lewisweller

Well I took out the injector rail today and stripped off each injector. Using a 9v battery I energised the injectors and cleaned them all with crc solvent degreaser cleaner. The injectors all were crap, and no amount of solvent would get a nice clean 4 spray pattern. Only 1 would remotely be acceptable I would think. I reinstalled everything and it started up fine. I ran it on each pump just to see if any difference between the left and right but none I could detect. Went for a drive (bare in mind I'm at just under the magic 1/4 tank) and it seems initially to be a bit cleaner to accelerate. So I put it through some mixed driving and the hesitation has not gone which is no surprise as I achieved nothing by cleaning the injectors, as they aren't clean. I put some techron fuel system cleaner in the less than 1/4 tank of fuel and went for some more driving, still seems a bit more lively bit not fixed by any means. Went through the auto car wash and vaccum bay engine was idling a long time and then shut off and then restart (loads of heat soak cycles I'm trying to accomplish here). Then I went and filled the tank to 3/4 full, this was on purpose because I didn't want a full tank incase the issue is some how to do with the evap canister getting saturated with full tank topped off etc. Restarted after fill up just fine but when I drove off the acceleration is terrible and hesitation is felt on way more places in the rpm range not just around 3k. I did some driving and acceleration testing, even stopped the engine, let it sit for 5 mins and restarted but was the same. So my conclusion is my injectors are wank. The picture is difficult to see the holes. But they look clear sometimes and sometimes blocked with something inside the pintle area. The reason why below 1/4 it not as bad is maybe simply because this is the time both pumps are running, this extra boost of pressure and flow capability possibly is enough to cover a little the blocked injectors, once I filled up its back to the left pump only and its dog rough again. Why are my fuel trims so good ???!!! Why don't I get lean codes ???!!!! Wtf????! New injectors are extremely expensive. Will proper injector cleaning work or are these just pass serviceable? Answers on a postcard. .......

Nice looking repair job done right there. Description of Fix and pictures, top man.

Yes I'm sure it's a pita to do. I would get a jubilee clip or two and some two part epoxy resin glue assemble it apply the epoxy when lovely and tacky but not already going off and then tighten up the jubilee clips. Once that epoxy goes hard it won't leak if you've done a good job. Suggest leave it overnight for adequate post curing of the epoxy resin. Jb weld is a product I've heard off on these forums works well.

After watching my injection pulse width milliseconds in relation to my rpm and load it seems apparent what the dme is instructing is looking correct and logical according to the fuel map. So this begs the question are my injectors partially blocked? Could this be why once warm and any warm up enrichment is reduced their is simply not enough fuel flow to get a decent burn and results in the stutters, hesitations and idle Dip ? As computer Diagnostics aren't going to help much here I guess there is only one thing for it. This is my next little project in the continued search.

Right about here?? Some people have epoxy bonded it back together as a fix but of course a new pipe (item 13 I believe excusing the terrible diagram representing the pipe that looks nothing much like it in reality) would give more piece of mind.

1-2 pumps is less than I expected so I would be looking for the leak. If the vac pump was bad it would likely produce a code but I may be wrong. Spongy pedal is suspect of the brake booster fault as well assuming brake fluid level is correct? If it was hydraulic then with engine off the pedal would depress to the floor and you confirmed it doesn't. Obviously at this point its prudent to say brakes are a major safety feature and taking advice on a forum from anybody is not as advisable as going to a well equipped garage and getting it diagnosed and fixed properly.

