Smoke

zzdiesel

Veteran Member
Joined
Dec 10, 2010
Location
sask. mostly now Wa.
TDI
05 passat tdi Geared BSM and Bewcam 2nd 2005 deleted ,converted and bew cam stage 2 Malone3 tune.
So on my BHW Passat wagon I am looking for an implausable MAF signal cure. It has been suggested here that a turbo system leak is a plausable cause. Some use smoke to find minor leaks. I am wondering how they do it. Is there a smoke machine?

I do not have one. My thought is to use a shop vac for pressure. Use a bee smoker to add smoke to the vacs inlet.

I could hook the vac up to the turbo inlet. Is there an engine position where all intake valves are closed?
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
Yes, there are smoke machines. Most commonly used for evaporative emission system leak diagnosis (on gasoline engines), but they are useful for other things like finding vacuum leaks, false air leaks, and in the case of turbocharged engines, boost leaks.

Many MAF implausible signal DTCs on BHWs (and BEWs, for that matter) are the first sign of a tiny boost leak somewhere, but not yet enough to flag a low boost (P0299) DTC.

Some BHW tips:

The S-shaped boost hose from the turbocharger to the crossover pipe, down low, often gets the ground cable rubbed through it. This hose also quite often gets holes rubbed through the metal collar (usually at the turbo end) right behind the tab that engages the lock bale. The only way to see it is to take the hose out, and look. Usually oily stains are the first sign. Sometimes this S-hose just splits on its own. The only other hose I have seen split is the little 90 degree one going into the intake flap. I have never seen either of the remaining two charge air hoses have issues but I have seen the o-rings not sealing very well. I have also seen small cracks in the intercooler from crashing into things, even if no obvious damage is seen on the bumper cover from above. They can crack at the upper tank mounting tabs, and you won't be able to see it unless you have a smoke machine OR you REMOVE the intercooler and look it over closely.
 

MukGyver

Veteran Member
Joined
Dec 11, 2020
Location
Sierra Ca
TDI
2004 Jetta PD
zzdiesel, you can also use soapy water. You will get some slow leak thru the cylinders but not enough to keep you from identifying a leak. Probably best to set it at TDC. Some use a pvc cap at the elbow at the turbo outet with a regulator set at 5-10 psi, pressurizing then closing the valve. Listen for hissing noises and watching for bubbles. You can use a shop vac too but you may lose the advantage of hearing the leak with the vacuum screaming in your ear.

So on my BHW Passat wagon I am looking for an implausable MAF signal cure. It has been suggested here that a turbo system leak is a plausable cause. Some use smoke to find minor leaks. I am wondering how they do it. Is there a smoke machine?

I do not have one. My thought is to use a shop vac for pressure. Use a bee smoker to add smoke to the vacs inlet.

I could hook the vac up to the turbo inlet. Is there an engine position where all intake valves are closed?
 

Mozambiquer

Vendor , w/Business number
Joined
Mar 21, 2015
Location
Versailles Missouri
TDI
2004 VW Touareg V10 TDI, 2012 Audi Q7 V6 TDI, 1998 VW Jetta TDI. 1982 VW Rabbit pickup, 2001 VW Jetta TDI, 2005 VW Passat wagon TDI X3, 2001 VW golf TDI, 1980 VW rabbit pickup,
We've got something similar to this at the shop Turbo test kit I think ours is a matco, which is made for large trucks and therefore it's a lot bigger, but that can help for diagnosing boost leaks. Then there's relatively cheap smoke machines, like This one and I'm sure your can actually make one too...
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
Fail
All you need is trash and a cig
1 gallon milk bottle plastic. Fill with water and poke a hole big enough for a cig to fit in the cap. One hole at the bottom you hold closed with finger. Light cig and out in the hole at the filter. Let water drain out, it draws in only smoke. Now put the cig out and remove. Put the hole the cig was in into the system and blow into the hole the water drained from.
I would expect most VW owners to know how to do this.
 

