No boost :( no matter what.. :(((

Andrei Rinea

Veteran Member
Joined
Jan 21, 2002
Location
Europe, Romania, Bucharest
TDI
VW Tiguan 4Motion 2.0 TDI 170HP (engine CBBB)
I have been experiencing low boost for some time now. Althought the story is long I'd rather put it here reversed, namely I would start with logs / pics and then the story.
Thank you for understanding.
 

Andrei Rinea

Veteran Member
Joined
Jan 21, 2002
Location
Europe, Romania, Bucharest
TDI
VW Tiguan 4Motion 2.0 TDI 170HP (engine CBBB)
A few notes about the graphs:

Graph 1: on the bottom line written vertically there is the throttle position (0..100%) logged "joined" with group 10 and the N75 duty cicle is multiplied by 10 i.e.: 100% corresponds on my graph to 1000 and 50% to 500 so it could be read easier.

Graph 2 & 3: On the bottom line you have engine RPMs
 

Andrei Rinea

Veteran Member
Joined
Jan 21, 2002
Location
Europe, Romania, Bucharest
TDI
VW Tiguan 4Motion 2.0 TDI 170HP (engine CBBB)
Here's the story.. I was having low boost since 2003 and I did these:

1. Replaced N75 and all its tubes
2. Replaced intercooler (ouch...) it was cracked badly
3. Replaced air filter
4. Taken out and cleaned the intake manifold. Not as much gunk as I expected. The intake ports had about 1.5-2 mm coating of gunk so I thought it wasn't that bad. I left it that way.
5. Installed a mechanical boost gauge T'd between the ECU and intake manifold and peaks are 0.9 bar!!
 

Andrei Rinea

Veteran Member
Joined
Jan 21, 2002
Location
Europe, Romania, Bucharest
TDI
VW Tiguan 4Motion 2.0 TDI 170HP (engine CBBB)
Interest things are that no limp mode is triggered although you can see the differences between actual MAP and specified MAP. Another interesent thing is how my PIERBURG MAF behaves. You can see how the air measured is going down although the pedal is to the floor.

The tests have been made at WOT, as long as I could (been driving up to 80mph - city exits).

Also I forgot to add to the "I've done this:" list:
6. Unfreezed turbo actuator. Pressure tested and full open wastegate happens at 1 bar. Not taken off the turbo.




----

I am thinking about:

a. Take out the tube from the N75 to the actuator; plug its N75 port. Carefully watching the mechanical boost gauge I will be accelerating (at idle for example - or rolling) slowly and attempt to obtain pressures over this 0,7 bar or so... If I get over 1,2 bar then it would mean that the turbo is not gone.

How dangerous is this?

b. If that checks OK then the next step should be connecting it back and T'ing the boost gauge there (between N75 and actuator) and see how much the actuator REALLY gets. BTW, is n't the WOT value of the n75 duty cicle a bit too high? 40% is there but I expected something like 0-10%.
 

Andrei Rinea

Veteran Member
Joined
Jan 21, 2002
Location
Europe, Romania, Bucharest
TDI
VW Tiguan 4Motion 2.0 TDI 170HP (engine CBBB)
Car is the one in the signature mentioning that I've recently been chipped. DimensioneSport is the tuner (Italy brand) called usually DimSport. Isn't the maximum MAP requested a bit low considering the fact that the car is chipped?

Below I put actual values of MAP (act. vs spec.) and N75 duty cicle:

