Hunting down FR 150 TDI surge issues

[iammooks]

Buying a new servo vacuum line in one piece looks like a lot of hassle. I'm guessing I can just fit new vacuum hose?

I've got a cutoff piece of hose from an old servo and it looks like the I/D is 7mm but if anyone can confirm, that'd be awesome.

Are there any other vacuum lines this size on the car? I could get a longer length to cover everything...


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[iammooks]

Right, so the car passed the MoT on emissions, so I can take a bit of a breath now I don't have that hanging over me. I've taken the car out for some long runs over the past week to get it ready for the MoT and have noticed that the lurch is definitely still there in spite of the changes I've made.

Pretty much all of the symptoms I'm getting, from the lurch to the higher fuel consumption, the smoke when I floor it under low load and the hissing sound when I'm on the gas, all point to a boost leak, so I'm eyeing up the red turbo to pancake pipe hose, and the pancake pipe itself, as they're the only ones I've not either inspected or changed.

I was thinking it was really unlikely to be the pancake pipe as it's aluminium, but I keep coming across posts on MK4 Golf forums and TDI Club etc. that suggest people have had lots of trouble with leaks from the pancake pipe, and some have upgraded to the 1.8t pancake pipe with a few mods. If anyone has any thoughts on that, I'd love to hear them!

For the turbo to pancake hose, I'm getting the same parts number - 1J0145828 - but they end in different letters - F, M or R. There doesn't seem to be any difference between them, but just wanted to confirm before I buy one and it ends up being the wrong one.

 

[Rich.T]

Can you make out what side of the engine bay the hissing is coming from?

 

[iammooks]

Can you make out what side of the engine bay the hissing is coming from?

I first noticed it when my girlfriend had the passenger window open - apparently, my driving makes her car sick - and I hadn't noticed anything before. You can definitely hear it more when that window is down than when the driver's window is open, but I'm struggling to think what's on the left side of the car that would make that kind of noise, and only on boost.

I opened the airbox yesterday to change the air filter, and that didn't change anything, and I didn't notice any cracks or issues in there either, and I've changed all of the 3-4mm vacuum lines as well. The only thing that's left on that side of the engine that might be releasing air is the connectors for the tandem pump and possibly the tandem pump itself, as well as the brake booster vacuum line that runs along the firewall.

I'm very tempted when I get the car up on axle stands next to ask someone to sit in the car and stick it in gear and put some power to the wheels - nothing serious, but enough to produce some boost and see where the noise is coming from...

It's just that the surge feels similar to what happened to the car when the intercooler pipe popped off after changing the cambelt - a bit like it's pogoing. Obviously when a pipe has fully popped off, it's much stronger, but it's in the same ballpark.

 

[Rich.T]

Dare i say cracked intercooler?
Maybe get the car smoke tested.

 

[MoToJoJo]

Want me to check my spare pipe for a part number?

 

[iammooks]

Dare i say cracked intercooler?
Maybe get the car smoke tested.

It's something I've heard mentioned - I'll definitely do some more research into smoke tests and whether I can do something like that without having to go to a garage to do it. If it does come to that, I'll need to take the bumper off eventually to respray it, so it would be the perfect time to sort the intercooler too if there are any issues.

Want me to check my spare pipe for a part number?

Please! I'll have some time next weekend to get the car up on axle stands and check the condition of the pipes. They could definitely do with a clean, and if there are any problems, I can just leave the car on the stands and order replacements if I need them.

In the end, there are only so many things it can really be, but changing pipes on the off-chance is a good way to spend a lot of money I don't really need to.


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[MoToJoJo]

Err...

Maybe not

 

[iammooks]

Err...
View attachment 29477

Maybe not

Ha! Story of my life. Next best thing is if you've got a photo of the whole thing. Some of the photos I've seen have a bend on it - almost like a right angle - and others show it as just having a bit of a ripple to it.


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[iammooks]

Spent a couple of hours today trying to get the horseshoe clip off the top of the red turbo hose (the one that connects to the turbo) but gave up after a while. I tried to go in above the CV shaft through the offside wheel well, but it's really hard to get the clip popped off because of the lack of access.

My options now seem to be to either take the undertray off and try to reach around so I can do it from the underside, or to take the TIP out so I can get to it from above. Both involve a certain amount of faff. The red pipe does seem to have some play in it at the turbo side. All the other connections are firm and don't move, but in this one I can definitely feel it move when I pull on it.

As I research more though, I'm coming across more things it could be, and the latest thing to come up is the flex pipe from the exhaust manifold to the EGR cooler apparently has a reputation for cracking. Given my problem tends to be at steady revs in low gears, is there a chance this pipe is cracked? My understanding is that when the car is cold and when it's being held at low revs (town driving etc.), that's when the EGR is fully open and when exhaust will be flowing through this pipe?

If so, this could be a right pain, as I hate trying to get nuts and bolts off that have been heat cycled, so ones on the exhaust manifold will be my idea of hell. If needs must, I suppose I'm going to have to though...

 

[MoToJoJo]

Does it smell like exhaust fumes under the bonnet?

 

[iammooks]

Does it smell like exhaust fumes under the bonnet?

I was going to say 'is the Pope a Catholic?' but at this point, I don't even really know. It's been about six months since this problem really became obvious, but thinking back, the symptoms have been there for years, so it's possible my engine bay smells a certain way and it's just what I've become used to.

Are the EGR pipes actually under enough pressure to make a noise like that? It seems new Transporters have a real problem with them breaking, but not so much specifically on the ARL that I can find. I know my top EGR pipe is fine, but I've never touched the one that goes from the exhaust manifold to the EGR cooler. I'll try and have a look at it with the airbox accordion pipe off.

