Exhaust Back Pressure

[Andys76]

Hello Everyone,

I hoping someone can answer a question for me, I’m having a few issues with my C320 CDI.

Car has no power and doesn’t currently Rev past 1500 rpm, when it starts hunting, put a scanner (No Codes Present) on it and Exhaust Back Pressure sensor is telling me it’s at 4355 HPA?.... but the engine isn’t running ?

When it is running the HPA is 4788.

Question is does anyone know what should it be ?
Thank you

Andy

 

[onefortheroad]

Not sure of the units now . But mine was between 908 and 1060. After I changed it . Before it was in the high 4 and 5 thousands .

I ran my car with it removed and plugged in. Using icarsoft mb2 the readings never changed , so I knew it to be duff !!

 

[M80]

On a 642 I recorded
800 hpa engine off,
842 hpa at tick over,
1080 hpa engine revving.

In truth I can't confirm if that's good, bad or whatever.

 

[M80]

Sorry if this confuses any, but another day I see i recorded at B18 sensor
966 hpa engine off,
977 hpa tickover,
1149 hpa revving.

 

[onefortheroad]

Those readings are about normal.

In the high thousands is failure of unit. Some say theres a pin hole in the side of the sensor that gets blocked. I couldn't see it on mine , I just replaced it.

 

[Andys76]

Thanks everyone, I thought the reading was spurious.

Not ideal I know, but I just took it on a rather athletic drive (not too far, just around the block) with the sensor removed but still connected, power difference was unbelievable.

Looks like I had better order a sensor then.

Regards

andy

 

[onefortheroad]

Thanks everyone, I thought the reading was spurious.

Not ideal I know, but I just took it on a rather athletic drive (not too far, just around the block) with the sensor removed but still connected, power difference was unbelievable.

Looks like I had better order a sensor then.

Regards

andy

Sound like a v8 don't they .

 

[M80]

Strange it didn't throw a wobbly with it not seeing the sensor,
but happy days.

 

[Andys76]

Strange it didn't throw a wobbly with it not seeing the sensor,
but happy days.

I still had the sensor plugged in, just resting between the intake and air filter.

was a bit noisy, but then the exhaust would just be venting the other side of the EGR.

 

[Andys76]

Sound like a v8 don't they .

As they say there is no replacement for displacement.

saying that I’ve got my eyes on a 53 plate CL55 AMG, not that would be fun I’m sure !