Here is a diagram of the AIR system that should be on your 1998. Parts #10 and #14 attach to the front of your exhaust manifolds. The A.I.R. pump is above removable panel underneath radiator. Including this info because I said I would take a photo so you could confirm installation. Please go ahead and do the cranking and running compression tests.


https://cimg8.ibsrv.net/gimg/blazerf...567047e755.jpg

Fair enough. I'll buy a kit and get the tests done, thanks.

Also, just for my curiosity let's say I have low/inadequate compression in a cylinder(s). What does that mean could be wrong? From general google answers I see it could be head gaskets, pistons/rings, valves/valve springs, ect. Are these the case for the 4.3s?

Say I have good compression, is it possible I have have bad intake manifold gaskets?

I know I'm jumping the gun here but my curiosity is peaked at this point.

Please carefully read ALL the info in the link in post #2. It discusses the different compression scenarios and what each means.

Yes you can have bad intake gaskets and good compression.

If you want to save $$$ you can get a compression tester as a loaner tool from your local parts store (with deposit).

Good luck and best wishes. Heres hoping all compression tests are good. Its just that we need to rule this possibility out. Its the most basic requirement.

Please do post a link to youtube video that has the sound. We need to make sure the engine bearings are not on their way out!

here’s a video. First clip probably the best but added a few extra anyways. https://m.youtube.com/watch?v=A6ivdY3sNZU

Hmmm... Is it the random slapping type noise? I don't hear a bad bearing. Strange noise. Not sure if the video is doing it justice.

Just wanted to update as I’ve obviously been inactive. My compression test kit finally came in. Hoping to find time to get the results this week and if not this weekend.

The link in post number two has me a bit confused. It seems to jump straight into static with no real explanation of what to do. From my research this is my interpretation (just looking for clarification before I go ahead):
Warm the engine to operating temp
Shut engine down and remove all plugs
Disable ignition, fuel system, and disconnect charge coil wire
Crank engine with throttle fully open
Test each cylinder and record max pressure from each after 5 "puffs/needle movement"
Move to idle and snap tests

Additionally, I noticed that it says idle should be at about 1200 rpm, my vehicle idles around 700-1000 do I need to apply throttle and take readings at 1200 or will my idle rpm's be sufficient?

Welcome back!

For the static compression test you have it exactly right. I would disconnect the coil and take out the fuel pump relay. 5 puffs is not a hard/fast rule. Myself, I typicaly go for max with extra puffs Consistency is the key. Also make sure battery is not running down/cranking slow.

For the running test I would hold at 1200 and burp gauge before taking reading. If you disconnect a cylinder and let it idle the RPMs will be even slower than usual.

I wish you luck doing this, and that you will not find anything with these tests (that all is fine with your basic engine).

Post your results when done please.

Only had time for static test tonight. Will hopefully get the rest at some point this week. Also noticed plug from Cyl 4 is fouled. Pictures of all plugs as they are located when standing in front of engine here. (PS Looking back at the pictures I think it makes the gaps SEEM bigger than they are but when I work on it tomorrow I will confirm proper gapping).
1 195
2 195
3 190
4 200
5 195
6 190