Almurray42

Yes, agreed. I don't have the capacity to test this without doing a lot of research first on limits and Continuous discharge thresholds etc. Having a quick look at the info on Halfords, they do it at their autocentre and hook it up to a machine which apparently tests various things including "Cranking capability" which is essentially a load stress test... As it's free I'll give it a go. Going back to the Throttle body though, I did manage to get it to stick a couple of times when manually actuating it, so I've got a second hand eBay one on the way to pop on and try out. (Was only £35 so worth eliminating I think!) Al

Sooo Throttle body is still fairly clean from when I de-coked it all.. (See below) Popped the cover off and looks in pretty good nick inside! Tested the full actuation with my Power supply.. Everything appears to be working normally? VID20230813111403.mp4 Seems unlikely, but wonder if it's a wiring/loom issue? OR actually what Cliff mentioned about a potential battery fault causing the ECU to somehow operate irregularly... The Saga continues... Al

Not a Bad shout Cliff, thanks. I will get the battery tested by Halfrauds think they do a "Free battery health check" Voltage is fine on it though. In other news, the Mrs was drivingl today and EML came on! Got a Code P2103 "Throttle actuator control motor(TAC) - Circuit High" First time I've ever been glad to see the Engine Light! Gives me something to start looking at 🙂 Will do some research on this and update.. any known common faults with these I should know about? Thanks again Al

I'm certain it's not the mounts. The Smoke and rough running is 100% linked. Engine off/on stops Both (Have even done so whilst driving, clutch in, engine off/on and clutch out temporarily stops it) Might need to do more digging! Maybe see if I can get some monitors logging whilst driving and capture some differences in the monitors...

I'm Returning to this thread as I have since resolved the more pressing issues being the Oil leak (Which if you've seen the thread turned out to be an almost full engine rebuild job!) I since had another problem with delayed boost and Limp mode on motorway... Turns out it was the turbo actuator (Suspect Torn Diaphragm) which I've replaced and that problem is resolved. So this is now one of the final issues I have. So...The Intermittent issue of what I described previously as a "Rough idle"... To clarify, what it ACTUALLY is: Seems to be excessive shaking of the engine. To summarise: SYMPTOMS: Whilst Driving, or on engine start, car enters an unstable state INTERMITTENTLY. On Idle, Engine is shaking - to the point where you can feel it when sat in the car. In this state, at Idle the Revs seem to be stable and aren't fluctuating. When Accelerating in this state it can have hesitation and almost be a bit "Jolty" on acceleration. When accelerating, lots of light coloured smoke is emitted. Turning engine off/on fixes this fault state 99% of the time. No warning lights or ECU Fault codes present. Known "Good" parts: From research, some suggestions are saying to check various things. I have done a lot of work on the car recently so have listed below some parts which I know or am confident are not causing the fault. As I check things, i'll edit the Known Good list. Pistons/Rings/Blow-by Turbo/Actuator Timing Head Gasket This leaves me with the following train of thought: As I've recently done a lot of work in the engine, I'm confident that the issue will lie with some sort of ancillary.. Could it be: Something in the Vacuum system? EGR related? Swirl flap related? CCV? Fuel pressure regulator? Injectors? Fuel filter? Not really sure where to go next. What's getting me is the fact that this can be fixed by an Engine on/off.

Thanks All, it was quite an undertaking considering I'm An electronics engineer - the polar opposite of a mechanic! Ultimately, it started as an oil leak fix and gradually spiralled to almost a full rebuild! All in though, I've learned a lot and very pleased with the results, thanks again for the advice here and there people! Al

