Low power, no codes... Need help!

Hi,

I'm from sweden but I want to see if anyone over there have any good ideas to help me find out what's wrong with my TDI.

It's a 2003 VW Caddy 1.9 TDI with the ALH engine.
Bought it recently to replace same model that's a rust bucket so I have parts to swap. The problem was present at purchase but I thought I could fix it since I've had similar problems with my old car but no luck so far...

It's runns fine on idle and no smoke or something else wrong with it except it lacks power like I have no turbo.
First and second gear feels ok but third and up it feels weak. I can get it up to 130kph but it takes time and upphill it does about 80kph.
It never goes in limp and I'm not getting any fault codes.
I have ordered that vcds cable but it haven't arrived yet.

So I've tried to figgure out what the problem is for a couple of weeks now but I'm not making much progress

Here's what I have done so far:
I replaced the MAF
I installed a new air filter and cleaned the intake manifold/EGR
Cleaned the air intake
The VNT vanes are moving freely
I replaced all the vacuum hoses
I replaced the Boost pressure valve N75
I replaced the fuel filter
Checked the fuel flow from the tank and it runns freely
(no pump in the tank on this one)
Turbo sound ok
Cam belt looks fine

And as i said no fault codes...

Any ideas much apriciated!

Sounds like limp mode - will lock out all but minimal boost, but will not set a code an OBDII reader can see. VCDS will be able to see the code though.

To diagnose in advance of your VCDS cable, connect a boost gauge into the intake plumbing and see what level of boost your car is making - should be 12-14 psi, or close to 1 bar.

When did this problem start - was there any other symptom(s) when the low power started to occur?

Ok, thanks! Will try that!
I bought the car with the problem included.
The seller said he didn't try to fix it so I hoped it would be as easy as a cloged intake manifold. But when I got home and opened it up it was clean so he probably did try to fix it... So to answer your question, I don't know if there was any other symtoms?

Moved to the A4 forum.

Turbo actuator?

Pull a vacuum on the turbo actuator. It should start moving at about 4 inches of Hg and stop at about 18. It should be smooth all the way through the range.

maybe a compression test? Nozzles clogged? Weak IP? Fill filter with diesel cetane additive run for a minute .20 leave it overnight.

How does it start COLD?

It rumbels a bit when starting cold but not worse than my other car, identical car with the same engine that runns great...
I have been looking to clean the injectors, better to remove them or fill the filter like indysoto describes? And what's best to clean them with?

I'm still waiting for the vcds cable, hope that will give me some good info!

MAP sensor?

fuel filter t o rings

did you change the fuel filter 't' o rings?

Cribb said:

It rumbels a bit when starting cold but not worse than my other car, identical car with the same engine that runns great...
I have been looking to clean the injectors, better to remove them or fill the filter like indysoto describes? And what's best to clean them with?

I'm still waiting for the vcds cable, hope that will give me some good info!

Click to expand...

I would either run a can of stuff straight or remove them and have a pro check them out (unless you are one).
I like Post #5, but there are several other possibles.

Where did you get the MAF?

If you disconnect it what happens?

Are you sure all the vacuum hoses are connected correctly? (make sure the one to the airbox is ON!)

Maf is from my other car and all hoses are correct compared with that car that runns perfectly.
Have even tried one from my wifeys skoda with the same engine but AGR...

Where is th fuelfilter o-rings? Did not change anything like that but I have mounted an electric fuelpump after the filter to give more pressure but that didn't do any good...

I haven't done anything with it for a week now since I'm working 12+ hours a day. But will swap injectors from another ALH engine that I have laying around after cleaning them first.
Also I'm still waiting for the vcds cable...
Lots to do next time I'll have a day off

Thanks for all ideas!

o-rings are on the thermostatic tee that sites in the top of the fuel filter. Normally they get changed with the new filter. Some folks have modified fuel filter set-ups.
I would not insert a pump into that fuel system, at least not right in front of the injection pump.

Wonder if there's any fuel blockage from the in-tank fuel pick-up?

The electric pump was installed in-line before the mechanical to ensure there wasn't a blockage issue. It was on 0.2-0.4 bar pressure so shouldn't be a problem for the mechanical pump. Got that advise from a diesel-engine-mechanic working on the pist machines we drive at work, only to exclude the possibility of blocked fuellines, pickup or filter. With a switch so I could turn it on when driving.
But it made no difference and as I mentioned before the fuel flows freely from the tank to the filter and even after the filter.
Checked the o-rings and they are in good condish, but I orderd new ones since they cost next to nothing and I was getting new seals for the injectors anyway for when I replace those.
Have checked the turbo vanes and they moved at correct vacuum and the actuator holds the vacuum too.

Could this be a pump timing issue?
What's the symtoms for that?

Do you have any black smoke? If so might be a weak pump or clogged nozzles, I had a weak pump stuck in oversize Brazilian nozzles 10 years later still runs like a champ. did you try the diesel additive 14 hour nozzle soak? Fill filter with diesel cetane additive and run car for 2.5 minutes shut off let soak.

No black smoke at all... It's a swedish sold car since new and we have -40 sometimes in winter so the cars are usually "prepared" for cold weather.
But it looks like warmer weather tomorrow wich means I get a day off work so I will look in to cleaning those injectors.
And it looks like that vcds cabel entered sweden today so that will be interesting!

Seeing as you just got the car and don't really know it's history I'm thinking that it might be a good idea to check static timing. It's possible that, given everything else appears to check out fine, that the cam timing is off. This and a compression test would help establish how healthy the basics are.

While one can check pump timing one cannot really know, I don't think, if the cam timing is off (other than by a physical approach).

Getting, and using, VCDS will really help.

Sorry for the resurrect of this post, but have you had any progress on this?
I've had the exact same experience, bought the car with the very same problem. I have VCDS and no errors whatsoever.
New turbo, new MAF, new N75, new vaccum lines, fuel filter with all o-rings in it, new fuel lines, new pilot injector, and the symptoms remain.

If you have vcds, have you logged requested boost vs actual?

Thanks for the fast reply Windex.
I've done all types of logs; boost, fuel, etc. All seems fine. I believe I have a log file somewhere on the external hard drive.
It's a strange one, I've seen compression aswell and all cylinders are on the exact same healthy value. The engine sounds great, cranks after one turn.

Could be the VNT actuator is froze or inoperable. Connect a vacuum pump and gauge. It should start to move at 3.5 to 5.0 "/Hg. then check if it does in fact move when you start the car.

It's all in good nick there aswell, BobnOH.
Probably the next step is to cleanse her soul in a holistic centre...
Intake clean as a whistle aswell, not a single particle of build-up.
I did take out the exhaust, same symptoms.
No leaks aswell.
I think I've exhausted all options.

Still wanting some more opinions on this matter, because surely I'm missing something. Just don't know what exactly.