Runs extremely rich...

Hello,

1993 Chevy S10 Blazer 4.3L 4x4 auto Vin W

Started running poorly intermittently, sometimes it ran bad for a little bit then it was fine. The other day it stayed bad (black soot exhaust left on ground)and nearly left me stranded. Engine light revealed a code 45 (O2 sensor rich) condition. Problem is, I got another O2 sensor and went to remove the old one and couldn't budge the darn thing. I ran the vehicle for a little to heat it up and still couldn't budge it, my body weight with pipe extension and wrench extensions too. I succeeded in rounding off the ends. Now I'm just short of breaking off the head and trying a box end wrench or socket. But once I do that, I really have to fix it right then. Anyone have any ideas for me to possibly get this off without having to do that yet? I don't have torches.

Thanks.

Cut the wire off and put a good socket or pipe wrench on it.
But
A good muffler shop may be the best way to go on 02 sensor.
They deal with them all of the time.
Many have messed up threads.
The 02 is probably not the problem on running rich.
Check fuel pressure for fast leak down.
You may have a regulator leaking or nut kit flooding it with gas.
MT

Cut the wire off and put a good socket or pipe wrench on it.
But
A good muffler shop may be the best way to go on 02 sensor.
They deal with them all of the time.
Many have messed up threads.
The 02 is probably not the problem on running rich.
Check fuel pressure for fast leak down.
You may have a regulator leaking or nut kit flooding it with gas.
MT

One thing I know is: it's a lot easier to check the regulator than get the O2 out. I'll try that first. Thanks.

10-4 on that.
02 sensor may not even be bad.
Code says check it out not replace parts.
Also watch the tempt sensors and egr valve for sticking open.
And check the evap canister.

10-4 on that.
02 sensor may not even be bad.
Code says check it out not replace parts.
Also watch the tempt sensors and egr valve for sticking open.
And check the evap canister.

yep, will do...

About the evap? What to check for? I think I read something about if it was wet then it's bad and change it. Not sure...I have a spare regulator and egr.

Oh, before it started running funny, it started taking a bit to start it in the morning. It wouldn't start right up anymore, I had to give it gas.

Putting the socket on it is the way to go. I further(if I have to) warm up the area around the o2 sensor. The idea here is to just expand the metal around the sensor and not the sensor itself.

yep, will do...

About the evap? What to check for? I think I read something about if it was wet then it's bad and change it. Not sure...I have a spare regulator and egr.

Oh, before it started running funny, it started taking a bit to start it in the morning. It wouldn't start right up anymore, I had to give it gas.

Remember proper testing before throwing parts at it.
Get a fuel pressure gauge on it and check for proper pressure and fast leak down.
If canister is wet unplug it and plug vacuum line from engine and see if engine starts running better.
MT

Remember proper testing before throwing parts at it.
Get a fuel pressure gauge on it and check for proper pressure and fast leak down.
If canister is wet unplug it and plug vacuum line from engine and see if engine starts running better.
MT

MT,

I was monkeying with it for the past 4 hours and here's what I noticed. I tried unplugging everything, one at a time, to check that particular sensor. TPS, MAP, IAC, EGR, O2 sensor, ATS, temp sensor. None of these did anything except some made it worse, some didn't and shoot codes. So I cleared the codes and started over, no codes now, not even for O2, but still running very poor and barely keeping running. When I give it alot of gas it almost sounds like it wants to clear itself up, but returns to very poor again. Smells gaseous. So glad the O2 wasn't it, but now I am still wondering. As for the fuel pressure and evap(not sure where it is), didn't get to that yet. Tried coil, but no go. I was searching and supposedly there is a fuel port on the rear of the intake somewhere. The evap I couldn't tinker with, didn't know where or what it looks like. The fuel pressure regulator sounds like a good possibility, but I saw online that it is internal with the CPI so how do I check that? Could a head gasket be a possibility also?

Thanks for your help.

As in post no 7 start with a fuel pressure test.
If it is leaking or nut kit you will have a fast leak down.
MT

Try putting breakfree on it for a few days,the hot and cold cycle from driving and sitting should help it loosen up.give it a few days though before you try it again so you give the breakfree a chance to work.Also if you have rounded off the end of the sencor,try useing a pipe wrench on it with your breaker bar.It works for me.

