Not sure why Cat failed.

99 Chevy Blazer, has noise the cat makes at idle like a NUT is loose inside. Putting it in neutral, or driving and it seems to goes away. I hit the cat from underneath and can hear the broken pieces inside.

I have been searching for and calling around for fixing. One thing that is important is too not replace the cat converter until I am sure that the cause of the FAILURE is fixed.

This car passed smog a month ago. HC, CO and NO were great.

"Check Engine Soon" light came on after, but it was for Secondary Air (P0410), that pump that goes on during startup for first 30 seconds or so.

Im hoping what caused the cat to go bad, was driving the car from Oregon, to Southern California, with a STUCK open Thermostat. Someone stated that running a car that way, could give you bad gas mileage, and from that I thought that maybe lean meant, that it was not burning the fuel in the cylinders but passing it on down the exhaust where the cat converter was turning red hot, and maybe causing it to fail.

So now that the Thermostat is functioning and the engine is getting close to the correct 195 degrees when hot, and the CEL is off again, after being on and off. I will check for codes tomorrow.

Do you think it will be safe to install a direct fit Cat that they sell for this Vehicle. Had to search for Caliifornia Approved cat, and not the 49 State version (Federal)

One Youtube Video stated that what was necessary was:

5 Steps

1. Correct all other PCM DTC codes.
2. Find any exhaust leak, converter relying on feed gases
3. Check for fuel control. Proper 14.7/1 Air Fuel Ratio
4. Check for causes for Converter contamination. If Bad, something killed it. Correct that issue, before new, or new will fail
5. Making sure that you have the correct converter to replace.

or Should I take it to a muffler place and spend the $210 or $225 each x2 $450, where they will weld in a correct cat, but aftermarket.

Or order ONLINE the California Approved Direct Fit Version, and do it myself. I have shot some WD40 on the bolts, and not sure what to expect. Think there is a total of 7.

$301.99
[www.oreillyauto.com]

$245.95
[www.partzdealer.com]

$230.13
[www.cheap4x4parts.com]

$167.20
[camilomoya.com]

The code that it threw after passing inspection, but then cleared, then reappeared. (P0410)

[blazerforum.com] 447212 seems to be the direct fit part no., that I need.

 

found this TSB. hope this helps

 

If coolant is not up to normal operating temperature, the engine will run rich, which can destroy the converter. If the secondary air system is not operating correctly, (P0410) the exhaust will be rich and can destroy the converter. Once the DTC's are cleared and all monitors pass after performing a drive cycle, it is safe to replace the converter. Direct fit is the best choice, and it must be Federal, (50 state) compliant if the vehicle is registered in California.

 

Tested the Fuse next to the battery, both 10 and 30 are good.

Got the bottom panel off, and have loosened up the Pump to disconnect electrical connection. I could never really tell if pump was turning or running, even with help. Is this a 12 Volt Pump. Should I be able to supply voltage to the connector and hear it run if polarity is correct?

Another thing, since this looks to be original equipment it has clamps holding the hoses in place that seem to be ONE TIME USE, so if I was to try and remove the pump to see if impeller is turning etc, I am not sure how to handle the clamps.,

So if I supply voltage to the pump and it does not turn, I would replace pump. Then I understand there is the Air Hose which seems to run up towards the battery and end is cut at a 45 degree aiming straight up and open to air. They say that should be replaced. And I understand a ONE WAY valve or two? And relay etc.

I have that flow diagram, telling what to check etc. I really need to get a CODE CHECKER that will perform some tests, as well as just read the codes.

So do I add some voltage to the pump, or buy a OBDII tester that will turn pump on?

 

A bidirectional scanner that can operate the pump is $1K or more.... for a used one!


If you apply battery voltage and ground to the pump motor, it must run.


Lineman's pliers, or diagonal cutters will do the job on the "one time use" clamps. Then use the worm gear style hose clamps.


Should be one check valve in each of the two lines to the exhaust manifolds.

 

Applied 12 Volts from a charger directly to the leads to the pump. RED to RED, etc.

Nothing, pump never came on.

So I will order a pump thru Amazon Prime, is there anything else, I see some come as a KIT with that extra hose that sticks up in the air, with a Cap that prevents water from rushing down as it points up to get air. Car now lives in Southern California. Nicer weather, than Oregon it came.

Could I just get away with the pump, or are there any other parts and should I go to Rockauto for those one way valves, which I really haven't located. I did follow this 1/4 inch hose that looked new all the way up the passenger side of the vehicle and over the top of the engine to a hookup for suction, I would guess. Thin hose must be 3 feet long.

Thanks….. Maybe I should check and next cold start if there is voltage to the other side of the connection?

 

There is a GM TSB that improves the hose routing etc. Maybe a Google search would find it, can't find it in my stack of stuff


Wouldn't hurt to check for power and ground at the connector with the pump unplugged.

 

Well thats the final result, after I replaced the Secondary Air Pump. I kept seeing the OEM Delcos on Amazon, but by the time I was convinced to order they were back ordered. Price went up $10 as well. So I ordered the ?Cardone, that just comes with the motor, and you replace your plastic cover to where the hoses go. I did that and after getting a code that says the drive side one way valve could be a problem, I decided to reset the codes and do a drive cycle. All the codes eventually went away when testing condition for code was reach.

And yesterday I replaced the Cat Converter with a Direct FIT California Approved MagnaFlow Converter Part No 447212.

I had in the last few weeks sprayed all bolts with pBlaster that I see recommended. Saved a ton of money doing it myself, but I have the aches and pains in this old body to prove it. Tightening those bolts even the new ones, needed a lot of arm power to bring to a tightened condition.

Now the vehicle is still worth $1200? but no more rattle. The old Cat rattles like a tin can inside. I know that don't pay as much for rattling cats. Will shop around locally in So Cal to see where I can get best $, or not

THanks, for all help, Now I would think it would pass smog easily. Even though it won't need it for 2 years, or if we sell

 

Well since the above work, it will go about 3 weeks, then I get the P0410 for the secondary air. Then I reset, and 3 weeks later get it again with the P1415 the one that says the ONE WAY VALVE on the drivers side is bad. So I replace it. Reset codes, and after 2 or 3 weeks get the SES. Its P0410.

So how do I test the Vacuum Switch that runs around $27. From What I have read, that may cause the P0410 Code. I guess this is the switch with small hoses attached down where I replaced the secondary pump, a few months ago.

Or Maybe its that big valve that I have a picture of above??

 

I tested the Diverter and the Solenoid with a vacuum tester. Diverter worked as tested via this great DIY on youtube. But the Solenoid acted just like a new one at the parts house when vacuum applied. However just prior to testing these two parts I discovered the small hose from the solenoid to the diverter had a small hole in it. Probably wouldn't hold a vacuum. So prior to running the tests on the Solenoid and Diverter I replaced the hose for .50 and the SES went out. I reset codes and lt hasn't lit up again in two weeks

Not sure why Solenoid didn't act or hold vacuum in test. But only Pump, One Oneway valve and a .50 hose to fix, so far.

You Tube Guy , great explaination of Secondary Air and troubleshooting:

AIR Air injection Reaction Diagnosis PT* 1

AIR Air injection Reaction Diagnosis PT 2

MY HOSE: