secondary air injection pump

[mp28560]

Help!. I have a 2004 Trailblazer 4.2. I am on my second pump. The first one a dealer replace and just told me it was a bad pump. Then the check engine light came on again with the same code. This time I looked at it. When I took the line off water came out.The pump was completely full of water.No one can tell why this happened or how to fix it. I replace the check valve on the block and replaced the pump. I had it reset and light came back on with the same code (p0410).

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[rbarrios]

theres a revised check valve to keep water from forming in the pump.

[usmilmom3kids]

Originally Posted by mp28560

Help!. I have a 2004 Trailblazer 4.2. I am on my second pump. The first one a dealer replace and just told me it was a bad pump. Then the check engine light came on again with the same code. This time I looked at it. When I took the line off water came out.The pump was completely full of water.No one can tell why this happened or how to fix it. I replace the check valve on the block and replaced the pump. I had it reset and light came back on with the same code (p0410).

I am having the same problem but I don't have the money to fix it I'm on my third one and I went to a small guage to get mine fix the times before I don't know which way to turn

[dspahos]

The pump is not the problem source. The pump fails because your check valve likely is not functioning. First replace the check valve. This will keep water from buildin up. This part is $100 - $125, and is easily bolted on yourself. Then replace the pump.

[Ear Mountain]

I have a 2005 Trailblazer that I bought used. The check engine light came on and the code indicated a problem with the secondary air injection. I pulled the hoses from the pump and found the pump and hoses full of water. Running the engine with the hoses off I could feel exhaust coming from the hose leading to the check valve on the engine. After cleaning out and drying the pump I reinstalled it.

Next I pulled the Secondary Air Injection Valve and disassembled it. The valve was completely corroded and would not function. Attempts at cleaning the valve were not successful. I was able to close the valve by forcing it. I reinstalled the valve (now stuck closed instead of open) and ordered a valve from my local dealer.

I will report back after it is installed.

[Ear Mountain]

I received and installed the new check valve. But the Check Engine Light did not clear itself. I cleared the error by disconnecting the ground terminal of the battery. After several trips the light came back on.

The next day I had some time so removed the air pump for a bench test. When I applied power to the pump it ran but only very slowly. Hardly any air came from the outlet port. There was still some moisture in the pump too.

I used a hair dryer and blew warm air through the pump. After it dried I again applied power and the pump seemed to clear some "gunk" and began running very fast. It unfortunately squealed some as well. Could be the pump is ready to fail but I'm not sure.

I reinstalled the pump and when starting the engine cold can hear it running until the engine warms up some. The Check Engine Light, even after several days of driving, did not clear itself.

Could it be the pump is not putting out enough positive pressure? Should I just go ahead and replace the pump? Any ideas here would be helpful.

[Ear Mountain]

I once again reset the Check Engine light by disconnecting the battery terminal.

Again, I can hear the air pump running when I start the engine the first time in the morning so I know it's working. And the check valve is new.

It's been 5 days now and the light has remained off. I'm assuming all is well now with this system.

[rework]

Originally Posted by Ear Mountain

it ran but only very slowly...
It unfortunately squealed some as well....
not putting out enough positive pressure?

Just been thru this. Your pump is going to fail soon. Code P0410 would come and go for a while.
Mine turned slow, had dead spots, finally fried.
Vac Solenoid above pump was sticking.
Also had one check valve (at exhaust , is the water source).) stuck open , the other stuck closed.
Loosened them up with solvent.
Take off rubber cover, if burnt smell and/or black windings, it is cooked.
You only need the pump, not the kit with extended hoses (waste of money).
Replaced bottom hose with clear PVC so I can watch for water and if found, time for new check valves.

[Ear Mountain]

Originally Posted by rework

... Your pump is going to fail soon.
Vac Solenoid above pump was sticking.
Also had one check valve (at exhaust , is the water source).) stuck open , the other stuck closed.
Take off rubber cover, if burnt smell and/or black windings, it is cooked.
Replaced bottom hose with clear PVC so I can watch for water and if found, time for new check valves.

rework,
Thanks for the info. I suspected that the pump will fail and will replace it when it does. I like the clear PVC idea so that any moisture buildup in the hose will be easy to see.

The SAI system on my 2005 Trailblazer is somewhat different than what must be on your vehicle. There is only one check valve located on the exhaust manifold. The pump (bolted to the frame under the drivers seat is a sealed unit. Here's a diagram showing the entire system.
#2 is the check valve and #6 is the pump. Fortunately these two items are fairly easy to access and replace.

[rework]

Originally Posted by Ear Mountain

somewhat different than what must be on your vehicle.

Yes, I was thinking V-6