Engine speed;Specified MAP;Actual MAP;Duty cycle
;;;Boost Valve
/min; mbar; mbar; %
2310;1957,2;1680;39,8
3108;1982,4;1671,6;39,8
3759;1982,4;1579,2;39,8
4242;1965,6;1579,2;51,6
2940;1940,4;1486,8;39,8
3192;1982,4;1612,8;39,8
3444;1999,2;1596;39,8
3675;1990,8;1612,8;39,8
3864;1982,4;1579,2;39,8
3696;1386;1285,2;64,5
3402;1159,2;1268,4;82,8
3108;1092;1234,8;94,1
2856;1075,2;1209,6;94,1
2625;1058,4;1192,8;94,1
2478;1033,2;1184,4;94,1
2373;1024,8;1184,4;94,1
2310;1117,2;1251,6;94,1
2247;1041,6;1150,8;94,1
2226;1184,4;1243,2;89,8
2058;1058,4;1108,8;94,1
1764;991,2;1083,6;93,8
924;940,8;1041,6;94,1
2394;1243,2;1243,2;63,7
2016;1058,4;1125,6;75,8
1449;982,8;1066,8;86,7
1407;1058,4;1083,6;69,9
1785;1411,2;1268,4;41,4
2541;1890;1646,4;39,8
3213;1898,4;1436,4;39,8
3885;1957,2;1554;39,8
4368;1932;1528,8;39,8
3024;1764;1747,2;39,8
3276;1923,6;1612,8;39,8
3570;1974;1596;39,8
3801;1974;1596;39,8
4032;1965,6;1629,6;39,8
4221;1940,4;1612,8;39,8
4368;1898,4;1570,8;39,8
3213;1898,4;1579,2;39,8
3276;1965,6;1654,8;52,7
3318;1839,6;1663,2;39,8
3423;1957,2;1629,6;39,8
3549;1982,4;1638;39,8
3318;1394,4;1352,4;67,6
3108;1159,2;1302;91
3171;1738,8;1596;48,4
3276;1932;1654,8;39,8
3381;1974;1629,6;39,8
3507;1982,4;1646,4;39,8
3591;1982,4;1663,2;39,8
3507;1470;1386;65,2
2142;1587,6;1436,4;39,8
2310;1755,6;1696,8;39,8
2667;1932;1638;39,8
3003;1982,4;1663,2;39,8
3318;1982,4;1629,6;39,8
3612;1982,4;1646,4;39,8
3885;1974;1612,8;39,8
4095;1957,2;1579,2;39,8
4284;1932;1570,8;39,8
4431;1881,6;1562,4;39,8
4326;1587,6;1402,8;57,8
2877;1201,2;1352,4;83,2
1176;1033,2;1150,8;94,1
924;949,2;1058,4;94,1
924;932,4;1041,6;94,1
924;924;1041,6;94,1
945;924;1041,6;94,1
1806;1234,8;1192,8;68
2121;1873,2;1654,8;39,8
2499;1974;1680;39,8
2835;1982,4;1646,4;39,8
2016;1352,4;1243,2;44,1
2226;1839,6;1646,4;39,8
2373;1974;1587,6;39,8
2436;1747,2;1503,6;39,8
2457;1587,6;1470;39,8
2415;1260;1251,6;65,2
2310;1075,2;1159,2;76,6
2205;1024,8;1150,8;89,8
2079;1008;1134;94,1
1974;999,6;1117,2;94,1
1890;991,2;1108,8;94,1
1764;982,8;1092;94,1
1617;974,4;1092;94,1
1428;966;1066,8;94,1
1218;940,8;1058,4;94,1
924;924;1050;94,1
924;924;1033,2;94,1
924;924;1033,2;94,1
924;924;1041,6;94,1
924;924;1033,2;94,1
945;924;1041,6;94,1
945;924;1033,2;94,1
945;924;1033,2;94,1
924;924;1033,2;94,1
924;924;1033,2;94,1
945;924;1033,2;94,1
945;924;1033,2;94,1
945;924;1033,2;94,1
945;924;1033,2;94,1
924;924;1033,2;94,1


I considered it may be useful to post a graph with group 4 as well (Injection timing) because there seem to be some abnormalities there too.



