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ASV 110 TDi overfueling? Advice requested.


asteconn

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Background:

 

110TDi ASV, a couple of months ago I had an oil leak. As part of the fix to get it home AA man topped up with some 10w40, apparently I'm needing 5w30 for reference, and since then I haven't been able to change the oil because my sump's oil drain plug won't come out.

Not too long afterwards, the car started running terribly: overfueling dreadfully and being very sluggish. Plugging it into a vagcom yielded a duff MAP sensor, since replaced, and that restored some semblance of performance into the car.

However, it is still noticeably worse on fuel under any acceleration than before all of these events started.

 

I've been advised so far that the MAF sensor could be a problem, or that turbo vanes could be playing up. I can think of either the oil, although I don't know if this is coincidental or not; or a sly boost leak somewhere. What other issues could I troubleshoot, or would looking anywhere else be advised?

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Best thing to do is get it plugged into vcds again and look for any other fault codes. Then get the timing checked as this can cause running issues. Also check that the brakes are not binding as this increases fuel consumption too.

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If we say you have 1l of 10W40 and 3 of 5W30, and then assume that the viscosity changes to the mix proportion, you're running 6.25W32.5 which is 1/12th (0.083recurring) thicker than new 5W30.

Oil drag on recommended grade tends to be about 1bhp on a 2.0l engine, so that will mean you have an extra oil drag of under 0.1bhp, so that shouldn't be your issue.

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Another potential symptom: quite reluctant to turn over when really cold.

 

Best thing to do is get it plugged into vcds again and look for any other fault codes. Then get the timing checked as this can cause running issues. Also check that the brakes are not binding as this increases fuel consumption too.

How would I check the timing and brakes? Haven't done either of those before.

 

+ sticky egr valve

Thanks for that suggestion! How would I test this?

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Get it plugged into vcds all problems you have asked about will either be logged as a fault, or can be measured when cold starting etc. Sticking vanes will come up with overboost detected. It could also be a faulty CTS (coolant temperature sensor), this can be measured with vcds, and someone who knows how to use it.

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Is the coolant temp sensor the same sensor that supplies the dashboard needle temperature readout? Mine's been intermittent for well over 12 months.

The CTS has two circuits, one goes to the dash, the other to the ecu. One can go bad but the other is ok.

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Is the coolant temp sensor the same sensor that supplies the dashboard needle temperature readout? Mine's been intermittent for well over 12 months.

Normally if it's playing up on the dash it's giving the wrong information to the ecu, which can cause overfueling.

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Just run a diagnostic - 01039 Coolant sensor not testable is the only status code that comes up related to the issue.

 

It's also detecting a problem with my radio, which is to be expected as I've removed it :D

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Just run a diagnostic - 01039 Coolant sensor not testable is the only status code that comes up related to the issue.

It's also detecting a problem with my radio, which is to be expected as I've removed it :D

I'd replace the CTS with a genuine item as fairly cheap and non genuine tend to fail very quickly.

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As well as the coolant temp sensor, after about 80k miles, you tend to get the injectors dribbling and spraying onto the bores a bit as the spray pattern goes out.

It's fairly simple to get them sonically cleaned or re-nozzled so they spray true again and worth doing if you intend to keep the car, as fuel on the bores won't help things.

 

I'd do the above first though and also check the condition of your battery as if it's low that can cause all sorts of problems with electrical systems.

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