With a maf plugged in the car runs very lean an thus pings badly. I cleaned it with a maf cleaner and tried another maf and still pings badly. If I unplug the maf no running lean and pinging. This all leads to a bad connection with the plug. What does anybody alse think?
maf lean on 2002 Chevrolet Camaro
by rich z in Garden Grove, CA on November 28, 2009
2 answers 7 comments
ANSWER by mahindra on November 28, 2009
If you feel that it is running lean it should set a code and turn the check engine light on. What do you base your assumption on? What are the fuel trim percentages, long & short? You could have a timing problem related to a faulty knock sensor, causing the pinging. When you unplug the MAF you put fuel trim, timing and other inputs into a base mode. You have assumed to much just based on unplugging the MAF. Post the codes and I can help you better. Contact me at email@example.com if you want anymore help from me.
COMMENT by rich z on November 28, 2009
I have a scanner to read fuel trims and they read a +12-22 with a mass air sensor plugged in. There +2-3 with maf unplugged. No codes. I
COMMENT by mahindra on November 28, 2009
If you are unplugging the MAF you have to have at least a code for the MAF. You need to drive the car , do not unplug the MAF. when the check engine light comes on then retrive the codes. The fuel trim should not be more than 12% minus or plus. Plus means that the PCM is adding fuel and minus means it is taking fuel out. If you want anymore help from me e-mail me firstname.lastname@example.org
COMMENT by mahindra on December 01, 2009
Listen rich Iv'e been doing this a long time. You are not giving me the answers I need to help you. What is the long term fuel trim readings, what is the short term fuel trim readings. If you continue to leave the MAF sensor unplugged, You'll need alot more than just a little help. If you can't provide me with the proper answers I suggest you take it to a pro before you grenade the ENGINE!
COMMENT by mahindra on December 02, 2009
If you want anymore help contact me at the email above
ANSWER by backyard tech on November 28, 2009
What kind of scanner are you using?
COMMENT by rich z on December 01, 2009
I am using a predator tuner/scanner. I added some lucas fuel system cleaner today and the cars not running quite a lean. Also the exhaust a making a weird nose. Like the sound of blowing through a metal pipe. Exhaust leak maybe?
COMMENT by backyard tech on December 01, 2009
I think for your sake I would pay attention to what Mahindra is telling you.
COMMENT by rich z on December 02, 2009
Update I plugged the mass air sensor back in. I only drove with it unplugged for maybe 15 mins. The other day I got a quart size bottle of Lucas fuel system cleaner, which I've used in the past. In a short time the car started to run not as lean. As far as long trims and short trims here are the following. Long trims are around + 6-12+ cruising, part throttle. The short trims read about the same, but as times go up to +22. Also the exhaust sounds weird once warmed up. Sounds like blowing through as hollow pipe. This noise isn't near the motor, but in the back of the exhaust. Also the gas mileage has taken as big drop. I have checked the spark plugs and they read a little lean. I haven't pulled the front 02 sensors yet. The 02's are switching back and forth as they should though.
Running a little lean with bad mpg and low power. Tried another mass air sensor, tps sensor, fuel filter, checked fuel pressure and for vacuum leaks. Long trims showing +6 to +8 part throttle and w...
My fuel trims have gone lean over time. I have cleaned the maf sensor and checked the fuel pressure and it's good.