Forum HotHatches Information

[SpdR]

1. Diverter valve failure

Background:
The stock diverter valve (dv) is prone to failure, whether chipped or stock. The diaphragm is prone to tearing (the orange shown in the pic of the stock dv (in the middle) below-may be a different color depending on the version of dv you have.)
(IMG:http://img.photobucket.com/albums/v406/dpham00/forgedvinstall1.jpg)
Symptoms:
-A failing diverter valve will generally lose boost.
-The boost can be checked either via a boost gauge, or the vag-com (mb 115). You will see a huge drop in boost when the dv goes bad.
-Pin-hole DV failures usually allow boost to spike, but will then suddenly vent boost.
Tearing in the DV usually only allows 6-7 PSI. Boost will not spike.
-You may see 000665 - Boost Pressure Regulation: Control Range Not Reached
p0299 - 002 - Lower Limit Exceeded - Intermittent
-Alternatively, you can remove the dv, and inspect the diaphragm for tears. It is held onto the compressor housing by three bolts:

(IMG:http://img.photobucket.com/albums/v406/dpham00/turbo.jpg)

Solution:
-You can replace it with the stock dv, vw #06F 145 710 C. This is the latest dv as of this post, however, many people have also seen failures with the “C” dv. VW is also supposedly coming out with a “G” dv, part # 06F-145-710-G, though it is not officially released as of this post.
-You can upgrade to the Forge DV #fmfsitv. Pics of the Forge DV are shown above.

2. Positive Crankcase Ventilation failure

Background:
The positive crankcase ventilation is supposed to let gases get sucked from the crankcase to the intake manifold when under vacuum. The problem is, when the pcv system fails, and allows positive pressure (boost) to go from the intake manifold back into the crankcase.
(IMG:http://img.photobucket.com/albums/v406/dpham00/pcv.jpg)

The latest PCV is the “G” version. To see which version you have, take a small mirror, and stick it under the pcv valve. The last letter identifies the revision (“E” is shown below). The part # is under the round section:

(IMG:http://img.photobucket.com/albums/v406/dpham00/pcv1.jpg)

Symptoms:
-Typically you will see a slight drop in boost pressure. When my pcv failed, I saw a 2 psi drop across the board.
-Some oil will be pushed out through the oil filler cap, and onto the valve cover, and may possibly go towards the coil packs. There may also be some oil on the bottom side of the engine cover, where the oil filler cap is.
-There might be a slight decrease in MPG.
-Rear PCV failure usually results in oil accumulation around the DV, and will produce a little blue oil smoke at WOT applications.

Solution:
-There is the Digitalhippie fix which puts a check valve into the line from the crankcase to the intake manifold. For those who want a spare of the hose where the check valve is installed, the part number is 06F 103 221 F. You can read more about it here: http://www.golfmkv.com/forums/...=8952
-You can also upgrade to the latest PCV “G” valve. There have been very few failures reported with this PCV. Please verify the PCV you have before upgrading.
Part numbers for this upgrade:
PCV valve cover assembly: 06F 129 101 G
PCV valve cover gasket: 06F 103 483 E
PCV valve cover to turbo hose: 06F 103 215 A
PCV tube to turbo metal gasket: 06F 145 757 F

-If you did the DH pcv fix, and you have a rear pcv failure, then you will need to change the tube labeled as "Exhaust turbocharged gas outlet" showin in the pic above. the Part #'s are the last two shown above (06F 103 215 A & 06F 145 757 F)

3. Broken intake ducting

Background:
Some people have reported that part of the intake ducting that connects to the stock engine (the part in front of the accordion section) breaks off and gets lost, or worst, gets stuck and/or shredded by the fan. Due to its location, the loss in power should be minimal.

(IMG:http://www.swankmonkey.com/vw/jetta/2006/images/engine_cover/intake_cover_damage.jpg)

Symptom:
-You may notice that part of the ducting is missing.
-You may see shreds of the ducting in and around the fan.
-You may see the coolant temps rising possibly due to a part of the intake ducting getting stuck and not allowing the fan to turn. If the coolant gauge goes into the red, then immediately shut the engine off, and check to see if the fan is operating.

Solution:
-If the fan is damaged, then you may need a new fan.
-An aftermarket intake will replace the ducting section, and is a possibly solution.
-You might be able to tape or epoxy the sections together, so that it will make them harder to come apart. You may also remove the top piece alltogether.


4. Cam lobe wear
Background:
Excessive wear of intake camshaft lobe that drives the high pressure fuel pump. The wear limits maximum pump piston lift, causing fuel rail pressure fluctuations. The intake cam drives the fuel pump:

(IMG:http://img.photobucket.com/albums/v406/dpham00/fuel20pump20-20cam20lobe.jpg)

Please see also #5 below.

