When you say hesitates do you mean it lacks power? If so if the PO had run it for awhile with a bad MAF it could have plugged your CAT... it happened to my '03 Astro... put in an aftermarket Magnaflow and a new MAF and it's been running fine since.

 

No it cant be the cat because it gets all its power back as soon As I unplug the maf. And yes big lack of power.
So it might not be the maf sensor of tps but I feel like there is something wrong when its running close loop but if I unplug it then it goes open loop and runs fine.
What other stuff is reading when in close loop?
Could it be a cracked booth after the maf?

 

Check your voltage and ground at the MAF harness. If you bought a brand new MAF, then the signal is throwing the computer off. Makes sure you are getting the proper voltage to it and out of it. The 5v reference signal should change as the engine runs..http://easyautodiagnostics.com/gm/4.3L- ... f-sensor-1

 

I did not buy a brand new maf but a used one but Yeah I did all these tests with both maf. As I said I have a good OBD2 reader and can see all the datas. So yes voltage varies with rpm. Ground is good and 12V is good. Dont really know what else to check.. I really dont think my problem is the maf sensor itself.

 

Whenever I have a MILF related problem, I usually sta...Wait...Oh sorry. I misread.

Lump

 

What are your 02 sensors doing? If it's running better in open loop, then I'd look at everything that isn't monitored in closed loop. That would include the 02 sensors, map and MAF. Closed loop means that the computer uses the parameters the engine ran on the last drive cycle the best, with input from the coolant temp sensor and air intake to adjust the mixture for cold or hot starts.

 

but the code that the reader is showing is Maf circuit signal low.. I don't see how it could have some to do with 02 sensor. I will check my MAP tho. What are the normal values I should get for the map?
I will check my signal wire from the maf to the ecm to see if any weird resistance shows up.
Is it normal to have a reading of 1.92g/s when engine is turned off? Shouldn't it be 0g/s?
Any other idea?
Thanks

 

Yes, it should read zero. Did you check voltage and ground by back probing or with the connection off the MAF?

 

Map should show atmospheric pressure when the engine is off.

 

at idle MAF should read 4.6 g/s and MAP should read 1.46 volts or 38kpa.

 

at idle MAF should read 4.6 g/s and MAP should read 1.46 volts or 38kpa.

okay good thanks, I think I've got about 6g/s at idle. Is that too much off?

 

Yes, it should read zero. Did you check voltage and ground by back probing or with the connection off the MAF?

Yeah I checked voltage and ground and was fine. What should I read on the yellow wire on connector (signal) when the engine is running and connector unplugged? 5V? or 0V ?

 

Well, I just had the same issue. I actually pulled the cables off the battery and shorted them overnight to reset the computer. I also pulled every piece of the intake tunnel off and reassembled everything nice n tight. Problem was gone the next morning.
I can't say that will do anything, the Bat Van has sooo many problems right now its like trying to figure out exactly which one of the photon torpedos knocked out life support.. don't much matter at that point.

I'll try to look up the test procedure in my FSM tonight and repost it.

 

Well, I just had the same issue. I actually pulled the cables off the battery and shorted them overnight to reset the computer. I also pulled every piece of the intake tunnel off and reassembled everything nice n tight. Problem was gone the next morning.
I can't say that will do anything, the Bat Van has sooo many problems right now its like trying to figure out exactly which one of the photon torpedos knocked out life support.. don't much matter at that point.

I'll try to look up the test procedure in my FSM tonight and repost it.

great thank you!!

 

Crap, sorry forgot to look it up. I'll set a reminder... stand by.

 

Crap, sorry forgot to look it up. I'll set a reminder... stand by.

No worries. I am thinking it could be my MAP as well but I cannot find what values I should read when testing it. Anyone has an idea?

 

Crap, sorry forgot to look it up. I'll set a reminder... stand by.

No worries. I am thinking it could be my MAP as well but I cannot find what values I should read when testing it. Anyone has an idea?

I think the manual covers both, I'll check.

 

PM Sent

 

So the code that is popping now is p0101 Maf circuit out of range.
The maf reacts well when I hit the throttle. The only datas that I've seen that are "out of range" would be the frequency. So as per the specs I found, frequency @ Idle should be about 2300Hz and I have 2500Hz.
@ 2500rpm should be 4200Hz and I have 3928Hz (@2518rpm exactly).

Do you think that is too much off?? Because the readings in g/s are good (5.87g/s @670rpm.

 

Buy a new MAF... If you've been having MAF issues and your getting codes bite the bullet and change it. If you run it too long with a bad MAF you WILL end up plugging up the Cat (ask me how I know).

 

Try manipulating the wiring to the MAF while you are checking voltage....but more importantly, it would be good to see the live data attached to the MAF code to see what the MAF is reading and RPM. If you have an internal wiring issue with the harness, it may just be getting stressed and causing the MAF to drop out of range.

 

Philippe, if all else fails, here's a new MAF at Rockauto for $46 with 2 yr warranty
http://www.rockauto.com/en/moreinfo.php ... 33&jsn=499

 

Buy a new MAF... If you've been having MAF issues and your getting codes bite the bullet and change it. If you run it too long with a bad MAF you WILL end up plugging up the Cat (ask me how I know).

Well since I've tried another MAF and had the same problem I wanned to verify few things before spending money on a new one. Also I have the tools to check the datas and they seem pretty good. This is why I am questioning so much about the faultiness of my actual sensor.
This being said, I thing I am at the point where I wanna try a new one. Any brand to recommend? I found a Dorman one for about 90$ Canadian (65$US). OEM will be over 200$ for sure.

 

Do you have access to a scan tool that can read live data? I'd like to see the values in the freeze frame data

 

Buy a new MAF... If you've been having MAF issues and your getting codes bite the bullet and change it. If you run it too long with a bad MAF you WILL end up plugging up the Cat (ask me how I know).

Well since I've tried another MAF and had the same problem I wanned to verify few things before spending money on a new one. Also I have the tools to check the datas and they seem pretty good. This is why I am questioning so much about the faultiness of my actual sensor.
This being said, I thing I am at the point where I wanna try a new one. Any brand to recommend? I found a Dorman one for about 90$ Canadian (65$US). OEM will be over 200$ for sure.

Do you have access to a scan tool that can read live data? I'd like to see the values in the freeze frame data

No I don't have a scanner... If all your wiring checks out and you aren't able to get readings and getting a trouble code from the MAF I would assume it's toast. I've never had any luck with a used one or cleaning it. My last 3 vans have all had MAF's go bad... 7 total... And once never set a code until after my Cat was toast as well. I don't remember which brand I got last time. Hopefully it clears up your issue. Good luck and let us know how you make out