tdi power loss

philliprobert

Active member
Joined
Jan 23, 2006
2002 130bhp passat that is overnight lost loads of power. No pull in low revs, bit better once you get about 2500/2800 revs. I have seen several recommendations on cleaning the maf (air flow meter?) and the egr.
Any writeups here on where exactly it is on this model? Pic anywhere on the net? I have seen all the info on how to actually clean it, but not where it is! Mate has my haynes manual, and i believe he is away at the moment, so cant check.
thanks
 

Dave Scott

Member
Joined
Sep 4, 2006
Location
Thailand
TDI
Passat B5.5 130
Ok, unplugged the maf sensor, and drove car. behaved exactly the same. one dead maf?
Not necessarily. I did the same thing, got the same results as you, and finally traced it to the turbo actuator control valve (N75).
 

philliprobert

Active member
Joined
Jan 23, 2006
simmilar enough, im the 2nd post on that thread too! have the maf ordered from local dealer, will swap that out, and check egr and a few other bits. I saw an faq for cleaning egr on an a4, simmilar to do the passat? sometimes, only in the last day, i have noticed a small hiccup/buck though.
 

ChrisB__1

Member
Joined
Aug 27, 2005
TDI
SE, 99, green
As Dave says, could be actuator that's stuck open, bypassing exhausts gases too much, giving you less power low-down but eventually picking up in the higher revs when exhaust gases would bypass anyway.
 

philliprobert

Active member
Joined
Jan 23, 2006
ok replaced the maf....
Still the same..sniff...had a mechanice mate have a peek in and around the car, he could only say that its a boost problem. Would it be better to replace that n75 or bite the bullet and drop it into dealer?
 

TurbineWhine

Veteran Member
Joined
Sep 16, 2005
Location
Asheville, NC
TDI
Jetta, 2003, Platinum Grey
I would try to get someone with a VagCom hook up to it and check the actual boost pressure that your seeing using the VagScope function. If you are down on or erractic in boost, it should show up. Check the VAG-Com List at the top of the homepage for someone close to you to call.

TW
 

ChrisB__1

Member
Joined
Aug 27, 2005
TDI
SE, 99, green
Phil - check for pipes that have disconnected mate, follow pipes from turbos to inlet including around the intercooler behind the left (nearside UK) wheel arch liner.

Is this the part?
http://www.geocities.com/tech4tdi/pages/maf.html

There are suggestions there that it could be anti-shudder valve causing low MAF readings - anyone know if would be enough to cause the prob?
 
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TurbineWhine

Veteran Member
Joined
Sep 16, 2005
Location
Asheville, NC
TDI
Jetta, 2003, Platinum Grey
philliprobert said:
I actually have one, what kinda levels should i be seeing at what kinda revs?
Not sure for your model but at full throttle, mine is about 19PSI once you do the conversion to PSI. The boost spikes when you nail the throttle are about 21 PSI and then it settles down to 19 PSI full throttle. I would guess that your model and engine would be about the same. It you are getting full throttle numbers below about 16 PSI, then I would start looking for turbo hose air leaks.

TW
 

philliprobert

Active member
Joined
Jan 23, 2006
ive it booked into local vw garage on friday. As well as the power problems, ill see if they can sort my external temp sense too. also a question, when you start the car, on the instrument panel, what lights should light up? The engine whatever one doesnt light up on mine at all, so i have a sneaky suspicion previous owner removed bulb?
 

philliprobert

Active member
Joined
Jan 23, 2006
Well car is in the local dealer now. Dropped it into a place that only recently got vw accredited, with a shiny new vw service sign on the road.

Told him i have huge power loss, suspect a boost problem, and that i had already replaced the maf.
Also asked could they check the instrument panel as not all the lights light up that should, so thinking sneaky previous owner.
Finally asked them to check the temp display on both the climatronic and the dash (mfa? can never remember its name) as both just have -.--.

Place your bets, roll up roll up! how much will they charge!
 

philliprobert

Active member
Joined
Jan 23, 2006
Ok, picked up the car. Good news is they found out whats wrong, bad news is their computer was down and wouldnt be able to tell me how much it would cost to fix till monday.
Apparently i need a new throttle housing... Is my throttle currently homeless? i dont know. Searching forums at the moment.
Anyone had one replaced? They said they tried to reprogam it but it didnt work.
On the plus side, there was nothing wrong with the instrument panel, and the temp not displaying was just a loose wire. All i was charged was an hours labour for the whole lot today!
Think i found my new dealer....
 

CAATS_Man

Veteran Member
Joined
Jun 21, 2003
Location
South Delta, BC
TDI
2006 Jetta, Pkg2, ESP, DSG, & 8 airbags
Diesels don't use a throttle so I'm guessing it doesn't need a new throttle housing. Be very careful dealing with the new dealer.

CM
 

DPM

Top Post Dawg
Joined
Mar 16, 2001
Location
Newtownards, N. Ireland
TDI
2019 Rav4 AWD Hybrid, Citroen C4 BlueHDI
CAATS_Man said:
Diesels don't use a throttle so I'm guessing it doesn't need a new throttle housing. Be very careful dealing with the new dealer.

CM
Nope, modern diesels *do* have a throttle body; it's used for EGR control and to provide a smooth shutoff...
 

philliprobert

Active member
Joined
Jan 23, 2006
ya just found out throttle body/housing is same thing. He wont have prices for me till monday, but they look to be over $400 on the net...
 

philliprobert

Active member
Joined
Jan 23, 2006
Ok back home, and so is the car, all fixed! woohooo

Problem was a split vac pipe. They ordered it yesterday, had it today, and fixed it this morning...god i missed my car!
2 hrs labour plus 60 odd euro for the pipe though.
 
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