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Dave's shonkers - bye bye S3 (sadface.jpg)


Dave_Q

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1 hour ago, Ghosty said:

They're extending the platforms at Morley this week so the Leeds-Hud lines closed and on diversion to Wakey. 

Liverpool through services got swapped to Manchester Victoria a while ago as it's better for operations, to get into Piccadilly P13 from the Huddersfield line is a massive move that causes a lot of delays as you have to get across every single line coming out of Piccadilly. 

Is that a permanent move to Victoria? 

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Home and already thrilling the neighbours, I'm sure.

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List of issues identifed on the way back:

  • Extremely annoying heatshield or exhaust type ratlle from LH rear
  • All 4 tyres both ditchfinder and low on tread
  • Many electrical items not working, heated seats, 12v socket, no FM reception, probably others
  • No history unless its in the broken glovebox I can't open
  • Rear window has been resealed with some sort of household sealant
    • Related - smells a bit damp in the boot
  • Power severely lacking

On the last point I did wonder if the turbo wastegate is siezed as I tried some logging and only saw 4-5psi with foot flat at 2500rpm. 

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Later I did see more like 11-12psi which I think is about right but still didn't feel very boosty. It doesn't have any fault codes stored. 

Will start with a VCDS sesh, a throttle body clean and some vac hose checking/replacement to tick off some of the easy things first and maybe test if the WG is moving.

Overall I have definitely upgraded to a worse version of what I had as per, but I reckon there is a good car hidden in there somewhere. 

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  • Dave_Q changed the title to Dave's shonkers - fire up the (1.8t) quattro

When you say no fault codes, is that with VCDS? I was pressure drop code between turbo and manifold from a duff MAF. Didn't show on standard OBD but did on VCDS.  That was halving the boost the turbo was getting. No warning light was showing with the code stored. Disconnecting the BBT branded MAF bought back my boost. DV not unknown to leak and cause boost drop out too. These 1.8t do seem to like to eat MAFs too. 

Can't remember on the A4 but many VAG I've had, there is an additional book holder in the top of the glove box where the manuals live. Many dealers don't know this and assume no history when it's just hiding there. 

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That was with torque and an ELM thing. 

VCDS says:

image.png.f9b6ef5944151c8e745aaecf88e904cc.png

These cleared OK.

No books hidden in the slot and I was able to get into the glovebox just now wherein I found: a MAF and an N75....

 

A quick run with VCDS logging and the MAF value looks OK at idle and got to 180g/s going up a hill which I think is OK-ish?

Although coming back with the MAF unplugged it felt better. 

Suppose a new genuine one rules something out, I will clean the TB first though as the revs are definitely hanging when you've had your foot down which can't be a good sign.

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5 minutes ago, Dave_Q said:

@SiC which measuring blocks do I need for actual vs requested boost? 

I got as far as 40 and didn't see it?

This isn't VCDS (as this is easier to use in the car when driving) but I believe the group numbering is the same. So group 119 for boost measurement blocks.

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32 minutes ago, Dave_Q said:

Suppose a new genuine one rules something out, I will clean the TB first though as the revs are definitely hanging when you've had your foot down which can't be a good sign.

Hanging revs is probably will be due to the clutch switch failure. It'll cut fuel quicker when it sees the clutch down and a failed switch is a common cause of hanging revs on these. 

When you've cleaned the TB, there is an adaptation (not very well documented) to reset the end points. These are documented here but interestingly don't show up in the drop down in VCDS. Even with the very latest (legit) version:

http://wiki.ross-tech.com/wiki/index.php/Throttle_Body_Alignment_(TBA)

I say this as I remember @phil_lihp had a Octavia MK1 VRS where there was a whole bunch of codes that wouldn't go away and rough running (air leaks iirc). Different garages couldn't figure the problem so he flogged it on here. @twosmoke300 bought it up and iirc the tl;dr a Throttle body adaptation unexpectedly fixed it. Suspected that it was slightly too far open (especially at idle) - effectively creating extra air and a lean condition. 

So despite it supposed to self adapt automatically, I'd suggest to run the adaptation block described above. 

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31 minutes ago, Dave_Q said:

A quick run with VCDS logging and the MAF value looks OK at idle and got to 180g/s going up a hill which I think is OK-ish?

You can log them versus boost pressure to see if the MAF is telling the truth or not. However I diagnosed my dodgy MAF simply by disconnecting it and getting twice the boost registered. Given mine had an aftermarket cheapy BBT, I wasn't going to do any further diagnosis until I had a genuine new Bosch unit on there. So I parts cannoned it with only that basic disconnection test. Which ended up being the correct part for the solution as I gained an extra 10MPG, twice the boost and far better drivability. 

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Check the clutch switch is working properly in whatever group block. I can't remember if it's dual contacts like the brake switch to detect a failed switch or it implies it from rev drops/stationary. That said, the brake switch in the A4 B7 I had failed intermittently. Working fine for a bit (quite a few actuations) and then failed randomly throwing the fault light on through Glow Plug light as these do.  

Basically what I'm saying is that if it's done it once, it's almost certainly will fail again. 

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Done a bit of logging and none the wiser tbh. 

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I assume these are the same as the diesels and requested/actual boost is in mbar absolute? Meaning that whether the MAF is plugged in or not it's requesting and receiving about 0.4bar max?

