Nice pics.

Yeah, these engine compartments sure are cramped!

 

Yes they are. At least my vehicle is. I hope my pics help someone out who was trying to change the radiator in a vehicle same as mine. Now I have another issue I have a check engine light on. The first code to show was a P0446 evaporative emissions system vent control circuit. That came out when my evap monitor completed. When I continued driving the car two more codes came on. One is a P0420 catalyst system efficiency below Bank 1. That came on when the catalyst monitor completed. I also have a P0101 Mass or volume air flow A circuit range / performance. Which of these codes should I address first? Again this is a 2002 Chevy S10 Blazer ZR2 that we are talking about. I appreciate any and all help. Thank you. Have a gr8 day.

 

Lowest numbered codes first.

Since you have had the air cleaner box out, i would make sure the snorkel in front still goes through the radiator support and is not bent over, shutting off air flow. I did this myself once!!

 

Thanks Les. Is the snorkel the plastic piece attached to the front (facing the front of the vehicle) of the air filter box? I will start with the lowest code. Any suggestions of what to check for for that P0101 code?

 

Yes, that is it. If bent over that could set a P0101.

For the P0101, first clear the code and make sure it comes back. Then using a scan tool check MAF sensor reading at idle and then again at full throttle 1-2 shift. Report values here.

 

Thanks for the info. I bought some mass air flow sensor cleaner and plan to use it on the MAF system. Do you recommend doing that? What kind of scan tool are you referring to? I want to use a smoke machine to try to locate any leaks in my evap system, P0446. Where is the best location to put the smoke into the system? Is there a better way to find the cause of the evap code P0446? I have checked the O ring on the gas cap and it looks good. I put some syn lube on it to keep it supple. What else should I do plz? Thanks again for all of your help. Hv a gr8 evening.

 

I recommend getting a capable OBD2 scan tool and diagnosing the P0101 before trying to clean the MAF sensor or worrying about smoke machines and the other codes. You're shooting blindly in all directions at once. Don't do that!
Will your existing scan tool monitor live MAF? Its one of the most basic things for OBD2 scanners to do.

 

 

Hi Les. I believe it did. I used an Actron AutoScanner Plus reader and found the MAF sensor reading. I will send you a couple pics and hopefully a vid of what it said. Couldn't send vid. So pic 1 car off, pic 2 and 3 idle, pic 4 and 5 2200 rpms...double idle. Did I do this correctly? Plz let me know what this means about my code P0101. I expect that it has nothing to do with the two other codes. As you say one code at a time. Thanks again for all of your help always. Hv a gr8 day.

 

Did the P0101 come back after you cleared the codes?

Yes, you found the MAF sensor reading.

For a given RPM it makes a big difference on whether you are at high vacuum (holding steady with pedal) or at full throttle. All your measurements so far are at high manifold vacuum.

Normal idle speed on a Blazer is about 550 rpm and MAF should read about 4-5 g/sec at that idle. Yours is 1.61 LB/min (on your scanner) @ 900 rpm = 12.2 g/sec. If you ratio that down, yours would be 7.4 g/sec @ 550

I would say MAF seems to be working but possibly reading a little high. We can ratio down the reading at 2100 rpm and check it too. 2.85 lb/min = 21.5g/sec @ 2100 rpm. If you ratio that down yours would be 5.6 g/sec @ 550 rpm. So in that case it would be normal.

The other thing you need to do is to watch for highest MAF reading on a full throttle 1-2 shift. Please report.

Also, does it always idle at 900? What about in gear? Should also be about 550.