My car has thrown a MAF code since I bought it, but last night it displayed
all the classic symptoms of a bad MAF. The car ran BAD, barely giving me
enough power to move until it got going. Then it would shut off when I
lifted off the gas and came to a stop. The engine light was on the whole
time. Well I got home and unplugged the MAF and it ran fine. Now today I
went to pull the codes to make sure it was the MAF. It won't flash codes.
You are supposed to connect the last (far right) terminals of the first and
second row together and then put the key in the on position, right? Well
should I ignore this or does this mean the computer could be bad instead of
the MAF?

Stephen Cavallo
1988 Chevrolet Camaro, 305 TPI, 5speed

 

Connect the top right terminal to the terminal directly to the left of it, not the one below it. Then turn the key to run but don't start it. It sounds like you got the wrong two terminals jumpered.

 

Sounds like a bad MAF to me. To check the codes, the 2 upper right terminals on the ADAL need to connect, nothing with the bottom row.

------------------
Rob
'86 TA 305 TPI
Gutted MAF
Ported Plenum
TB Bypass

 

When I connect the two on the top row, (farthest right), the fans come on but nothing is blinking.

 

Rumir,

Make sure the MIL lamp comes on when you turn the ignition on (no jumper). Actually, watch the light before you turn the key to RUN. The lamp should turn on for about a half-second, turn off for about a half-second, then turn on and remain on until the engine is started.

If the lamp works, procede to the code scan.


With the engine and ignition turned off, locate the ALDL connector under the dash, just to the right of the steering wheel in the driver's foot well area. There should be a small rectangular cover over the access hole in the lower dash trim.



Insert a tool as described above (paper clip) into the 'A' and 'B' terminals on the ALDL connector:



WITHOUT STARTING the engine, turn the ignition to the "RUN" position. Watch the Malfunction Indicator Lamp (MIL) and it will begin to flash. This is also commonly called the "Service Engine Soon" or "SES" lamp. The first code will flash three times, and will usually be a code '12'. This is encoded by one flash of the lamp, a brief pause, then two successive flashes of the lamp. Each code will repeat three times, so you should see a "Code 12" flash three times. Any other error codes will follow in numerical order, and each code should flash three times. After all codes have been displayed three times, the "Code 12" will again flash three times, then all other codes will follow as described earlier. This cycle will continue until the jumper is removed or the ignition is turned off.

After you have made a note of all error codes, turn off the ignition and remove the jumper immediately. If you forget to remove the jumper and attempt to start the engine with it in place, you could damage the ECM. For this reason you should remove it immediately.

Once you have a note of all error codes, check this file for the decoding:

GM Error Codes.pdf.

You'll need Adobe Acrobat Reader to open/print the file.

Incidentally, before you condemn the MAF sensor, check the MAF power and burnoff relays. If you have to replace the MAF, you should replace the power relay anyway. You should also check the intake ducts and plumbing for cracks and openings that would allow unmetered air into the engine. This includes all vacuum lines, brake booster, the PCV system, and requires that you DON'T have a breather-type oil filler cap.

------------------
Later,
Vader
------------------
"No matter how hard you try you can't stop us now..."
Adobe Acrobat Reader 4.0