GM OBD1 and no O2 codes?

We have a 1990 Cutlass Ciera that blew out the O2 sensor and went into
limp home mode. The sensor physically blew out from rust.

So I put a new Bosch one in and at about 500 km later, it starts acting
exactly the same, with a miss all the way up the throttle and basically
no top gear or bad shakes in top gear, just like last time.

It also dropped to 18 mph highway from over 30 again.

I decided to get the codes to see if maybe something else has gone bad,
and after reading '12' three times, no more codes came up.

The question is should the bad O2 give a code and/or any other
suggestions for a no code miss?

The engine has new plug wires also and the fluids are all up.

Thanks,

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
'New' frame in the works for '08. Some Canadian Bush Trip and Build
Photos: http://mikeromainjeeptrips.shutterfly.com

In article om>,
Mike Romain > wrote:

> We have a 1990 Cutlass Ciera that blew out the O2 sensor and went into
> limp home mode. The sensor physically blew out from rust.
>
> So I put a new Bosch one in and at about 500 km later, it starts acting
> exactly the same, with a miss all the way up the throttle and basically
> no top gear or bad shakes in top gear, just like last time.
>
> It also dropped to 18 mph highway from over 30 again.
>
> I decided to get the codes to see if maybe something else has gone bad,
> and after reading '12' three times, no more codes came up.
>
> The question is should the bad O2 give a code and/or any other
> suggestions for a no code miss?
>
> The engine has new plug wires also and the fluids are all up.
>
> Thanks,
>
> Mike

Why would you associate the 02 sensor with what sounds like a misfire
and/or clogged cat problem?

1990 MY GMs don't have any code capability WRT misfires.

aarcuda69062 wrote:
> In article om>,
> Mike Romain > wrote:
>
>> We have a 1990 Cutlass Ciera that blew out the O2 sensor and went into
>> limp home mode. The sensor physically blew out from rust.
>>
>> So I put a new Bosch one in and at about 500 km later, it starts acting
>> exactly the same, with a miss all the way up the throttle and basically
>> no top gear or bad shakes in top gear, just like last time.
>>
>> It also dropped to 18 mph highway from over 30 again.
>>
>> I decided to get the codes to see if maybe something else has gone bad,
>> and after reading '12' three times, no more codes came up.
>>
>> The question is should the bad O2 give a code and/or any other
>> suggestions for a no code miss?
>>
>> The engine has new plug wires also and the fluids are all up.
>>
>> Thanks,
>>
>> Mike
>
> Why would you associate the 02 sensor with what sounds like a misfire
> and/or clogged cat problem?
>
> 1990 MY GMs don't have any code capability WRT misfires.

Because it acts exactly like it did a couple weeks ago when the O2 blew
out....

I also thought I read about some shaky Bosch O2 sensors.

Can a vacuum test ID if it is a blocked cat? I have a vacuum gauge, but
my experience is more with 'vintage' vehicles.

It does 'miss' at idle and all the way up though.

Mike

Mike Romain wrote:
> We have a 1990 Cutlass Ciera that blew out the O2 sensor and went into
> limp home mode. The sensor physically blew out from rust.
>
> So I put a new Bosch one in and at about 500 km later, it starts acting
> exactly the same, with a miss all the way up the throttle and basically
> no top gear or bad shakes in top gear, just like last time.
>
> It also dropped to 18 mph highway from over 30 again.
>
> I decided to get the codes to see if maybe something else has gone bad,
> and after reading '12' three times, no more codes came up.
>
> The question is should the bad O2 give a code and/or any other
> suggestions for a no code miss?
>
> The engine has new plug wires also and the fluids are all up.
>
> Thanks,
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 'New' frame in the works for '08. Some Canadian Bush Trip and Build
> Photos: http://mikeromainjeeptrips.shutterfly.com

Wife's Beretta idled like crap for a long time. Was EGR. Replaced with
a junkyard one.

My 2 cents - if it's not tossing a code, you're going to have to go back
to basics with regards to diagnostics.

Does it do it hot/cold/both?
Does it do it at idle/full throttle/both?

If it was my car, I'd do what I did - head on to a wreckers and start
pulling parts. I replaced the IAC and the EGR on the wife's car for 10
bucks and it fixed the problem.

If you pull the front plugs, do they all look the same? Could be a bad
coil?

If you know someone with a Tech 1, there is a way to scan them, but I
don't have an OBD1 scan tool... so I read through the manual and trusted
my gut. Maybe try a junkyard 02 sensor - almost free and if it works
then you'll have found your problem.

Ray

Mike Romain wrote:
> We have a 1990 Cutlass Ciera that blew out the O2 sensor and went into
> limp home mode. The sensor physically blew out from rust.
>

btw, which motor? I have the GM shop manual for the Beretta, so if you
have a motor which was in the Beretta (2.2 or 3.1) I might be able to
give you some useful hints from the manual on what to check.

Ray

In article om>,
Mike Romain > wrote:

> > Why would you associate the 02 sensor with what sounds like a misfire
> > and/or clogged cat problem?
> >
> > 1990 MY GMs don't have any code capability WRT misfires.
>
> Because it acts exactly like it did a couple weeks ago when the O2 blew
> out....

