Purpose of the Secondar air injection pump on ML320
Thread Starter
Junior Member
Joined: Mar 2007
Posts: 27
Likes: 0
Purpose of the Secondar air injection pump on ML320
I have a 2000 model ML320, For the last 15000 miles
The 40Amp fuse marked secondary air injection pump
has been blown. I removed the engine cover and at the
front is an electric motor that drives a blower.I have been told that this is the secondary air injection pump.
The motor has been damged by over heating the armature and the brushes have melted the casing(Plastic)
What does this pump do and how does it effect perfomance I have driven for 15k without any gerat loss
in performance and it has been to the dealer for a and b service and was not picked up.
Any advice would be greatly appriciated.
Thanks
The 40Amp fuse marked secondary air injection pump
has been blown. I removed the engine cover and at the
front is an electric motor that drives a blower.I have been told that this is the secondary air injection pump.
The motor has been damged by over heating the armature and the brushes have melted the casing(Plastic)
What does this pump do and how does it effect perfomance I have driven for 15k without any gerat loss
in performance and it has been to the dealer for a and b service and was not picked up.
Any advice would be greatly appriciated.
Thanks
Junior Member
Joined: May 2006
Posts: 28
Likes: 0
From: london. united kingdom
C230 komp (202)
HI,
Its a pump that directs air into the exhaust gasses to cool the temperature of the gasses during cold starts. and reduce your nitrous oxides which are created during cold starts. so its to do with your emissions. since its not working your engine managment light should be on.
The actual pump is signaled from the engine management when cold starts are recognised. the signal goes to a relay in your front sam (fuse box located in engine bay ) and that triggers the pump. Relay sticks closed, due to regular use and pump runs constantly. hence melt down cause its only designed to run for short periods.
you need to replace pump,fuse AND faulty relay.
And dont forget to check/find out why engine management light is not on. may have another fault
Its a pump that directs air into the exhaust gasses to cool the temperature of the gasses during cold starts. and reduce your nitrous oxides which are created during cold starts. so its to do with your emissions. since its not working your engine managment light should be on.
The actual pump is signaled from the engine management when cold starts are recognised. the signal goes to a relay in your front sam (fuse box located in engine bay ) and that triggers the pump. Relay sticks closed, due to regular use and pump runs constantly. hence melt down cause its only designed to run for short periods.
you need to replace pump,fuse AND faulty relay.
And dont forget to check/find out why engine management light is not on. may have another fault
MBWorld Fanatic!
Joined: Nov 2001
Posts: 4,260
Likes: 6
From: Philadelphia area
2010 ML550, 2010 E350 4M, 1966 Corvette Convt C2
HI,
Its a pump that directs air into the exhaust gasses to cool the temperature of the gasses during cold starts. and reduce your nitrous oxides which are created during cold starts. so its to do with your emissions. since its not working your engine managment light should be on.
The actual pump is signaled from the engine management when cold starts are recognised. the signal goes to a relay in your front sam (fuse box located in engine bay ) and that triggers the pump. Relay sticks closed, due to regular use and pump runs constantly. hence melt down cause its only designed to run for short periods.
you need to replace pump,fuse AND faulty relay.
And dont forget to check/find out why engine management light is not on. may have another fault
Its a pump that directs air into the exhaust gasses to cool the temperature of the gasses during cold starts. and reduce your nitrous oxides which are created during cold starts. so its to do with your emissions. since its not working your engine managment light should be on.
The actual pump is signaled from the engine management when cold starts are recognised. the signal goes to a relay in your front sam (fuse box located in engine bay ) and that triggers the pump. Relay sticks closed, due to regular use and pump runs constantly. hence melt down cause its only designed to run for short periods.
you need to replace pump,fuse AND faulty relay.
And dont forget to check/find out why engine management light is not on. may have another fault
Member
Joined: Jun 2005
Posts: 75
Likes: 1
From: Chicago, IL
2000 ML 320, 2003 CBR600F4i, 99 Eclipse GSX
I'm not trying to start an argument, but I felt I should correct the previous description of the purpose of Secondary Air Injection. Secondary air is injected after the exhaust ports in the exhaust manifold or actually behind the exhaust valves in cylinder head. The air is injected to react with unburnt hydrocarbons that are common w/ cold start. Oxygen is necessary to react w/ the hydrocarbons in the catalysts. The purpose is to warm up the catalyst, as they are inefficient at colder temperatures. Once the catalysts are up to temperature the pump is no longer necessary.
Not having this system functioning normally will cause a check engine light to illuminate. When the motor fries, it is typically due to a stuck relay causing the motor to overheat.
If you have any more questions, feel free to ask.
Not having this system functioning normally will cause a check engine light to illuminate. When the motor fries, it is typically due to a stuck relay causing the motor to overheat.
If you have any more questions, feel free to ask.