The MAF reading goes from 3.5g/s at idle to 150g/s at 6250rpm, I think this is too low?

I did also confirm the clutch switch isn't working regardless of codes and I also have a code for temp sensor implausible that has come back so will order those as a starter for 10.

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1 hour ago, Dave_Q said:

I have the one I found in the glovebox, not sure about known good.

The stuff I am reading suggests that the overall MAF reading might be about right so I'm still a bit baffled as to why its asking for so little boost.

It may be completely irrelevant as the last time I had a VW, it had a Webber Carb and was in Jetta form, so I'm out of the loop with VW stuff. 

But, I've had a couple of PSA diesels which performed as poorly with a bad MAF removed as it did plugged in. Both times resolved with a good brand or OEM replacement MAF.  No codes, just felt a bit flat, lack of boost. 

Maybe a blast of contact cleaner? May be covered in crud? Worth a go for not a lot of cost. 

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My 180 peaked at just under 1690mbar absolute. So 690mbar = ~10psi which I believe is correct.

Check of the reg says yours is a 163bhp. I don't know much about that engine but the 150bhp TT iirc is around 7psi of boost so about 1480 mbar absolute.  Sounds like yours maybe a tad low but not excessively. 

What's interesting is that it tracks the demanded to actual pretty closely (ignoring under 2k when it'll be spinning up). So looks like the ECU is happy with the turbo and what it is doing. 

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Actually the enlarged scale on that excel graph isn't helping here. Looking again, the demand looks a good few tens of millibar away from the actual. At 2k requesting 1.5bar absolute but getting 1.4bar (1.45psi loss). 3k requesting 1.4bar and getting 1.37ish bar (0.5psi loss).

Boost leak? DV valve not sealing? Vacuum hose/solenoid control valve leaking?

Can get a hand vacuum pump on those lines and see if they hold a vacuum. 

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On 26/01/2023 at 13:32, motorpunk said:

I had an early Zoe as a press loaner, along with (IIRC) 5 other people. Of the 6 cars, 4 broke down within days. Mine had a freaky wobble at speed, then wouldn't charge up, and Renault were clueless. They gave us each an ipad not to say anything in the media. None of us published a feature about the  car in the end. 

I like the seats and the gentle styling and hope the car works well for you. Good luck! :)

 

You'd better give the iPad back. How long did you have to stay quiet? 

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8 hours ago, SiC said:

Actually the enlarged scale on that excel graph isn't helping here. Looking again, the demand looks a good few tens of millibar away from the actual. At 2k requesting 1.5bar absolute but getting 1.4bar (1.45psi loss). 3k requesting 1.4bar and getting 1.37ish bar (0.5psi loss).

Boost leak? DV valve not sealing? Vacuum hose/solenoid control valve leaking?

Can get a hand vacuum pump on those lines and see if they hold a vacuum. 

Thanks, I'll repost it with a better scale later. I do have a vac pump so will test the DV.

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2 hours ago, New POD said:

You'd better give the iPad back. How long did you have to stay quiet? 

On a very good day, maybe 10 people read this thread.

I value the reputational damage of stating that early Zoes were a bit (or maybe a lot) shit to those 10 people at about £0.001.

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Here is the boost graph with a better scale.

image.png.45a79a7f3e8da238746c305630543f7f.png

I think that standard it should be somewhere around 0.5-0.6. Seems like it requests this at 1500rpm but never gets there and therefore starts limiting the boost?

I have been out to try and test the DV but managed to snap off the vac hose stub. Pretty sure the DV is original due to the type of hose clips so replacing it anyway can't be a bad move. 

Sadly I can't really get my arms in to any of this stuff so I'll probably have to assume the service position to sort this out. 

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Also collecting some service parts later to replace this sort of thing.

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Should be boost be constant? I thought it would drop back with revs but haven't really looked into it. As the revs increase, the engine is sucking more air in anyway (as it's a compressor) and so to limit bhp/torque it'll reduce boost with revs? Which give a fairly flat torque curve that everyone likes for driveability. That was my assumption anyway. 

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Might be a hard thing to do on the road but if you hold the revs at say 2k on a steep hill (to keep under load), does the actual boost match the requested? Just thinking of ways to test for a boost leak versus a sticking/seizing actuator. 

 

Early 1.8t had dodgy DVs. This age should have the revised design part out of the factory. 

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1 hour ago, SiC said:

Might be a hard thing to do on the road but if you hold the revs at say 2k on a steep hill (to keep under load), does the actual boost match the requested? Just thinking of ways to test for a boost leak versus a sticking/seizing actuator. 

 

Early 1.8t had dodgy DVs. This age should have the revised design part out of the factory. 

Well it now has a broken one due to some ham fisted idiot so will be getting a new one either way. 

Someone on a 1.8T FB group suggested that the temp sensor implausible code could put it into limp mode, so I have a temp sensor due today. 

Will do that + clutch sensor + DV as a start then see where we're up to.

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CTS and clutch switch arrived today. 

Clutch switch: got it mounted despite past bodgery. The switch (Intermotor brand off Amazon so more fool me I guess) was DOA.

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CTS is the wrong type, ordered one based on model checker which has 4 pins, mine only has 2.

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