When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hello! I need a little help / advice on an issue Im having with my 2001 blazer. So the check engine light came on, went to autozone. It said it was the secondary air injection pump. I replaced it. (I should note when the engine is idling, or it's really hot, the engine makes a loud noise, once I pickup speed the sound goes away. And i can smell exhaust, and the mpg is horrible.) The service engine soon light came back on, now it says its the air injection reactor pipe. Did the mechanic mess up putting the pump on? I dont want to keep replacing parts , I dont know what the problem is. The car runs and shifts good, oil and water temperature is good.
Do you have the number of the code that it's setting?
What Tom said to start with.
There is more than one trouble code for the air injection system and the pump is not the only thing that can fail or need attention. In addition there may be other codes that give additional clues. Example: The main trouble code for the air injection system is a P0410 which means that the O2 sensor did not report the proper response to an air injection test. The O2 sensor may be getting sluggish, there may or may not be an O2 code. Other potential issues: the plumbing can be clogged, the relay may be failing, increased exhaust back pressure, wiring, check valve, ...
We really need the codes to help you but sure the repair may not have been necessary, may have been done incorrectly or there may be more than one problem. Either way, the mechanic may not have properly verified the repair. I don't know off hand if this vintage system can command the air pump on with a proper scanner or not which can help verify the problem and the fix.
Did they verify that the pump was bad when they pulled it out?
George
Last edited by GeorgeLG; Aug 19, 2020 at 09:54 AM.
The check valve on one of the exhaust manifolds has failed and has burnt the rubber hose connecting it to the tubing leading to the A.I.R. pump. Also when these check valves fail, this can put hot exhaust through the A.I.R. pump and ruins the pump. So fix it now before you screw up your new pump. You will need a minimum of two check valves, two molded hoses to attach to them, and two gaskets for the check valve assembly to exhaust manifold mounting.
Autozone diagnosis is worthless. Codes are not parts replacement codes. They guide you to a factory diagnostic chart with specific procedures to be performed to complete the diagnosis.
p.s. I had this same failure on my 2001 Blazer. Most difficult thing is removing the old check valves without twisting up the metal tubing leading to the manifold or breaking the bolts off in the manifold. I was able to unbolt both of my check valve assemblies from the manifolds without breaking off the stuuds, but the valves themselves were really stuck on the end of the metal tubing. I was able to take a Dremel cutting tool to the side of the valve in the thread area (ON WORKBENCH) and go just deep enough to split the valve threads. Then the valve itself screwed off easily. If you ruin the check valve assemblies getting them off, you can buy them - but they are EXPENSIVE. If you break off the studs in the manifold, you are screwed and in for a lot more work.
Finally, I hope you bought the AC Delco upgrade pump kit. It relocates the A.I.R. pump intake to high along side the radiator so moisture does not tend to enter so much (also a big reason for A.I.R. pump failures)
You can search for these on Rock Auto, Amazon, Ebay by part number
Note that the 12561250 / 219-255 (#10) and 12561251 / 219-256 (#14) check valve tubes/assemblies are now discontinued. So treat the metal tubing from the exhaust manifolds to check valves like they are made from unobtanium (because they are). Used ones at a junk yard will likely be no easier to remove successfully but will be your only option if yours get screwed up.
Also be aware there is a shutoff valve assembly (#3 below) and two more hoses (#5) between the check valves and air pump that can get cooked but that is not as likely.
I think the guy is a first time poster trying not to get ripped off by his mechanic. We plunged him into the sorted world of DIY mechanic work and filled his head with the crap that clutters our heads all day long. LOL.
OP: If you still need help we are not as scary as we look. We like helping people here.
2001 chevy blazer ls 4x4 check engine light
