LP EGR is used mainly to help fuel economy, it sends oxygen-poor air back into the intake to reduce the amount of fuel needed for the proper combustion in the engine. So if you were running in fuel economy mode (low engine loads) chances are you LP EGR was being used at a higher rate.
Hard Start / No Start - Is your intercooler frozen? Check Here!
- Thread starter GraniteRooster
- Start date
tcp_ip_dude
Veteran Member
Negative, primary function of the LP EGR is Nitrogen Oxide (NOx) reduction and it's used under high loading conditions (not low loads). [reference Pg. 24-25 VW Self Study Guide 826803]
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gpshumway
Veteran Member
"High" load is relative. The transition between HP and LP EGR is not abrupt, the LP system operates at "middle" loads according to the self study guide. My guess is there is substantial LP EGR whenever the engine is producing boost, which would mean long periods of highway cruising are pretty much the worst case scenario for intercooler icing.
From p.25 of the self study guide, the same page with the schematic posted above.
"With rising engine load and engine RPM, the
recirculation of exhaust gases is shifted to the Low
Pressure EGR system to increase the recirculation
rate. This happens in order to obtain optimal
NOx reduction at middle and high engine loads.
Particularly in the high engine loads, the cooled Low
Pressure EGR is a very large advantage over the High
Pressure EGR system."
MonsterTDI09
TDIClub Enthusiast, Veteran Member
- Joined
- Jul 3, 2009
- Location
- NoVa/NJ
- TDI
- 2010 Jetta DSG/ up keep on 2009 Jetta DSG 2006 Jetta Pag 2 in North SEA Green
Not good for people on a cold day who hit the highway before the exhaust temp is high enough to evaporate most of water vapor.On a cold day the I/C never lets the air temp rise enough to evaporate the moister in the I/C.
It is just though I had, there has to be more research has to be done on this.One member has a trip like this to work and his engine ate some water enough to destroy the engine.
It is just though I had, there has to be more research has to be done on this.One member has a trip like this to work and his engine ate some water enough to destroy the engine.
Well my car is running great after the water was drained form the intercooler. I also have noticed, maybe coincidence, that the lower mpg I was getting before the water was drained from the intercooler has gone back up. I had attributed the loss of mpg lately vs October driving when I got the car was due to lower outside temps. I had been getting 40 mpg highway ride in to work last month now 46-47 combined mpg home to work and still cold here. Should I watch for a drop in mpg as a sign of water accumulating again. Any reason to explain this that those more techie than I can come up with? I'd like to be able to bring it in before the next 2 hour limp home at midnight (or worse) and watching for a mpg drop would be easy to do. Thanks
740GLE
Top Post Dawg
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- Aug 19, 2009
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- NH
- TDI
- 2015 Passat SEL, 2017 Alltrack SE; BB 2010 Sedan Man; 2012 Passat,
I don't have a boost gauge, but I have a feeling when she's boosting, and many a time when I was cruising around, it was with very minimal boost, but I can't really back that up.
Also after the dealer performed their inspection and drained "some" water out, I swear I also noticed the MPGs increase a bit and it feel a bit more pep, which would make sense.
ddorrer
Veteran Member
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- May 19, 2010
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- WVa
- TDI
- 2015 GSW Tdi, 2012 JSW Tdi DSG (Sold w/80k miles), 2010 Sportwagen TDI 6spd (Traded)
Report It to NHTSA
Report it to the NHTSA. www.nhtsa.gov
If enough people report the same issue, the will investigate a design flaw.
Report it to the NHTSA. www.nhtsa.gov
If enough people report the same issue, the will investigate a design flaw.
VeeDubTDI
Wanderluster, Traveler, TDIClub Enthusiast
- Joined
- Jul 2, 2000
- Location
- Springfield, VA
- TDI
- ‘18 Tesla Model 3D+, ‘14 Cadillac ELR, ‘13 Fiat 500e
After this little episode, I would insist on a compression test of the engine.
The only way I can think of to eliminate this humid LPEGR problem without eliminating the LPEGR is to dehumidify the LPEGR stream. Of course, now you have to figure out how to do this without the LPEGR gas clogging up your dehumidification system. This can be done with a mechanical compressor (a/c system or filter drier like you'd see on a large air compressor) or perhaps with a passive device designed to trap the water in the LPEGR stream.
