one S-shaped boost hose costs, you could buy VCDS.
Also, rereading your post(s), there is no "normal turbo whistle" on that car. That may indicate your problem right there.
For years I've heard slight turbo whistle as it spins up on many other TDI cars at various RPMs.
You're saying that's not normal?
Or just particular to my car?
I've been pricing the Hex tool but I just have to wait a bit until I can afford it.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
For years I've heard slight turbo whistle as it spins up on many other TDI cars at various RPMs.
You're saying that's not normal?
Or just particular to my car?
I've been pricing the Hex tool but I just have to wait a bit until I can afford it.

I have driven more BHW cars than most, and have owned mine since day 1. They do not "whistle".
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
Possibly, yes. Or the turbocharger itself is failing. Usually turbochargers do not go very long if they are making noises though.

Luckily, you can just brake torque them and usually find any charge air leaks in seconds.
 

Windex

Top Post Dawg
Joined
Apr 1, 2006
Location
Cambridge
TDI
05 B5V 01E FRF
Possibly, yes. Or the turbocharger itself is failing. Usually turbochargers do not go very long if they are making noises though.
Luckily, you can just brake torque them and usually find any charge air leaks in seconds.
Not all of us can do a brake-stand with two feet any more...:p
 

CalebHart

Active member
Joined
Jan 12, 2016
Location
Nashville, Tennessee
TDI
2004 VW Passat Wagon - BHW 2.0L TDI
Possibly, yes. Or the turbocharger itself is failing. Usually turbochargers do not go very long if they are making noises though.
Luckily, you can just brake torque them and usually find any charge air leaks in seconds.
Oh I've done that number already. Set the parking brake and floored it. Small rise in RPM but the car barely moves.
 

CalebHart

Active member
Joined
Jan 12, 2016
Location
Nashville, Tennessee
TDI
2004 VW Passat Wagon - BHW 2.0L TDI
Update:
Upon pulling the back intercooler hose elbow loose and inspecting it I found a pretty large split on the inside of the elbow turn.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
There ya go, that's what I figured. Is this the one that goes into the throttle flap near the firewall?

If so, the part number is 3B0-145-838-A (we keep these on the shelf).
 

CalebHart

Active member
Joined
Jan 12, 2016
Location
Nashville, Tennessee
TDI
2004 VW Passat Wagon - BHW 2.0L TDI
There ya go, that's what I figured. Is this the one that goes into the throttle flap near the firewall?
If so, the part number is 3B0-145-838-A (we keep these on the shelf).

The very hose. It may not be the only issue here but its a start and it needs replaced due to the split. Thanks for the direct part #.
 

CalebHart

Active member
Joined
Jan 12, 2016
Location
Nashville, Tennessee
TDI
2004 VW Passat Wagon - BHW 2.0L TDI
I'll order the hose elbow in a few days but I'll be out of town until next weekend and won't be able to install it until I return.
Once I do, we'll see if it fixes the turbo lag issue.
I'm also going to have my alternator tested in-car today with the engine running to see if it is putting out the necessary charging amps with and without A/C running.
 

vwztips

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Aug 30, 2009
Location
Greenville, SC
TDI
2005 Passat GLS Wagon TDI 5 spd manual w/BSM delete 2011 Tiguan TDI/DSG 2005 Audi A4 Avant 6MQ TDI 2011 BMW X5 35d
Well one step at a time. Have you scanned and cleared existing codes since replacing the hose? If not, try that first.
 

CalebHart

Active member
Joined
Jan 12, 2016
Location
Nashville, Tennessee
TDI
2004 VW Passat Wagon - BHW 2.0L TDI
I can't afford to get the Hex-Can tool yet (also don't currently have a laptop) and the soonest I'll have time to get to the local Euro car shop is Monday.
 

CalebHart

Active member
Joined
Jan 12, 2016
Location
Nashville, Tennessee
TDI
2004 VW Passat Wagon - BHW 2.0L TDI
UPDATE: Had it inspected at a local german car shop for these issues, and the pointing result is to the camshaft and/or lifters.
I've had the camshaft and followers replaced within the last year so I am taking it back to the original shop in my hometown where it is under warranty for that job to see what is what. Fingers crossed.
 

boobap

Member
Joined
Apr 26, 2016
Location
fallon, NV
TDI
BHW
I agree with Oilhammer, they do not whistle at all. I've tried to make it towing a load up a 6% grade and floored it...nothing. Even after my recent SNAFU when one of my boost lines separated, no whistle...Now, my Cummins does and I love it!
 
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