92 S10 Blazer TBI Rich

jd

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#16
If ROCK's picture and another I found are accurate, this sensor pokes into a grommet somewhere, like a PCV valve pokes into a valve cover grommet. I remember changing one that screwed into a branch of a Ford V6 intake manifold, but this AX32 looks different. Does your V6 have a Space Age Plastic Composite thingamajig with a sensor sticking out of it?
 
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#17
Nope. The air cleaner assembly looks like one you would find on a carbureted engine. When you open the hood, you might actually think it has a carburetor until you either take off the wing nut or notice some of the other components that you'd only find for fuel injection.

As intimate as I am with the top half of this engine, I am 100% certain that it never came with any sensor to measure the flow or temperature of incoming air. I'm familiar with the IAT sensors shown in those pictures, and they just push into the intake tube. One of those would never work on this tube as it's just thin, flimsy plastic and not "rubberized", so it would never seal. Plus, there are no pigtails disconnected anywhere.

And there is definitely no temp sensor in either head. The only temp sensor I can find is at the front of the intake manifold next to the thermostat.
 
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#18
Sensor at thermostat 2 wire? this is ECM use, Its a 5v reference and other is ground... testing is ohm reading of sensor terminals.
- There is a 'memory' of a ECT sensor issue* BUT this is a 92 and would be addressed by now.
Dave mentioned fuel pressure - I am thinking why would it run OK before head R&R but go to shit now, same EGR, fuel pump, MAP, TPS, my thinking kind of leaves wiring, sensor inputs GIGO.


* something about plastic type vs improved type ? hoping this helps someone remember OR as often I am confused.
 
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#20
Hello again everyone. I've been very busy over the past couple days and didn't even get to go get my multimeter and vacuum pump as planned, but I was able to pick up a new multimeter and a compression gauge today. Tomorrow afternoon I will definitely be doing some checking on sensors and testing compression on all cylinders after we pick up our daughter from Head Start.

No, I didn't have the heads rebuilt. This truck was destined for the scrap pile long before I ever touched it, and will be going there come Tax time. I hate to see vehicles get scrapped, but this one just flat out isn't worth fixing everything that's wrong with it. New front diff, door panels & hinges, rear hatch hinges and latch mechanism, etc etc. The list goes on. The parts alone, new or used, would cost more than the truck would ever be worth. I'm just trying to make it last 6 more months, and if I hadn't changed the gaskets it might not have. The pistons were starting to burn through from the antifreeze in the combustion chamber, but they should be perfectly fine for a while longer as long as it's not burning anymore antifreeze.

On a side note, I accidentally caused a vacuum leak readjusting the rocker arms. One of the bolt holes in the intake manifold (used for the MAP/Purge solenoid mount only) stripped out, so now it's running so bad that it actually dies when idling occasionally. I'll be taking care of that tomorrow with some Ultra Black that I picked up as well. If anyone has any recommendations on where to buy an affordable, but not crappy, Tap set, I'd appreciate it. I should have bought one long ago.

Thank you again everyone, and I will be getting back to you tomorrow afternoon/night with some hard data.
 
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#21
look at a "heli coil" repair kit for the manifold. NAPA part.
Maybe 1 size up self tapping bolt. - not critical fit more of a clamp am I right.

don't rush into a full tap set purchase either you will over pay or get 'screwed'.
 
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#22
Yeah, it just holds a bracket on that never has any sort of stress.

But I have a much more critical issue and somewhat found the source of all the issues. I'm in the middle of testing compression, finished the 1-3-5 bank. 1 & 3 are good at 152 psi. But I have absolutely no compression whatsoever on 5. Yay....
 

jd

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#23
Can't come up with a phrase for how sick that makes me. Let me try these silly things...:(:giveup::eek:
 
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#25
Lol Thanks JD.

Yep, Krazy, same as all the other cylinders. I even did #5 again today to be sure. There was a 1 psi difference between 1 and 3, then pretty much no compression at all on 5, and I can hear the compression just hissing out of 3 and 5 when turning the engine by hand, so I'm betting that it's the gasket and not a valve. Maybe something got stuck between the head and block at the rear without me realizing it. (Thankfully the other bank is fine, 170 psi across)

My next move is to take the head back off and see if it's the gasket or a valve (Pretty sure we all know it's the gasket after today). Since this gasket is new, what are the chances that I'd be able to reclean my mating surfaces and reuse it (even if I put an extra 5-10lbs of torque on the bolts)? I'm just wondering because I can't rent a pulley puller this time. I'm going to have to buy one, and it's going to cost an arm and a leg in this town. Or is it possible to remove the head without taking that entire Alt/Pump bracket off? Would it be possible to pop the alt off, take out the bracket bolts that go into the head, and squeeze it past? If I can get away without buying the puller I have no problem buying a new gasket for that side.

Thank you everyone for your time, and I only wish it had been the TPS or a temp sensor.
 
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#26
Thats a bummer bro, but as they stressed to us in college... "Haste makes Waste" if you try to shortcut you typically end up in a worse situation than you started in, as painful as it sounds its best to take your time. Depending on type of gasket you may b able to reuse but if a tinybit gets left on block or head must replace. I would check for warpage on cylinder head while u have it back off. Good luck and my condolances
 
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#27
Before you remove head, you should loosen valve adjustment for cyl 5 so that rockers have a little slack and retest for compression. Also, do a "wet" test...where you squirt some oil into cylinder and see if that gets you some compression. Do you know what a "leakdown test" is?
 

kev2

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#28
billr suggested compression ck early on, his first reply-

there will be no living with him now.... :beer:;)
 

billr

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#29
No, I won't gloat, but I do have to ask if the compression there is really "near zero"? If so, I'm betting it is not a simple gasket issue. Something would have to be grossly bad for a gasketed joint to leak that bad.

Resist the urge to tighten those head screws "a bit more". It isn't going to cure the root problem and may leave you with broken screws to dig out or stripped threads to repair. Don't make a bad situation worse...
 
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#30
Bill is right again. When I put the spark plug for #5 back in last night, I loaded the threads with Ultra Black as a thought. Went to get a new gasket for that side just now, and it purred like a kitten the whole trip.

I'm still going to do that gasket again tomorrow since there was a 20psi difference between the banks, and while it's off I'm going to fix the threads for the plug.

Thank you everyone for the help!