The simplest way to fix this would be to mount the intercooler upside down (possibly with a redesigned unit so that it will fit properly) so that the moisture collects in the bottom of the intercooler - away from the charge air pipes - where it can be periodically drained with a petcock rather than be ingested by the engine. This will obviously require some redesigning of the intake plumbing.
bhtooefr
TDIClub Enthusiast, ToofTek Inventor
There's actually a couple other ways to deal with it.
First off, I've read a post on Vortex claiming that the ECU is supposed to disable the LPEGR below certain outside temperatures, specifically to prevent this problem. If that's the case, simple tweaking of the parameters may cure it.
Second, valves could be used to route boost around the intercooler in freezing temperatures. In the temperatures that intercooler icing would be an issue, the IATs will be low enough even without intercooling.
First off, I've read a post on Vortex claiming that the ECU is supposed to disable the LPEGR below certain outside temperatures, specifically to prevent this problem. If that's the case, simple tweaking of the parameters may cure it.
Second, valves could be used to route boost around the intercooler in freezing temperatures. In the temperatures that intercooler icing would be an issue, the IATs will be low enough even without intercooling.
VeeDubTDI
Wanderluster, Traveler, TDIClub Enthusiast
- Joined
- Jul 2, 2000
- Location
- Springfield, VA
- TDI
- ‘18 Tesla Model 3D+, ‘14 Cadillac ELR, ‘13 Fiat 500e
A heated intercooler would do the trick, too. Either an electric heating element or a coolant passage to keep it above freezing.
MayorDJQ
Top Post Dawg
A heated intercooler....is that kind of like jumbo shrimp?
Seriously though, that seems like an overly complex fix that VW probably won't go for. The coding tweek seems more likely.
Seriously though, that seems like an overly complex fix that VW probably won't go for. The coding tweek seems more likely.
bhtooefr
TDIClub Enthusiast, ToofTek Inventor
Assuming it doesn't negatively affect the emissions, though.
Ski in NC
Top Post Dawg
Even without LPEGR, if boost is kept high at cruise, icing can still occur. It does not take alot of PSI to cross the saturation line if atmospheric conditions are right.
Elfnmagik
Veteran Member
:d lol
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B25guy
Active member
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- Jun 22, 2010
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- Yakima, WA
- TDI
- '10 JSW 3-pedal. '07 Dodge Cummins, '04 Caterpillar 420D IT, 43' Blue Bird Wanderlodge DP
so i called the shop mgr this morning to discuss and he said he wanted to see the car
They put it up on the rack and took the output i/c hose off and 8-10oz of water and frozen chunks came out! I got pics. These guys are actively looking into this so stand by for developments.
BTW, it is nearly identical conditions as last week, so there's no way of knowing if this accumulation is since last Fri (mostly above freezing up to this am) or since the drive to work and back and then dealer. Again, since the no-start last week, I've had abt 200 miles of reasonably high rpm's so it could've cleaned it all out or not, don't know.
Here I sit, waitng to get my "drained" car back.
Marc
They put it up on the rack and took the output i/c hose off and 8-10oz of water and frozen chunks came out! I got pics. These guys are actively looking into this so stand by for developments.
BTW, it is nearly identical conditions as last week, so there's no way of knowing if this accumulation is since last Fri (mostly above freezing up to this am) or since the drive to work and back and then dealer. Again, since the no-start last week, I've had abt 200 miles of reasonably high rpm's so it could've cleaned it all out or not, don't know.
Here I sit, waitng to get my "drained" car back.
Marc
VeeDubTDI
Wanderluster, Traveler, TDIClub Enthusiast
- Joined
- Jul 2, 2000
- Location
- Springfield, VA
- TDI
- ‘18 Tesla Model 3D+, ‘14 Cadillac ELR, ‘13 Fiat 500e
Crazy. Please post the pics.
this morning I started my car in my 34F garage, and drove down my drive to the street (it was 9F out this morning) and went to accelerate slowly (maybe 5~10% throttle) and between the first and second shift (DSG mission) I had my first ever hestation. I had probobly 5 seconds of hesitation, engine was stuttering felt like water in fuel and then I let off the accelerator and tipped back in it cleaned up and everything seemed fine after that.