It's also worrying that you can't seem to buy them new anymore...


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[iammooks]

I just realised that it doesn't have to be the pipe that's cracked - they're the same gaskets that have been on there since the car was new, so they could have degraded and be letting some exhaust gas out.

I think I know what I'll be doing today...


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[MoToJoJo]

I just realised that it doesn't have to be the pipe that's cracked - they're the same gaskets that have been on there since the car was new, so they could have degraded and be letting some exhaust gas out.

The gaskets are shaped metal (possibly stainless steel), unless you've parked it in the sea for a while or have been taking the pipes on and off a lot I can't see them degrading.

 

[iammooks]

The gaskets are shaped metal (possibly stainless steel), unless you've parked it in the sea for a while or have been taking the pipes on and off a lot I can't see them degrading.

That's what I was thinking - but of course, changing gaskets is much more preferable to exhaust manifolds and sourcing (probably discontinued) EGR pipes.

Some of these problems have got more obvious since I started digging around, so while it's possible sealing a boost leak has revealed another one, there's every chance there's a loose bolt or nut somewhere. I wasn't particularly keen on the idea, but it might be time to get the car in the air and start checking nuts and bolts - especially the nuts on the exhaust flex pipe to turbo.

There are only so many things that I've done, and given how little I've driven the car these past six months, I don't see how that many problems could develop just on their own.


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[MoToJoJo]

Maybe it's how little it's been driven. Silly question but have you given it a decent "spirited" drive?

 

[iammooks]

Maybe it's how little it's been driven. Silly question but have you given it a decent "spirited" drive?

I ragged the **** out of it on the way to the MoT - partly because it needed it and partly because I was late. Took it up Ditchling Beacon in mostly second gear that day, and my go to test drive is over Devil's Dyke, so... hopefully...

It could well be because it's been left standing a while. 2020 was the worst for mileage other than a drive to Wales and back, it wasn't being run a lot of the time. Maybe soot and grime solidified or something.

Right now I don't really feel like I have the energy to start really stripping things down to give them a good clean - but every single time I think about these issues I have the intake manifold in the back of my head and I don't think I'll ever be 100% on anything until I've taken it out and cleaned it. I've got a new gasket ready to go as well and I feel like I won't have my wrenching chops until I've taken it out.

The good thing is that it doesn't sound like the camshaft - I've checked as much as I can and I'm not getting the 'tappet' sound at idle or acceleration, and the car itself does everything it's supposed to - it's just that stutter at steady revs. I heard that the dodgy camshaft only affected earlier models, and mine is a 54 reg 2005 model.

The fact that it sounds like the car is taking a breath or gasping makes me wonder if one of the intake ports is just totally clogged, but it's not a regular thing. Maybe that points to an electrical fault, like the N75, but I've never had any codes so...

If anyone is ever down south and wants to take it for a drive, just drop me a line!


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[iammooks]

Another update after trawling through various websites yesterday. The worst thing about this problem is trying to think what other people might call this so I can do a proper search - I've called it a 'surge' but other people call it a hesitation, a miss, a misfire, a jump, a jolt, a gasp, or they'll say the car's pogoing or kangarooing...

The good thing though is that you come across lots of different problems and lots of different things to narrow things down to - but there are some things I'd rather not do unless I really have to. At the moment I've got some cat cleaner in the tank and I'm going to change the oil in the next few weeks.

My most recent discovery though is that it could be the injector loom. I can take it out to check continuity and resistance, which means I can have a look at the cam condition at the same time, given I'd have to take the rocker cover off. The fact that the boost gauge seems to suggest it's holding boost, and that the issue is intermittent, makes me think it's more that kind of issue than boost, but we'll see...!

I actually read on one of the Transporter forums that they tested their injector loom by clamping the fuel return line? Said that their 'miss' went away when they did that. Is that something I'm going to be able to do on my car? I've got hose clamps for closing off brake hose, which I'm guessing would work, but I just didn't want to cause any damage or have fuel gushing into my engine bay because I can't do that on my car...

 

[Rich.T]

I've called it a 'surge' but other people call it a hesitation, a miss, a misfire, a jump, a jolt, a gasp, or they'll say the car's pogoing or kangarooing...

Sounds like air in the fuel system.

 

[iammooks]

Sounds like air in the fuel system.

I did think it was something like that - so I changed the fuel hoses from the filter to the rails, as well as the ones going to the tandem pump, but no change at all.

I'm going to take the car out later, partly to see if I can hear the fuel pump priming when I turn the ignition on, because I can't remember hearing it recently, but I'm also going to clamp the vacuum hose to the EGR valve as that might give me an idea of whether the problem might be linked to the EGR in some way. I do still have my replacement EGR valve (I missed the end of the returns window for Autodoc so I'm stuck with it now) but don't want to fit that just yet in case I can sell it on, given that it's still in the original sealed wrapping.

Looking at the EGR cooler pipes etc. I can't see any signs of cracking there and it all looks pretty healthy. There's some oil coming from the back of the tandem pump, but I think it's been there for a really long time and my oil level has been smack bang in the centre of the dipstick for ages - no rising or falling. I'll get a new gasket on the tandem pump sometime and if it carries on, I'll either rebuild it or get a new one.

There are only so many things it could be now. I've heard some people suggest the coolant temp sensor could be bad, as well as the crank position sensor, but in the circumstances, I feel like I'd be better off checking the cam and the injector loom as I can kill two birds with one stone.

Thankfully at the moment I've got some time and a little bit of money to throw at it, but obviously I don't want to spend on things I don't need to...