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Cleaning sticking dump valve
Posted: Thu Jun 21, 2012 5:48 pm
by Ollie
Need help please!Engine light iluminates on hard excelleration on long road,goes to limp mode.Suspects dump valve is sticky.can one reach without removing turbo?3,2 GLX,130 000 KM
Thanks
Ollie
Re: Cleaning sticking dump valve
Posted: Thu Jun 21, 2012 6:23 pm
by 4ePikanini
Spray some penetrating fluid by the back of the turbo on the wastegate arm. Let it sit for awhile.
Then get a hand pressure pump and connect it to the pipe that goes to the wastegate and slowly increase up to max 2 bar and see if it loosens up and moves.
If not you will have to remove the turbo.
Am i correct in assuming your egr hasn't been blocked off?
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Re: Cleaning sticking dump valve
Posted: Thu Jun 21, 2012 6:24 pm
by 4ePikanini
You might want to remove airbox and turbo intake pipe for access behind the pump.
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Re: Cleaning sticking dump valve
Posted: Thu Jun 21, 2012 6:36 pm
by Ollie
Thanks,wanted to know if i have to remove air box.EGR not blocked off.
Leaving work now,will log on at home.
Re: Cleaning sticking dump valve
Posted: Fri Jun 22, 2012 9:54 am
by Ollie
I removed the filter box,turbo pipe,but still cant see the dump valve meganism?Where else?Thanks
Re: Cleaning sticking dump valve
Posted: Fri Jun 22, 2012 11:10 am
by Bigwill
If I am not mistaken our diesel Pajeros do not have a dump valve. It does however have a waste gate. My understanding is the wastegate maintains and controls the maximum presure at an ongoing basis. A dump valve normally on a petrol engine with a big turbo avoids damage to a turbo when the driver shuts off the throttle suddenly while the turbo running at ultra high revs and pressure at that stage has a "pressure crash" as the pressure has nowhere to go. The dump valve is there to dump all this pressure immediately, else damage to the blades may occur.
Re: Cleaning sticking dump valve
Posted: Fri Jun 22, 2012 11:32 am
by 4ePikanini
Bigwill wrote:If I am not mistaken our diesel Pajeros do not have a dump valve. It does however have a waste gate. My understanding is the wastegate maintains and controls the maximum presure at an ongoing basis. A dump valve normally on a petrol engine with a big turbo avoids damage to a turbo when the driver shuts off the throttle suddenly while the turbo running at ultra high revs and pressure at that stage has a "pressure crash" as the pressure has nowhere to go. The dump valve is there to dump all this pressure immediately, else damage to the blades may occur.
correct. When a certain boost is acquired determined by the wastegate diaphragm spring the diaphragm spring pressure is overcome that moves the wastegate actuator arm that opens the wastegate on the exhaust side. This bypasses exhaust gasses away from the exhaust turbine on the turbo and because of that the exhaust turbine spins slower and the boost is limited.
Re: Cleaning sticking dump valve
Posted: Fri Jun 22, 2012 12:34 pm
by Ollie
Thanks for the feed back.What can my problem be?Occasionaly the engine management light comes on on hard excelleration.Had similar problem with Td5,which was the dump valve or waste gate.Thought both were the same.Paarden island wants R550 to do dianostic,5 Hrs labour to remove turbo to clean.Thought i could lubricate myself.Will proberly have to that way.
Re: Cleaning sticking dump valve
Posted: Fri Jun 22, 2012 1:19 pm
by 4ePikanini
Re: Cleaning sticking dump valve
Posted: Fri Jun 22, 2012 1:49 pm
by Nismo
Sorry if off topic, what can it be if you connect a boost gauge and see the boost go up "rukkerig" its not smooth on the boost gauge?
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