'97 TDi 110 (AFN) not boosting?

Meant to say on previous post:

I've now ordered a cheap VAG specific diagnostic computer off fleabay (even if it doesn't diagnose the running fault itself, I will at least know when I manage to get the diagnostic socket working) and have ordered a job lot of 3mm silicon tubing so will look at replacing all the vacuum pipes at the weekend and trying to get the diagnostics working. Think I will also be checking the AMM wiring as best I can. Hopefully this will solve matters but we shall see...

Thanks again guys, you're all stars!

Hi all, an update:

Replaced most of the vacuum pipes and the fuel return lines today. I don’t think any were actually leaking but they were all in need of replacement. Did not cure the poor running though.

Then set about checking all the wiring for the diagnostics socket. Sadly I did not apply the KISS (Keep It Simple Stupid) principle here before pulling out the centre console and stripping back fabric wrapping to check the wires – turns out it was just a sodding fuse! (Thanks Dad!) I hadn’t realised this would have been fused as I thought it was run from the radio loom and would therefore be covered by that fuse.

IMPORTANT LESSON everyone – check the simple things first!

Anyway, the diagnostics has thrown back:

Code 01237 – Fuel Cut Off Valve N109
Code 00553 – Mass Air Flow Sensor – G70 (I did say it was a cheap code reader otherwise it would probably have said Air Mass Meter or AMM!)

I gather the Fuel Cut Off Valve could explain the revving to 2000rpm on start up but does anyone know if this could throw back a false reading on the AMM as well? It’s just that I did try replacing the AMM with a genuine part and it made no difference at all to the running. But there again, I wasn’t aware of the fault with the Valve at this point so maybe it wouldn’t have done anyway.

Anyway, searching other threads leads me to believe best option for now is replace the Fuel Cut Off Valve and take it from there.

Thanks to everyone for comments and suggestions so far and if anyone else has anything else to add, please feel free!

Final installment:

Checked the wiring to the Fuel Cut Off Valve, wiggled it a bit, then cleared the fault code.

Result; car runs fine! Gave it a good hard drive around then checked again and no fault codes, car still running fine.

I suspect I may have to change it at some point as I have seen other threads about them sticking sometimes but I'm mighty relieved it has not turned out to be anywhere near as bad as it might have been, eg new turbo!

Thanks to everyone for advice and I hope this thread proves useful for others.

(A happy) BadgerBoy

Out of curiosity whereabouts is the fuel cut off valve,I'm changing all my vacuum lines tomorrow so hopefully it will solve my problem!

Quote:

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Originally Posted by galaxy98s

Out of curiosity whereabouts is the fuel cut off valve,I'm changing all my vacuum lines tomorrow so hopefully it will solve my problem!

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Hi Galaxy,

Apologies for not replying sooner - I no longer have internet access and haven't been on for a while, I'm using a friend's as it is.

I hope you were able to sort your problem but just in case - the fuel cut off valve was located in the unit above the fuel filter. A bit of a pain to get to as the injector pipes are running all round there but a bit of patience and you can do it. I couldn't see an actual fault with mine though - I located the problem with a cheap diagnostics computer off Ebay (£23 including p&p if I remember correctly) and I would recommend going down this route rather than trying to second guess things.

Apologies again but I hope someone finds this useful.

Cheers,
BadgerBoy