Symptom:
-Fuel cut-out when driving, esp. under WOT.
-Fuel cut-out symptoms range from soft pulsations of power to long-pulse bucking while in high-gear high-load situations (high gear at WOT, or up a grade). MIL may flash if cut-out is severe. Car will also go into hard-limp (no boost, 4500RPM limit) if severe enough.
-MIL ON
-P0087 Fuel Rail / System Pressure - Too Low
-P1093 Fuel Trim 2, Bank 1 Malfunction
-P2293 Fuel Pressure Regulator 2 Performance

Solution:
Increase surface hardening of camshaft lobe for the high pressure fuel pump. Improved intake camshafts have Part No. 06F109101B. Refer to TSB# 15 07 04

5. High pressure fuel pump failure

Background:
The high pressure fuel pump sometimes is not able to supply enough fuel, especially at low to mid range RPMs because it is cam driven. Please note that the high pressure fuel pump is different than the in-tank fuel pump. Please see also #4 above.

(IMG:http://img.photobucket.com/albums/v406/dpham00/fuelpump.jpg)

Symptom:
-Fuel cut-out when driving, esp. under WOT.
-You may see the following DTC
004767 - Low-Pressure Fuel Pressure Regulation: Pressure too High
P129F - 001 - Upper Limit Exceeded - MIL ON

Solution:
-If you are chipped, then try to put the car in stock mode to see if the fuel cuts will stop. If it does, then you might want to wait until a fuel pump solution comes out. APR and Autotech are currently working on solutions.
-If you are stock, then it is possible that you have a bad fuel pump. The dealer should replace this under warranty.

[Nicky]

Pentru cei interesati, am tradus un document de la Ross-Tech pentru erori aparute pe Vag-Com.

Ajustari in alimentarea cu benzina - FUEL TRIMS (VAG-COM)

Unele dintre cele mai des intalnite coduri de eroare (DTC – Diagnostic Trouble Codes) sunt legate de ajustarile in alimentarea cu benzina (amestec bogat, amestec sarac) In cele ce urmeaza, vor fi prezentate ajustarile in alimentarea cu benzina, cat si repercusiunile acestora asupra functionarii motorului.

Unitatea ECU (Engine Control Unit – Unitatea de Control a Motorului) regleaza amestecul Aer/Combustibil (A/F – Air / Fuel mixture) in scopul mentinerii nivelulurilor optime de putere, randament si emisii poluante. Raportul A/F se exprima fie ca un raport (14.7:1, spre exemplu) sau drept o valoare Lambda. Cu o benzina buna (isooctane – cifra octanica ridicata), valoarea Lambda 1.0 este egala cu 14.7:1 A/F. Aceasta valoare este cunoscuta sub numele de "Stoichiometrica", si presupune o conditie in care exista un echilibru perfect intre moleculele de oxigen si diversele molecule de hidrogen si carbon prezente in carburant. Cu benzina aditivata pe care majoritatea o folosim, raportul A/F real de 15:1 este apropiat celui stoichiometric.

Daca valoarea Lambda este mai mare decat 1.0, atunci se poate spune ca exista un surplus de aer si ca motorul functioneaza cu amestec sarac (running lean).

Daca valoarea Lambda este mai mica decat 1.0, atunci se poate afirma ca exista un surplus de combustibil si ca motorul functioneaza cu amestec bogat (running rich). De notat este faptul ca raporturi sunt determinate pe unitati de masa (grame) si nu de volum (cm3).

Cineva ar putea intreba de ce nu ruleaza motoarele in permanenta la valoarea Lambda = 1.0? Ei bine, ele ruleaza asa IN MAREA PARTE a timpului. La un regim de deplasare economic (cruise) sau la ralanti (idle), amestecul este mentinut la valoarea Lambda=1.0 pentru a mentine convertorul catalitic la o eficienta optima, in acest fel diminuand emisiile poluante. Cu toate acestea, atunci cand este nevoie de acceleratie, amestecul devine mai bogat. De ce? Puterea maxima se realizeaza intre valori Lambda de 0.85 si 0.95 (intre 12.5 si 14.0 raport A/F cu iso-octan). Asadar, in timpul accelerarii, amestecul devine mai bogat. Cateodata se doreste ca amestecul sa fie si mai bogat in timpul accelerarii pentru a evita detonatiile (pre-aprinderea amestecului generata de temperaturile excesive de la nivelul cilindrilor. Motoarele VAG 1.8T au un raport de compresie relativ ridicat pentru gama de motoare turbo, ceea ce le face foarte susceptibile la detonatii sub valori de Boost ridicate.

Asadar, acum stim ca ECU intentioneaza sa fie in masura sa controleze raportul A/F. ECU are un set prescris de valori (maps - harti) pentru o anumita turatie, sarcina etc. Prin urmare, ECU dicteaza injectoarelor timpul in care ele pulverizeaza combustibil (**.* millisecunde) si acest lucru AR TREBUI sa conduca obtinerea raportului A/F dorit. Ei bine, daca ii spui unui angajat sa mearga sa faca ceva, trebuie sa te si asiguri ca acel angajat duce la indeplinire sarcina, nu e asa? ECU se bazeaza pe niste martori (senzorul de oxigen O2 din fata si MAF-ul (Mass Air Flow – senzor de curgere aer in admisie), in principal) care vor transmite inapoi la ECU daca amestecul dorit a fost atins sau nu. Senzorul de oxigen din spate este folosit, in principal, pentru a monitoriza starea convertorului catalitic (catalizatorului), desi, in unele aplicatii, acesta contribuie la atingerea unui nivel mai exact de informare.