Try putting breakfree on it for a few days,the hot and cold cycle from driving and sitting should help it loosen up.give it a few days though before you try it again so you give the breakfree a chance to work.Also if you have rounded off the end of the sencor,try useing a pipe wrench on it with your breaker bar.It works for me.

Yes. Thanks, but it isn't the O2 sensor.

If you don't have a gage, then to test for a leak in the intake turn key on every so often (5-60 minutes) for a dozen or less times.

See if it starts very badly and smokes upon startup far worse than normal. If it doesn't start (hold to floor to get going) then it has a leak in the intake.

If so yours has got to be a huge leak and can be spotted quickly by removeing the top plenum and turning on key.

If you don't have a gage, then to test for a leak in the intake turn key on every so often (5-60 minutes) for a dozen or less times.

See if it starts very badly and smokes upon startup far worse than normal. If it doesn't start (hold to floor to get going) then it has a leak in the intake.

If so yours has got to be a huge leak and can be spotted quickly by removeing the top plenum and turning on key.

Interesting. I'll try that.

As in post no 7 start with a fuel pressure test.
If it is leaking or nut kit you will have a fast leak down.
MT

MT,

I have been away for a while so just now getting back to looking at this. Here's what I got for fuel pressure.

KOEO - 50psi
then after 2 mins, down to 36psi and would prob keep going if I let it.

KOER - 55psi and holding steady.

Starting to think I didn't change the wires and cap/rotor when I got it. May start with that because I checked just about everything else except the cat.

check plugs if one side is black its the FUEL PESSURE REGULATOR. diaphram has ruptured causing raw fuel to enter the pelnum

check plugs if one side is black its the FUEL PESSURE REGULATOR. diaphram has ruptured causing raw fuel to enter the pelnum
I pulled the plenum and there was no wetness whatsoever. It was black, but not wet. Plugs looked good when I changed them before. Once again I got a code for the O2 sensor after running it. SO I'm in the process of trying to get that out, but it ain't going easy. Nut is rounded.

Checked fuel pressure regulator under plenum. Was black-ish, but dry. Could the regulator still be bad?

If not, then what? Bad/leaky injector?

What's interesting is the fast leakdown I saw with koeo from 50psi down to 30 something in 2 minutes. I think this is the problem, but nothing obvious is jumping out at me right now.

If it isn't leaking under plenum then it is either going thru the regulator or back thru the pump.

If you can block off the return line and do another pressure test while observing lines under plenum. If it's leaking inside you'll see it. If not then it must be leaking back thru the pump.

If it isn't leaking under plenum then it is either going thru the regulator or back thru the pump.

If you can block off the return line and do another pressure test while observing lines under plenum. If it's leaking inside you'll see it. If not then it must be leaking back thru the pump.

I think I got that AHA moment last night, but won't be positive until tonight when I finish it.

After pulling the plenum again, there was wetness on the driver side of the intake, not the regulator side. That was after I turned the key on a few times, even started it. I pulled on all the injector hoses to check for fitment and sure enough two of them on the driver side pulled right up as if they werent snapped in. After snapping them in and checking the rest, I changed the regulator anyway and buttoned it back up.

It sounds like it is running somewhat better, by not stalling out every second. It still is running extremely rich, BUT I had the O2 sensor dismantled underneath. Only the base remained in the pipe, rest was broken off. So, I started it up, drove about 50 miles earlier, roundtrip, to the muffler shop. It was easy for them to remove it with torches, the one thing I don't have. Now it's an empty hole and surely contributing to the rich condition now. I do have another O2 to put in later. We'll see how it is after that.

Finally got it where it needs to be. Buttoned up the O2 sensor, regulator etc etc. Now it is running well again.

I want to thank all who gave me helpful hints, especially MT and 534, whom I have gotten info from before on other tasks. Automotive forums is really an amazing resource for the home mechanic.

CHeers!

You are welcome and thanks for posting back how it went.
Glad all is well.
Good Luck

You are welcome and thanks for posting back how it went.
Glad all is well.
Good Luck

I appreciate it MT. Just now I got a bigger problem with the Park ave. That's another thread.....

Take care.