Yep that's it, its called the Evap Purge Solenoid Valve. About 100 dollars. Also have a good look at the wiring to the plug, Thomas had it break inside and was causing him some trouble until he found it and replaced the plug. When you unplug it just use a multi meter to test the two pins to measure the purge solenoids resistance it should be quite low maybe 5-15ohms. If high resistance, open circuit or nearly 0 then it faulty for sure. The plug will likely be negatively switched so with ignition on you can test the 12v supply is present if you use test between one of the pins and a ground/engine block. (This will generate a p0441 code so expect that and clear it once plug is reconnected and cycle ignition key on off on first) The plug ground will be via the dme so testing that to engine block/ground won't give you anything tangible I don't think. If you don't find anything unusual buzz the solenoid out using two pieces of wire connected to the + battery jump point on the engine bay right side under the beauty cover. Note the positive and negative pin on the purge solenoid by knowing the + wire on the plug and which pin it goes on to.

Engine running all connected ok, then switch off engine. Then pump brake pedal, count the pumps before it goes hard? Then press and hold the brake pedal hard and start the engine, the pedal should depress straight away. The results of this test may give a indication how big the leak is, but it's not really going to help you find it.

p2401 is the evap detection pump circuit low P0448 is evap vent valve short circuit I would be checking the vent valve first and the wiring, it is probably shorted and knackered and likely causing the p2401 code as a result. Fix this first the clear all faults, take for drive and see how it also affects the p0300 codes as well. Don't rule out the coils yet if they are old, even though they look OK. How many miles you done?

I have suspected an ECU or related wiring issue but as you said very hard to find a bad connector. I've had the Ecu out and open. Nothing obvious and connector and plug looked in decent shape. Whats the ideal ecu voltage (straight 5v?) and does anyone know where to look for the specific ECU voltage group? I'm using the ......ahem...... Vcds vagcom so label files not available to tell me all the group names I'm looking at. Need to buy duremetrics I know, would make life easier in these situations but that don't work on the Audi. I Will invest soon.

Got any pics? I remember I had some red with black strip wire which looked a bit suspect and thick black wires with the factory crimp exposed but nothing was wet or corroded or broken and I did a neat wrap and didn't think about it again really. Considering its a hot running issue it's not concurrent with a wiring problem on a loom inside the car.

127,000km. m3 bimmers use 10w60 castrol oil.

Found this interesting case of running issues caused by oil viscosity too thin when engine is hot resulting is incorrect hydraulic tappet lift. Make me wonder if my hot engine stutter hesitation could be caused by the 10w40 oil simply not being thick enough? Maybe having an effect on the variocam change as well? This may in fact point towards a less than optimum oil pressure (tiring pump maybe) which the thicker oil would help I guess as well. Anybody have any experience of oil thickness causing running issues? I'm due oil change in the near future and will try a 10w60 or 10w50 depending on what I can find here.

It a broken record but a necessary one to play...... Is your battery in good order? If battery and charging is in good shape it would seem like a module or wiring to module fault. Check the fuses as well 27+48 on the right side dash fuse box ! Could be a fuse popped due to another issue and it not the module fault at all!

Sweet. Thanks for posting your successful Fix.

Yep. Part number as per picture item 3 is 94811020201

To eliminate the P0441 simply replace the purge valve. This could also be an contributing or causing other running issues and definitely is the reason for hard starting after fill up.

That's the vac pump (second picture item 19) for you brake booster. You have a vac leak from the (second picture item 14 to 13) pipe that runs around and back to the brake booster (through the firewall). The parts diagram is misleading as its a lot longer and more bends than It shows. One of the pipe associated that runs to the inlet manifold and Y pipe (first picture item 4) can also be cracked. Can you pls explain and take picture where you connected your vacuum checker to? And what readings you got? Thanks.