An 02 blowing out wouldn't cause a misfire though the racket might be
easily mistaken for one.

> I also thought I read about some shaky Bosch O2 sensors.

Dan Stern doesn't/didn't like Bosch 02 sensors, I use them because of
limited options in this fair Village, don't see chronic failures though.

> Can a vacuum test ID if it is a blocked cat?

Yes.

> I have a vacuum gauge, but
> my experience is more with 'vintage' vehicles.

Engine vacuum is engine vacuum no matter how old the engine is.
Better would be if your vacuum gauge is a compound gauge that also
measures pressure. Use the 18mm adaptor for you compression gauge and
install it into the 02 fitting in the manifold, connect the compound
vacuum gauge, start the engine and measure back pressure directly.
(no, this won't hurt the gauge if you do it reasonably quickly)
Anything over 3 PSI is suspect.
(note; if there is a Shrader valve in the compression gauge
hose/fitting, remove it for the back pressure test)

The old standard; engine vacuum should be higher at 2000 RPM versus idle
-may- show the clogged cat but it is by no means definitive.
(be sure the EGR is disabled)

> It does 'miss' at idle and all the way up though.

These vehicles were lousy for injector problems, lousy for ignition
problems, both of which as you probably know will cause a cat-con to
plug.

Another thing you can try is to unplug the alternator while running at
idle, if the misfire improves, there's a very good chance that there are
shorted injectors.
>
> Mike

Mike Romain > wrote:
>
> We have a 1990 Cutlass Ciera that blew out the O2 sensor and went into
> limp home mode. The sensor physically blew out from rust.

So how much other rust damage is in there? If the pressure is high enough
to blow the O2 sensor out, you must have hell of a blockage in there, even
if the pipe is rusty.

> So I put a new Bosch one in and at about 500 km later, it starts acting
> exactly the same, with a miss all the way up the throttle and basically
> no top gear or bad shakes in top gear, just like last time.

Check the exhaust system. I bet there's a lot more rust somewhere else,
and I bet it's blocking the muffler or the converter almost completely.
--scott

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

ray wrote:
> My 2 cents - if it's not tossing a code, you're going to have to go back
> to basics with regards to diagnostics.

Yup, guess so.

>
> Does it do it hot/cold/both?

Both
> Does it do it at idle/full throttle/both?

Both

> If you pull the front plugs, do they all look the same? Could be a bad
> coil?

Good guess! Plug #3 is gas soaked, the other two show normal burn.

It is a 3300 engine with a new O2 by the way.

> If you know someone with a Tech 1, there is a way to scan them, but I
> don't have an OBD1 scan tool... so I read through the manual and trusted
> my gut. Maybe try a junkyard 02 sensor - almost free and if it works
> then you'll have found your problem.
>
> Ray

Thanks Ray.

Mike

Mike Romain wrote:
> ray wrote:
>
>> My 2 cents - if it's not tossing a code, you're going to have to go
>> back to basics with regards to diagnostics.
>
>
> Yup, guess so.
>
>>
>> Does it do it hot/cold/both?
>
>
> Both
>
>> Does it do it at idle/full throttle/both?
>
>
> Both
>
>> If you pull the front plugs, do they all look the same? Could be a
>> bad coil?
>
>
> Good guess! Plug #3 is gas soaked, the other two show normal burn.
>
> It is a 3300 engine with a new O2 by the way.
>
>> If you know someone with a Tech 1, there is a way to scan them, but I
>> don't have an OBD1 scan tool... so I read through the manual and
>> trusted my gut. Maybe try a junkyard 02 sensor - almost free and if
>> it works then you'll have found your problem.
>>
>> Ray
>
>
> Thanks Ray.
>
> Mike

O2 sensor will cause all rich or all lean, if you have one plug soaked
and others not look elsewhere for your problem. If you've been running
with a dead hole for any length of time you may have a clogged cat,
which would explain the old O2 blowing out.

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

On those cats if they are burned out they have a big ball in the cat that
rattles around and makes a lot of noise. It can also intermittently plug the
output pipe and not show up in a pressure test. Finding plug 3 wet has
isolated the problem. How about the rear plugs? I think that blowing the O2
is just a distraction and you need to start with the basics. Many people
keep driving for ages with problems showing up and then wonder why it all of
a sudden turns into disaster.


"Scott Dorsey" > wrote in message
...
> Mike Romain > wrote:
>>
>> We have a 1990 Cutlass Ciera that blew out the O2 sensor and went into
>> limp home mode. The sensor physically blew out from rust.
>
> So how much other rust damage is in there? If the pressure is high enough
> to blow the O2 sensor out, you must have hell of a blockage in there, even
> if the pipe is rusty.
>
>> So I put a new Bosch one in and at about 500 km later, it starts acting
>> exactly the same, with a miss all the way up the throttle and basically
>> no top gear or bad shakes in top gear, just like last time.
>
> Check the exhaust system. I bet there's a lot more rust somewhere else,
> and I bet it's blocking the muffler or the converter almost completely.
> --scott
>
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."