98 lesabre,p0133 code,mechanic thinks MAS sensor,but???

[ziggy]

Hi all! Past few weeks,my leaves had given me p0133 code.I have a reader. Bank 1,sensor 1, slow circuit. Erased it,comes back every 4 or 5 days. Mechanic did smoke test today,told me it was leaking,from mass airflow sensor area..I bought the far,craigslist,few years ago,and it was someone's chopjobber. Struts had wood where the mounts are,thermostat middle was missing..replaced the intake gaskets. Tired all chewed up.fixed it up since. He asked me,where I got the MaS sensor from.came with car I told him. He thinks,it's not the correct senor, though it has worked,3 years,up till few years ago.no codes,ect.
What are the chances,it's the sensor?and not the 02 sensor? Looking for some info,before I go buy a new mas sensor. OEM only!did my reading.autozone,a.c. DElco..$124 plus $70 back,when you bring in old one. Looked at top of sensor..just a blue square dot,no factory wording,symbols,nothing.I
Echlin from napa any good?

 

[AutoMechanic]

I’m confused. What is a MAS sensor? Are you referring to MAF sensor or MAP sensor? Generally that code means the O2 sensor is not responding fast enough.

 

[mk378]

Find a better mechanic, or really don't go to any mechanic unless a serious problem comes up. This is the kind of car not to spend any money on unless you absolutely have to, and keeping the CEL off is not one of those "have to" things.

There's no such thing as a "MAS" sensor. Nothing about sensors can be diagnosed while an air leak exists. Again you need a better mechanic(*). But fix that air leak if there is one.

(*) A good mechanic will recognise this as a "you touch it, you own it" situation and refuse to get involved with your car. So you're kind of stuck here.

 

[MParr]

You can throw parts at it all you like and still not fix your problem. P0133 “suggests” an upstream O2 sensor. However, there could be other things at play. I would suggest a certified General Motors mechanic and not some guy with a bunch of rusting junk sitting around his place of business.

 

[ziggy]

Sorry guys! MAS sensor...Mass airflow sensor,is what I was trying too say.he seems too think, it's that. They smoke tested the exhaust system. Told me the smoke,came out from the mass airflow sensor..where it meets the intake.as far as I know,it was torqued down .he seemed too think,the sensor,is for another car. Despite it worked for 3 years since I bought it used.I found out,having the car,someone chop shopped it.

 

[clinebarger]

Without testing the O2 sensors ability to quickly respond to AFR changes...Injecting propane (rich) & Inducing vacuum leaks (lean)....You're guessing.

While monitoring scan data....If the O2 sensor voltage kinda hangs around a 1/2 volt (450mV) intermittently....Suspect a failing O2 Sensor or the O2 Sensor is losing power to the Heater Circuit.

 

[partspro]

Was the MAS new or rebuilt, many MAS, also incorporate the barometric pressure sensor

 

[andyd]

You can pull the vacuum line off the fuel pressure regulator to make exhaust rich . A good O2 dances between .2 and .9 Volts. A bad one runs like Clinebarger says

 

[frankd]

Ziggy how about posting a picture of that Mass Air Flow Sensor?

 

[tiger862]

GM of that Era had 02 sensor problems as they age. Throw a sensor in. 20.00 at rockauto.