MukGyver

Veteran Member
Joined
Dec 11, 2020
Location
Sierra Ca
TDI
2004 Jetta PD
Oh yeah I used to do that one without auxiliary air pressure.. but doc says I can't take that kind of vein-bulging strain any more.
 

dtrvler

Veteran Member
Joined
Jul 21, 2017
Location
Las Vegas
TDI
2006 Jetta TDI 5 spd
Thats just to get some smoke in it. Then cap and pressurize. Look and Listen for leaks. I usually can hear the leaks. Without the smoke. IDparts has a test kit. Similar to the one Mozambiquer posted above.I like to test the whole boost pipe system from the turbo to the intake. I turn the hoses to whatever position i need to to hook it all together out where i can see and listen better. I just did this on my 05 bhw after hitting a 'yote caused intercooler damage. Intercooler was leaking. Will test again after i plug in the new intercooler.
 
Last edited:

zzdiesel

Veteran Member
Joined
Dec 10, 2010
Location
sask. mostly now Wa.
TDI
05 passat tdi Geared BSM and Bewcam 2nd 2005 deleted ,converted and bew cam stage 2 Malone3 tune.
Rather than a milk jug I would use the bee smoker to add smoke.

Many good ideas here.
 

zzdiesel

Veteran Member
Joined
Dec 10, 2010
Location
sask. mostly now Wa.
TDI
05 passat tdi Geared BSM and Bewcam 2nd 2005 deleted ,converted and bew cam stage 2 Malone3 tune.
So I managed to pressurize the system, actually got no pressure. I found a missing O ring in the connection to the last hard pipe. Probably mechanics error as I had this apart changing the tandem pump. Anybody else ever have mechanics error? It still did not hold pressure as I assume the air was going out the exaust valves. I did not try turning the engine as i quickly founf the problem. Luckily I had an O ring on hand. I took it for a 30 mile test drive and no errors showed up. Yeh
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
Glad you found it.

When I smoke check these, I plug the exhaust pipe(s) with a rag, and we have plastic caps that can be used to close off the intake side somewhere convenient to get at.
 

Scubanero

Veteran Member
Joined
May 30, 2007
Location
Calgary AB
TDI
2005 Passat Wagon
So I managed to pressurize the system, actually got no pressure. I found a missing O ring in the connection to the last hard pipe. Probably mechanics error as I had this apart changing the tandem pump. Anybody else ever have mechanics error? It still did not hold pressure as I assume the air was going out the exaust valves. I did not try turning the engine as i quickly founf the problem. Luckily I had an O ring on hand. I took it for a 30 mile test drive and no errors showed up. Yeh
I had an O ring disappear once and it wasn’t because I or anybody else forgot to put it back in. Other errors, yes but not that one.
I am not sure how it got out but there it was, gone. It must have broken and then squeezed out.
 

zzdiesel

Veteran Member
Joined
Dec 10, 2010
Location
sask. mostly now Wa.
TDI
05 passat tdi Geared BSM and Bewcam 2nd 2005 deleted ,converted and bew cam stage 2 Malone3 tune.
It is still driving me nuts. I had a 2 hour drive. 2/3 of the way there while going 80 and the temperature was showing 110 outside, suddenly limp mode. It would not go away by restarting the engine. I limped the rest of the way to destination then limped 2 hours home., Vag shows usual underboost and MAF. Also P0118-000 G62 temperature sensor signal too high.

Can the temp. sensor cause it to go into limp mode? Can it cause the underboost? The temperature gauge stayed in the middle, and there was no sign of the engine overheating and no smoke from the underboost.

I assume the next step is to replace the temperature sender.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
The green (and before that black) dual temp sensors are a common failure item. There are two circuits, one goes to the Instruments, one goes to the Engine controller. Either side can fail.

Unfortunately on the BHW they are not easy to get at. That would have nothing to do with your boost leak issue.
 

zzdiesel

Veteran Member
Joined
Dec 10, 2010
Location
sask. mostly now Wa.
TDI
05 passat tdi Geared BSM and Bewcam 2nd 2005 deleted ,converted and bew cam stage 2 Malone3 tune.
So I got the temperature sensor out. It is green. Does that mean it was changed before, all the originals were black?

