VW Passat Tdi110 Loosing Power

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Fri 12 Dec 2003 00:46
VW Passat Tdi110 Loosing Power - dieselnut
My sons Tdi 110 with AFN engine looses power. If you accelerate hard in say 3rd gear, as the rev counter reaches about 3000rpm, which must be about maximum boost pressure from the turbo, the engine looses power as though the turbo had been disconnected. I suspect the ECU has detected a problem & restricted the fuel supply. I swopped the Air Flow sensor off my Tdi Golf but symptoms were exactly the same. You can hear the turbo still singing after the power loss but there is obviously not enough fuel reaching the injectors. If you turn off engine & restart, the engine pulls strongly again until 3k revs as before. Has anyone got any ideas ?
Thanks.
Philip.
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Fri 12 Dec 2003 08:21
VW Passat Tdi110 Loosing Power - Peter D
Waste Gate Stuck Open ??
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Fri 19 Dec 2003 23:36
VW Passat Tdi110 Loosing Power - dieselnut
Problem has returned , so it wasn,t the EGR valve as its still disconnected.
At the same time as I disconnected this valve, I picked up on Peter D's reply & gave the wastegate pivot a squirt of WD40.
So i'm thinking that may have unstuck the wastegate for a short time.
Does anyone know if this can be fixed permenantly or is it just a case of getting an exchange turbo ?
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Fri 12 Dec 2003 10:57
VW Passat Tdi110 Loosing Power - Malcolm_L
There\'s several threads on this, but IIRC there\'s a small pipe leading from the turbo to the ECU(?).
If this is split/leaking this causes loss of boost.

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Fri 12 Dec 2003 11:42
VW Passat Tdi110 Loosing Power - Craig_1969
ALso look at the intercooler pipes. That was my problem with my 110 + maf failure.
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Sat 13 Dec 2003 20:19
VW Passat Tdi110 Loosing Power - dieselnut
Thanks for the replies.
I've cured the problem, but not 100% sure how.
I disconnected the electrical connector to the EGR control valve
& full power has been restored throughout the rev range.
I can only assume the valve was operating at full throttle instead of at partial throttle , letting too much exhaust gasses back into the inlet, unless anyone has any other ideas ?
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Sun 14 Dec 2003 09:24
VW Passat Tdi110 Loosing Power - DL
The EGR valve is a common culprit, I suggest you leave it disconnected - you will do no harm.
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Wed 17 Dec 2003 14:59
VW Passat Tdi110 Loosing Power - Craig_1969
Is the egr valve in the middle of the intercooler air feed pipe right at the rear of the engine bay at the top? I have also been told to remove the battery and reset the ecu in this way to solve my problem.
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Wed 17 Dec 2003 20:40
VW Passat Tdi110 Loosing Power - DL
Nah, the EGR valve is right on top of the engine IIRC, on the offside, above the turbo.
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Thu 18 Dec 2003 21:05
VW Passat Tdi110 Loosing Power - IDIY
I had a similar problem on my passat which turned out to be the MAF sensor. The acid test to determine this is to unplug it & run the car (as advised in car mechanics mag) - if it performs better then it this likely to be the culprit as I believe that the computer defaults back to it's default setting. The other test with the EGR valve is to clamp the vacuum pipe clsoed that operates the valve. cheapest place for MAF sensor is eurocarparts or german & swedish c £115 +VAT.
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Fri 19 Dec 2003 12:40
VW Passat Tdi110 Loosing Power - Craig_1969
I reset the ecu by diconeecting the battery, its got a bit more power now. Ordered a cable for vag-com £43 inc so I can try to diagnose it myself. Thanks for the info.

My confidence is a bit dented in VW my new Beetle convertible has had an abs failure, and its going to take 3 weeks for a new module!
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Fri 19 Dec 2003 13:40
VW Passat Tdi110 Loosing Power - DL
Please don't let this thread turn into another VW bashing thread!!!! :-)
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