Well i just replaced my maf about 3 months ago. Now its spitting a code 44 at idle when in gear. (Lean exhaust indicated) The idle is really choppy, bobs between 350rpm up to 550 in gear. The o2 sensor is probably going on 6 months old. I've also noticed that my voltage is all over the place as well. The idle will bob as the voltage bobs as well. I just put a new powermaster 140amp alt in it to run my 12" subs and alpine deck, when im cruising around it'll run at about 15 volts on the guage. Isnt this a little high?

 

code 44 may indicate you have an vacuum leak somewhere. it could be a vacuum hose has fallen off or leaking. either the intake bellows (rubber boot after maf) has a small tear or a runner to plenum, runner to base gasket has failed. even the intake base gaskets can fail.

you just got go over all the vacuum lines and make sure they are connected and make sure they are not torn. if they look old and leave your fingers black after you touch them, replace them.

 

Other possible vacuum leaks are the PCV system, brake booster, EGR valve, and CCV/EVAP system. Of course, gasketed joints should be included, but that is a "given".

Other possible "44" causes are:

• A leak in the exhaust system;
• Leaking or faulty A.I.R. system;
• Poor electrical connection (including ground) at the O² sensor;
• Low bias voltage to the O² from the ECM;
• Contaminated or otherwise failing O² sensor;
• Low fuel pressure;
• Clogging injectors;
• Poor injector spray patterns;
• Incorrectly set TPS;
• Incorrect injector timing or FI constant in a custom programmed CALPAK.

I'm sure there are others, but those are relatively easy tro check.

 

Check your fuel filter, it might be clogged. Blow in it. If you can't blow through it then it's failing.

 

sounds like your 02 i bet that's your problem replace it again

 

ok, well i just replaced the o2 sensor, fuel filter, pcv valve, checked all the vacume lines and everything looks fine. I recently had the fuel injectors serviced by the fellas over at TPiS, flow tested em and put new screens in them and what not. I also bumped the fuel pressure up to 45psi. Its still spitting code 44 when im stopped at a light in gear. The idle will begin to stumble and trys to stall out then the SES light will appear. Does this sound like it could be the IAC valve sticking? Cant seem to find any leaks in the exhaust either. I did have the AIR pump disconnected for a short time without the cat. But about a year ago i hooked it all back up for emissions, and it worked fine. I also installed a set of SLP runners a couple months back with new gaskets. Any suggestions would be greatly appreciated.

 

I was just browsing the web when i stumbled upon this:

http://www.troublecodes.net/GM/86-89_50F.shtml

and it specifies the follow for a code 44

Oxygen sensor voltage was under 0.2 volts for 50 seconds of closed loop operation.

In my code book that came with the diagnostic tool it just states lean exhaust indicated. How would I go about fixing the voltage to the o2 sensor? I just replaced it so I know its good.

 

same with me 2 codes come up 32 and 44 its not running good cold and runs rough when its warm. it backfires through the intake and idles between 900 and 1000 in park sometimes it stalls when cold. when it is warm in drive when i accelerate it hesitates then it is good it idles low in drive. the transmission is fine not like that matters, Heres what i did to it
Replaced:
the mass air flow sensor
O2 sensor
Electronic Spark control mod.
Wires
plugs
distributer cap
rotor
air cleaner
oil change
fuel filter
oil filter
adjusted the timing my car is a 1985 trans am 305 tpi i also cleaned the throttle body

 

You "fix the o2sensor voltage" when you find the problem.

I'd suggest this in addition to the things Vader has already mentioned. If you have access to a scanner or you can use a good voltmeter. Disconnect the MAF sensor and watch your o2voltage. If it goes back up you likely have a defective MAF regardless if its new. They're pretty temperamental. Besides by your original post the problem started after the MAF was replaced.
Also if your idle smoothes out with the MAF disconnected it's probably gone south.

 

Check #4 on the list - "Low bias voltage". If the O² doesn't receive the 450mV bias from the ECM, the output signal can be interpreted as low (lean). Diagnosis of this would also include testing all ECM and engine grounds - half of the circuit used to bias up the O².

 

Excuse me, How do you check to see if your injectors are clogged? I am having a similar problem.-Mike

 

Welp I've been trying to deal with this issue for the past 6 months now. Still stalling at lights and spitting a code 44 (lean exhaust at idle) I've replaced the following parts:

o2 sensor
maf sensor
IAC valve
fuel filter
pcv valve
intake gaskets
ignition module

Still with no luck, i took it to a shop yesterday, they ran a leakdown test on the fuel injectors said the swing & voltage at the o2 sensor was good, voltage & swing at the MAF was good. No vacume leaks. The only issue that was aparent was that with the ignition on it wasnt pressurizing up the fuel rail. Makes for difficult starting. Then when the motor is turned off it doesnt hold pressure. I had the fuel pump replaced about a year and a half ago. Machinic told me they are stumped, after dropping another $200 im back where i started Im not quite sure as to what to do next, any suggestions would be greatly appreciated.

 

Have u ever bothered to test continuity fo the wires for the ecm ground to the ecm and the 02 wire to the ecm?

Seems like it is the only thing that you are missing?

Is the ground strap broken or loose?

I have seen alot of busted ecm grounds on TPI cars cause codes relating to the 02..

later
Jeremy

 

Have u ever bothered to test continuity fo the wires for the ecm ground to the ecm and the 02 wire to the ecm?

Seems like it is the only thing that you are missing?

Is the ground strap broken or loose?

I have seen alot of busted ecm grounds on TPI cars cause codes relating to the 02..

later
Jeremy

 

ground straps are tight and appear to be in good condition. Im not sure where the "ECM grounds" might be at. Im going to try the TSB on the 86 LB9 prom maybe Ill find something down that road. How do I go about testing continuity on the o2 wire? When the shop did a diagnostic on it said the voltage and swing on the o2 was good.

 

hey, jw if you ever got your problem fixed cuz im pretty sure i have the exact same problem now for about a month... ever since i installed new injectors to replace my old leaky stock ones. let me know, thanks!

 

My car justr started this today

 

I recently replaced the fuel pressure regulator diaphram, reset the minimium idle speed, and havnt experienced the problem sense. Its been fine for about 2 weeks now. I think part of the problem may have been the vacume port on the fuel pressure regulator. The kind that i bought is the TPiS and the vacume nipple just screws into the housing and that had vibrated a little loose. I went ahead and replaced the diaphram while i was in there and it seems all good now

 

my problem ended up being my ECM lol.... figures

 

How do you know or diagnose that it is the ECM? How much to replace?