2.5 TDI Transporter BPC 2009 info thread

[Greg Roles]

Well after doing a LOT of priming, the engine started right up and ran fine, I ran it at 2000 rpm or so for 20mins and it didn't miss a beat. Sure is a tractor of an engine, sounds quite agricultural! Priming the lines was a mission, and I noted the fuel tank pickup pump only runs for a split second each key turn, so you really do need to turn it a lot of times to get an empty line to prime. I used a syringe to fill the lines and filter as best I could, and even then it took like 20 key turns to get it to start! Expect priming to be a challenge when messing with anything fuel related. EDIT You can do this with VCDS - Engine, basic settings, group 035, press on/off button to run lifter pump for 30 second intervals.

I had a few minor coolant leaks to fix, problem when using the old rubber hoses that often split when removing them, had to trim them down to get new rubber to clamp. I'll replace the lot if ever I reco the engine internals.

Something to note, the gates tool set I received has the unicorn long t10 triple square tool you need for that one PITA turbo bolt, so no need to get one individually if you ever get the Gates SX400 set.

I also had one small oil leak from the turbo feed, so decided to take it back off and try again. The turbo does indeed come off easily once you install new exhaust studs, and the studs tend to screw back out as you undo the exhaust manifold nuts, and this allows you to remove the manifold straight upwards, and the turbo the same way, with the rear engine mount in place. Piece of cake compared to the first way with stuck exhaust studs!

Another thing I noted it that there seemed to be no real errors that needed clearing via VCDS. I had read that unplugging the PD loom to the injectors stored errors that needed to be erased. Went looking but apart from a basic dash error there was nothing much at all from the rebuild. I was actually amazed there was no errors showing up on the dash on that first run!

So RWC and rego next, then I'll report on how she drives. On a quick RWC preparation lights check, the low beams sure look dim!

[Greg Roles]

Spoke too early about no VCDS errors, they popped up after a few small runs!

Well some more developments, and a few more parts in the post from the UK. Turns out I have at least one injector down, if not two. Would seem the "tractor" feel my van has, and it's lack of performance is because one or more cylinders isn't doing much. I tried a "diesel purge" you read about online with the Liquimoly can of cleaner you circulate through the fuel rail, and had surprising results, at first I had cylinder one injector maxing out at the +2.99 mg/stroke trim, and after purge, had #4 trim right out as well!

Very odd, but to be fair I was seeing "multiple misfires error" in that first reading, and the trims sure move around a lot from cold to warmup, but it seems once an injector exceeds the 2.99 max positive trim the car freaks out, and it's time to replace or rebuild them, after investigating other possible problems with that particular cylinder starting with compression!

In the below screen shot, Left side was pre purge, right side after ( to be fair measured while running ON diesel purge ) but levels remained the same on normal fuel afterwards. Car probably needs a bit of a drive to relearn injector trim properly, but I bit the bullet and got two used but tested injectors out of Darkside, I obviously need at least one.



Took me a while to understand all this, but basically positive is bad, as the car is holding the injector open longer to account for a perceived problem in that cylinder, and that can be compression, valve leak, injector, cam issues, you name it. Injector seal and even injector fuel supply / drain can be the issue, and in my T5 they have to be set at a very specific angle, no doubt to get the fuel supply / return ports to line up to the tiny holes in the injector body. Seems anything up to about +1 is normal build variation, and after about 2 you are looking at trouble pretty soon. At +2.99 you get misfire errors.

EDIT: On reflection, I think my WHOLE problem was the injector bore wear and consequent fuel pressure leak, and the probably FINE injectors were maxing out trying to provide adequate fuel. Before you go down the road of buying new injectors, pull them out and have a real good look for injector bore wear in the head, tons of pics coming up below. I feel I wasted $2k plus on recon injectors, when I should have just got a new head first given the bore wear I eventually found. When I wrote this I was super worried about the angle of rotation of the injectors, which does matter, but nothing compared to any fuel leaks from head wear! If the fuel supply pressure to the injectors is low, then how can it function as it should? end EDIT.

The negative values are just the other cylinders being held back in injection to try and smooth the engine out, so those injectors are FINE, and the car is forever trying to make all injectors add up to a zero total ( apparently ). You can see in my odd second post purge result more -3.01 injectors trying to account for the extra +2.99 one. I realise the total now isn't zero, but again the ECU runs negative to try and get even idle, and my car sure shakes a lot. I'd not worry so much about "zero" and a lot more about any injector over +2 mg/stroke. Car still runs and not much changed power wise, but I figure a new injector in #1 and #4 should get the old girl back on her feet. This is something to watch via VCDS/Vag Com under engine measuring blocks, channel 14 being the 5th cylinder.

Tons and tons of posts online with all manner of conjecture, but basically a +2.99 is a maxed out injector, and it may not necessarily be the injector per say, so a compression test in any high reading positive cylinder would be a good idea, and despite my weird outcome, the fuel rail lines in a can of Liquimoly diesel purge plus ( or three cans like me, thankfully on special when I bought them ) can't hurt. Just beware the fuel sure heats up after a while, and the purge plus in my small container I had the fuel lines in was steaming by the time I got through two cans, so I stopped there!

For the record whilst pondering this problem, I decided to check / tweak the problem injector fitment angles, and did get all excited when I measured #1 being different to the rest. Tweaked them to all the same as the "good" ones, and sadly zero change. It did however show me the seal was fine, which on a higher mile engine is a concern, especially how the stock holders make the injectors wear on the other side and even supposedly creates a burr on the head port the injector sits in. I couldn't notice anything, but people have talked about it so it's something to take into account as a possibility. T10210 is the wedge tool. EDIT: I was looking in the wrong place, my head did indeed have these "burrs", I was thinking it happened down at the nozzle hole, not up at the top of the body / bore junction! See post 15 below!!!



If your loom / injector connection is the issue you won't get a constant reading under channel 12/13, was again a possibility I considered, that I hadn't plugged in #1 properly. Sadly wasn't that simple!

[Syncrotek]

Subscribed.
Thanks for sharing info.

[RobTrans]

Thanks Greg, for in depth explanations. A great reference guide.

I have a ‘09 2.5 6 speed manual (BPC motor).

Currently on 159,000km, had it since 75,000km, hasn’t missed a beat except for standard stuff like driveshaft, stub shaft, egr, water pump etc.

It’s maintained by a guy who has a TDI background and I have been using liquimoly top tec 4200 engine oil with 10,000 interval changes using genuine oil filters.

I need to consider doing the gates couplings, inlet manifold clean and a few other things soon so your info was really helpful.

I normally spend hours researching and sourcing parts then my tdi guy does the rest as I don’t really have any off road parking.

[Greg Roles]

This van had better be a joy to drive in the end!!

The latest.....well, the upside is I'm pretty much going to have a rock solid engine by the end of all this, the down side it the time and money all this has taken!

Anyway to continue the story I ended up with all new ( rebuilt ) injectors, a new tandem fuel pump, and was still having misfires no matter how much I checked and rechecked things. I then gave up for about a week, and started watching random non-english videos until I came across a russian guy who had shimmed his injector bores to stop fuel getting down into the cylinders. He had turned up a bronze plug to account for the injector bore wear on his engine, and that got me to thinking. Can you shim / resleeve a worn PD injector bore? Probably, but so too some of the video I froze showed me the grooves worn into the bore hole opposite the injector holder, at about 3 o'clock. You young'uns may have to google that : ) I decided to pull my injectors for the eleventy millionth time, and low and behold my bores have these very same marks. No idea how I had missed this before, given how many times I've actually had the injectors in and out, but there you go. In my defence there are ring type marks meant to be there, and the wear marks from 2-4 o'clock that correspond to the flares that hold the two o-rings up on the injector body. Easy to overlook till you know what to look for! It's obvious fuel is still leaking around my new injectors via the wear marks in the head. My new injector bridge now holding them dead straight has probably opened the gap up a little more and made it even worse!

