Advice for stripped threads upstream oxygen sensor exhaust manifold

On 2 Aug 2018 13:34:28 GMT, Clare Snyder wrote:

> The tap required to chase out the thread will be metric - usually an
> 18mm spark plug tap. (or thread chaser)

Hi Clare,
I had the teen run a short test (the car isn't street insured and the kid
doesn't yet have his license so I had the kid test it on a bunch of private
roads at 10 mph (if that) where it's legal to drive at least on private
property - where all the neighbors have been prior warned).

There was some smoke around the exhaust manifold where we were working, and
the car stalled a few times when it just about warmed up (so I presume the
choke went off), but I am hoping that the mist of oily smoke is just the
oil that got on the manifold when we removed the old lambda sensor.

Of course, the amber "Service Engine Soon" light was lit the whole time:
<http://www.bild.me/bild.php?file=2780083o2sensor27.jpg>

I cleared the SES light such that the SRS is the only remaining warning:
<http://www.bild.me/bild.php?file=7936105radiator_12.jpg>

There are a few other anomalies I noticed, but the main question is how to
test if the oxygen sensor is in tight enough.

On Thursday, August 2, 2018 at 8:21:36 PM UTC-10, Arlen Holder wrote:
>
> There are a few other anomalies I noticed, but the main question is how to
> test if the oxygen sensor is in tight enough.

This is not brain surgery. You torque it to whatever you feel comfortable with. If you strip out the threads, you'll have to repair it with an insert. What's the problem? If you're afraid to work on the car, then don't.

On 3 Aug 2018 18:03:11 GMT, Clare Snyder wrote:

>>http://www.bild.me/bild.php?file=3408929o2sensor13.jpg
>>http://www.bild.me/bild.php?file=8568761o2sensor14.jpg
>>http://www.bild.me/bild.php?file=5285317o2sensor15.jpg
> Thanks for reposting. Yes, it is a fabricated manifold. What metal
> it is is hard to say - likely a high nickelteel - similar to
> Stainless.

Thanks Clare for your always wise and wonderful advice.

I have a friend with welding equipment lined up if I need to drill it out
to insert a bung and have it tack welded in place.

At the moment, I'm sticking with the simple plan of...
1. Hope the thread chaser worked (how would I know if it didn't work?)
2. If needed, try the M20x1.5 tap to add a M18x1.5 insert
3. If really needed, drill it out to have a bung tack welded in place

I think, as you astutely predicted early on, that #1 will suffice.

My main mental dilemma is only how to tell if gases are leaking past the
lambda sensor threads under pressure.

On 3 Aug 2018 18:00:56 GMT, Clare Snyder wrote:

> What did you want it to do? A "thread chaser" is supposed to clean
> foreign material out of the thread. If the threads are not badly
> deformed, it will NOT remove metal.
>
> You now have a pretty fail percentage of a thread - - -

Thanks Clare.

To answer your question of "what did you think was gonna happen?", I pretty
much was hoping it would "feel" like I was tapping new threads, as I've
tapped things before.

But it just felt loose.

Still, it tightened the last 1/8th of a turn, so, if that's enough of a
"bite", then I'm happy.

I don't know how to *test* if the lambda sensor is leaking, but there's no
sound coming out of it (of course, the engine is loud so the sound would
have to be huge like it was when we moved the car a bit with the sensor
out).

On 3 Aug 2018 18:12:20 GMT, Clare Snyder wrote:

> First of all - it has NO CHOKE. The computer may have to "relearn"
> with the new sensor. Any finger prionts or penetrating oil etc on the
> manifold will make it smoke. Let it cool down and start it again. If
> it smokes a lot less, or not al all, you are good.

Thanks for that choke advice. It must have "some" mechanism of increasing
the fuel-to-air to achieve the 14:1 stoichemotry when cold, so that's kind
of sort of what I meant by choke.

Basically, it stalls at low speed (which is all we've been able to do)
whenever it's transitioning from warm on the gauge (about 10 minutes or so
of low-speed driving). It did this *before* the oxygen sensor, so it's
unrelated to the sensor.

The OBDII tester gives us a 800 rpm reading at idle. Dunno how to increase
the idle speed yet, as this car isn't mine (mine is a bimmer which is a
drive by wire mechanism).

> As for "tight enough" - if you could get 120 foot lbs out of it it's
> tight enough. Only takes about 10 to squash the washer.

