Grr, AFN problems

Last couple times I've driven the van it's felt fine, but a bit down on power, then it would drop into limp mode. I'd cycle the ignition, then it would go back to normal. Now it seems to be staying in this low power mode (not limp mode) basically there is not as much boost as there should be and the boost pressure stays low until pretty high up the rev range(and even then it pegs at around 10psi, normally 15-17psi)
. I am thinking either N75 or vacuum pipes? Or maybe stuck vanes on actuator? MAF readings are lower than what the ecu is expecting, but this is the same with my spare MAF, I presume this is because the ecu is expecting more boost hence more air? I can also here the turbo whistle as normal, but as said the actual boost pressure is lower than normal.
Am I looking in the right area? Meant to be going away saturday and I'm working all hours at the moment, fucking typical

No fault codes logged even when it went into limp mode (using one of those £5 eBay leads)
The N75 is the boost pressure valve as far as I'm aware? I'm leaning toward this as the person who put the engine in told me this valve was 'screaming' until he gave it a knock.so maybe it's sticking?

No codes coming up? That is bizarre. I tried the Mr Muscle oven cleaner into the turbo method. Well worth a go. remove your egr into exhaust manifold(or blanking plate) and feed a long tube straight down into the correct vein chamber, connected to the oven cleaner. Blast it full, wait an hour or so, and then go for a drive.

Good news! Had a good look around the engine bay as I managed to get home in daylight. Found two kinked vacuum hoses,, basically where the main vacuum hose is I have two hoses T'd into it going to the n75 and n18. Instead of using a little silicone elbow a straight bit of fuel pipe (same as between the injectors) had been used and just folded over. I reckon over the months they have been getting worse until the stage they have almost closed up, giving me poor vacuum. Straightened them up and big boost! 20psi now, never been that high.
Back to work now, will give a bit more of the story later

simplest things sometimes - strange it didn't show up codes though...

Good news

So off to York for the weekend?

Surprised an under boost wasn't seen but yeah, simple things often cause the big problems.....and it's always best to trial somebody else's expensive component before shelling out for a shiney new part!


Have you ever run with no egr system? Is it still all connected up or blanked off?

No, but it would stop the limp ness, code will be stored for 50 starts or something but won't affect running etc. I would be inclined to fully block that egr off, it's just one more thing to go fucked if say the valve did open a smidge and stick,

Might well do that when I replace my vac lines as looks like it been fitted by someone who was thinking of spaghetti. Plus it's all in fuel pipe? Is that right? I thought people used silicone.
Egr wise, blank at what end

lloydy wrote: Might well do that when I replace my vac lines as looks like it been fitted by someone who was thinking of spaghetti. Plus it's all in fuel pipe? Is that right? I thought people used silicone. Egr wise, blank at what end

blank at the manifold or the valve, makes no odds really but the valve will come off easier, if it runs fine and doesn't chuck a low flow code up then may as well loose the valve, vac pipe, and as much as poss of the system, I suspect if you lose the n18 it will sulk, my early 1z hasn't noticed it even gone yet! Later systems are a bit more fussy.

Leak off pipe is what vw used for all the vac plumbing...or silicone vac tube but I find it can snap or tear in two quite easy, fuel pipe is a bit big but lone as its all air tight will work...