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+--- Thread: OM603.971 Turbo issues (/showthread.php?tid=7819)
OM603.971 Turbo issues - Doug F - 08-01-2017
I am new here but have had my Benz for a few years now and the turbo just recently 'stopped working'?
The turbo has been converted to the pressure type actuator before I bought it and the turbo would scream now and again when under load etc. however it has stopped, yet the performance is the same.
Here's what has changed and my observations:
The pressure line used to go from the spare port on the side of the intake manifold to the wastegate actuator, however because it was a poor fit and leaked oily mess all over, I plugged it and moved the port to the crossover tube hoping it would work better. Well, it has stopped turbo whining all together and I thought when testing the actuator that it ruptured etc, however it still holds pressure.
My observation from Sunday, while laying under the car with someone working the actuator with a low pressure air gun, it seems to work HOWEVER, with no pressure the actuator has the wastegate closed and air pressure opens it. Is this correct functioning? The original turbo had the wastegate open at rest and the vacuum closed it, however that stuff is all long gone from the car. I am thinking the manifold pressure is just pushing the wastegate open and I thus have no turbo at all, but when the intake was leaking and had the longer hose, it was able to let the wastegate stay closed some of the time.
Does anyone else have their turbo set up this way and can you give me any input as to how to actually get the turbo to work and be consistent?
Thank you for your help!
Doug
RE: OM603.971 Turbo issues - NZScott - 08-01-2017
Pressure Waste gates are held shut by a spring, and open by air pressure. There (should be) is an internal adjustment to change the pressure it starts to open at. Without seeing your setup the rest is guesswork really, try installing a boost gauge and see what you get
RE: OM603.971 Turbo issues - Doug F - 08-05-2017
Thank you NZScott,
The "should be" is where I am lost, but I know what you mean. I have a picture of the actuator, I will see if I can post it. (NOPE)
It is just a regular cadmium plated metal actuator with the bent stem on it... Where would the adjustments be made? Obviously it isn't like the old vacuum distributors with the tiny screw inside the stem.
As far as a boost gauge, I have been trying to find a place to punch a hole in my W140, but it seems EVERYPLACE has something!
In short, a manual boost controller would be what I need if it wasn't internally adjustable, correct?
I really do appreciate your help! Thank you!
RE: OM603.971 Turbo issues - NZScott - 08-06-2017
Yea sorry external is probably more common than internal (was thinking of my old T3). Otherwise there's a thread on the rod and you adjust it with that. Now I'm a little out of my depth here but doing it that way I think can affect the preload of the wastegate so high backpressure can start to open it...manual boost controller would be the best option.
Hook a hose to the intake and run it under the bonnet with the boost gauge sitting somewhere so you can see it while driving
RE: OM603.971 Turbo issues - barrote - 08-06-2017
Hy sorry to highjack...
Pneumatic actuators may be posituve pressure driven or negative pressure driven... (vacum).
In automotive industry most manufacturers use to ident them by the position of pressure port. Vac actuated have the port in center rear. The positive press is lateral or in the botom like a L shape.
Vac operated WG need a computer and vac modulator. They are intended to open the WG partially and other features that require opening the WG.
Boost press operated WG are intended only to control boost press. And they do that by opening a port on the gas stream.
One set the actuator and tune the rod so that the spring inside the actuator maintain the WG port closed. When press rises it will start to open the port.. . Easy... ofcouse if drive press EGP is too high it will also leak...
Any case the simptom with the hose off is that the turbo will not control boost..correctly. and it does not explode only the engine will experience too high back pressure and may increase Temp to a dangerous mark...
Anycase when turbos start to make funy noises they are about to give birth... may last a week or a year . But watch out ...
RE: OM603.971 Turbo issues - Doug F - 08-06-2017
Thank you guys!
I'll get under there and check out adjusting the rod length. But first order is checking boost levels. I know this turbo does leak oil out the front, so it does need a rebuild, but I am moving and this is my daily driver.
As for noise... It used to have a nice 'turbo whine' but now it doesn't, thus how I know there is something wrong.
RE: OM603.971 Turbo issues - ecFSE - 08-06-2017
It stopped whining when you fixed the boostleak at the intake?
I think you are searching for a problem you dont have.
A leak in the boost pipes or intake can give you a whine when under boost.
Have you checked the turbo for excessive play?
Oil leak at the front of the turbo could be blowby from
engine too.
RE: OM603.971 Turbo issues - Doug F - 08-06-2017
(08-06-2017, 09:50 AM)ecFSE It stopped whining when you fixed the boostleak at the intake?I think you may be right as well, but there is NO noise from the turbo anymore.
I think you are searching for a problem you dont have.
A leak in the boost pipes or intake can give you a whine when under boost.
