Dave's shonkers - one in

[SiC]

Is the switch locking into place properly if there some bodging previously involved? They are self adjusting switches. It's the act of twisting into place that allows the ratchet mechanism inside the switch to set/lock the end points. 

[Dave_Q]

I am testing it completely off the bracket and not getting anything in VCDS.

[Dave_Q]

Having looked at these switches I think some bodgery might be on the horizon. 

To replace the broken mount you need to  replace the whole pedal box. Did consider this but having stuck my head under, it's a no. I see what you mean now about the switch needing to twist in to the mount to set a ratchet.

All it needs to be is a momentary switch that is closed when the pedal is up. 

I've gutted one of these switches to use the connector and ordered a generic switch for £2, I will lash something up with some nuts and bar through the remaining bit of mount so I can adjust it to contact the pedal right.

[SiC]

Push it in to set the ratchet and then use a screwdriver to move the pins to lock it? Then zip tie into place.

Bodge yes but the car still needs to prove itself before big expenditure over fixing the basics? Certainly how I’m trying to roll on moderns now. 

[Dave_Q]

It's more the effort than the cost, you can get a pedal box off eBay for £30-50 it just looks like a total arse to get it out, the steering column looks like it would have to come out along with possibly the brake and clutch master cylinders.

Would be happy to do it at a later date once the car has proven itself a bit more.

[SiC]

Own time still costs and is not free! While monetary is zero, it's time spent that could be doing other stuff. Now it's easier to justify when it's fun to do but a pedal box replacement does not. 

[Dave_Q]

A replacement switch came as I claimed it as broken with amazon, could kinda get it into the remains of the bracket but it still didn't work, just showed 0 in VCDS whatever the pedal was doing. 

Looking at the switch I can see what you mean about the ratchet thing and I just don't think there is enough left of the bracket for it to work with an original switch so I'll bodge something up. 

Spent my big Friday night assuming the service position to replace the BPV:

Already did the temp sensor which is easily accessible in the bottom hose. 

Not been able to test drive it as hilariously managed to break a stub off a coolant hose by leaning on the front clip while it was detached. 
TBF I think they advise sliding it out on studs or long bolts rather than just chucking it on the floor.

You can get a new hose for £25 or so but nowhere that will deliver anytime soon. Considering some sort of bodge with a bit of brake pipe or something or may go visit a scrapyard tomorrow AM.

[SiC]

I wonder if the ratchet mechanism thing needs to lock as if it's in a bracket for the switch to work?

[SiC]

Surprised the DV is down there especially given the size of the engine bay. The TT is up top and a five minute job max. 

[Dave_Q]

10 minutes ago, SiC said:

I wonder if the ratchet mechanism thing needs to lock as if it's in a bracket for the switch to work?

Yes I think that's what it is. There are extra bits on the switch that get turned when its twisted into the slot which I guess sets the zero point?
Having taken one apart, I think the switches are a really shit design anyway so a generic switch might even be more reliable.

The DV is in the turbo outlet hose which comes out down and into the front panel to go across to the other side where the intercooler is.
I don't think there was anything wrong with the old one, spring seemed OK.

I think in hindsight if you put it on axle stands and went in from underneath then you could get to it without all this, probably took about 15-20min to disassemble and less to put it back together, will get better with practice.

Made extensive use of this little cordless ratchet I got for xmas, its pretty good as it fits in most places and has enough power to run stuff down but not enough to strip anything like a big windy gun. 

You can basically use it as a manual ratchet to crack stuff off if required then buzz it off the rest of the way.

https://www.ebay.co.uk/itm/353827324288

[AndyIggs]

Going off course a little but is it possibly a dodgy N75 sensor? My 1.8t (BAM) had horrendous boost issues when I first purchased and a replacement N75 valve fixed it.

[Dave_Q]

5 minutes ago, AndyIggs said:

Going off course a little but is it possibly a dodgy N75 sensor? My 1.8t (BAM) had horrendous boost issues when I first purchased and a replacement N75 valve fixed it.

Yes it is possible, there was an N75 in the glovebox!

I am trying to work through 1 thing at a time so will have a look at that next. 

I have been told on a 1.8t FB group that I could have had limp mode caused by the temp sensor so will see if that's made a difference when I've managed to fix my latest piece of ham-fistery on the rad hose.

[Dave_Q]

Couldn't get a rad hose at the scrappy, they are a VAG speciailist but deal mostly with taxis so didn't have any relevant petrol models.