Final Update! So, I've completed all the work (Finally!) and the car is back together and running! No Oil leak! 😄 In the end, I did: Replacement Cylinder Head (Stripped, cleaned, cleaned and soaked Rocker arms & lifters) Head Gasket (+Plenty of other gaskets & Seals!) Camshaft Oil seal Piston Rings (& Cylinder Hone) Big end bearings (& Big end cap bolts) Intake manifold & EGR teardown & Clean Balance Shaft Mod for 100mm Keyway Oil pump check/clean/soak Timing belt (Including water pump, Tensioner, all pulleys, idlers, studs & bolts) Aux Belt ------ Note: When refitting the balance shaft assembly, you're supposed to use a locking tool that's around £40, which I couldn't justify for minutes use, so I took some measurements and made a locking tool from Acrylic on my Laser cutter, Happy to share pics of this if anyone's interested.. Could even sell them for a small amount if anyone needs one! ----- Thanks for following along, MOT up next! 😮 Al

Update for anyone else looking at the Balance shaft mod to 100mm with improved shaft... Kit arrived from ZED performance, and Using a combination of Common sense and similar torque ratings with same size/grade bolts on the car, I'll be using the below Torque settings for The two halves of the balance shaft: 1 - Hand Tighten 2- Diagonally Outwards from Centre: 8nm 3 - Same pattern, 20nm 4 - Additional 90 Degrees. Note: If anyone plans to re-use the old bolts, I'd recommend NOT doing step 4 and instead adding a decent high-temp threadlock to the threads. Building my knowledge as I go, but want to share as I do so... There doesn't seem to be a wealth of info out there relating to this mod even though the issue seems quite common! Al

I've taken a step back and agree with your Logic. Ordered a Full kit now with Tensioners, Idler rollers, Timing belt and water pump (INA so should be good quality!)

Update: Parts on way from Germany. I am Doing the 100mm Balance Shaft Mod to avoid this from happening again as this was all the result of the SH1t3 Engineering on the Oil pump hex drive keyway in the Balance Shaft. For anyone else reading, after a LOT of research it seems that unless you want to spend £150+ on a replacement/exchange balance shaft part, the only available option is the Kit from ZED engineering here - https://shop.zedperformance.co.uk/passat-a4-2.0-tdi-balance-shaft ?search=balance shaft This kit comes with a SS threaded "Bolt" insert with a 6mm Hex shaft and a longer, 100mm Hex key. This is what I'll be doing. I've got a chap I know that works in a machine shop and he will drill & Tap the shaft and put in the insert for me. The problem that this creates is that there's nothing in the Audi Workshop manuals or it seems anywhere about disassembling and reassembling the balance shaft... I loosened off the bolts in a diagonal out-in sequence. For the 2 halves of the balance shaft assembly there are: QTY 9: M8 x 50mm (1.25mm Thread Pitch) Grade 8.8 Bolts (Unserrated Flange Bolts) QTY 3: M8 x 30mm (1.25mnm Thread Pitch) Grade 8.8 Bolts (Unserrated Flange Bolts) Unfortunately as Audi only sell the complete balance shaft unit, they don't list part numbers for replacement bolts or torque settings. I'm assuming that being Grade 8.8 they are also stretch bolts and as such need replacing. The closest VAG part numbers i've found for replacements of these bolts are: QTY 9: N91063901 QTY 3: N10665001 I have ordered some of these for reassembly. Need to figure out appropriate torque settings... I'm assuming it'll be similar to the torque settings needed for attaching the Balance shaft assembly to the block. Happy to share photos and final results when reassembling if it'd help anyone... The saga continues... Al

Thanks Steve Replacement head arrived today, from an engine on 85k and it's in remarkably good nick! Are the valve seats and relapping strictly necessary would you say? I don't really want to have to disassemble the head and take it to a shop to get the seats cut... Wouldn't that also mean new valves for fresh seats? Then if I'm doing valves may as well do valve stem seals, lifters and rocker arms... Its a bit of a rabbit hole 😂 Al

Hi Cliff I was thinking about this - water pump was last done at 70k and it's at 115k now... Reckon it needs doing?

Update: Big End Bearing Caps Off, Bearings look very good, but will replace while i'm at it. Cylinder head off - Cylinder Bores look good. Plan of action: New (Used) Cylinder head Head Gasket Exhaust & Inlet manifold Gaskets Clean EGR valve Cam belt & Tensioner New Big End bearings + Stretch Bolts Piston Rings & Hone Cylinders Anything else I should do while stripped down this far?

Well.. I appear to have found the cause of the leak. Camshaft oil seal... Until I looked deeper.. Took off the Cambelt and Camshaft sprocket -To see a nice oily drip from the Camshaft seal. Image below: I looked on the inside after spotting this, and noticed that the where the exhaust cam exits the Head, there looked to be excessive rubbing/wear on one side and a gap on the other (the green is UV dye from when I was tracing).. Image below: So I decided to take the Camshaft retaining frame off to have a better look and ohhhh dear... See images: Interestingly, There aren't Bushes/Bearing shells to replace as i'd have thought there would be... The Cams just run directly in the seats of the Head & Cam carrier... Is this even fixable? 😞 Al

Thanks Steve I don't think it's coming from the Crankshaft seal as this is much lower than where i'm seeing the oil dripping from - I've decided that my best course of action is to do the Camshaft oil Seal. I've started taking things off in preparation, just waiting for my Locking kit to arrive. Cambelt Was last changed at 85K and now at 115K, so only 30K on it but think while I have it off, it's worth doing. I'll update here Hopefully tomorrow provided Amazon deliver my locking kit before dark! Having the Rear timing belt cover off will definitely give me visibility as to where it's actually coming from. Al

Hi All I'm going to try and be as descriptive as possible here, but the short story is that I have a BAD oil leak on my 09' A3 8P (CBAB Engine code), back of engine and need help locating where It could be coming from! Long Story: So, I obtained the car with an issue of low oil pressure. After Taking the Sump off, I discovered that the oil pump Hex drive key was excessively worn and as such was slipping in the shaft. New key - Problem solved. After fresh oil & filter, I started noticing a strong burning smell of oil. I took the undertray off and ran it for a while to find a consistent Drip, drip of oil from the back of the engine - Drivers side (Cambelt end). I've tried tracing where the drip is coming from and have discovered the "Trail" so far.. Image 1 is an Image from the Web of a Reconditioned CBAB engine for reference to help show where my images relate to. IMAGE 1 At first sight, I spotted the oil dripping from the lower bracket of the engine mount, and traced this up the engine. Image 2 shows in RED where the oil is coming from, and Green where there is no trace of oil. (This is an image of a used engine from ebay) IMAGE 2 Image 3 shows the Oil leak as high as I can see where it starts to Pool, and drip/run down the block. Yellow Circles show where the Oil appears to be coming from. The Blue line is where oil is sitting along the Head gasket, but I believe that this is where it's running down to, as the source of the oil is pooling on the Rear Cambelt Cover Bolt. Image 4 is the same as Image 1, but cropped. Yellow circle shows where I'm seeing the oil "Pooling" around the rear cam cover bolt. The only places that I can think that the oil COULD be coming from is: Camshaft Oil seal or Front Cam Blanking Plug (GREEN) - However I'd have thought I'd see oil flicking around the cambelt or on the cam sprocket, which I don't Camshaft Carrier to Head (PINK) - This is a Sealing surface that clamps the CAMS into the head.. There doesn't appear to be oil running down from here, but hard to tell as the oil "trail" seems to disappear above the bolt. Rocker(Cam) cover gasket (BLUE) - I have had the Rocker cover off, cleaned the sealing surface and replaced the rocket cover gasket - no joy whatsoever. The Rocker cover is currently OFF again so I could check again! IMAGE 4 SOO.. This is driving me mad, I really want to get this back on the road but need to get this sorted. Has anyone experienced a similar leak? I'm reluctant to go taking the Cambelt off if unnecessary, as then I'd have to get a new belt & Tensioner, and will need to buy all the locking tools etc. - Obviously if I HAVE TO, then I will. My question is, is there something that i've missed that could be the cause? I've already taken off the Camshaft position sensor and it's not coming from there. Any help/advice would be GREATLY appreciated. I'm half tempted to get a new Rocker cover, as these are the plastic ones that can apparently warp and understand that potentially if the PCV has failed then it could be causing higher pressure in the engine thus forcing the oil out from somewhere? I Very much look forward to hearing opinions or advice! Kind Regards; Al