Have you checked the turbo for excessive play?
Oil leak at the front of the turbo could be blowby from
engine too.
There is lateral play in the shaft, but no front to back play, thus why I want to rebuild the whole thing or get another one.
RE: OM603.971 Turbo issues - Doug F - 10-16-2017
New info...
I FINALLY hooked up the boost gauge I bought last year and saw that it wouldn't boost over 5 psi. After doing research on that, I read that someone suggested to take the actuator hose off and see what happens and it shot up to 18-19 psi quick and felt much more "free" in acceleration. So a manual boost control is coming, as it must be that my hose is too big and flows well to the actuator, whereas the old one the car came with was smaller in diameter and much longer.
Question,
With my ALDA turned up about 1 turn and a puff of black on hard acceleration, what is the max psi I should set my stock Garrett TB-03 at?
One of these days I want to purchase a 7MM DieselMeken pump, F-Tune exhaust header, 3" oval exhaust and a bigger twin-scroll turbo so I can run with the gas cars without being a hazard! I see the guys in Sweden are modding their 722.3 autos, is there a link to a company that does that, makes beefed up valve bodies etc? How about LSD rear diffs for the W140.134 300SD?
Thanks for ALL your help everyone, I love this site!
Doug
RE: OM603.971 Turbo issues - Antonio - 10-16-2017
(10-16-2017, 09:46 AM)Doug F New info...
I FINALLY hooked up the boost gauge I bought last year and saw that it wouldn't boost over 5 psi. After doing research on that, I read that someone suggested to take the actuator hose off and see what happens and it shot up to 18-19 psi quick and felt much more "free" in acceleration. So a manual boost control is coming, as it must be that my hose is too big and flows well to the actuator, whereas the old one the car came with was smaller in diameter and much longer.
Question,
With my ALDA turned up about 1 turn and a puff of black on hard acceleration, what is the max psi I should set my stock Garrett TB-03 at?
One of these days I want to purchase a 7MM DieselMeken pump, F-Tune exhaust header, 3" oval exhaust and a bigger twin-scroll turbo so I can run with the gas cars without being a hazard! I see the guys in Sweden are modding their 722.3 autos, is there a link to a company that does that, makes beefed up valve bodies etc? How about LSD rear diffs for the W140.134 300SD?
Thanks for ALL your help everyone, I love this site!
Doug
i am getting the same problem with boost, did boost controler help? i should get one to?
RE: OM603.971 Turbo issues - Doug F - 10-16-2017
Antonio,
If you have a pressure activated wastegate actuator and boost gauge, disconnect the hose and see if the boost goes up... If it doesn't, there is something else wrong.
RE: OM603.971 Turbo issues - Antonio - 10-17-2017
Thank you Doug, i tried it a few days ago, goes up to 1.5 with a leak from that same hose... so could sort it with boost controller?
RE: OM603.971 Turbo issues - barrote - 10-17-2017
Its interesting how u have all the info in the post above and eventhough u don't understand the principles of turboing a engine...
The waste gate is window... in the turbine section used to discharge drive pressure...wereas to say if it leaks drive press is gone ... no work will be done...
It is held closed or open with a pneumatic actuator wich has a chamber for pressure and a spring, this actuators are very well spread across automotive industry cause the last years without loosing capabilities and properties, they are rated for many diff pressures (operational force).
In what turbos concern the most common are positive pressure actuated, when pressure rises in the chamber forces the spring and the rod extends, and when conected to a WG it bleds out drive pressure killing the turbine force to drive the compressor (no boost or limited boost)
Your problem is just u have a low press actuator, it operates at .5 bar, probably is not from that turbo or it was moded since almost all turbos have actuators in the 1 to 1.3 bar actuators, except industrial engines wich are other story.
That problem as i said can be solved by installing a decent rated actuator, but if u don't want to spend money and brain power just get a spring and a wire and put the spring closing the port ... change spring force untill u reach the desired boost... wich should be less that what u can obtain with the WG locked close.
Wich u luck
RE: OM603.971 Turbo issues - Antonio - 10-17-2017
yeah i know how it works but im not paying 100 euros for a actuator if there is a cheaper fix, better safe than sorry
RE: OM603.971 Turbo issues - barrote - 10-17-2017
What is more cheap than a junk spring and a wire???
RE: OM603.971 Turbo issues - Antonio - 10-18-2017
(10-17-2017, 10:06 AM)barrote What is more cheap than a junk spring and a wire???
oh no one mentioned it, just wandering how to do that, never done it myself, hopefully it will work when i try
RE: OM603.971 Turbo issues - barrote - 10-18-2017
it will , one got to be ingenious ... i had mentioned that... but its so basic that ... sorry to that harsh...