That area of the engine looks like it was worked on before.

Is there any way to check that the wiring is functional before I put it all back together?












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zzdiesel

Veteran Member
Joined
Dec 10, 2010
Location
sask. mostly now Wa.
TDI
05 passat tdi Geared BSM and Bewcam 2nd 2005 deleted ,converted and bew cam stage 2 Malone3 tune.
Another question. There is some wiggle in the nipple of the recently installed tandem pump. About 350 miles on it. Is that a problem, will it leak vacuum? Does it have an o ring possibly?
 

Mozambiquer

Vendor , w/Business number
Joined
Mar 21, 2015
Location
Versailles Missouri
TDI
2004 VW Touareg V10 TDI, 2012 Audi Q7 V6 TDI, 1998 VW Jetta TDI. 1982 VW Rabbit pickup, 2001 VW Jetta TDI, 2005 VW Passat wagon TDI X3, 2001 VW golf TDI, 1980 VW rabbit pickup,
Another question. There is some wiggle in the nipple of the recently installed tandem pump. About 350 miles on it. Is that a problem, will it leak vacuum? Does it have an o ring possibly?
The wiggle can be remedied with a light ball pein hammer, tap around the vacuum connector until it's tight. On my golf, I actually used Indian head sealer when the car was running. I learned that trick from a Navy machinist, he said that's what they used to repair vacuum leaks on the ships, as the vacuum would pull the sealer in and then it would set and be sealed.
 

zzdiesel

Veteran Member
Joined
Dec 10, 2010
Location
sask. mostly now Wa.
TDI
05 passat tdi Geared BSM and Bewcam 2nd 2005 deleted ,converted and bew cam stage 2 Malone3 tune.
I never heard of that sealer. I was thinking of some JB weld. Wouldn't want to suck it into the vacuum pump though.

It seems like a dumb design and a common problem.
 

CantWrite

Veteran Member
Joined
Jun 8, 2021
Location
Placerville CO
TDI
2005 Passat Wagon (BHW/5-spd conv, 03T). I keep in touch with the (2) ALH's I sold.
I just got the rear put back together, my temp sensor wire was cut in half, luckily the the gauge portion as VCDS would show engine temp.

My tandem pump is a LUK "BMF" and has a date code (I believe) of 06/07 timeframe, I have not yet googled how to read the dots. Anyway, I notice my plastic vacuum nipple wiggled as well. I did nothing. Car is back together and I just put a vacuum gauge on it at the brake booster. Read near 20in at 7500' elevation idling. Maybe it seals itself when started...... (I did this to confirm my OEM booster is bad)

I realize the vacuum leak is not your issue, just trying to help in regard to focusing on your problem, vs getting side-tracked like I so often do...

I have a low pressure smoke machine used for stages/halloween etc, plugged the exhaust, and installed it at the air box outlet to the turbo. I never did find or hear a leak. But I did go ahead and replace all the o-rings in the boost hoses for piece of mind. Some were very flat. I was going to test each piece individually but I think my "emissions workshop" message is because my GP-#2 has failed. (168k-ohm, test lamp did not light)

If each piece tests good, and you replaced O-rings, what if you grabbed some narrow band clamps? Or swapped boost hoses/MAF sensors between cars and then went for a drive? I am not sure if a Malone stage 3 still uses a 3-bar, I assume so.

Hope you get it figured out.
 

zzdiesel

Veteran Member
Joined
Dec 10, 2010
Location
sask. mostly now Wa.
TDI
05 passat tdi Geared BSM and Bewcam 2nd 2005 deleted ,converted and bew cam stage 2 Malone3 tune.
I got her all back together. I did stake the plastic nipple and JB weld around the outside. When I took it apart I unbolted the hard boost pipe and it came out of the elbow without removing the clamp. It must have blown out somehow and caused the boost problem. I put it back with a gear clamp. After a 15 mile drive, no codes. Today I will take it on a 5 hour drive. We shall see. I am of little faith.
 
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