Seem to have an issue with my 2001 3800 Series II Supercharged engine. the code P0102 which is low mass air comes up, that is the only code. The motor will actually STOP going down the road. I have performed a lot of checks and so far no proof that the Mass Air sensor is bad. Some say to unhook the PCV valve and block it off and then check for a vacuum in the dip stick, BUT the Supercharged motor is not set up with a hose and such as a normal aspirated motor is. The Supercharged 3800 series II has a black plate on top of the Supercharger and has two #10 bolts holding the plate on. Under the plate is a spring and the PCV unit. A smaller hole goes to the Supercharger while the larger hole goes down into the plenum, ( Intake ). I did just try to check on item. I removed the PCV valve and plugged the end of it to eliminate the passage of air from the plenum to the Supercharger. I put the plugged PCV, spring and plate and bolts back on and started the engine and it ran GOOD. I then removed the plugged PCV valve and reassembled the PCV as to it’s normal configuration and it was back to normal, not running good,but what did I prove by doing this test? I thought that this test may have proved that the (lower intake manifold )was not leaking, but not sure right now. I removed the Mass Air and I do have resistance between the + and -, so that part is good, but I know that is not the full answer as it could still be bad. Replacing the Mass Air is about $150.00 for this one. I am just not sure the Mass Air sending unit is BAD at this time. No vacuum leaks on or around the outside of the supercharger or plenum as far as I can notice and no vacuum lines leaking, I replaced the main one already. Many people on the normal everyday car forms do not understand that there is a big difference between a normal aspirated 3800 and a Supercharged 3800.
The PCV valve (Positive Crankcase Ventilation) doesn’t connect to the plenum. It connects to the crankcase to ventilate it. If what you plugged does connect to the plenum, its function is something else, and it’s not a pcv valve. Once you determine what you really plugged, you can go to the next step.
If you want to do your troubleshooting in some kind of organized way, you could get the troubleshooting charts from some service like www.alldata.com. It will cost you $25 for a year’s subscription; but, you could, easily, blow much more with guessing at repairs.
What I plugged, was the PCV Valve, no the test did not constitute anything, it was just a test that a certified mechanic said to try, I guess he did not think of this motor being a supercharged motor even though we discussed it in detail. Your statement on the PCV and not knowing what I plugged is in question, but no biggie. Most people do not understand that the Supercharged motor is not the same as the non Supercharged Motor. The point that I was trying to make is that if this is the Mass Air Sensor I wonder why more postings have not been made on the forums as this should seem more like a common problem. I think a better scanner may have helped a lot more as the one I picked up did not tell much other then the code.
I do appreciate your time to respond to my question. If someone was to take this same vehicle to a repair shop it could cost them an arm and leg. I do not guess at repairs, that is why I posted the question and that is why the car is sitting and I am not just ripping it apart to replace parts. I have looked at a lot of of the trouble shooting guides for this code. Auto Zone even has a print out of all of the items that COULD cause this CODE, but again, well I will not go into it.
Thanks again for your reply.
I know that you have a Bonne, but check out
They are renowned as one of the best GM 3800 (NA and Supercharged) forums on the net. I have little doubt that they will know exactly what’s going on.
Best of luck.
This article may give you some ideas: http://www.justanswer.com/questions/15q9q-dtc-code-p0102-checked-mass-air
And, this one: http://www.obd-codes.com/p0102
You can look at the output of the sensors, such as MAF (Mass Air Flow) sensor, with a OBDII scanner such as this: http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=98614 On the page, you can scroll down to Download Product Manual to see what the scanner can do, in a 79 page manual.
The DTC (Diagnostic Trouble Code) P0102 indicates low air flow; but, when you blocked the pcv valve, which (further) reduced air flow, the engine ran better. This is counter-intuitive. So, the scan tool could show what the MAF is actually indicating to the engine computer.