Ordered a new one and bodged this back together with the outside of a bike presta valve and some chemical metal for now.

Made my clutch switch:

Sadly this didn't really work, I didn't measure it up before wobbing the switch to the bolt and it ended up too long. I'll have another go, could always deploy the 3D printer. 

Been out for a drive and nothings changed, the pull up the hill was the same and I also logged actual vs requested for some general driving around:

This maybe gives a better picture of what is happening, actual is consistently less than requested. 

I guess maybe the N75 is the next thing to look at? Or whether the wastegate is stuck partly open?

[Dave_Q]

I did also get a new fault code of P0299 - Boost pressure regulation control range not reached.

[SiC]

Don't forget the N249 too. That can be bypassed to see if the boost hits the right levels. 

[Dave_Q]

The N75 fell apart in my hands when I tried to take it off. The one on the car was a generic one and the one in the glovebox original? Perhaps someone replaced it once already when fault not finding.

Also changed the plugs, the old ones were definitely old. Also, getting a mild vibe that I might need to change the rocker cover gasket. As well as all this oil on the plugs there is a smell of it when you stop as it's leaking down onto the manifold...

Test drive to the supermarket, will report back.

[Dave_Q]

Not really any different. Have 2 codes now, G62 and boost not reached - intermittent.

Will order a G62 (to replace the one I returned thinking it was wrong...) as the 1.8t group tells me this can cause limp mode. 

Then I guess a test with the N249 bypassed? Do I need to get some sort of connector to join the vac lines or just disconnect at the diverter valve end and plug it with a bolt etc?

What does the N249 do? Is it the valve that opens the DV? So with it bypassed I should get no boost leakage through my DV and sick turbo flutter bro?

[SiC]

Yeah N249 regulates the air into the DV. It'll work fine connected together bypassing the valve. 

It also performs two other tasks. One it allows part throttle/cruising to bypass the turbo and increase efficiency when off boost. Secondly and more importantly, if the N75 has failed in a stuck condition, it prevents the turbo over boosting and over speeding. So if you're unsure on your N75 just go easy until you've watch the live boost levels. Sounds like it's boosting too low anyway. 

Coolant temperature - what is the live readings showing? I'd expect that to be showing something incorrect to throw that code. Also don't forget to IR thermometer the hoses to see if it is reading the wrong value. Could be a thermostat duff too.

The TT uses four wire sensors - one pair goes to ECU and one pair goes to instrument cluster. So one can read correctly while the other getting duff information. Later designed CAN equipped cars are only two wire as the coolant temperature gets broadcasted across the car from one source. 

[SiC]

A good discussion on what the n249 does and consequences of bypassing it. 

 

 

 

[Dave_Q]

The temp sensor reading is definitely implausible, I checked it after I got back and it was reading 12 degrees.

Just a bit annoyed that I did order the right sensor (4 wire) but then replaced the wrong one, the one in the lower rad hose(2 wire). Should have checked what the G62 was first, in my defence it's pretty hidden between the back of the head and the bulkhead on these.

Had also found that video so think I understand now. I have ordered 3m of vac hose so will use that to try a bypass and see what's what. The car seems to hold decent vacuum at idle (150-250kmbar abs from VCDS which I believe to be 20+inHg vacuum) so I don't think it's leaking, as surely that would lead to not being able to open the DV when you need to?

Whatever, I feel like a have a set of steps to work through to see what's what and even if it did turn out to be WG seized it's not the end of the world.

[SiC]

Is the WG accessible by hand to see if it's moving freely and cleanly?

It's not unknown for them to give trouble. WG actuators are available aftermarket and often changed, even though they're supposed to be calibrated to a turbo. 

[Dave_Q]

2 hours ago, SiC said:

Is the WG accessible by hand to see if it's moving freely and cleanly?

It's not unknown for them to give trouble. WG actuators are available aftermarket and often changed, even though they're supposed to be calibrated to a turbo. 

Not really at all, it's underneath the turbo. Might be from underneath but I've not stuck my head under yet.

I am wondering if it could also be fuel related as it does feel like it's building boost a bit better on part throttle. 

Going to pick up a fuel filter just in case.

Also noticed leakage around all 4 injectors, which can't be good. Presume these have an O-ring or similar on them? Worth trying to get new seals or are new injectors relatively cheap?

