alright...haven't been her to update on this...i took the car to inspection hoping to get by...i hadn't repaired anything to see what would happen...it failed the CO portion of emission testing...i would figure that if an o2 sensor isn't kicking on like the computer is saying...that would probably fail it...according to the printout i got it says that "primary systems that affect CO (which is incomplete fuel combustion) include: mixture control, exhuast after-treatment and engine mechanical, o2 sensor and fuel injector/carburetor are common problems. Ignition components, retarded timing, vacuum routing, inlet manifold seals and catalyst become more prevalent causes with age. Check MAP/MAF, TPS, RPM, and CTS Sensors." So, the only thing i'm picking up for a code is 13 which is the sensor not being there or responding....i changed the sensor originally when i got the code...so thats new and i'm still getting the light as i've stated...i attempted to check the voltage but did so at the sensor end of the pigtail and i remember a reading of 1.5 volts...this is off from what you guys said it should be at...should i run a new wire from the o2 sensor to the computer if there's a direct link to it....or is there anything else i should check...
i just ran a diagnostic and now i'm getting a code 34...so the MAF is also malfunctioning...this code is recent...i'm gonna get to work on a few thigns and see what i can do...thanx guys

 

1.5V at the O2 sensor is A LOT. The computer only feeds it 0.450V and it only has the ability to make up to 1 volt. Check the wire for a short to power, if that's accurate. Check it again to be sure. When diagnosing, it's better to check again if you're in doubt that assume that you remember 100%

Either the O2 OR the MAF can be the culprit here. I doubt that the CO problem is because of the O2 sensor though, seeing that if the computer were getting a 1.5V signal back, it run it LEAN and you would fail for HC and NOx.

First thing I would do is to make sure that you have NO vacuum leaks anywhere in the intake tract. The code 34(MAF low frequency/High Vacuum) means that it's reading a lower amount of air entering the engine than is calculated based on RPM and TPS values. If leaks downstream of the MAF are not found, then check TPS voltage and adjust as needed. This is because it's used to cross reference MAF flow numbers so if it's out of whack, it might set a MAF code too. Then you should break out a test light(available at any auto parts store) and make sure that the MAF is getting power and ground. If wither one of these is interupted, then you won't get a signal from the MAF and get a code 34. If all this checks out OK, check the signal wire between the harness connector and the pin on the computer. You'll need really long leads on your DVOM and to find out what pin the MAF is, but I can look that up for you if you need it. Check to make sure that it has VERY low resistance. If everything is OK, replace the MAF itself.

As far as th O2 code goes, Check to make sure that the wire isn't hitting the exhaust or anything else it might ground against and check the voltage with the engine running again. Like I said, better to check than to guess if you're not sure.

Do the MAF stuff first, as that's probably where the CO problem lies, then the O2. Let me know if you need anymore info.

Jeff

 

well...i fooled around with it a little yesterday...i noticed that the clamp on the MAF was loose...so i went to fix it...i pulled out the sensor and the elbow that is on the end of it was loose and the seal was busted apart...which may have been causing a leak...so i used some fenoseal to seal up that elbow because the printed circuit on the MAF checked out...i put it all back togehter...cleared the computer and haven't gotten a code...now...i have a 1985 shop manual with how to diagnose all the codes and how to check stuff...the MAF checks out pretty much...but it said to run voltage check on the connector with the key on...i got a reading of 5 volts there...it said it should be between 1 and 4...then i jumped pins A and C on the connector with a test light and it lit up...it says that if this is the case...there might be a faulty connection...its only saying this should happen though if i'm getting a code and i drove it around after i fixed the sensor physically and haven't gotten one...i got a 40 mile drive home today...and i got my diagnostic with me...i'm gonna see what i get...i set the TPS voltage some time ago...but i'll try it again...and i'll probably fix the o2 sensor problem because i don't like seeing the engine light on when i'm driving...but i'm gonna work on it some more this weekend...and i'll tell you what i've found...

 

The thing that you have to remember is that you have to look in a V6 specific book for MAF testing. Our MAFs put out a frequency proportional to the amount of air passing over them, while the V8 MAFs put out an analog voltage. If you have POwer and ground, then the MAF is most likely faulty.

 

yea...the diagram is for the 2.8 MAF...what do you mean by both power and a ground...shouldn't the sensor have 1 ground...1 reference...and 1 power wire...my skill with car electrical is not the best...but the thing is...i drove all the way home today...and didn't pick up a MAF code...shouldn't i get a code even if its the wiring thats causing it to fail...i always thought so...but like i said...me and car electrical aren't best friends...mechanically i'm better off...thanx again...i'll probably fool around with it this weekend when i get a chance...thanx