Mine is a 2006 ctt so I don't have the hpfp. The set up of the hpfp is very similar to my 2013 Golf R (sold) I rebuilt the Hitachi hpfp with auto tech internals to increase pump pressure to match the APR stage 2+ tune and mods. The earlier engine had a very weak and soft cam lobe which flatten and caused lean burn and low pressure also the cam follower would wear a hole in it and smash everything up. Lucky the 2013 Golf R engine had revised cam and as long as you checked and replaced the cam follower every 30-40,000 km it was bullet proof with good oil quality and regular changes. The porsche setup is a bit different using a clutch and stopper which can break. Does anyone do a refurb/exchange rebuilt unit of the hpfp? I'm sure its very similar to vag hpfp used in millions of applications across the range since 2005 or even before. I bet someone does. Edit: just found this, suncoast do ....... https://dorkiphus.net/porsche/showthread.php

This stinks of a fuel filter blockage despite your lp tests. You change the regulator but the filters do get clogged with thick black filter paper yuck. Your set point looks to be hunting for fuel delivery and then over compensating. A caution to add to this is some owners have had the lp fuel pump(s) tested OK but intermittently fail or underperformed in certain circumstances ie low fuel level or hot/cold weather running. A real hard one to diagnose unless your lucky enough to catch it when it's failing during test. A scope and amp clamp set up to measure current of the lp pumps is the best way to detect even a possible intermittent fault. I wish I had a scope like the pico four channel. Maybe its totally fine fuel wise and we're thinking about this the wrong way?

Fault Codes would be good if any? Also check for corroded wires under front foot Wells and also wires under both seats. As both the suspension and transfer low / high range are separate controller and equipment it sounds like a wiring or weird control modules error. Very strange. It shouldn't raise at highway speeds anyway by default setting. It should lower at speed and then return to normal when you are at slow speed or stopped.

Thanks for the tip. I always removed and tested the tail lights but neglected to check the third Led brake light because stupidly i was looking for the tail light issue and not the brake light but its all on the same circuit duh! I will check that first before going to the trouble of removing the trim etc to get at the comfort control module. For anyone who is reading this thread in the future the hesitation issue returned and I'm still searching for a cause. The new fuel pumps did not fix this long term and I think the short term improvement was either a fluke or just the result of the battery being disconnected for some time and resetting something. Repeating this disconnection of battery doesn't result in better running everytime its frustratingly random.

O2 sensor post cat won't cause misfires. Start at the likely misfire causes. Make a home made smoker from 1 litre bottle, air compressor set at 10psi and some cigars easy peasy. Use the map sensor port. Disconnect the maf pipes from the air boxes and thick freezer food bag and duck tape them tightly this will keep your smoke inside. I posted picture of this Hill Billy method before and it works pretty good. Youtube it. Another train of thought is blocked injectors and or fuel delivery issues. Your old cats can't cope with the unburnt fuel in the exhaust caused by the misfire events that's what the code actually is telling you, not that the cat is necessarily knackered and inefficient. Have you check your AOS diaphragm and 3 way check valve? Pipe connection to bottom of Y pipe and throttle body gasket. Even the Y pipe is known to split but that would normally give sound when on boost. Whats your boost gauge say full throttle? Not to offend but spark plugs tightness and also the coil tightened onto the spark plug securely is a key factor in misfires. I've done this myself not tighten the coil fully down! Spark plugs are 22lb/ft torque I think. Well worth checking quickly and also pull out plug 8 and plug 3 and take picture and post please.

Didn't last! Drove to warehouse this morning and crap as usual. I decided to fix a niggling leak in the intercooler to Y pipe connecting pipe with new oring (for some reason it won't let me add more than two pictures?) which was yuck with oil gunk and dirt. I thought maybe fixing this would have some positive effect if not a miracle one but Na who was I kidding. Fyi getting the Allen bolt out from the inside is a complete pita and getting it back in was an absolute ball ache. A telescopic magnet holding the bolt in my left hand, a torch in my mouth and an Allen key in my right hand doing a reach around to impress a contortionist. Left warehouse and total pants, needed fuel and put in up to 3/4 full after it ran especially dog rough stuttering, throws hands in the air. Wtf.

Look for vacuum leaks I would suggest first at 140,000km and 12-13 yrs would be likely to find some cracked and brittle pipes and hoses. You have changed all your coils right? What did the old spark plugs look like? Any pictures. The cat code are worrying. If not due to the misfires which they may well be failed/melted blocked cats are expensive to replace.