I bought the car in November beginning and this is first ever hint of anything wrong.
I currently have just over 5000 miles.
My commute is 1 minute of 25mph city, 2 minutes of 50mph country road, 25 minutes of 69mph hwy cruise, then 2 minutes of 60mph country road and 1 minute of city mode.
I drove this commute 90% of the 5000 miles, the other 10% is city mode and 1 hwy trip of around 400 miles.
I bought the car in November beginning and this is first ever hint of anything wrong.
I currently have just over 5000 miles.
My commute is 1 minute of 25mph city, 2 minutes of 50mph country road, 25 minutes of 69mph hwy cruise, then 2 minutes of 60mph country road and 1 minute of city mode.
I drove this commute 90% of the 5000 miles, the other 10% is city mode and 1 hwy trip of around 400 miles.
MayorDJQ
Top Post Dawg
I've been wondering something that might serve as an interim solution. I think it's unlikely to even be possible, but maybe it'll work.
Is there enough room to raise the driver's side of the IC an inch or so? This would allow liquid to collect on the passenger/hot side. I would guess there's no room to do this, but it might be an option.
Is there enough room to raise the driver's side of the IC an inch or so? This would allow liquid to collect on the passenger/hot side. I would guess there's no room to do this, but it might be an option.
Ski in NC
Top Post Dawg
On marine engines, many have aftercooler drain valves mounted in a low point. At low boost, valve is open and drains with gravity (or slight boost). At boost, the valve closes. It should drain on parked, thaw conditons.
If I owned one of these cars, I would install one of these valves, at least for the winter. In warm conditions, no need. I'd probably remove it except winter.
If I owned one of these cars, I would install one of these valves, at least for the winter. In warm conditions, no need. I'd probably remove it except winter.
B25guy
Active member
- Joined
- Jun 22, 2010
- Location
- Yakima, WA
- TDI
- '10 JSW 3-pedal. '07 Dodge Cummins, '04 Caterpillar 420D IT, 43' Blue Bird Wanderlodge DP
Ok, we thought the 8-10oz was it, but the longer it sat there, water kept dripping out of both the in and out hoses...it appears that it will be at least 2 cups by morning. They are catching it to confirm.
Looking in through the input of i/c, you could see lots of frozen water still in there even after about an hour in the shop. They decided to keep it over night to let the whole i/c drain and dry out, road test and go from there. The tech spoke with a VW tech line and learned that there IS a fix in the works, will involve "piping" to reroute (what, I don't know...EGR or I/C lines are a guess). He verified my car's s/w version (oh no, not Microsoft I hope) and i'm running the latest. No ETA on the fix so my discussion with the shop mgr is to bring it in after the next cold snap (below freezing) and see how much accumulates.
Given that it was nearly 60 degrees last weekend, this amount of ice up inside the cooler had to have happened this morning; one hour to work, one hour back to dealer, roughly 45mi total at ~2k rpm/40mph on snow/ice and 18 degrees (again!). Guessing that some of this water was still pooled in the i/c since who knows, but i gave it a good couple of 3-4k revs over the warm weekend and no sputter/issues at all.
BTW, they did a compression check of sorts; evidently the glow plugs have a pressure sensor and they all came back with approximately 14bar (I think that's what the tech said). So, still wondering if there's any latent damage given that this WAS water ingestion???
The dealer is stepping up and is taking this very seriously so i'm just tickled for now...and i'm sportin' a new CC as a loaner! Wish these came in TDI.
Stay tuned.
Marc
Looking in through the input of i/c, you could see lots of frozen water still in there even after about an hour in the shop. They decided to keep it over night to let the whole i/c drain and dry out, road test and go from there. The tech spoke with a VW tech line and learned that there IS a fix in the works, will involve "piping" to reroute (what, I don't know...EGR or I/C lines are a guess). He verified my car's s/w version (oh no, not Microsoft I hope) and i'm running the latest. No ETA on the fix so my discussion with the shop mgr is to bring it in after the next cold snap (below freezing) and see how much accumulates.
Given that it was nearly 60 degrees last weekend, this amount of ice up inside the cooler had to have happened this morning; one hour to work, one hour back to dealer, roughly 45mi total at ~2k rpm/40mph on snow/ice and 18 degrees (again!). Guessing that some of this water was still pooled in the i/c since who knows, but i gave it a good couple of 3-4k revs over the warm weekend and no sputter/issues at all.
