EGR = Power Loss?

[aka$h]

My S320cdi is still giving me problems.
The only thing I can see now is the EGR is sticking closed.
The vacumn transducer is working, I connected a gauge then actuated it from DAS. The EGR rate does not change when told to open or close.

Could this be the reason for power loss during initial acceleration, and black smoke when the power is finally delivered?

 

[television]

Your EGR valve only opens when cruising say on the motor way or running light, and it will be closed when idling, its only purpose is to return harmful gases back into the intake.

Stuck closed will not effect the running

 

[Dieselman]

Sorry Malcolm, don't agree.
The EGR on a diesel will be most open at idle and will close when under way.

Akash, if it's not playing ball then I suspect it is partially open or leaking, thus the black smoke.
Try sucking one the vacuum pipe to see if the valve diaphragm is split or working.

Have you had the injectors tested?

 

[aka$h]

Sorry Malcolm, don't agree.
The EGR on a diesel will be most open at idle and will close when under way.

Akash, if it's not playing ball then I suspect it is partially open or leaking, thus the black smoke.
Try sucking one the vacuum pipe to see if the valve diaphragm is split or working.

Have you had the injectors tested?

When I had the EGR out, I cleaned it all out and it did seem to hold pressure, but once back in the car its not working correctly.

With regard to the injector, theres no one locally that can check the ones from a CDI, not sure why.

The car has been giving me hell for far too long now, its spent more time in a garage over the past year than at home.

 

[Dieselman]

Sounds like the valve is duff and erratic.

I can't understand why no one can test the injectors, there must be a diesel specialist or MB dealer that can.

Smoke would be caused by a poor spray pattern and the leakage test is simple.

If really struggling speak to BlackC55 as I'm sure he can perform a leakage test.

I still supect the EGR valve, but the injectors may be duff also.

 

[1998K]

is it easy to dismount and clean the EGR?

Do you suggest any cleaning interterval?

 

[television]

I have always heard that the spring gets weak due to the environment that it lives in and that it is a waste to try and clean it.

 

[1998K]

I have always heard that the spring gets weak due to the environment that it lives in and that it is a waste to try and clean it.

thanks television so it seems it's not worth the trouble

 

[BlackC55]

I would be more than happy to test the leak off for you.

 

[Parrot of Doom]

Depends how dirty your EGR is. I found cleaning mine made a big improvement. Although mine wasn't as dirty as this:

 

[Dieselman]

Akash
If the EGR valve was working when off the car but not when on it, then possibly it's the modulator or control signal is strange.
Try disconnecting the vacuum line to see if it stays closed then.

 

[KLP 92]

I would be more than happy to test the leak off for you.

Is that the test where you place the small beakers on top of the injectors?

Is there anyway to check and make sure the injectors spray pattern is correct? The reason i ask is tht i have a slightly smokey 270 CDI, i've cleaned the EGR valve and checked the actuators but everything appears fine.

 

[BlackC55]

They do smoke a bit under hard acceleration anyway.

Yes it is the beaker type test.

 

[Dieselman]

A spray of diesel pressurised by a garden sprayer will be something of a reasonable test of spray pattern, or will at least show a badly spraying one as it will dribble.

Pressurise the fluid and connect 12v to the solenoid to open the injector.
This is a great way to run injector cleaner if coked up.

 

[KLP 92]

This is a great way to run injector cleaner if coked up.

I removed my diesel filter, emptied it, filled it with injector cleaner and put it back together. Was feeling lazy at the thought of removing the injectors

Didn't help though, neuther did an extreme high speed journey across Europe!

 

[KLP 92]

They do smoke a bit under hard acceleration anyway.

Yes it is the beaker type test.

Mine smokes in neutral if i rev it. A puff of smoke when i press the accelerator quickly. It just puffs initially, not constant.

The beaker test shows no loeaks.

 

[Glenn Smith]

Sorry Malcolm, don't agree.
The EGR on a diesel will be most open at idle and will close when under way.

Akash, if it's not playing ball then I suspect it is partially open or leaking, thus the black smoke.
Try sucking one the vacuum pipe to see if the valve diaphragm is split or working.

Have you had the injectors tested?

Sorry have to disagree, the egr is closed on idle, any leakage of the valve allowing too much exhaust will cause poor running, the egr puts a small amount of exhaust into the intake, this has the effect of reducing certain gases in the emmissions, but also causes black smoke due to reduced flame temperature in the cylinders.

 

[Dieselman]

Sorry have to disagree, the egr is closed on idle, any leakage of the valve allowing too much exhaust will cause poor running, the egr puts a small amount of exhaust into the intake, this has the effect of reducing certain gases in the emmissions, but also causes black smoke due to reduced flame temperature in the cylinders.

No need to be sorry.
Please expand on the exact reason for EGR on a DIESEL engine and at what points those will be and how the subsequent desired results are achieved.
In addition could you please explain why there would be no EGR at idle condition.

Are you aware of the readings obtained from a MAF sensor when EGR is operational?

This should be interesting.

 

[cheshirecat]

EGR's

Sorry have to disagree, the egr is closed on idle, any leakage of the valve allowing too much exhaust will cause poor running, the egr puts a small amount of exhaust into the intake, this has the effect of reducing certain gases in the emmissions, but also causes black smoke due to reduced flame temperature in the cylinders.

can only speak for VAG engines but they DO open EGR on idle for two minutes then close to prevent overheating, what do Merc's do?

 

[BlackC55]

I will find out later. Just sifting through some info on EGR.