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Wastegate check using airline


Peaklander
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Hi

Can I ask an easy question and get a quick answer? Hope so...

One of the last checks I want to make on my 300 tdi is that the waste gate is opening. I'm planning to fit a pressure gauge so that I can see the boost and if necessary adjust the time that it occurs but I don't have that yet.

I firstly thought I'd verify that the gate does in fact open and as I haven't any experience I don't know if my normal driving experience would show this - it probably would if I knew what to look for.

So my quick Q is that I have removed the pipe to the FIP and stuck an airline into the fitting that also goes to the waste gate actuator but nothing happens. I have air compressor tank pressure of 2 or 3 Bar (I can have more) and I'm using a trigger blow gun thing with a short length of tube on it. Most of the air comes back out of the turbo intake (I have the in-feed pipe from the air filter off at the moment). Should I bang in enough air, put my hand over the turbo inlet or what?

The engine is in the vehicle.

(be gentle)

Thanks

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Remove the pipe on the compressor housing and try again.

Sorry I know what you mean - stop the air going into the turbo. The reason why I went in at the T was because the pipe that goes directly to the actuator has gone / is hard and I'll destroy it by removing.

That's what I'll do. Thanks

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Sorry I was a bit over dramatic yesterday :mellow: . I removed the pipe to the waste gate actuator and I've put just over 1Bar in there but the waste gate won't budge. The pressure holds so I assume that the actuator itself is OK. I tried pulsing too but I suppose that I'm only using the same sort of air pressure that the turbo generates anyway. How high could I go?

I slackened the lock nut thinking that the rod could be loosened but I can't get in there with anything.

I've made a short lever to try to pry against the lock nut and move the arm that way but I can't do it. I'm levering on the turbo which with my inexperience I don't like doing.

Is there any other way to get some movement? I've sprayed with penetrant too.

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If youre putting 1 bar direct into the actuator it should move out very easily.

The rod connects to the wastegate arm with a pin that is secured with a small spring clip

Gently pry the clip back with a small flat screwdriver (catch before it drops), move actuator arm aside and see if wastegate arm is seized.

Clout things till free : )

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It's closed - managed to hit it gently against the closed position from the front. Then moved up to a longer bar and now it will move open with the long lever on the nut.

Air will hold it open but not open it, so I'm going liberal with easing oil.

(Really didn't fancy trying to undo the pin - already lost a spanner down into the side of the block / mount bracket and only just able to retrieve with a lot of @£%£@@!)

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The gate now moves - took a lot of levering to free it but now it will open with air - needs about 1.5 bar / 20psi but it does move.

I've sprayed with WD40 then used a bit of engine oil. It really is quite a lot of spring to overcome.

I would be happier if I had released the rod from the arm but I took a pic of the waste gate pin from an impossible angle and I'm amazed that it's supposed to be possible to remove that clip - I can hardly see it.

post-105237-0-95596900-1462535195_thumb.jpg
Do people really undo this? I suppose if you want to alter the length of the arm then that's what has to be done.
I'm off to buy a t-piece, pipe and a gauge.
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It's getting it recconected that's difficult.

Oh I can believe that :D

I've now got a boost gauge plumbed-in. If I'd known how easy it would be to pick up the bits in Sheffield, I might have waited and seen what pressures I had before the waste gate free-up session this morning.

Been for a short ride but there isn't a lot of open road here, just some steep hills. The boost pressure never got past 1 Bar so that shows that the waste is opening. I didn't know the rpm and I'll have to find a table somewhere that will get me to rpm from road speed, through a 1.4 ratio LT230 and an R380. Maybe I can work that out?

The interesting bit is that is couldn't hear any turbo whistle and that is usually very noticeable. Is whistle a result of turbo back pressure (seized waste gate)? If so that would explain it - otherwise it's because I have just put some sound deadening material under the bonnet (at last)!

So it's been a good day - started with an impossibly seized waste gate that I didn't know I had and now it's free and I also have a boost gauge too.

Just have to be sure it's all OK and try to stop myself undoing that operating arm because I don't believe the spring clip could ever go back on with the turbo in situ.

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Ashcroft transmissions have a gear ratio calculator on their site....

Just used it - very handy tool. Now I have found out all my ratios and their rpm v road speed graphs and table are just what I needed.

Thanks

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Update: Today I had a run-out to see the effect of freeing-up the waste gate. I also plumbed-in the pressure gauge from the T piece at the turbo - it sits nicely in the cut-out for the dash ashtray - made a little plate of ally to drop in there and hold it.

The boost is a little low - didn't rise much over 12psi / 0.75 Bar. I presume (hope) that this is a waste gate adjustment rather than a poor turbo because I can see the pressure dropping when it reaches this high point as though the gate is controlling, rather than it struggling to get to that point.

The most noticeable thing is that I can no longer hear any turbo whistle; none at all. It's as though I haven't got one. My untrained ear just thought that a noisy turbo is normal. I hope that it hasn't been affected by the closed waste gate of the last twelve months (minimum) - certainly going up the Winnats Pass this morning was no strain at all.

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I have just driven 250 miles and the boost never gets over 12psi. and I'm assuming that the waste gate rod does indeed need adjusting but I'm not going to tempt fate and loose the clip just before a long trip. I'll forgo any additional boost duration for now.

The boost gauge is a nice to have in the cab but I may be suffering from cheap gauge syndrome. Maybe someone can advise - as the pressure increases I can hear the engine noise in the gauge. It's a kind of pulsating noise - is that normal with such low air pressure?

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You can use a ball and spring manual boost controller in the line between the turbo and actuator to get a bit more boost, without touching the linkage. Bleed valves work too, but those tend to dull the onset of boost and can make it feel a bit sluggish, so your better with the ball and spring type.

Vibrations etc are commonish, often guages come with a restrictor or similar to help smooth them out.

If the gate was jammed shut, you were probably getting huge overboost before, which is likely why its a lot quieter now.

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I'll probably disconnect the feed to the gauge at the T as I have a screw-in blanking cap and the noise is annoying. If I get chance I'll investigate a slightly better gauge.

As for the manual boost controller - I'll have a read about them - thanks.

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