BTW, they did a compression check of sorts; evidently the glow plugs have a pressure sensor and they all came back with approximately 14bar (I think that's what the tech said). So, still wondering if there's any latent damage given that this WAS water ingestion???
The dealer is stepping up and is taking this very seriously so i'm just tickled for now...and i'm sportin' a new CC as a loaner! Wish these came in TDI.
Stay tuned.
Marc
B25guy
Active member
- Joined
- Jun 22, 2010
- Location
- Yakima, WA
- TDI
- '10 JSW 3-pedal. '07 Dodge Cummins, '04 Caterpillar 420D IT, 43' Blue Bird Wanderlodge DP
While looking at the two hoses hanging down, it occurs to me that a stop-gap solution is to go to Lowes and get a three foot piece of 2 1/2" PVC pipe and just bypass the i/c during below freezing, cold weather. Until the source of the moisture is identified (LP EGR vice charge air, etc.), eliminating the condensing source, i.e. the i/c, would just allow whatever air is going through the system to do just that...go through and not collect, freeze and thaw.
I'm still looking forward to an engineered solution however. The pressure valve from our marine friends seems to make the most sense but we still don't know the accumulation rate...that's something i'll actively dog.
Marc
I'm still looking forward to an engineered solution however. The pressure valve from our marine friends seems to make the most sense but we still don't know the accumulation rate...that's something i'll actively dog.
Marc
Jack Frost
Veteran Member
Any repiping or rerouting won't work very well. If it solves anything, it will solve it by reducing the effectiveness of the IC and make the turbocharger work harder. So why have an IC at all?
The source of the problem is that the LPEGR raises the dew point of the entire air intake system. The only way to reduce condensation inside the IC is to warm up the air before it enters the IC. What a lame idea!
nicklockard
Torque Dorque
Has anyone investigated this solution:
Install a 1psi check valve at the bottom, center of the intercooler.
Whenever the car is running, turbo pressure will force it shut and no boost leakage will occurer. Whenever the car is stopped, the check valve will open and drain the contents.
Edit: I caught up with a lot of posts and saw it discussed. Although the check-drain valve could freeze open, it might be worth a try. Maybe if it were located closer to the hot inlet side so it would melt the blockage??
Install a 1psi check valve at the bottom, center of the intercooler.
Whenever the car is running, turbo pressure will force it shut and no boost leakage will occurer. Whenever the car is stopped, the check valve will open and drain the contents.
Edit: I caught up with a lot of posts and saw it discussed. Although the check-drain valve could freeze open, it might be worth a try. Maybe if it were located closer to the hot inlet side so it would melt the blockage??
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UberVW_TDI
Veteran Member
More water found in intercooler today:
Today it got cold again here in Austin, TX (~20F this morning with relative humidity at 80%). My commute to work is ~25miles. Mostly highway.
So, after finding almost 2 cups of water in my intercooler on 03FEB2011 (see post #368 on page 26 of this thread) . I decided to take my jack, jack stands and some tools along....just in case.
Upon leaving work this evening, I started up the car and it idled VERY rough. Crap. I shut off the car took the intercooler hoses off the intercooler. Yep, more water and some thick slime too. Here are the pictures from my phone.
Here is the water on the ground. I probably got about +1/2 to 3/4 cup out.
After reconnecting the intercooler piping, I started the car and everything ran fine. I then drove home.
~25miles. The temp was about 31 F on the way home. Like I said above, it was ~20 F this morning.
I'll open it up again to see what I find after driving home tonight. I expect not to find much, but I'll post again if I find anymore water, slime etc.
I've got to get a fix for this soon. This is pretty crappy that I've got to jack up my car and drain condenstate out of the intake before I drive anywhere when its cold outside.
I hope VW posts a fix soon, or I'm going to have to come up with one myself....
I knew owning a VW was going to be fun and it would probably have some quirks and not be the most reliable vehicle on the road. But this is scaring me a bit. I still don't understand how VW didn't foresee this issue when designing the LP-EGR system. Does the Euro version of this engine have a LP-EGR? Or do we get to thank California for this =) Oh, I mean I'm so happy my car meets TierIIBin5 regulations, I just wish I didn't have to drain my cars intake in the parking lot before I drive home from work. Nice.
