Still trying. I just replaced the Intake Air Temp sensor just because, but was reading other secondary air threads and someone mentioned the IGN E fuse is was runs the relay for the secondary air pump. So since I got power to the pump and the pump runs with direct power I would check that out.. the fuse looked fine but put a new one in anyway and then i noticed this (picture). Knew to me truck so i don;'t know and I am not finding any pictures over the fuse box when in stalled in a truck.. is there supposed to be a retaining number on this or is it supposed to be open? I don't see any wear where a nut used to be.

 

Here's a picture of mine: I think you are ok. You know, fuses can break from stress cracks. It is rare but it happened to me once.

 

Great thank you. i am tempted just to replace all the small fuses in the underhood as I did for the side of the dash.

 

I figured you'd appreciate an answer to your question asap.

Yeah, I get the idea of replacing the fuses. It seems silly but it would not be the first time that something as simple as a fuse mucked things up. I once had a radio fail and short out fuses that cut power to my instruments. Turned out there were two nickles that I think were there for over 8 years from before I purchased the truck. As Sherlock Holmes has said:

“When you have eliminated the impossible, whatever remains, however improbable, must be the truth.”

 

If the secondary air pump will not come on with Car Gauge Pro (or by grounding the brown wire at the AIR fuse block) , then the secondary AIR system is not working and the readiness monitor will never complete. If it does come on with Car Gauge Pro, then it's working and requires no repairs. Coming on by grounding the brown wire does not check the PCM component in the system, but it does imply that system is capable of working.

I see in post #64 that you apparently have been to the secondary air fuse block before, but maybe this information will be useful.

There are four fuses involved in the secondary air pump operation. Below is the electrical schematic for the secondary air pump in 2001.

In my 2001 the secondary air fuse block is inside the front of the passenger front fender. Not sure about 2000, but assume it is the same.

Not sure of you expertise in reading and testing based on schematics, but if you end up needing help grab your test light or multimeter and let me know. I would recommend doing everything at the AIR fuse block. All fuses and inputs/outputs/relays can be definitively and easily checked there.

 

Hi Les, Thanks for the reply.
Regarding car gauge I still cannot seem to get that setup right. I am still at the same point as reported in posting #57-#59 with that app. I hit connect, follow your steps to run the full scan and save the PID file on my phone. I can then connect and select No Scan, load the PID file I saved "Jimmy" and it seems fine however it will then not connect using that file. Every time I connect it will send me down the same path to either do a full scan, or no scan and reload the PIDs but it never "stays".
After I do a connect, full scan, I am then able to get to diagnostics and try the air pump options I get the "invalid/no data". I am sure its something dumb I am doing or not doing.--
---edit. I was just in the truck for about 30 minutes going through your previously mentioned steps and I just cannot get it to work right. Still store the full scan PIDs and go back to load them again it always requires to pair bluetooth. I cannot load them without being in the truck bluetooth on. After I connect and load I can go into diagnostics and neither work. Over and over and then one time it connected and had a difference screen, diagnostics I got the below screen, no options for selecting tests though. I have gone back through the same exact steps after and cannot get it to connect the same way again.





Regarding the schematic. Thanks for that, I am quite sure its the same but this confirms my test/guesses. The secondary Air Injection Reactor is the area I was doing my tests and it is indeed inside the passenger side fender right behind/beside the battery. I had to manipulate the and shift the battery where I could pull out that fuse block with the battery still connected so I didn't clear my codes which wasn't easy.
So as I posted I did test continuity on the "AIR SOL Fuse 10a" as well as the AIR Fuse 30a maxi. Both tested fine but I replaced the 10a just in case, but didn't have a maxi around to swap just because.
I didn't know about IGN E fuse until last night, which I replaced last night as well. At this moment I haven't tried the cold starting this morning.
On the AIR Relay, not having the schematic before, I just tested it using the number diagram on the relay itself. I did a continuity between 639 and 436, and I hard wired the relay and grounded terminal 436 and then got a solid 12v to my DMM after the energized "click" so that told me the relay was working.
I first then went to the pump itself and ran straight 12v to it and it fired up no problem, Then I worked back to the Air Injection Reactor and ran direct 12v power down wire 78 and the pump ran just fine as well.
Most of this takes so long because I am currently in an apartment and cant work on my truck here and have to keep all my tools at my dad's and drive 40 minutes there to do any tests after posting on here.
So from the schematic, and what I have done I believe correctly, it leaves me with either the PCM not working to ground or the under hood fuse block not providing power to the relay.
Out of frustration I just ordered a new relay, set of maxi fuses, the secondary air shutoff/bypass valve, the vacuum check valve and an engine coolant sensor. I will sap the 30 maxi, replace the check valve, and then think about the engine coolant sensor. The thought there was that maybe the it was faulty, even though it seems to be reading fine in torque pro, and maybe telling the PCM it was higher that it was so it would not try to turn on the air pump on cold startup.

As I believe you said yourself the test will run and clear when it wants to and with that and the above tests/info I have just been doing the drive cycles hoping it will trigger, like it did itself just a couple weeks ago while I was waiting for the catalyst and EVAP tests with the secondary air. So it worked as some point in just the last few weeks that I have been messing with all of this. I did removed the battery between then, clearly not thinking it would be this tough to get all the tests to pass again so i am stuck on this secondary air.
I now have purchased a powered OBD II plug to keep the codes while taking out the battery and am going to try that here shortly to retest the relay and wires from your schematic and if it stops raining I will try to do my body lift as well.

 

I just went down and quickly popped the hood and double check continuity on the IGN E fuse and checked the voltage at the block in the run position and oddly I am only getting about 11.3v there whereas at my battery terminals I am getting about 12.10. Odd there is a drop at the main fuse block, and tiny bit odd I have lower volts at the battery as it is brand new, but I have only done a lot of cold starts and idles before shutting down recently with maybe 1 or 2 around the block drives.. not much for the alternator to recover from the cold starts. I will try to put the battery on a charge next time out to work on it too.

Even with that lower voltage I would assume the relay would still function and close the circuit if the PCM is grounding 436.

 

The functional check of absolutely everything but the PCM control (all fuses and wiring and relays, etc) is to turn key on, ground 436, and the air pump should then come on.

I'll see what I can cook up for Car Gauge Pro instructions - maybe some sort of video while I'm connecting to mine. Please don't expect it right away, though.

 

I'd appreciate that. I was going through your steps on the cam retard thread (https://blazerforum.com/forum/2nd-ge...d-90496/page3/) no luck. I also tried it on my tablet instead of my phone, to eliminate the phone, and still had the same exact issues.
I am really wondering if it is different for 2000s or my adapter. I just deleted all the saved profiles and PID files did the steps and created a dash board. No matter what I do after loading the PID via No Scan, I think have to go back and hit connect and do all the same steps until I select OBDII. The dashboard works just fine but I got back to diagnostics and the active tests do not.
That screen shot from above I found is when I select generic OBDII rather than GM.

 

Got my maxi fuse pack and a new relay just a minute ago and installed those, another cold start and not a sign of the pump kicking on again.