First pic shows the bore wear marks in the russian video, second is his shim, third is bronze shim installed. Problem is that only covers the lower seal leak - fuel into the head, doesn't stop top seal loss - into the oil, and that would also drop the actual pressure getting to the injector, which will have to trim up and try to open more, and likely still max out and throw errors!







Further research and I decided to just accept my losses and get a new aftermarket head. Seems you can stop gap the problem with new seals and things to fill the wear holes for a while, but these all fail pretty quickly and you end up with fuel loss into the oil or into the head, and the injector is under-fuelled as a result. This all leads me to believe I probably didn't need to spend near $2k on rebuilt injectors, as it was obviously the head wear causing the misfire problem. Now the injector body itself can wear too, but as it is a much harder carbon steel, wearing into an alloy head, well it's the head bores that cop the damage.

If you have a lower km engine, NOW is the time to fit the blue injector bridge I've shown at the start of this thread that holds the injectors from both sides, preventing this problem, GLAD I have one!!!!!

SO, for anyone with misfire problems on random injectors, and a higher mile engine, I'd be puling the injectors and checking the injector bore holes in the head. My gut feel is the head is more likely to give out before the actual injectors do - for sure injectors can fail, but with rebuilt injectors costing more than an aftermarket AMC head out of the UK ( cost approx $1800 landed ), I'd be replacing the head and just doing a new seal kit on the old injectors rather than the other way around I just did!! EDIT: The AMC head is made in Spain, and is the head to get, there are China "FAI" heads for about $500 less, and these are probably OK, but it seems the genuine AMC from Spain is the way to go from what I've read. I used Lymm engine parts in the UK, Darkside was WAY too dear on this part ( near $3k for an AMC ).

[Greg Roles]

FYI found two Russian you tube videos that showed up in my recommended feed where they are honing out and re-sleeving injector bores, using liquid nitrogen to shrink the sleeves before fitting.

[Greg Roles]

There are also tons of Russian videos of re-sleeving T5 blocks, so despite some negative comments on various UK forums about doing this, it seems in Russia it's quite common. My bores look fine, and Plasma is supposedly super low friction, so I'm just gonna run Lucas upper cylinder lube to be safe and not thrash her when she's cold.

[liangdotchen]

Thanks for your breakdown so far, very informative. Im also looking to replace my cylinder head. Do you know if the AXE head will fit the BPC engine? Ive asked many parts suppliers and they said it will suit my vin number, so answer isnt definite.

[Greg Roles]

Well all I can tell you is both the FAI China aftermarket head and the AMC heads ( pictured ) list both the AXE and BPC in their listings, so I'd say you've a good chance that it's all the same. EDIT - NOT the case, the AXE has a different turbo mounting to the BPC, different gasket and casting!!! Got this info off a Darkside video, so unsure if the "mounting" on the older AXE is just a bolt on component and not cast into the head, but they both have different turbo gaskets, again perhaps just to suit the turbo, but I'd suggest from this info the heads may not be inter-changable at all!!

[Greg Roles]

Put the new valves in the new head last night ( you need a deep valve spring compressor as pictured, normal one won't suit ), and all my injectors etc have FINALLY arrived, been almost a two month wait on rebuilt injectors out of the UK. Planning a big weekend of engine building at long bloody last, I'm actually a bit excited.



And... as is the way with these things, I came across the link below today. A T5 remanufacture specialist in Latvia, I've easily spent more than they are asking for a rebuild. I'm sure freight would be a lot, but at least the entire thing is rebuilt.

VWT5ENGINES.COM - REMANUFACTURED VW T5 2.5 TDI AXD, AXE, BNZ, BPC, BLJ ENGINES