The Mitsubishi Pajero Owners Club®

Quid · Posted: Sat Jan 24, 2015 12:19 Post subject: Waste Gate Valve Spring Issue?

Hello all,

Fresh issue on my V44 4D56 2.5 MK II Paj.

I have little or no power between 1250 and 2250 RPM - particularly when moving from a standing start - but sill present at high speed (say motorway at 60km/h)

Pressing the accelerator feel like I am attempting to move with the handbrake partially on.

One the RPM get to 2000rpm the turbe starts to kick in and by 2250 there a reasonably decent puff of black smoke and away she goes!

emissions out the back are otherwise "normal" for a 92 Paj Smile

I am guessing the spring for the Waste Gate Valve has become defective/worn

Looking at other threads/posts I need check the pressure on the inlet manifold and observe with the waste gate actuator operation.

Am I on the right track -

anyone know the pressure for the 2.5? (have seen 0.8 bar quoted for the 2.8)

Many thanks for thought/insights/suggestions.

Quid

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trekker · Posted: Sat Jan 24, 2015 20:15 Post subject:

For the purpose of a boost pressure test, 0.85 bar is ok. My older model has that spec, later ones may go to 0.9 bar.

If you have good boost after 2200 rpm, that sounds like the turbo id working fine, though a bit late.

More to follow.

Quid · Posted: Sat Jan 24, 2015 22:54 Post subject:

As always, thanks for that Trekker

So, that the turbo is coming into play a little late - would that support the hypothesis that there is an issue with the waste gate valve/spring?

Quid

Mark3 · Posted: Sun Jan 25, 2015 7:03 Post subject:

No, the waste gate spring being weak would effect max boost pressure not at what point the boost comes in.

magn1t · *** Joined: 07 May 2006 Posts: 153 Location: NZ

But if the spring is OK but the actuator is loose it'll happen.

You need a boost gauge.
Then you'll know.

Mark3 · Posted: Sun Jan 25, 2015 10:27 Post subject:

It would have to be very loose indeed though.

trekker · Posted: Sun Jan 25, 2015 10:47 Post subject:

As said, I doubt the turbo is at fault, and that includes it's waste gate.

Quid · Posted: Sun Jan 25, 2015 13:11 Post subject:

Thanks Guys....

Hmmmm..

Bit at a loss.

Behaviour is fairly consistent at this stage - but that said, for one drive yesterday it really felt there was no issue..

Nice pick-up form standing starts and "normal" acceleration while on the move...

Next suspect?
- Intermittent fuel pump issue (is there such a thing)?
- Injector issue?

Alas, sigh, No clue myself.....

Smile

Quid

trekker · Posted: Sun Jan 25, 2015 15:15 Post subject:

Follow up on your feeling...... check how hot the each wheel hub feels after driving a few km, avoiding using the brakes where possible. If there is brake drag, the affected hub will be hot, other cool to cold if no brakes used.

Quid · Posted: Sun Jan 25, 2015 15:34 Post subject:

LoL Trekker,

The brake warning light has just illuminated in the dash.

As always - great suggestion....

Will update later this evening.

Quid.

Quid · Posted: Sun Jan 25, 2015 22:21 Post subject:

Dont think its a braking issue Trekker....

Did 10k up and down a motorway nearby.

Everything cool as cold steel.

Quid

Quid · Posted: Thu Jan 29, 2015 1:38 Post subject:

Got the braking system professional checked at FAST FIT

It is in perfect order.

Interestingly I am not on day two of the car driving, running, performing perfectly normally.

The only think that has changed is a fresh, full tank of diesel.

So I am now wondering was it a fueling issue?

Quid · Posted: Thu Feb 12, 2015 13:26 Post subject:

Need to revist this one folks .....

So this is all somewhat anecdotal but it *** appears *** to be a pattern.

Problem goes away with a full tank of fuel.after about 40lts (~ half a tank) the problem seems to appear again.

No power or pick up between 1200 and 2200 rpm

Turbo kicks in, big enough of puff of smoke.... and away she goes....

Demented.

Loman.

Simon_W · ******* Joined: 21 May 2013 Posts: 4881 Location: Watford

If it only happens with less than half a tank of fuel, maybe corroded fuel pick-up in tank? Pinholes covered when tank is full, exposed to let air in when half full?

trekker · Posted: Thu Feb 12, 2015 14:22 Post subject:

Last year a member was plagued by this very issue, many suggestions on pin holes, partially blocked pipes.

And I don't recall the solution, but others may, or find it in Search.