[Dave_Q]

To answer my own question they do have O-rings and I've ordered a kit with new O-rings and internal filter/screens for £17.

[Dave_Q]

Think I have some progress, I have fitted the new G62 and run the DV straight from the manifold:

This is a pull up my test hill from earlier. Originally requested boost peaked at 1500mbar at about 1500rpm, the actual was well behind and peaked at 1400mbar at 2000rpm, dropping down to about 1250 by 6500rpm.

Now we are requesting about 1750 and getting it (although a bit late) and maintaining 1600 through the midrange and at about 1350 at 6500rpm.

I do wonder if there is still some issue with the WG, N75 or hoses in that area due to the actual boost lagging a bit then slightly overshooting? Or is that just how the control system works?

With warp speed* restored I tried a couple of 0-60 runs on a flat road. It's not amazingly fast at all, the best run was 10.001 seconds. Book time is 9.2 so I reckon I may have restored most of the horses? It is only a 163 which is presumably a slightly higher tuned version of the 150hp in the mk4 Golf. 

I do think there is also an element of driving it making it better the MOT history says it didn't really move from 2020-21 although it has done a few thousand since then.
I have been running it on V-power for now as well.

Think the plan will be to continue with the maintenance stuff then look into a remap.

[SiC]

Control system might be regulating boost with the N249 valve to prevent it overboosting which it can't as bypassed? Could log and graph N249 control value to see if that's the case for sure. 

At least it's meeting it's requested boost value now. 

Won't be that quick a car as heavy and only 163bhp. What can you turn the wick up to on them?

I know the TT180 can be turned up to 210 before the Ko3s turbo is pretty much maxed out. Iirc the 150 has a regular Ko3 turbo and can't safely reach quite that high? 

Celtic tuning reckon 186bhp after remap. They're usually very optimistic in their bhp figures, so I suspect that's probably about right for a max. 

[Dave_Q]

Yes I had read 185-190 with some places claiming up to 200. A decent bump up although a MaxSpeedingRods K03s is only £130 so if you were going to do it it could be worth putting the slightly bigger turbo on for a bit more.

Not sure on whether the N249 could make much difference as it can only bypass boost that is there? I would have thought the primary control is the WG via N75. Will log it though and see if it is trying to do anything.

[SiC]

I'm not sure I'd trust a cheap Chinese turbo to last. A used ko3s can't be that expensive from a TT180 though. Or go Ko4 but I think new injectors are needed then. Also I don't know what strength rods/pins these lower boost engines have. I know there is a point that is reached reasonably quickly where those bits need to be upgraded. 

I'm thinking the N249 could be preventing the overboost peak at the start. Wastegate fully closed trying to get as much air through as possible. Turbo starts spinning and boosting. Revs keeps climbing from inertia, engine isn't consuming all the air provided and as it starts to overshoot/overboost, DV is opened to reduce a peak. DV react quicker than WG control by the fact pressure is instantly bypassed rather than waiting for the mass of a turbo to slow down. That's my theory anyway. 

The period at the start where it's far under, is it not just the fact its turbo lag and it's still spinning up? 1000mbar start suggests it's not boosting and the compressor is probably stationary. 

[Dave_Q]

Yes, I think there is also an element of me needed to get used to driving a petrol turbo car.

The other A4 is a diesel with a VG so makes all it's torque low down. These test pulls I have been trying to start from 1500rpm or so in second and just putting my foot to the floor so it could just be turbo lag.

If you go from part throttle at 2-3000rpm then put your foot down it builds up boost much more quickly.

I think one problem with a s/h turbo is that the inlets/outlets aren't in the same position on longitudinal Vs transverse engines so I'd need to find a K03s off an A4, A6, Passat or Exeo.

[Dave_Q]

"Are you actually having a proper mid-life crisis?" - Ms_Q.

[Dave_Q]

Driving to work this morning and got a rough idle, thought it might be because I had just unplugged the N249 and N112 (PCV valve I think) so swapped back to the original routing.

The good news is that the boost still seems OK so I guess the N249 is ok and it was the temp sensor all along.

The bad news is this little conical bastard seems to have become unstuck and was the cause of the rough running.

I've pushed it back together but think it probably needs some epoxy etc.

I'm sure the valve is about a million quid from Audi and the chances of finding a good s/h one must be minimal so there's a chance I might do what all the yanks do and simplify the vac system to just the diverter valve and the brake servo as there are many hoses and getting them all working as per factory seems like a lot of effort.