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Discussion Starter #1
My 04 TB was making a strange noise when I turned the engine off; a whining or winding noise similar to a jet engine shutting down is the best I can describe it. My mechanic said the bearing in the AIR pump was bad and the pump needed to be replaced. Despite a hefty bill, replacing the pump didn't correct the noise although it doesn't make this noise all the time (wouldn't you know it didn't to it when I took it to the shop). Also, since the AIR pump was replaced, I've been having issues with my battery draining down. Any suggestions on what might be causing the noise and what could be wrong with the battery would be greatly appreciated.
 

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2004 gmc
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Welcome!

Can you be more specific? Trailvoys have what they call a Secondary Air Injection Pump, but it only runs for 20 seconds on a cold start, or on specific times in the first 5-20 minutes after start up. It's under the driver mounted to the frame rail.

If it's running at engine shut-down, it's an electrical problem and not a bearing problem first off.

Do you have the mechanic's itemized bill with a part number perhaps?

A battery drain-down is something that could be caused by any of a hundred items in the vehicle not going to sleep when they should. If you don't have any other observations, it's going to be a tedious process of pulling fuses and seeing if the battery doesn't drain.

Is it the original battery?

Do you have a meter and know how to use it?

Can you describe the location of the noise you described to the mechanic?

That he wasted your money replacing the Secondary Air Injection pump (if that's what he did) is something that not even a sophomore Trailvoy Certified Mechanic would do.
 

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2003 gmc envoy_slt
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Is the noise coming from the front? Or the back? Do you have the rear air suspension? Does the sound stop with the key off and the door open? I have the rear air suspension and even with the key off, the pump will sometimes run from the retained power, until I open the door.:m2: Oh and :tiphat Welcome :tiphat
 

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Discussion Starter #5
I'm not sure that I can be more specific about the noise other than what I described other than it occurred intermittently when I shut the engine down and lasted for only a few seconds. Regarding the part number, the invoice says 215-454, which I was able to find on the AC Delco website and it is the secondary air injector pump. The reason I believe the new pump and the battery issue are related is that I began having issues immediately after the new pump was installed and had no issues prior. I had the back door open for perhaps 15 - 20 minutes and the battery died and I needed to get it jumped. Also, I had the vehicle sitting for a couple hours with a TomTom GPS locator plugged in and it nearly didn't start, I wouldn't think the GPS locator would draw that much juice. Finally, with everything unplugged, when I let it sit for a few hours, the horn sounds extremely weak when I unlock the doors, so there is clearly a slow drain on the battery. When I run the engine, the alternator seems to be charging the battery. I believe the battery is original but I don't know for sure, I bought it used and haven't looked at the battery.

It may be electrical related, my blower motor went out a few weeks ago as well which was the original reason I brought my TB. However, the part had to be ordered so that has yet to be replaced (so I can rule this out of the equation for now ... but may help explain a larger issue). I go back tomorrow to get that replaced. I informed the tech about the battery issues so they are going to look at it again to see if something was installed incorrectly but I was just curious if there was a common issue that might help explain the cause. I know it could be a number of issues but given the facts and the timing, I am led to believe the battery issues are related to the replacement of the secondary air injection pump. I could be wrong and just plagued with a series of bad luck.

I'll follow up if/when the issue gets resolved. Thanks for the replies!
 

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The secondary air pump will NEVER run at shutdown. Whoever diagnosed that was wrong or crooked.

If the battery is original, it's LONG past due for replacement. Get it tested at a shop before doing much of anything else.

And what's wrong with the blower motor? If one or more speeds are not working, it's almost always the speed control module (or resistor pack) not the blower itself. Who diagnosed this? The same goof who worked you over on the air pump issue?

If you only had a meter, you could check the battery voltage right at shutdown time, and 30 minutes later, and we could tell you in a heartbeat if it's bad.
 

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Discussion Starter #7
The invoice says they did recheck the battery, I'd hope they would have seen something wrong with it if that is the case. Unfortunately, I don't have a meter.

Regarding the blower, none of the speeds work any longer and it only worked on high prior to that. The tech said some of the wires (can't remember what they were called) were melted so it needed to be replaced.

Thanks for your help, roadie, I'll be able to ask some more intelligent questions when I bring it back tomorrow. I wish I had known about this site before I took it in.

Thanks again.
 

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2003 gmc envoy_slt
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Air suspension wasn't an option on normal (non-SS) TBs, just so you know. Still waiting for the OP to get back to us on the other questions.....
( My best Johnny Carson voice) I did not know that.:confused: I thought it was an option on the whole 360 platform.
 
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