Today it got cold again here in Austin, TX (~20F this morning with relative humidity at 80%). My commute to work is ~25miles. Mostly highway.
So, after finding almost 2 cups of water in my intercooler on 03FEB2011 (see post #368 on page 26 of this thread) . I decided to take my jack, jack stands and some tools along....just in case.
Upon leaving work this evening, I started up the car and it idled VERY rough. Crap. I shut off the car took the intercooler hoses off the intercooler. Yep, more water and some thick slime too. Here are the pictures from my phone.
Here is the water on the ground. I probably got about +1/2 to 3/4 cup out.
After reconnecting the intercooler piping, I started the car and everything ran fine. I then drove home.
~25miles. The temp was about 31 F on the way home. Like I said above, it was ~20 F this morning.
I'll open it up again to see what I find after driving home tonight. I expect not to find much, but I'll post again if I find anymore water, slime etc.
I've got to get a fix for this soon. This is pretty crappy that I've got to jack up my car and drain condenstate out of the intake before I drive anywhere when its cold outside.
I hope VW posts a fix soon, or I'm going to have to come up with one myself....
I knew owning a VW was going to be fun and it would probably have some quirks and not be the most reliable vehicle on the road. But this is scaring me a bit. I still don't understand how VW didn't foresee this issue when designing the LP-EGR system. Does the Euro version of this engine have a LP-EGR? Or do we get to thank California for this =) Oh, I mean I'm so happy my car meets TierIIBin5 regulations, I just wish I didn't have to drain my cars intake in the parking lot before I drive home from work. Nice.
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tcp_ip_dude
Veteran Member
Idea has been suggested previously, personally I like it, but the EPA would never allow it, they'd have a field day over these cars belching out green oily snot every so often (quoting a responder to the earlier thread).
Only way it'd fly is in conjunction with a catch vessel of some sort.My guess is that it'll be a combination of an ECU tune that manages the dew point / temperature ratio (via EGR) in the intake system more closely to minimize condensation and still stay in the NOx budget (hoping they have some margin to play with here) and that they'll re-plumb the ducting to allow for some kind of drainage/reservoir mechanism that can be emptied at oil changes, perhaps a double walled duct (with the check valve) that is a self contained reservoir, easy installation, similar form factor, etc. But as long as they're using EGR, there's going to be condensation in the intake system at low points.
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UberVW_TDI
Veteran Member
After very rough idle, draining intercooler (see post #475) I drove home. I then pulling intercooler hoses off again to see how much water was back in my intercooler after ~25 miles in 31F. Here is the outlet intercooler hose. Got ~2 tbsp (~30ml) of water. Also, the outlet hose had lots of the slimey snot like stuff. I cleaned everything up and put it back together.
Here are some pics:
Here are some pics:
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Jack Frost
Veteran Member
I agree. We can't have a TDI carrying out its bodily functions in a nice parking lot. If the LPEGR can't be modified to account for cold humid weather, the condensate will have to collected in a vessel and drained by the vehicle's owner. Such a vessel would have to be called a DCV (Diesel Condensate Vessel). A little outhouse icon on the dash would light up and if ignored long enough, the car would go into limp mode whereby the driver step out and drain it.Idea has been suggested previously, personally I like it, but the EPA would never allow it, they'd have a field day over these cars belching out green oily snot every so often (quoting a responder to the earlier thread).
It is interesting to think that if the LPEGR wasn't there, the green goop would be be ejected out of the exhaust eventually in some form (either as a vapour, an aerosol or a drip). All cars must do that.
MayorDJQ
Top Post Dawg
If the LPEGR weren't there, the green goop wouldn't build up in the first place. Think AHU, ALH, BRM, BEW, etc. It was never an issue on those vehicles.
bhtooefr
TDIClub Enthusiast, ToofTek Inventor
I think the point is more that the things in the green goop would have gone out the tailpipe - they're all either combustion byproducts, or oil.
Anyway, if there isn't enough NOx reduction headroom, VW may have to retrofit a urea system to these cars. Not something I'd complain about, it could allow for better fuel economy...
Anyway, if there isn't enough NOx reduction headroom, VW may have to retrofit a urea system to these cars. Not something I'd complain about, it could allow for better fuel economy...