2010 cobalt 2.2 mass airflow problem
 

mass airflow reads 0.00 lbs to 0.01 at idle and goes up a few points when i drive but not much. car runs horrible with the mass airflow pluged in. once i unplug it the car runs perfect and no issue. ive tried 5 different mass airflow sensors so i doubt that is the issue ive checked continuity of the wiring because it has a new pigtail on the plug side. any ideas where else to look?

Any codes set and are you tuned?

With the key on you need to make sure you have 12v at terminal C on maf connector and .3 or less ohms to ground on terminal B. I recc using a test light after checking with a multimeter and make sure the light is bright between C and B. Use a incandescent test light, not led. If that's good then you probably have high resistance or loose terminal somewhere between the signal circuit terminal A and the ecm terminal 37.
Attachment 62173
Attachment 62174

A 5.01 v
B 0.00v
C 11.82v
D 0.00v
E 5.00v
these are all with the key on nothing running. also the test light between b and c are bright
terminal A is the yellow wire and ive followed it from plug to plug into ecu and the wire has contiuity so theres no break in the yellow wire

How many ohms are you reading from a(maf) to 37(ecm) with both connectors disconnected?

also when mass air is plugged in the upstream 02 sensor goes from 800 down to 0 and stays there and engine dies

pin to pin reads 0 ohms

using my cheap scanner it reads about 7grams per sec airflow but on my autel it only reads 0.01 so its picking up something. i do have a refurbished reprogrammed ecu mayb a issue in there?

Quite possible, your at the point now I would be breaking out a signal generator to test the and see what the ecm was reading based on what the signal generator puts out. Pretty much your next steps based on signal generator results are replace maf or replace ecm. What mafs have you been using? used? new A/M or new oem?

the first one was a know good maf that worked before i put the motor back in and then 4 other used maf i had laying around for that year of car. they were all oem just used. i mean i guess they all can be bad but hard to believe. i do have my old ecu that was factory just had a hpt tune i could relearn it and see if that reads mass airflow signal?? im not familiar with a signal generator unfortunatly

I would try the other ecm and see what the scanner reads. Maf sensors are picky, if they were laying around open then any dust can ruin the sensor. The signal generator is something we have at the dealer but it is something you can purchase, I wouldn't invest in it though since you wont use one enough to get your moneys worth. Id try the other ecm, and if your still getting nothing then id grab a new ac delco sensor.

ok i will try the other ecu tommarow. i appreciate the info and help. thanks

wont even stay running with the old ecu i am going to order a new ac delco sensor and go from there thanks again for taking time to help i appreciate it

Not a problem, update with the results.

Any intake leaks? Also is this on the factory tune? Possibly the car was tuned for a leak and now you fixed it and the MAF scale is that far off? Just some thoughts.

didnt think about that, curious...

Im doubting its tuned because its a 2.2 but a hole in the intake somewhere after the maf would cause this.

Ive smoked tested it quite a few times thinking it was unmeatered air but no leaks. I do have a code p0480 has to do witj the cooling relay could that cause a stumble at idle?

The computer has no tune anymore its a new refurbished reprogrammed ecu i used. Thinking the ecu was bad

i believe i found the issue. the hose comming from the brake booster to the intake i used an elbow to connect two lines together and didnt notice is was a one way valve