Group A:;'010;;;
;Mass Air Flow;Barometric;Manifold ;Position
TIME;;Pressure;Pressure;Throttle
STAMP; mg/R; mbar; mbar;%
0,6;648,4;999,6;1528,8;100
1,99;661,7;999,6;1654,8;100
3,38;588,5;999,6;1570,8;100
4,77;558,6;999,6;1562,4;100
6,16;648,4;999,6;1680;100
7,56;658,4;999,6;1688,4;100
8,95;595,2;999,6;1554;100
10,34;618,5;999,6;1663,2;100
11,73;578,6;999,6;1587,6;100
13,12;419;999,6;1310,4;0
14,52;425,6;999,6;1276,8;0
15,91;425,6;999,6;1243,2;0
17,3;435,6;999,6;1218;0
18,69;445,6;999,6;1192,8;0
20,09;458,9;999,6;1184,4;0
21,48;462,2;999,6;1167,6;25,1
22,87;482,1;999,6;1276,8;27,1
24,26;399;999,6;1176;23,5
25,65;478,8;999,6;1209,6;29,4
27,04;319,2;999,6;1150,8;0
28,43;352,5;999,6;1083,6;0
29,83;352,5;999,6;1066,8;0
138,34;445,6;999,6;1234,8;27,1
139,73;369,1;999,6;1159,2;0
141,13;349,1;999,6;1083,6;0
142,52;425,6;999,6;1050;33,7
143,91;512,1;999,6;1184,4;38,8
145,3;708,2;999,6;1705,2;100
146,69;651,7;999,6;1663,2;44,7
148,08;605,1;999,6;1646,4;100
149,48;532;999,6;1528,8;100
150,87;438,9;999,6;1402,8;87,1
152,26;595,2;999,6;1528,8;100
153,65;615,1;999,6;1646,4;100
155,05;585,2;999,6;1579,2;100
156,44;591,9;999,6;1638;100
157,83;571,9;999,6;1612,8;100
159,22;535,3;999,6;1587,6;100
160,61;678,3;999,6;1764;100
162,01;621,8;999,6;1612,8;85,1
163,4;721,5;999,6;1722;100
164,79;605,1;999,6;1579,2;100
166,33;621,8;999,6;1654,8;100
167,72;458,9;999,6;1394,4;0
169,11;455,5;999,6;1310,4;0
170,5;668,3;999,6;1738,8;100
171,9;618,5;999,6;1587,6;100
173,29;638,4;999,6;1654,8;100
174,68;621,8;999,6;1621,2;100
176,07;628,4;999,6;1671,6;100
177,46;452,2;999,6;1436,4;0
251,22;552;999,6;1377,6;100
252,62;675;999,6;1621,2;100
254,01;668,3;999,6;1663,2;100
255,4;625,1;999,6;1638;100
256,79;618,5;999,6;1629,6;100
258,18;605,1;999,6;1629,6;100
259,58;565,3;999,6;1587,6;100
260,97;552;999,6;1587,6;78,4
262,36;522;999,6;1554;74,1
263,75;502,1;999,6;1537,2;0
265,15;442,2;999,6;1360,8;0
266,54;409;999,6;1226,4;0
267,93;349,1;999,6;1075,2;0
269,32;352,5;999,6;1041,6;0
270,71;379,1;999,6;1041,6;0
272,1;379,1;999,6;1041,6;0
273,49;355,8;999,6;1033,2;25,9
274,88;724,9;999,6;1671,6;77,6
276,28;711,6;999,6;1680;67,5
277,67;665;999,6;1654,8;63,9
279,06;415,6;999,6;1419,6;0
280,45;728,2;999,6;1713,6;69
281,84;665;999,6;1612,8;56,5
283,23;621,8;999,6;1520,4;36,9
284,63;601,8;999,6;1495,2;31
286,02;455,5;999,6;1369,2;17,6
287,42;362,4;999,6;1167,6;0
288,81;362,4;999,6;1150,8;0
290,2;355,8;999,6;1125,6;0
291,59;352,5;999,6;1117,2;0
292,98;359,1;999,6;1100,4;0
294,37;359,1;999,6;1092;0
295,76;362,4;999,6;1083,6;0
297,15;349,1;999,6;1083,6;0
298,55;349,1;999,6;1066,8;0
299,94;365,8;999,6;1058,4;0
301,33;359,1;999,6;1033,2;0
302,72;372,4;999,6;1033,2;0
304,11;402,3;999,6;1033,2;0
305,5;379,1;999,6;1041,6;0
306,89;379,1;999,6;1041,6;0
308,28;379,1;999,6;1033,2;0
309,67;379,1;999,6;1033,2;0
311,06;379,1;999,6;1033,2;0
312,46;379,1;999,6;1033,2;0
313,85;379,1;999,6;1033,2;0
315,24;379,1;999,6;1033,2;0
316,63;379,1;999,6;1033,2;0
318,02;379,1;999,6;1033,2;0
319,41;379,1;999,6;1033,2;0
320,8;379,1;999,6;1033,2;0
 

rdkern

Top Post Dawg
Joined
May 21, 2004
Location
Humboldt Co CA
TDI
Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
Can we assume you have rather slow accelleration?

What about the exhaust? I don't recall you mentioning trying anything on that side of the turbo. Can you disconnect it and see if anything changes? I think its possible for too much back pressure to basically prevent the turbo from working. It looks like you've checked most everything else. I assume you got that little bit of vaccum tube in the ecu - but that would probably throw you into limp instead of preventing the boost to start with.

