AMF TDi 75 2002 no boost, no codes

nin

nin

A2OC Donor
Hi folks

Here’s a conundrum that I’m sure someone can solve quickly - but has me stumped.

Background:

My new to me TDi was running fine, but needed a service. So on Saturday it got the full works - new air, oil and cabin filter, new engine oil. I took the EGR off and replaced it with a clean one. And then replaced rear shocks. During this I took the undertray off and replaced with no drama.

While working on the EGR, I had to run the car off the ramps so started it with the charge pipe disconnected. It threw a code that I deleted.

Put everything back together, took it for a test drive - no boost.

I replaced all the vacuum pipe connectors on the control valves, except the green hose.

VCDS lite is giving me this info:
IMG_7086.jpg

IMG_7087.jpg


No leaks from the intercooler that I can see, and no fault codes.

Thoughts?
 
The green hose on the N75 valve is the turbo pressure line. If it is disconnected anywhere from the turbo or its transition from rubber to plastic pipe or the right angle connector onto the N75 there is no regulation of boost by the N75 valve. likewise if the waste gate control line is disconnected or leaking there again is no boost regulation. The joins between plastic to rubber MUST be good. The joins half way down the bck of the engine or on the turbo itself are the most problematic. The N75 valve also needs good contact with the electrical connector.
 
Ta. I have some silicon hose on order, I’ll replace the whole green hose and waste gate control line and see if that does the trick.
 
Try just making sure all connections are tight. If it was working before then most likely is a loose or disconnect pipe for the N75.
 
Ok so replaced all the hoses, still no boost. And now I’m getting MAF - implausible signal P0101 intermittent.

And the arm form the wastegate actuator is rock solid - no slack or movement in it at all - is that normal?

f614dda0fc71ca062333432ee4209908.jpg



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nin said:
Ok so replaced all the hoses, still no boost. And now I’m getting MAF - implausible signal P0101 intermittent.

And the arm form the wastegate actuator is rock solid - no slack or movement in it at all - is that normal?

f614dda0fc71ca062333432ee4209908.jpg



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Click to expand...
Hi nin,
No it should be free to move with the c clip removed or by applying air not vacuum to it on the early tdi’s it’s a simple flap valve in the exhaust port of the turboIMG_0495.jpegIMG_0492.jpeg
Hope that helps
Keith.
 

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nin said:
Hmmm. It’s rock solid.
Click to expand...
Mine was very stiff , spray some penetrating oil (not WD40)on the arm where it goes into turbo body as it’s a brass sleeve it runs through & see if that helps, had mine off as I broke the cam belt so I removed shaft from waste gate & cleaned & polished sleeve/ shaft & relapped the flap into the turbo seat, relubricate with a ceramic grease (Febi) do one if your going down this route.
Hope that helps
Keith
 
I recently tried fitting my own turbo, gave up of course, but along the journey I had a new turbo to hand.
The wastegate rod is surprisingly strong and the spring strong holding it shut\closed. Even off the car the new turbos gate was hard to hold open.

On am 02 amf..With wastegate closed surely you get 100% boost all the time so it can't be this can it?
The regulation comes by opening the waste gate slightly to vary the pressure. This is done by vacuum pipe controller by thr valve and ecu?
Unless the turbo goes limp if the ecu detects a stuck wastegate? But then don't some people join the vacuum hoses at the turbo to leave it 100% boosting? And therefore wastegate shut
 
Thanks Crispy. Had a good chat with the guys at Stealth, and have some tests to run this evening. Also have replacement solenoids in order in case …
 
Right now I am officially confused.

I’ve replaced all the vacuum hoses with new silicon, and N75 with a known good replacement. I’ve connected the hoses as per the 2002 AMF 75hp TDi parts diagram.

I’ve cleaned the MAF

I’ve been able to move the turbo wastegate actuator using an airline, so it’s not seized.

But, still no boost, and the VCDS test in basic settings isn’t actuating the wastegate - so not getting any boost.

Holding the N75 I can feel it switching, so don’t think it’s the signal getting to the solenoid.

Flummoxed. Ideas?
 
I would try it with maf unplugged and/or EGR vacuum pipe unplugged and rubber pipe blocked off with something like a golf tee

Looking at this in black and white the new/replacement EGR has potentially caused this problem
 
Joga said:
Have you doublechecked the turbine can rotate freely?
Click to expand...

I’ve not - mainly because it was working perfectly when it rolled onto the ramps, no noises, oil, smoke etc and it’s only a 70k engine.

I’ll try options with the EGR, if that doesn’t do it I’ll drop it off at Stealth and let them loose on it.
 
If they don't work I would serious consider refitting your old EGR then it's back to how it was and hopefully rules it out of the equation
 
Howey said:
If they don't work I would serious consider refitting your old EGR then it's back to how it was and hopefully rules it out of the equation
Click to expand...

That’s the plan …


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Please report back when you find the cause as this is a real puzzle. No doubt it'll be something super simple!!
 
Old EGR fitted, all vacuum hoses replaced, MAF cleaned, still no boost.

About an egg-cup full of oil in the lower intercooler pipe.
 
An egg cups not toooooo bad, check the intercooler seals, maybe that the egr swap has allowed the engine to run better and that tiny extra pressure has popped a decaying lower intercooler seal, this is common.
 
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