Yep, this is why I'm so baffled by the fact it disappears! Will get it on a proper diagnostic machine - but first I have a rather bad oil leak I need to investigate... Will post an update if/when I figure out what's causing this smoke issue! Thanks Al

Hi Gareth That's a good question, i've not actually checked - I Didn't even get out of the car when I Turned engine off/on 🤣 Will check when it next happens! Al

No Fault Codes Found with Torque Pro or Car Scanner Pro...

Thanks Steve Funnily enough I hadn't actually thought of that - I do have an OBD2 reader, I'll chuck it on in a min with Torque Pro see if anything comes up.. Not sure if i'll need a proper VAG one with VCDS though... We shall see! Al

Hi, wondering if anyone has had a similar issue... Info: A3 8P 2.0TDI Engine Code: CBAB So this morning driving to work, I noticed as I started the car that it was idling very rough, shaking but didn't feel like it was a misfire... Anyway, when driving there was a large amount of white smoke coming from the exhaust, which i'd not had before. Heavier acceleration led to more smoke. I pulled over, turned off the engine and turned it back on. To my surprise, the smoke had stopped and Idle was much better! (Still slightly rough, but maybe unrelated?) Seemed very odd to me that an engine off/on event made it stop? Took it out for a couple spins and managed to re-create the issue with the smoking, which once again disappeared after a quick engine restart... I'm Baffled! Appreciate any thoughts/advice! Al

Hi Cliff Sorry I haven't replied before now! Somehow didn't get notified of a reply... As I don't have the time/patience nor money to go taking off the camshafts (Apparently need an expensive alignment tool just to get the cams back in correctly?) I took a risk and put the rocker cover back on to test, as I didn't know if there were any other issues too! Seemed to run just fine without these clips - I assume that they are there to prevent the followers from slipping when the cam lobe is up? But either way these have been fine - There's some decent sized oil passageways from the Head down to the sump, but these clips were broken up into 3/4 pieces. When I had the Cam cover off everything did look still fairly well lubricated, and turns out that the cause of the Vacuum pump failure was due to a piece of debris blocking the oil entry to the pump. I've had the Cam cover off again yesterday and all looks good under there, no excess movement on followers and nothing looks damaged. I have recently noticed another issue - but that's one for another post - Just wanted to provide an update on this post! Al

Hi! What length are the wires? Ideally I'd like to have all my connections fully inside the door card! Also, how much for a set of 2 for OSF/NSF? Thanks Al

Hi All, First post here 👋 I've recently acquired an Audi A3 (2.0 TDI with CBAB engine) With issues, and attempting to fix. Long story: "Brakes pedal is hard" I was told, on investigation I found there was no vacuum to the Brake Booster/brake master cylinder - traced back to Vacuum pump (Camshaft driven) - took this off and found it to be completely torn apart, looks like it seized. My guess was it had seized due to no oil reaching it - so thought it wise to check the oil pickup pipe and pump. Pickup pipe was fine, and pump was also in very good condition. I did however identify a rounded end on the hexagonal oil pump drive shaft bar - apparently a common problem on these! New bar is on the way, but then I noticed.... In cleaning out the sump, I found a small clip which looked like a retainer for the rocker arm to tappet.. looked up the rocker arms and it matches perfectly! So... I have now removed the rocker cover and found that 3 of the rocker arms are missing the clips - luckily I believe I've managed to collect all the broken bits, but my question is - are these necessary? It seemed to run fine without the clips and unsure what purpose the serve other than for ease of installation... I will replace if needed, but it'll mean the whole TDC cambelt off water pump job which I'm not fancying! TLDR: Audi A3 Rocker arm - hydraulic Tappet retainer clips: are these strictly necessary? Or are these more of an assembly aid? Image below showing a rocker, the clip being the Mild steel on the left of the Arm. Thanks In advance for any replies! Al