Finally tested compression on my 300D - PeachParts Mercedes-Benz Forum

barry12345 · #1 01-24-2020, 03:29 AM

Obviously if the car was sluggish from the first time you drove it. You did not create the problem..

Just before you hook up the new hose to the alda. Blow on the end to make sure there is no obstruction in the over boost valve or the manifold connection. That line when functional does not really have constant air flow as such. It relays the air pressure from the manifold to the alda. By just compressing the air.

With that line open there would have been air flow. This might have included some of the egr garbage fed into the manifold going through that line. That increased the chances of soot buildup in the manifold fitting and the over boost protection valve.

So you just make sure that the system is still open by reducing the air pressure applied. Or just take the car for a short drive to make sure the sluggishness is gone. The engine was just simply fuel starved.

cmac2012 · #2 01-26-2020, 01:13 PM

Quote:

Originally Posted by barry12345

Obviously if the car was sluggish from the first time you drove it. You did not create the problem..

Just before you hook up the new hose to the alda. Blow on the end to make sure there is no obstruction in the over boost valve or the manifold connection. That line when functional does not really have constant air flow as such. It relays the air pressure from the manifold to the alda. By just compressing the air.

With that line open there would have been air flow. This might have included some of the egr garbage fed into the manifold going through that line. That increased the chances of soot buildup in the manifold fitting and the over boost protection valve.

So you just make sure that the system is still open by reducing the air pressure applied. Or just take the car for a short drive to make sure the sluggishness is gone. The engine was just simply fuel starved.

I blew on it, could just barely get air through. Does the union thing on the firewall have any dirctional flow or is all just connected there? I see the one line that goes over to the manifold.

Perhaps I should remove that and see if cleaning is needed.

barry12345 · #3 01-26-2020, 02:09 PM

Quote:

Originally Posted by cmac2012

I blew on it, could just barely get air through. Does the union thing on the firewall have any dirctional flow or is all just connected there? I see the one line that goes over to the manifold.

Perhaps I should remove that and see if cleaning is needed.

Air normally just gets compressed and decompressed in that line. So there is no signifigant air flow as such. It should be okay. You will know as soon as you drive the car.

It appears that over time some of the soot etc from the egr introduction to the intake manifold lodges in the manifold fitting specifically. Plus sometimes reaches the boost limiter. Since the time the line broke off there would have been air flow in that line with some of the egr gasses and soot etc. Was why I though to blow on it was a good ideal. The boost limiter could be directional. Is a possibility. When there is an obstruction it usually will be in the manifold fitting.

Maxbumpo · #4 01-26-2020, 04:22 PM

Quote:

Originally Posted by barry12345

Obviously if the car was sluggish from the first time you drove it. You did not create the problem..

Just before you hook up the new hose to the alda. Blow on the end to make sure there is no obstruction in the over boost valve or the manifold connection. That line when functional does not really have constant air flow as such. It relays the air pressure from the manifold to the alda. By just compressing the air.

With that line open there would have been air flow. This might have included some of the egr garbage fed into the manifold going through that line. That increased the chances of soot buildup in the manifold fitting and the over boost protection valve.

So you just make sure that the system is still open by reducing the air pressure applied. Or just take the car for a short drive to make sure the sluggishness is gone. The engine was just simply fuel starved.

This is a great point, the pressure line fitting at the intake manifold and the over-boost control valve can get plugged up with soot, and then you get a sluggish engine. You said you can barely blow through it, to me that means a fail. I'd recommend you remove the fitting from the manifold and spray it out with brake cleaner and maybe push a bit of wire in / out.