Pe baza raspunsului de la martori, ECU invata sa aplice un factor de corectie asupra comenzilor lui catre injectoare. Daca stii ca angajatilor le va lua mai mult timp sa realizeze o sarcina, acest lucru trebuie avut in vedere in faza de planificare a lucrarilor (injectoarele sunt intr-o uniune, deci este greu sa le demitem). Aceste valori invatate sunt introduse in circuitul dintre hartile din memoria Flash ROM a ECU ("chipul") si semnalul catre injectoare. Aceste valori compenstoare sunt cunoscute sub numele de "ajustari" ("trim"). Asadar, unde se regaseste cuvantul "trim", aceasta inseamna "compensare".

"Add" inseamna ajustare aditionala, se refera la un dezechilibru al motorului aflat la ralanti. Atunci cand ECU foloseste o ajustare aditionala, el comanda injectoarelor sa stea deschise o anumita perioada de timp mai lunga sau mai scurta. Defectul (e.g. pierderi de vacuum – vacuum leaks) devine din ce in ce mai insesizabil pe masura ce turatia motorului creste. Pentru valori de adaptare aditionale, reglajul aprinderii (injection timing) este schimbat cu o anumita valoare fixa (un anumit increment). Aceasta valoare nu depinde de reglajul de baza al aprinderii.

"Mult" inseamna ajustare multiplicativa, se refera la un dezechilibru al motorului pe toata plaja de turatii a acestuia. Defectul (e.g. injector blocat / infundat) devine din ce in ce mai pregnant la regimuri de turatie mai ridicate. Pentru valori de adaptare multiplicative, exista o schimbare procentuala in reglajul aprinderii. Aceasta schimbare depinde strict de reglajul de baza al aprinderii.

Puteti verifica starea actuala de ajustare a motorului prin folosirea VAG-COM, mai exact inspectia Grupului 032 din blocul de masura a motorului. Primele doua campuri vor avea procente. Primul camp se refera la ajustarea la ralanti (Additive). Cel de-al doilea se refera la ajustarea la turatii mai inalte ale motorului (Multiplicative). Valorile negative indica faptul ca motorul functioneaza in regim foarte bogat si senzorul de oxigen il face – din acest motiv – mai sarac prin reducerea timpului in care injectoarele stau deschise.

Valorile pozitive indica faptul ca motorul functioneaza in regim foarte sarac si senzorul de oxigen il face – din acest motiv – mai bogat prin cresterea timpului in care injectoarele stau deschise.

Este perfect normal ca oricare dintre cele doua campuri sa fie diferite de zero. De fapt, valoarea zero in ambele campuri indica fie faptul ca au fost recent resetate codurile (resetarea va anula si valorile de ajustare) sau faptul ca ceva nu functioneaza corespunzator. Daca valorile se indeparteaza prea tare de valoarea zero, aceasta va genera un cod de diagnostic al unei probleme (cod de avarie) si pot aprinde indicatorul MIL (denumit in mod current Check Engine Light, sau CEL). Specificatiile pentru operare normala sunt in spectrul a +/- 10%.

In general, o valoare iesita din comun regasita in primul camp (Additive) indica o pierdere de vacuum deoarece este prezenta in principal la ralanti, cand valorile de vacuum sunt maxime. O valoare iesita din comun pentru cel de-al doilea camp (Multiplicative) indica un defect la regim de turatii mai mari, si poate insemna si un senzor MAF cu probleme.

Aceasta este o verificare simpla a functionarii senzorului MAF. Realizati o acceleratie completa pana la linia rosie a turometrului (de preferat cu treapta a II-a, a II-a sau a IV-a de viteza). Grupul 002 arata in mod normal masa de aer in g/s. Valoarea maxima a masei de aer trebuie sa fie mai mult sau mai putin egala cu 80% din puterea masinii.

Asadar, daca aveti o masina stock de 150 CP, motor 1.8T, asteptati-va sa aveti in jur de 120 g/s. Daca valoarea inregistrata este mult mai mica decat cea calculata, senzorul MAF nu functioneaza corect. Acest calcul este valabil si in cazul masinilor chip-uite (remapped), dar programele "race" pot produce mai multi cai putere cu precadere prin intermediul reglajului aprinderii, decat printr-o mai mare masa de aer. Tocmai de aceea, citirile trebuie interpretate cu indulgenta.



Sursa: http://www.ross-tech.com/vag-com/cars/fuel-trim.html
© Nicky Dobreanu, May 2010

PS Pentru cei nefamiliarizati cu Sonda Lambda, un articol mai mult decat interesant puteti gasi pe http://www.pilotauto.ro/magazin/home-mainm...77-sonda-lambda