The Mitsubishi Pajero Owners Club®

waterbabie · *** Joined: 01 Nov 2004 Posts: 249 Location: surrey

can someone please help if ive got a wastegate on my pajero then what is the valve that keeps releasing at about 3500revs and is located at the rear of the inlet manifold is this there releasing pressure as an emergency back up meaning my wastegate is sticking or is this valve nothing to do with wastegate boost pressure etc please help as this problem is driving me mad.2.8 turbo diesel lwb 1994

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Blues N Twos · Posted: Wed Dec 08, 2004 19:30 Post subject:

I'm no expert but that sounds like the dump valve.

I believe that this will release excess pressure generated by the turbo.

You havn't explained very well what the actual problem is.

A valve releasing excess pressure is quite normal in turbo charged engines. You will have some more replies soon as there all getting in from work about now. Rolling Eyes

Jon

Richie · Posted: Wed Dec 08, 2004 19:52 Post subject:

Your wastgate , as yu call it, the return vlve, is not operating correctly, hence the valve on top of the manifold is douing it's job, and relaeasing the pressure.

Now, has it always been like this, or is it something that has just started, the reason I ask, is, if the vehicle is newto you, then someone could have fitted a new rellease valve 9dump valve), which is design to open at about 3500 revs , and give a sound to everyone around, or it is faulty wastegate.

Which ever, so long as it dumps the prssure, all should be OK.

sonic-1 · Posted: Wed Dec 08, 2004 20:21 Post subject: waist gate n dump valves

waist gates n dump valves , well the reson for havin em is different the waist gate is to stop the turbo over boostin, what it dose is lets some of the exhuast gasses by pass the turbo at a preset pressure ,if its stuck you will get more performance or a loud hissin sound as it blows past yer hoses on yer mannifold, but it should feel quicker, the dump valve well they are there to stop the turbo from stalling when yer change gear , how this is done is you are raggin along on full boost yer take yer foot off the throtel to change gear the pressure in the system will cause the turbo to stall, hence turbo lag but a dump valve dose what it says it dumps the boost which keeps the turbo spinnin so when yer stomp back on the throtle the turbo is allready spinin so full boost aint far away, but thinkin adout it diesle motors shouldnt need dump valve as they aint got a throtle body to get in the way n hold up the the air flow like a petrol turbo motor has ,so i would say yer prob is waist gate related or hose clip gone weak , forgot to say if yer waist gate is stuck it will go well for a while then blow up prob do a piston or two Crying or Very sad

so dont thrash it till yer get it sorted

waterbabie · *** Joined: 01 Nov 2004 Posts: 249 Location: surrey

thankyou so much everyone for your replys i think im finaly getting to grips with this waste gate and release valve thing.right its a long story so am goner keep it as short as possible.original problem started as loss of power on motorway,turned out to be camplate in diesel pump had it fixed motor ran a lott better but still not as quick an powerfull as it was, took back to garage they turned diesel pump up and motor was definently quicker, but only if i gradualy exelorated if i kicked the exelorater right downthe vehicle seems to hold back like its staying in gear to long and struggling for power, then at about3500 revs you can hear this pstshshsh noise which i take it is the pressure release valve.now about 2 weeks ago i changed i changed auto gear box oil and it was like anew motor ,ithink it was the first oil changed it had ,anyway it was smoother faster but release valve was still cutting in not as often but still doing it.now 2weeks later vehicle is not running as smooth so have decided am going to do another auto box oil change as iread on one of the topics posted that when you do an oil change the new oil can become contaminated with the small amounts of old oil that are left in the gear box.but am still at aloss why this valve keeps releasing and motor is holding back not as fast as it used to be,do you think i could have a problem with the waste gate or this release valve or worse still auto gear box problems.hope your still awake after reading all this and sorry if ive waffld on a bit but wanted you to see the whole picture and i might finaly get it sorted out

arkadiy · Posted: Thu Dec 09, 2004 15:22 Post subject:

I would connect the pressure meter to one of small pipes on your intake manifold (using T-piece). Max pressure must be 1.8-1.85 Bar depend of model. If you have more than that, your waste gate not working properly and releasing valve doing right job (prevent engine). So may need to fix waste gate.

BR,
Arkadiy

waterbabie · *** Joined: 01 Nov 2004 Posts: 249 Location: surrey

sorry arkadiy forget to mention that did pressure test about 2 months ago, mind you that was when i had problem with diesel pump before this pressure release valve thing was cutting in so it might be worth checking it again.but am i right in thinking that the waste gate is probaly sticking, have tried three times now to find this thing the bl**dy waste gate,but still no joy,ill never make a mechanic

phil.p · Posted: Thu Dec 09, 2004 22:21 Post subject:

its bolted to the turbo Wink

waterbabie · *** Joined: 01 Nov 2004 Posts: 249 Location: surrey

ok that sounds simple enough,open me bonnet and my turbos o n the left do i have to remove anything to get to it or is it just a case of searching round the turbo and sooner rather than later ill find it, its just abloke i know told me that the only way to get to it is from underneath the engine but ive had no luck,obviously this was duff advice will try as isaid going in from the top many thanks

arkadiy · Posted: Fri Dec 10, 2004 18:32 Post subject:

On my Paj it's about 70mm. diameter and 30mm long cylinder with diafragm inside. Attached to front side of turbo (on exost pipe).
But it would be much easy to check the air prassure in intake. If it exeed 1.85 Bar something wrong with waste gate.

BR,
Arkadiy

BUZ · ** Joined: 27 Oct 2003 Posts: 97 Location: NEWCASTLE

Hello-had this problem on lots of our vehicles-wastegate sticking-
remove air filter box and braided pipe from turbo - the long one that comes from front to intercooler-then you can see what looks like a round tin fastened to the turbo by two bolts it has a rod cmming out of it going back along behind turbo.dont waste your time looking to see its attachment to wastegate as its impossible. undo two bolts and let lots of freeing oil run along rod towards back. gently hold round tin shaped actuator and gently work till rod moves backwards towards rear of turbo. if rod doesnt move wastegate peg is stuck. keep jiggling and oiling till you feel it free up... it will, eventually.-

air from diaphragm in diesel pump inflates rubber balloon in actuator tin which pushes rod out moving a peg on turbo housing which opens wastegate on overboost.--hope this description is simple enough can e-mail photo of turbo of on bench if still unclear. very common fault .