2.5 TDI Transporter BPC 2009 info thread

[Greg Roles]

Still fighting. Took the motor right down to the near bare head, and rebuilt, checking and rechecking every step. Still honestly can't work out which crank rotation is the right one, but am narrowing it down, next effort will be to flip the cam on this current setup, and if still nothing, well it's off to the mechanic, I'm done.

Did find some weird things. On bleeding every step of the fuel lines, I found if you run the lifter pump for the 30sec via VCDS and unhook the return (brown ) line, fuel comes out of the tank via the return!! WTF. There is also the normal pressure in the black VF line as you'd expect, this is very strange. Anyone shed some light on this??? It seems the lifter pressurises both lines???? I had to run the pump, unhook and block the brown return line with my finger to get all the froth etc out of the lines. Also had to bypass the HPFP to get any sort of flow with the lifter through the fuel rail and injectors, I'm getting suspicious on my new HPFP, going to put the old one back on before I swap the cam again, it does seem like something just isn't working as it should. I did take the new HPFP apart and checked it over, but it all seems fine. Even filled it with diesel and carefully bolted it back on, so there's no air bubbles anywhere, but still nothing.

But yeah if anyone can tell me the VW pump should be pressurising the system enough that it gets backflow up the return, then please let me know, does not seem right.....

[Greg Roles]

OK, caught up with family over Easter, my Dad and Brother are good mechanics, and we nutted out the possibilities. Long story short today I am convinced timing is spot on, cam is correct, and there is no specific TDC that matters despite what both VW and Haynes say. I think VW just meant the black arm tool is keyed like the crank turning tool.

I tried the old HPFP but it has the same restriction to priming via the lifter the new one does, so made no difference. Checked new one, seems fine, so it's back on.

Pulled glow plugs to check both TDC and to eject any accumulated fuel and guess what. ZERO FUEL out the glow plug holes despite repeated efforts. Dry as a bone. I've been wasting time thinking it's timing, when each effort shows me everything is spot on, every mark is perfect. Seems I've just wasted time......

Diagnosed this lack of fuel down, and I have a loom signal problem, there is no signal going to injectors, messed with the round head plug and got a brief voltage change to cylinder 1 on cranking, but it appears my whole problem is no electrical signal to the injectors to fire. Might have a loose plug to head or to one injector, as these PD injectors wired in series all drop out if one goes down / has a bad connection. Will mix up old and new injectors, and play with loom tomorrow, but I think I've solved my nightmare. Sure hope so....

[Greg Roles]

Well she's showing signs of life, won't keep running as yet, it's absolutely pumping out the soot from months and months of old diesel cranking and endlessly being pulled apart.....just waiting for the battery to charge back up, the runs are lasting longer and longer, guess it's just air in the fuel lines etc now.....so god damn close.....

Loom problem was in the plug, with injector on cylinder 1 and 2 having dodgey connections, no doubt from me plugging and unplugging it multiple times, had to use a multimeter to check for continuity. Tightened up the female portion of the plug, made sure the male part was straight and hey presto, we have fire.

[gregned]

Really appreciate your hard work and documentation

Cheers

[Greg Roles]

I'm bringing in the local VAG mobile mechanic, we had a long chat, he said he has had drama with the cheaper timing tools and wants to put his genuine set on the car, reckons they are so super sensitive to timing it's not funny. He started out with a copy set, and threw them away after two bad experiences. My van will kinda fire as it is, stumbles but won't actually run, all I'm doing is overheating my poor starter and ripping the life out of the battery, plus I'm giving myself lung cancer with all the soot I'm breathing in the shed!

Will report back when he's had a crack at the timing. Going to drop the tank again and investigate the in-tank lifter pump, as he agrees priming both lines is all wrong, sure seems so to me!

[Greg Roles]

OK been a while but I've still had no luck getting it to actually go.

The mechanics Taiwan "HCB-B1419" tool set ( $1k ) definitely puts the cam several degrees more advanced ( clockwide ) compared to the China tools, but there is a fair bit of freeplay in the China cam tool. This fancy tool set still shows no special TDC on the crank, so I'm at a total loss what VW were on about. Mechanic suggests 5 cylinders is the reason, but the better tool has no specific TDC.

I plan to spend this weekend diagnosing the injectors, as I pulled them recently and three had surface rust on the god damn tips thanks to all the rain we have been having. I wire brushed them back to shiny and penetrating oiled them, but the actual injector holes may be rusted up, so I've got to pull the inlet and see if fuel spray is coming out of each inlet hole. I've three good old injectors so may swap them back in just for ****s and giggles.

I'm still convinced there is something wrong in the fuel circuit given the fact the return line is pressurizing, gonna drop the tank and pull the pump and test it. Still should at least start a bit though. That too makes no sense.

PD injectors and the internal nature of the loom and fuel supply make it hard to diagnose, but I have put my multimeter across all the wiring and checked for continuity. I guess a oscilloscope is the next thing to check they are actually firing.

Probably going to have to send the injectors back to the UK to get them tested, will be the quickest and most reliable way, my VAG mechanic doesn't know of anyone decent who does PD injectors in Australia.

I've got all new stretch bolts so my final step is to pull it down to the head gasket and get my mechanic build it up from there bit by bit.