Thanks for that advice Clare, where you have always been spot on in
accuracy. I'm gonna assume it's tight enough since I did get a good last
1/8th of a turn on it with a wrench, and where I can't think of how else to
test it other than to see if the cleared codes come back under 10mph
driving (which is all we can do at this time).

> I believe the torque spec is 33 ft lbs on a Mitsu.
> Many others are spec'd as finger tight (no movement) plus 1/4 turn -
> about 18-25 ft lbs.

If that's the case, then I think the torque is fine.

The funny thing is I wonder why the mechanic who screwed it up didn't just
do what I just did. What did he gain by jb welding it (or whatever that
gray hard metal-like paste was)?

Arlen Holder > wrote:
>Basically, it stalls at low speed (which is all we've been able to do)
>whenever it's transitioning from warm on the gauge (about 10 minutes or so
>of low-speed driving). It did this *before* the oxygen sensor, so it's
>unrelated to the sensor.

Right. The error message you got about the sensor was ALSO unrelated to
the sensor. The error message says the output of the sensor is out of
range. It's out of range because the engine is running way too rich
or way too lean.

>The OBDII tester gives us a 800 rpm reading at idle. Dunno how to increase
>the idle speed yet, as this car isn't mine (mine is a bimmer which is a
>drive by wire mechanism).

You don't. You find the vacuum leak or the bad idle control valve or
whatever it is that is causing the mixture to be all wrong, and then
your idle speed will stabilize and you will be able to accelerate again.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On 3 Aug 2018 18:52:56 GMT, Scott Dorsey wrote:

> Right. The error message you got about the sensor was ALSO unrelated to
> the sensor. The error message says the output of the sensor is out of
> range. It's out of range because the engine is running way too rich
> or way too lean.

Understood. The error is just an error in the input, output, or power of
the sensor.

>>The OBDII tester gives us a 800 rpm reading at idle. Dunno how to increase
>>the idle speed yet, as this car isn't mine (mine is a bimmer which is a
>>drive by wire mechanism).
>
> You don't. You find the vacuum leak or the bad idle control valve or
> whatever it is that is causing the mixture to be all wrong, and then
> your idle speed will stabilize and you will be able to accelerate again.

Always wanted to buy a good smoke tester at a good price that a home
mechanic can make an argument for on cost/benefit analysis.

Arlen Holder wrote:
> On 3 Aug 2018 18:03:11 GMT, Clare Snyder wrote:
>
>>> http://www.bild.me/bild.php?file=3408929o2sensor13.jpg
>>> http://www.bild.me/bild.php?file=8568761o2sensor14.jpg
>>> http://www.bild.me/bild.php?file=5285317o2sensor15.jpg
>> Thanks for reposting. Yes, it is a fabricated manifold. What metal
>> it is is hard to say - likely a high nickelteel - similar to
>> Stainless.
>
> Thanks Clare for your always wise and wonderful advice.
>
> I have a friend with welding equipment lined up if I need to drill it out
> to insert a bung and have it tack welded in place.
>
> At the moment, I'm sticking with the simple plan of...
> 1. Hope the thread chaser worked (how would I know if it didn't work?)
> 2. If needed, try the M20x1.5 tap to add a M18x1.5 insert
> 3. If really needed, drill it out to have a bung tack welded in place
>
> I think, as you astutely predicted early on, that #1 will suffice.
>
> My main mental dilemma is only how to tell if gases are leaking past the
> lambda sensor threads under pressure.

I wouldn't worry about it. Any leakage would be minor.
However, if you are worried about it you can put some high temp
sealer around it.
Don't know if a hose would work in this situation or not due to engine noise.
Get lenght of small hose, stick one end in ear, and use the other end
to listen for leaks.

On 3 Aug 2018 23:27:26 GMT, Paul in Houston TX wrote:

> I wouldn't worry about it. Any leakage would be minor.
> However, if you are worried about it you can put some high temp
> sealer around it.
> Don't know if a hose would work in this situation or not due to engine noise.
> Get lenght of small hose, stick one end in ear, and use the other end
> to listen for leaks.

Thanks for that advice on the high temp sealer.
Someone said that the threads are the ground for the electrical connection.

We will leave it for now (it's parked in my driveway but it's not my car).
I'll have the kid drive it on private roads until we can get the registers
to set (we might not get them all to set if they need highway speeds).

The most critical thing is to get it smogged.

I'm gonna start working on the other issues now (for example, the SRS light
is lit so I'm gonna have to figure out how to reset that first).

Thanks everyone for all the help on the stripped threads!
You guys give me the confidence to keep going!

