Pneumatic_Tire

Hey guy's heres the lowdown. 1986 Camaro 305 tpi. My Camaro has been throwing code 34 and 33, and 44 for some time now, and I suspect the MAF sensor is going bad. I have tried different relays to no avail. Heres what my cheap autozone scanner reads.

Engine Idling-

MAF GR/Sec- ranges from 247 to as high as 1036 at idle. It should stay consistent and not move much at all correct?

Here's a couple others i would like to know if are in spec, since I don't know much about what the specs should be for our cars.

Injector pulse width reads 91-96 at idle

BLM- 130

O2 crosscounts-86-172

O2 sensor is constantly reading lean. I know thats not right for sure.

Now yesterday I took off my Throttlebody, removed the IAC, cleaned it as per Vaders instructions, cleaned the heck out of the TB butterfly's, and the IAC passages. Reinstalled the IAC and T/B with a new gasket. Reset TPS to .54 volts at closed throttle. Reset Min air idle as per vaders instructions, and the car doesnt want to idle on its own 98% of the time. I unhooked the PCV hose, and it idled on its own since more air was being sucked in i guess. Car is still throwing MAF codes 33 and 34 and 44.

Please help me guys i need my car!

quickchicken

your BLMs are reading lean, 128 is what ya want. i would check the coolant temp sensor. that lil sensor affects ALOT of its running. it has a few differnt metals in it and will expand and contract upon diff temps. this sends signals to the ECM telling it what temp the motor is at.
my 86 S-10 was running crappy at almost the same amount of run time. after thinking about it i changed the CTS and all was cool imidiately.

92blue

Pneumatic_Tire, what condition is the MAF connector in? If it is damaged, it could be the cause of the contradictory code 33 and 34. The code 44 is a result of the MAF signal problem.

The car should run (not great, but should run ok) if you disconnect the MAF completely. You can do this if you want to check/do any work but the car keeps stalling.

Although, a BLM of 128 is ideal, 130 is pretty good for a high mileage (assuming from it being an 86), stock promed car. Don't worry about that, or the CTS sensor at this point. Theres no reason to suspect its bad. A bad CTS would make the car run pig rich, but the car is running lean.

Like I said before, make sure you don't have any bad connections, stripped wires, etc... Then check the inputs/outputs to the MAF with a voltmeter. If you need help doing this, send me an email to tpi_parts@yahoo.com. I'll explain it in further detail.

92blue

Forgot to mention one thing with the BLM. So long as his O2 is reading so lean, the car will stay in open loop. So long as that happens, the BLM will not be modified. The current BLm thats stored in memory, is most likely from way back before the problem started. Its not very useful to make note of it at the moment.

raul.garcia

I don't think Vader would instruct anyone to set the TPS first. The minimum air needs to be set first, then the TPS.

Pneumatic_Tire

I don't see how that could have a difference in outcome. Elaborate? I'll try resetting them in that order.

92Blue, thanks for the response, I do indeed have a broken connector to my Maf sensor, it's retainer clip snapped off, and a wireing repair was done to it. I'll have to check the voltage and what not. I'm gonna drop you a email if you could please give me some tips on how to step by step check it out, It would be greatly appriciated.

quickchicken

the reason i sugguested the CTS is code 44 is oxygen sensor lean. thats what came up on my 86 S-10 when the CTS was giving me fits. i can see where if the MAF plug was in bad/poor shape it would cause a lean condition as the ECM only sees the fuel its putting in and would pul the mixture back.

2fbodies2NV

It doesn't matter if the engine is sitting on an engine stand. If you set the TPS while the car is skidding down the road on its roof, it'll STILL be at whatever you set it at at closed throttle.

Looking at the temp on the scanner, you'd know whether the CTS was bad or not.
Like 92blue said, unplug the MAF and try to run it. I'm guessing from past experience it'll run rough at a little higher idle.

RedIrocZ-28

Code 44 is MAF sensor, go to auto zone and buy a Bosch Unit. Do not get the cheapo replacement. They're about $20. That will clear up 1 problem. As for the car staying in open loop if its constantly lean.... huh? There is a closed loop threshold temperature set in the eprom, IIRC its 143* for a stock vehicle. After that temperature, it will stay closed loop until the engine is shut off. The only time that a car will fall out of closed loop is the newer OBD-I and OBD-II cars who have a pair (or 2 pairs) of heated O2 sensors, when the temp falls below a certain point the PCM will default back to open loop until the temperature rises to the preset limit.

Dave89IROC

okay.......

Brad, a MAF for that car will cost $162.99 from Autozone, and it has a $80 core charge.................



and 44 is a O2 sensor code, 33 and 34 are MAF codes

91-Z28-L98

If you set the TPS, then adjust the minimum idle air, you will change the value of the TPS from where you set it. Thats why you would change the minimum idle air first, then set the TPS.

2fbodies2NV

Umm, no. If you set the TPS at CLOSED THROTTLE, NOT IDLE, it doesn't matter if you set it before you bolt the throttle body on. It will not change.

CrazyHawaiian

I'm gonna take it a step further and say dont adjust the minimum idle. I recently had to replace both my IAC and TPS and I didnt touch the minimum idle. I just made sure the IAC was the proper length (28mm from tip to flange), and the TPS was set to .54v with the throttle plates closed (aka at idle) and everything works great. While troubleshooting I thought about doing the minimum idle procedure, but decided against it. I figgure it would only need to be adjusted to compensate for faulty IAC/TPS or the IAC/TPS at the wrong settings. And since I was putting all new stuff and setting it up correct, no adjustment was needed. Turns out that was the case. Of course I was lucky, the rubber cap was still on the minimum idle screw, appears it had not been touched since the factory set it. If the cap is missing or you already adjusted it, then you probably need to adjust it.

To the original poster I would unplug the MAF and see how the car runs. And I would also replace the 02 sensor since its a cheap fix and cant hurt. I would also check the PCV valve and make sure it is working properly. If the car is acting different with the PCV unplugged it could indicate a vacuum issue. So might as well get the vacuum guage and make sure the vacuum is good.

92blue

There are O2 Qualifiers that will not allow closed loop unless the O2 is fluctuating across the range. Its not just timers and the cts which determine closed loop operation. I can post the assembly code if you like.

In addition, there is no code for a baf MAF sensor. The only thing that codes say is that there is an unusual situation causing a problem. Codes are helpful in diagnosing and tracking down the source of a problem. It does not mean, that the MAF is bad, the ecm has no way of knowing that.

Code 44 is oxygen sensor reading lean, not MAF related. I think you meant $200 instead of $20 though.

As far as setting the TPS after minimum air, the TPS will move slightly when you adjust minimum air. Think about it for a sec. When you adjust minimum air, you adjust the position of the throttle blades when the throttle is closed. The TPS is attached to the throttle blade axis (not sure what to call it?) and will move slightly when an adjustment is made. Granted, it will most likely not be a significant change, but it will change.

RedIrocZ-28

Lol, do I feel like a Jerk. Dave, you're right. I meant to say O2 sensor. I had the exact same problem with my car before when my O2 wire splice went awry. I screwed around changing things because I was sure that the BRAND new O2 wasn't bad. 4 months later, I decided to grab a new O2... problem solved. My specific problem was from the O2 shorting and constantly reading sub .450 volts. I.E. showing a constant lean condition. What it would do is dump fuel into the motor at idle, to the point that it tried to sputter out and die. I had to keep 1 foot on the brake and one on the gas at a stop light to keep it running. This was compounded by a bad TPS sensor reading a flat spot right off idle... blades open 20% but still show closed. Wow... that was fun almost getting creamed when making left turns.