[Greg Roles]

Well Fook me it FINALLY runs, and it started right up from bone dry injectors once happy.

I've been busy at work / unmotivated to keep slogging it out with this engine, but I DID buy a "smart hook" powered probe tester that has injector pulse and oscilloscope functions, and used this to check all my injectors. They all fired fine when sent various signals, so I figured there had to be something else. My "new" reco injectors had some mild surface corrosion on the tips from all the time they have been sitting, and this led me to think, how are the fuel orifices? I got out my jewlers loupe/monocular and low and behold, half the god damn holes were clogged up, most likely from me brass wire brushing the tips back. I got the finest needle I could find in the missus's sewing kit and poked them all, there's 6 holes in the end of each tip, about half way down the "cone". They are tiny, and even a super small needle point only just went in. I cleaned up all the holes, soaked them in injector purge overnight, and put them back in.

I replaced the injector loom with a cheap China one ( $34 ) just as an added precaution, given how any times I had plugged and unplugged the new VAG one I had put in way back at the start, and thought there may have been a bad connection. I did check continuity with the multimeter and it said all was fine across the plug, but why not for $34. Seems the same as the $150 I got from Darkside anyway!

So in hindsight I reckon I solved some problems, which lead me onto new problems, and all the time the injector tips were surface corroding creating still more problems. Getting decent cam timing tools was no doubt a key part. Anyway it was amazing how easy it started, just cycled the key about 20 times and cranked for 30 seconds and away she went. Got her up to temp, have an oil leak from the crank timing cover to fix and one of the rockers is knocking a bit so I'll go back in and reset all of those when hot, but she is amazingly quiet for what it is, smooth, and happy to rev up. WAY quieter than all the going motors I've heard, hardly any gear noise, must have gotten the lash just right!

SO this ends my journey with this engine, I reckon it will run forever now, it's built like a Panzer tank, but when it plays up, well best bring in an expert and avoid thinking you are as clever as I initially thought I was!!

[Transporter]

I'm glad you've fixed it. Great job there. Yeah, it pays to look after them. I've been very happy with my T5 4mo AXE for 11 year, I wish I've never sold it, it was great van. Pity they don't make them anymore.

[Greg Roles]

I'm glad you've fixed it. Great job there. Yeah, it pays to look after them. I've been very happy with my T5 4mo AXE for 11 year, I wish I've never sold it, it was great van. Pity they don't make them anymore.

Nice to hear from you ol' mate, yeah it's been the most challenging engine I've ever come across, but thankfully now all I have to do is maintain it. At least the struggle has left me quite educated on this engine, so I do know it backwards. Keeping it cool, and swapping the oil a lot is my plan!

[Greg Roles]

Finally ready and washed for RWC.

[Silver Caravelle]

Excellent effort Greg. Now enjoy driving it!

[JimmyFingerz]

Excellent thread! Very informative. Thanks Greg!!
As a VW hobbiest, I too have worked on a few engines in my time, but this VW 2.5 BPC is next level! There have been many, many FML moments ... and that was just on the strip down before I had even gotten access to the cylinder head.
I was in the process of doing a Darkside cam replacement + injector seal replacement + head gasket replacement on my 2008 Multivan (2.5 BPC 4-Motion 6 Speed manual) and found this thread by chance. I bought my van in April 2021 in the middle of COVID. I bought it knowing that it had issues (typical tapping noise cause by dodgy cam/cam followers). The body was in really good shape and I needed the 4-Motion as it will be doing light-offroading-camping from time-to-time. My young kids absolutely love this van, so once they'd driven in it, not-fixing it was NOT an option.
So glad I found this thread when I did, as my van is high-mileage (350000Km's). I had cleaned my cylinder head and had not even noticed the scaring/wear on the injector inserts/holes as Greg pointed out. I'll include screenshots of all injector slots (sequentially) from RHD-drivers-side to passenger side (when I get a chance)
Interestingly, the original lower-end engine (block/sleeves/top-of-pistons) all look like they're in great shape for a vehicle with this much mileage. That is obviously just my novice opinion and there could well be more sinister bits hiding internally. That said, the van drove really well and was very smooth, even with the cam and cam followers stuffed (only one of the cam followers was worn through).
So now, I need to decide whether to take a chance with the old cylinder head or bite the bullet and order a new AMC as Greg mentioned.
As mentioned in this thread, getting parts in the Sunshine Coast-QLD is either dealer or order-via-Europe. I order most of my stuff from the UK/Germany, so my progress on this might be a little delayed.

[Greg Roles]

Welcome to the old forum, glad this has helped, apologies for slow reply, only check in from time to time.

I'd suggest the AMC head over the China FAI, not from Darkside though, they are a bit pricey compared to other UK suppliers, but unless you can get someone to push in some metal liners there's not much other option. I considered liquid steel and running the injector bridge to prevent toggle, but to be honest I don't want to have this god damn engine apart again for quite some time, still have PTSD because of the experience!! I have my old head and injectors if you want to see if someone will machine up and press fit some steel liners!

Interesting to hear your cylinder bores still seem good at 350k!!

Please feel welcome to add any info or experiences you have to this thread, for if I had found a comprehensive post like this before I started, I would have saved a lot of time and money, and probably have more hair still!

[JimmyFingerz]

Thanks for the info Greg. PM sent .

[Greg Roles]

Double post