went on about a 40 minute test drive...runs well enough to get around, but not properly. I'm sure some has to do with the o2 sensors, and the cat not being in place, but I have always had a "higher idle than expected" code. I blamed it on the lack of IAC motor hooked up, but after putting a few in there, I don't think I can blame it on that. Will swap the other ECM tomorrow, see if I get any different results. In the mean time, I am happy I can stop playing taxi driver, using 1 car to drive the woman to work and kids to school...2 cars is a MUST for my family!

 

Leave the original PCM in the vehicle. The crankshaft position sensor data in your original PCM should be correct, (unless the crank sensor or timing cover have been disturbed). If you install a different PCM, the crankshaft position sensor data will be incorrect and a relearn MUST be done. If the relearn is not performed, the engine will still start and run, but ignition timing and injector timing will be incorrect.

If the converter was restricted, there's a reason, they don't just plug up by themself. An overly rich fuel mixture will eventually plug the converter.

Key ON, engine OFF, fuel pump running: fuel pressure must be 60psi to 66psi. It must remain above 55psi for at least 10 minutes after the pump shuts off. GM does not publish any "engine running" fuel pressures for this system, all tests are done with the engine off.

 

Thanks for saving me with the swapping of the computers, really do not need to add any issues on top of the ones I've got already!!!
SO, over the weekend, I removed the exhaust manifolds to get the busted studs out, and put new in. I noticed the plastic housing that goes around the a/c evap unit (i think that's what's in there) and blower motor is melted at the bottom, guessing from the exhaust leak from broken studs blowing right at it...
Might as well replace that housing while I'm in there. Before I got into the manifolds chore, the OBDII scan with that EasyOBDII program said higher idle than expected, and that was the only thing sited in there. I need to buy a tank of oxygen for my torches today, I really would like to get this thing all back together today, or at worst tomorrow.
I do know the cats don't clog unless there's a reason, maybe it was because of the leaky FPR? I'm guessing the scan will be more accurate once I get the exhaust sealed up, and weld the cat back into it. It's been below freezing here lately, but a trip to the junk yard is totally unavoidable.

 

Anything that causes a rich fuel mixture will cause a meltdown in the converter. The more unburned fuel that goes through the converter, the quicker it will meltdown. If the fuel pressure regulator is leaking externally, that will definitely do it.

 

Guessing that bad FPR killed it. It has been replaced, as of a week ago. Made it to the junk yard, and got a new housing that goes around the evaporator, and noticed that *some* trucks were equipped with a fabric like heat shield, but not all?>? Anyhow, hope to get the housing swapped out, and manifolds back on today. Would be nice if I could get it ALL together, but every step it seems has been a struggle, and I find more broken stuff the more I get into it!!
I have not looked into the stored code of the idle higher than expected issue, I will save that for when I get it back together. It may see another round of plugs/wires/cap/rotor as well. The parts store said all but the plugs are under warranty still, and they'll swap them out, no hassles.

 

It needs to have the insulation covering the evaporator housing or it will melt again. Very close to the exhaust manifold, and normal heat will be a problem.

Make sure you install AC Delco parts for the tune. It makes a difference, especially the plugs, cap & rotor..

 

Here is what I bought and installed last week
Might be a little overkill, but what the hay. I decided to use the bolts and screws that hold the evaporator cover plus a couple bolts on a bracket that were put there specifically for the heat wrap. Problem I ran into is the fiber is so tough that it caught on the screws as soon as I tried to put them in. If you can see the bracket on your truck at the bottom right of the heat wrap, OEM used 1/4" ID grommets. So I did the same thing.

I started off with a 2' x 2' square and push the wrap into the position and marked where the heads of the screws and bolts were with a Sharpie. I had to take the wrap up and down about 3 or 4 times while I did this so I could get it to form correctly because of all the angles. I trimmed the wrap little by little as I went along.

I don't envy you though. I installed the wrap from the bottom while I sat below the engine compartment with engine removed. DEI makes a high temp spray adhesive bought but decided not to use. Didn't want to make a mess, and if I ever needed to take the evap cover off for some reason it would be an utter mess tearing the wrap away. So, I decided to use the mechanical method.

When you look at the link, they might have suggestions for similar products. Take a look and decide for yourself what will work best for your situation. There are adhesive backed products which may be the better choice for you. I didn't use it because the reviews talked about some smells when it warmed up, plus I'm trying to make my truck bone stock so I can start with a clean slate if I want to make improvements.

 

I will for sure purchase some sort of heat shield...I do not want to replace that housing and cover anytime soon! The junk yard had about 25 blazers of my generation, but there was only ONE that had a totally damage free part.

So...I just got home from driving the Blazer....

Had to do junk yard exhaust manifolds, as melted more of the cast iron than the broken studs trying to torch them out. They were 15$ each at the one I went to, so price was good for me. There was about 5" of snow, which was terrible!! Anyhow, had a nice 20 volt IR impact that made it as easy as could be, which still took 2 hours and 2 trucks to get both.

I did the tune up on it, new plugs/wires/cap/rotor/coil.
Plugs and wires were Delco. The guy told me that since they were double platinum plugs, I shouldn't try to gap them. The last time I put plugs in it, about 4 or 5 months ago, the guy told me to make sure I did gap them....Thanks for the conflicting information?


Truck power seems pretty good. The OBDII program says short term fuel trim is rich. I have the check engine light on again, code 507, idle control system higher than expected. I have put 4 different IAC in this thing. The one I had prior to tearing the thing apart recently, I "customized" it where it wasn't able to move, so I had a steady and normal idle. There was a few times it jumped to 2k rpm's for a second or so, and that's what it did before I put in the customized one. Id started fine with the thing how I had it, any ideas about that? I don't want people to think I'm trying to rev my motor at them.

SO glad to finally have this thing running, makes it much easier for the family to use 2 vehicles. I do hope to get the minor stuff taken care of soon though, I'd like it to run as it was intended to.

 

The cap & rotor really need to be AC Delco too.

P0507 is usually caused by IAC related issues, it needs to be operating correctly so the PCM can control idle speed. You might need to remove the throttle body and the IAC to clean out all of the passages with carb spray. Replace the throttle body gasket, and make sure there are no vacuum leaks, including a defective PCV valve. DO NOT tamper with the idle stop screw. It is adjusted when the throttle body is manufactured, and if it is tampered with, P0507 is very likely to show up, even if everything else is OK. Readjusting it requires a bi-directional scan tool.

 

For certain, there are no vacuum leaks. The passages inside the throttle body have been cleaned, and it looks pretty nice in there. One of the junk yard IAC motors self destructed while I watched, I wanted to make sure it moved...didn't realize it was going to keep moving til it broke!! Anyhow, I DID mess with that idle stop screw, BUT it was about a year ago. I backed it all the way off, so the throttle stops at the throttle body itself, instead of the screw. I did that in an attempt to get the idle at a normal setting. Is it maybe acting as a choke with it closing too far? Hmm....See what happens when you go to mess with stuff you don't know exactly how it works? Dang it. I just replaced the upper intake gaskets, including the throttle body a few days ago. The idle issue is not a new one. Do you suggest I buy a throttle body from the junk yard, or is it worth adjusting a little at a time without a bi directional scan tool to see if I can get it right?

Thanks for the info thus far, too BTW, everyone.

I will for sure get the remaining ignition components in the Delco brand, but not for a few weeks.