I'm hoping to learn from your graphs - hopefully some of our gurus with graph experience will help with this.
 

Andrei Rinea

Veteran Member
Joined
Jan 21, 2002
Location
Europe, Romania, Bucharest
TDI
VW Tiguan 4Motion 2.0 TDI 170HP (engine CBBB)
No... it's not too slow acceleration. Test have been made at WOT and pauses (traffic). As times of acceleration I get 80-120km/h (50-75mph) in 7.5 sec

Exhaust? I did it all... No mufflers, no cat, 57mm (2.25") stainless exhaust straight from th turbo.

When they did the chiptuning they opened the ECU in front of me and the tube inside the ECU was perfect! I checked it myself as I heard of horror stories of it breaking and spreading oil there...
Anyways it's not that important in this case because if there were a leak between intake manifold and ECU then the mechanical boost gauge would have read much different. And I changed the whole tube between ECU and intake manifold anyways.
 

Andrei Rinea

Veteran Member
Joined
Jan 21, 2002
Location
Europe, Romania, Bucharest
TDI
VW Tiguan 4Motion 2.0 TDI 170HP (engine CBBB)
What I am trying to determine is if there are bubbles under hard acceleration (WOT + high speed) which could diminish the power that the engine develops. I am stating this phrase because at high speeds sustained (110-113 mph) I got stumblings of too much air in the fuel feed line. I changed previously the fuel line from the filter to the pump, from the filter to the thin one that goes to the tank, the return line too, inter-injectors too, and still got this problem. However I don't think it could be linked to the low boost problem. The only unchanged line(s) are from the tank (8mm inner, rubber made, thick one) to the looong plastic thin one (8mm outer, plastic made) and this plastic one. In rest everything else replaced.

The 8mm rubber made line is like 10$ a meter, and the plastic loooooong one (from back of the car to engine bay) is like 28$. Labour of replacement can't be too expensive so that is on my list too.

Now going back to my low boost thingie I would try to think systematically the normal (desired, not actual) functioning of the car:

1. Start car, engine idling. 9xx RPM, 0 mbar boost above atmospheric pressure, wastegate fully closed, turbo gets all the exhaust gasses
2. Accelerate gently, RPMs (engine) rise, turbo spools a tad faster, engine reads go-pedal sensor and MAP sensor and decides it's not too much boost so it leaves the N75 alone and doesn't command it different than (1) - above
3. Accelerate more and harder, MAP pressure (actual) goes beyond MAP pressure (specified) and then ECU starts telling the N75 (Pulse modulated electronic signal) to open a little the wastegate. Reads again MAP pressure and decides again .........................
..... (the model above is simplified by ignoring factors such as MAF flow, smoke map, inj.map, RPMs etc., air temp, fuel temp etc. etc)


In my case the ECU never sees a case where actual goes beyond specified (MAP pressure) so
either :

* the wastegate remains somehow open;

* N75 somehow lets more pressure than it should to the actuator and opening the wastegate
[checkable by T'ing mechanical boost between N75 and actuator]

* Turbo itself cannot produce sufficient boost because the blades are worn out (theory.. I've rarely heard of this)
[checkable by disconnecting the pressure line that goes to actuator]

* Wrong command from the ECU itself to the N75.. Is it possible? What tells us the graph (first one) about this? is 39% normal for WOT??? seems too high to me.

aaaaahhh........ and one more?

* Bad adjustment of the actuator rod? [I guess I need to take turbo off the car to see this...]
 

BleachedBora

Vendor , w/Business number
Joined
Oct 16, 2003
Location
Gresham, Oregon
TDI
'81 DMC-12, '15 GL350 CDI 275 hp/448 tq - '81 Caddy ALH, '05 E320 CDI 250hp/450 tq
Wow--I will have turbo that you could buy from me in a week--but shipping would be crazy--I have a friend that just left for Bucharest...shame she couldn't have taken one with her for you...
Sigh, oh well,
Good luck!
-BB
 

Andrei Rinea

Veteran Member
Joined
Jan 21, 2002
Location
Europe, Romania, Bucharest
TDI
VW Tiguan 4Motion 2.0 TDI 170HP (engine CBBB)
Thank you anyway.. I still hope I don't have to replace it, just to determine the command problem. Someone is opening the wastegate too soon. I just have to find out who is doing this..

Today (now it's 11:32AM) I will take my boost gauge, mount it on the intake manifold, unplug the actuator tube (so the wastegate won't be openable) and watch how the pressure is rising and where it peaks. If it doesn't go beyond 0.6-0.7 bar (9-10 PSI) then either the wastegate is open a little at all times (bad adjustment of the actuator or actuator toast) either turbo is toast. I hope I will get above 10PSI with No problem...

Wish me luck.....
 

Andrei Rinea

Veteran Member
Joined
Jan 21, 2002
Location
Europe, Romania, Bucharest
TDI
VW Tiguan 4Motion 2.0 TDI 170HP (engine CBBB)
IT WORKED !!!!
I pulled out the actuator tube from the N75 and it worked! I go easily beyond 1.5bar on the gauge (1.5bar = 22PSI) and it settles lower (couldn't see where exactly yet - I ran tests only in city).

Anyways I suspect the N75 tubes have been connected wrong to the N75 itself. That is why I took 2 pictures (my camera really sucks and I took 2 pictures in order to have at least one that you can understand)



and



You can see that the top tube is taken off N75 valve. That tube was leading to the actuator.
Now, I don't know which are the correct places to connect the tubes to the N75. Currently the tubes are connected as follows:



In the picture the blue marked port went to the actuator, the red marked port to the turbo discharge and the black marked one to the low pressure side of the intake (pre-turbo, post MAF).

IS THIS THE CORRECT ORDER? This way the wastegate opens too soon.. before building any boost. I am seriously considering buying a Dawes boost controller and leaving this crap of N75 only electrically connected (no tubes attached). Only problem is they don't ship to Romania..
 

rdkern

Top Post Dawg
Joined
May 21, 2004
Location
Humboldt Co CA
TDI
Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
I found this in the photo section -


If I'm understanding correctly, it looks like the red and blue are switched around. I assume Black with to the intake (you state two blues, but I assume your first blue is the real one).
 

Andrei Rinea

Veteran Member
Joined
Jan 21, 2002
Location
Europe, Romania, Bucharest
TDI
VW Tiguan 4Motion 2.0 TDI 170HP (engine CBBB)
Thank you very much for the diagram! This is very valuable information to me. I will correct the hoses' position and test it again!
All my thanks to you!


Exactly how I thought it was: Reffering to the notations on your diagram things were like this on mine:

"Atmospheric pressure" was connected to my actuator

"Charge pressure control" was connected to the turbo discharge

"Intake manifold pressure" was connected to atmospheric (between MAF and turbo = low pressure side)

Things probably happened like this: ECU saw low turbo boost and therefore de-energized the N75 namely connected the "atmospheric" with "turbo" which in my case really meant connecting turbo with actuator which meant opening the wastegate before obtaining requested boost.
 

rdkern

Top Post Dawg
Joined
May 21, 2004
Location
Humboldt Co CA
TDI
Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
I certainly hope that this fixes it. I'll have to photo my setup now, just in case I should ever have to switch out the N75. I'm keeping the same color codes so that replacing should be a big problem.

By the way, since you can sign on to the photos (I saw yours there) you can search for anything you want on the site. This can be a very valuable resource that isn't well publicized.
 

Andrei Rinea

Veteran Member
Joined
Jan 21, 2002
Location
Europe, Romania, Bucharest
TDI
VW Tiguan 4Motion 2.0 TDI 170HP (engine CBBB)
Well it fixed it!
I won 1 sec on 50-75 mph

As for the pictures my knowledge regarding the english language is degrading and I don't quite understand what you tell me about posting pics.. and searching..

I've searched a lot of topics before I began posting here so I don't put redundant info in the forum. As for the pictures I posted them on the pics server and added keywords to ease search for others. On the pics server I didn't quite search for something because I didn't think I could find something useful for my problem...


If did something wrong tell me and I will fix it as soon as I can.
 

rdkern

Top Post Dawg
Joined
May 21, 2004
Location
Humboldt Co CA
TDI
Passat 1997 silver (sold after 11 years), Jetta 2000 atlantic blue
Congratulations!


I was glad to help.

You did nothing wrong, and I hope my English stays as good as yours.

I just pointed out that the photo section can be searched, and that's how I found that graph. Others may not know the amount of information that is available there. You're photos were the first that popped up with a search on "N75". I believe they are in order of date.

I'm glad it was inexpensive, but too bad it took so long to finally figure out.
 
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