VW T4 2.5 TDi ACV Vacuum Pipes & Turbo Pipe Air Leak
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- čas přidán 24. 09. 2022
- A recent starting problem prompted me to check for vacuum leaks. In doing so I discovered that some of the smaller cotton covered rubber pipes were wearing through and the large 50mm pipe that connects the MAF to the turbo inlet was very loose.
Some advice:
1. if you are removing the EGR valve, I strongly suggest that you stuff a rag into the hole in the inlet manifold to prevent anything dropping into it. That would really ruin your day!
2. If you are going to remove the coolant reservoir and the valve assembly behind it, be sure to remove the mounting bolts completely to avoid having them drop down under the engine (ask me how I know!).
I didn't need to heat the end of the turbo pipe to soften it, I just fitted a 50mm jubilee clip and tightened it until the pipe was held firmly in place.
Inlet manifold cover part number: 074 129 900 A
Turbo plastic pipe part number: 074 129 715 F
Silicone hose: 3m of 4mm ID & 1m of 6mm ID (you could probably do it all with 4mm since it stretches quite well).
Hose clips: 4 for 4mm & 3 for 6mm (check OD and allow for compression). The original clips are single ear hose clips.
Adapter: 1 x 4mm to 6mm reducer (ECU end is 4mm, inter-cooler end is 6mm)
It may be possible to fit 4mm pipe to the 6mm fittings, silicone does stretch rather well. The lengths shown above are the lengths of the OEM VW pipes. Extra length would allow for better routing to avoid rubbing on other parts.
The outcome:
After fitting the jubilee clip and replacing the vacuum pipes the van drives better, it is more responsive at low RPM, however it did not fix my starting problem. - Auta a dopravní prostředky
Hi, for the very awkward to refit turbo inlet pipe bracket, I used a cap headed bolt possibly 45mm long with a flange nut loctited midway to clamp the dipstick bracket and inlet pipe. Much easier to refit and hold to start the thread
Hi Kevin, thanks for this and other videos. I’m about to do exactly as you have done as mine. At first it wouldn’t start which turned out to be an ignition switch. I also changed the Stanadynes as PedroPickle mentioned here. Have not had the benefit of seeing their full glory as now i have a bad white smoke issue from the exhaust and back of the engine. Can’t accelerate as the engine dies and engine won’t go past 1500rpm. Not diagnosed the issue yet but starting with this video. Also mine is an AJT with an ACV plastic cover as PedroPickle pointed out. Back to problem solving!
Great video, I checked my inlet hose and it was really loose too. I have done the fix and so far I have not had limp mode kick in on hills! It has improved the performance dramatically. I had done all of the vacuum pipes, checked the n75 was working, tested the actuator and was loosing my mind so thank you! Someone had mentioned it on T4 forum but it is better explained in this video.
I'm glad that it helped you. I find the ACV engine very reliable but there are a few issues to watch out for, particularly as most of them are over 20 years old now. The other one to watch out for is the diesel pump timing. As you can imagine, that makes a dramatic difference to performance and particularly starting.
the hose near the two heater matrix inlet pipes controls your recyle air flap. (reticulation)
Hello Kevin. I’ve got an ACV swapped into a US eurovan. It’s been a journey. I’ve got my inlet manifold off and replaced my turbo and did some other mods. What is really hard for me to understand is what valve is for your turbo control, I’m using the N75. Also which pig tail contacts to it? I believe it’s the brown and blue wire one. Could you send or post a video of your turbo lines and control valve as a reference for when I get mine back together? Thanks.
I have same problems, I found that turbo hose loose and used rtv and hoseclamp. But still same as you, its hard to start. 2 years ago I blocked EGR, but no big differences. So my 2 problems are bad idling and bad starting. Other than that it runs great and efficient.
I fixed my starting problems by adjusting the diesel pump timing and fixing the contacts in the fuse box for the glow plug relay. The contacts had melted into the plastic of the fuse box and were not making good contact with the relay terminals. I've done another video on that problem.
@@bvqbvq thx man!
Thanks for this, I'm currently investigating a drop in turbo pressure which I think is due to an air leak somewhere. Be interested to know if your low-down engine response improves.
I didn't have much improvement to the engine performance as a result of fixing this fault. I did however gain a noticeable improvement after I adjusted the diesel pump timing.
Hi Kevin. I have the exact same model and vintage. Even though ACV is printed on the cam cover, that's only because the ACV model cam cover is also fitted to this engine model - the AJT. Does the engine smoke white upon first starting after a day or two of rest? If so, the inlet air leak you refer to here is not the reason. Although a good idea to find a nice securing clip for that pipe, it is almost certainly the OE injectors of the 88bhp model - the Stanadynes - that are leaking fuel into the chamber after a rest that is causing any starting issues. I have a custom body and nozzle combination that you can get from International Diesels that are stamped "GERMANY VW Audi" - that are actually Bosch units - I can dig out for you if you reply to this comment - See Ron Rake on T4 Forum - he did mine for me but he's in Liverpool. Completely transformed the running of mine. At least 102bhp now and beautiful to drive.
Hi, thanks for your information, very useful. I traced the starting problem down to burnt out glow plug relay contacts. I made another video about the problem. I never had any smoke from mine, just the poor starting which is now fixed.
He is Project Power, and he calls my custom body and nozzle setup the "PP0.5". It's the largest flowing injector setup you can get without needing to remap the ECU. I nursed it once and on a long trip I got 76mpg. Yes, 76. Did a 310-mile round trip to Santa Pod and it used less than a quarter of a tank of diesel.
Hi. I’m planning to swap out our braided rubber vacum hoses for silicone ones. However on the forums I read 3mm internal @ 5mm internal hoses. I see you used 4mm and 6mm. How did you get on with fitting the new hoses on.
For me the 4mm and 6mm hoses worked perfectly. If you have any doubt, measure your old ones to be sure. If you are planning to use the 6mm for the intercooler then you will need an adapter to allow the 4mm to connect to the ECU as per the description above.
@@bvqbvq thanks Kevin. Pulled off one of the hoses and 4mm it is. Shame I came across your video after placing order. 4mm ordered. 👍🏼
Hi, I wonder if you can do me a favor? I think I may have mixed the two pin plugs up which connect either the n75 valve or the lower pressure converter valve. Are you able to photograph the wiring colours or describe which connectors fit either the top pressure converter or the lower one? I have a Pierburg 1H0906627 upper N75 valve. Thanks I will check out your other vids as you have the same engine as my Caravelle T4.
According to the wiring diagram the N75 wires are black/yellow and brown/blue. However, looking in my van the colours look more like black/yellow and orange/green. The wires are thin, dirty and difficult to see, so I could be wrong.
@@bvqbvq oh thats so kind, thanks for this info it is really helpful to me.
@@bvqbvq Me again, where did you get the wiring diagram as the Haynes manual doesn't show the N18 and N75 pressure release valves/solenoids?
@@aaronharris5275 There are various diagrams online and I have a copy of the Bently T4 manual which has diagrams for the USA variants. You could take a look here: dokumen.tips/documents/vw-t4-engine-wiring-2002.html?page=1
Hi what was the sound did it mate? My one is popping
Mine didn’t make any noise so I can’t help you there.