On 4 Aug 2018 07:52:48 GMT, Clare Snyder wrote:

> DO NOT put sealer on it. The "cell" needs to breathe - anything that
> would restrict or poison the air getting to the cell will kill the
> sensor.
>
> I repeat - DO NOT PUT ANY KIND OF SEALER AROUND THE BASE OF THE SENSOR
> - and yes I AM yelling!!!!

Hi Clare,
Over the decades, you have ALWAYS been right so I will follow your
instructions to the letter!

I'm an electrical engineer, by the way, but they do NOT teach us any of
this pragmatic stuff in school ... they don't even cover ground connections
in op amps, for example. So I learn a LOT of this stuff from you!

*THANK YOU FOR ALL YOUR CORRECT HELP & ADVICE OVER THE YEARS!*
(and yes, I'm shouting gleefully!)

I very much appreciate that you are (a) so helpful, and (b) so experienced,
as I am not educated in automotive mechanics (other than a high school shop
class many decades ago when rwd & carbs & distributors & rusted out exhaust
pipes were the norm).

You give me the confidence to keep going, which I very much appreciate,
since I'm always helping this neighbor who is living off her savings and
whose husband died leaving her a house in need of tremendous repair and a
few kids that she loving dotes upon (whom I try to help as much as I can).

The *only* time we really differed, in all these years, is on the
feasibility of unmounting, remounting, and static balancing tires at home,
which I find so easy to do (particularly on the 14-inch wheels of this
Mitsubishi) that it takes fifteen minutes, easily, from start to finish,
where, to just drive to a shop and back would be multiple times that in
terms of time & effort.

The only other place, I think, we differ, is that I "think" alignment is
"doable" under the circumstances of whatever is "adjustable" on each
vehicle (e.g., my bimmer only has front toe, and rear camber & toe - so
those are the only three measurements & adjustments I'm talking about).

I know you guys seem to despise me simply for purchasing Harbor Freight
equipment, and, you're right in many ways as the tire changer isn't the
best tool on the planet (but at least it already paid for itself a while
ago at about the fifteenth tire) and the additional bead breaker (which is
a requirement for SUV tires) needed to be slightly modified (the base is
too short for larger diameter tires) - but it works just fine once I put a
plank of wood on the base to lengthen it for the 17-inch larger tires.

The one other thing some of you guys seem to hate is that I look things up
(e.g., I have realized that brake rotors just do not warp in normal street
use, and anyone who says they do, has actually never measured the warp (as
you would measure engine head/block warp, for example). Some of you who
hate that call that 'book knowledge', and I agree it's book knowledge - but
all knowledge is good, even book knowledge (I've read a billion textbooks
in my time, and nobody complains about them for example).

There are still six "big jobs" that I posit few people choose to do at home
(each for different main reasons), where I now have half of them under my
belt, and where I hope to do the other half before I die!
============
1. Habitually refuel a vehicle at home (I have been refueling for years)
2. Habitually mount, balance & patchplug tires at home (I've done 20 now)
3. Remove & repair a transmission (just did my 1st clutch, thanks to you!)
============
4. Measure & align what is designed to be adjusted (that's next on my list)
5. Prep & paint an old vehicle (that is also next on my do-b4-I-die list)
6. Remove & repair an engine (haven't done this - major downtime issue)
============

I "think" most people don't know what I know (and you know) about
re-fueling and changing tires at home, but the rest of the issues I can't
say that I know anything that most people don't already know.

I "think" the main reason most people don't do those six things are
(keep in mind the reasons below have to be short to fit on one line)
1. They don't have the room, privacy, or delivery options that I have.
2. Lots of reasons - but mostly it's that it's easier to pay someone.
3. Lots of reasons - but mostly it's too big of a job for most people.
4. I think the main reason is that they "think" it can't be done.
5. Lots of reasons - mainly that they want the results to look perfect.
6. Lots of reasons - mainly I think few can afford the lengthy downtime.

If you see a thread, in the future, about alignment checks of a Mitsubishi
Lancer ES, you'll know that I've finally tackled my first alignment job!

But first, I have to purchase toe plates that allow toe to be more easily
adjusted without having to roll the car back & forth - and I'll need to
find camber plates at a reasonable price that offset the electronic level
from the tire bulge while keeping the level parallel to the wheel.

Thanks again, Clare, for helping give me the confidence to do what most
people are afraid to try to do - where I can help others - save money - and
end up with the best parts at the lowest cost possible (and I end up with
the fun of figuring out where to store all the new tools I needed!).