Club 80-90 Forums

I have a T25 with a hightop, and a 1.6TD which I was told was a reconditioned engine. My query is - should I be able to feel when the turbo starts blowing? I can't. It will get up to 65 ish I think, which seems good enough, certainly good enough for my ears! But at no point in the rev range do I feel it get a little more power. I've had several turbo diesel's over the years, and all (except my current '98 Sharan which has a lovely variable vane turbo) have had a definite low-power-at-low-revs/whoa-here-comes-the-turbo character. This seems as progressive as the Sharan, but much slower.

I'm expecting replies along the lines of either "They are all like this" or "there must be a leak - you should feel the turbo at xxxx rpm". I don't have a rev counter, so if I should feel boost, could you let me know in terms of xx mph in y gear? (I have a 5sp box).

Many thanks

Pull the pipe off the boost valve actuator cannister on top of the diesel pump & try driving it again. If there is no apparent difference you have no turbo boost. The engine should feel really flat in comparison with the pipe removed.

Cheers, synchonised. Could you humour an utter incompetant, and tell me what the actuator canister looks like, and where the diesel pump is?
Thanks!

Top left of picture where my finger is pointing;

It would be a good idea to see if it is working while you are at it as its not unusual for the rubber diaphragm inside develops a leak. Just put a pipe on & suck & you should see the mechanism move

Seems a simple test. Do you mean, uncouple the white pipe by your finger, attach a similar pipe and then suck? Is that it? Thanks.

Hi synchronised, nice clean bit of engine there. Thanks for the explanation and photo. I'll try disconnecting this and go for a spin when I have the chance. Curious about sucking on the pipe tho (but haven't done it as I pipe handy to use) as the mechanism on mine is such that the only movement available on the plunger coming out of the canister is for the plunger to extend. As it sits now the plunger is fully withdrawn and the lever it acts o. Is back against it's stop. Maybe when I get a pipe all will be clear.

I have a separate question about the cold start device but will post separately after further research.
Cheers
Roger

Sorry for any confusion, I should have said remove the existing pipe , attach a clean piece of pipe to the capsule & blow hard into it. I was getting confused with vacuum capsules on dizzys On boost capsules you need to blow to get the actuator arm to move out

Hi
It takes around 0.2 bar that's 3 psi to move thew actuator and 10 psi to fully move it harder than I can blow!
to test the actuator remove the pipe , pull arm full back (towards the rear of the van) quite stiff , put finger over the metal pipe connector to seal it, let go of the arm it should not move if it moves back then there is a leak in the diaphragm . This part is the LDA and controls the boost mixture Brickworks I think has them at a cost!

Its a 2 ton van with a 1600 TD engine. If you'd had a 1.6 NA diesel I expect you would definitely.notice it wasn't flat as a pancake and simply gathered speed.
JX has a small turbo with a turbine that speeds up quickly and drives a modest compressoe. The turbine chokes early and thus is set to wastegate bleed early about 8 psi.
Expect to just sense it starting to get busy by 1800 rpm ish with foot down.
Unlike petrols and light diesel cars heavier and draggier diesels tend to run on boost most of the time including cruising. . Say above 40 mph.
I expect its working fine

There are a few easy mods to.perk.it up
But this is not the place

Thanks tensilekid, complete freedom of movement in both directions with a finger firmly over the connector. That'll be part of the problem then...

JX LDAs common failure.

HarryMann wrote:JX LDAs common failure.

Just curious (as I am all petrol) but what is an LDA please ?

Well, took it up the same hill twice with and without the hose on the LDA, might just have been able to tell the difference, but might have been imagining it. Put a bike pump on the tube, it moves the piston, but it just moves a few mm and then returns to it's resting position. Guess it's done for. I might try wedging the pivoting doobry open and see if that makes a difference (not as a solution tho - it'll maybe tell me if my turbo is blowing anything?)
Cheers for the help.

If the LDA is knackered you wont get proper boost. All that wedging the thing open will do is increase the fuelling

I thought I had read somewhere that if the turbo was blowing, and the LDA was open (no matter how it gets to be open) then boost would be produced. If I get around to it I'll let you know the results. Of course no boost might mean my method is flawed, or the turbo is not blowing or leaking pressure downstream, or maybe something else entirely