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MAF Sensor

O

OSO86

Guest
I have an '86 coupe with an auto trans. This past weekend I was cleaning up my plugs and around the engine compartment. I took off the air cleaner element and the MAF sensor and cleaned them up. After I put everything back together, my car would not idle and the "Check Engine Soon" light stays on. After I get it started and raise the idle manually, it runs but if I let up on the throttle it quits. Anything below 800 RPM and it dies. Did I break my MAF in any way? Thanks for any help.
 

BigRed

Well-known member
Joined
May 23, 2001
Messages
948
Location
Edmonton
Corvette
1985 Bright Red Rocket
UH OH! Im thinking you bent that microscopic wire in the MAF!!
My guess is you just spent 300 bucks.

Before we panic:

Did you AT ALL Break or undo any Vaccum lines?

Is the Air tunnel on properly? Is it off mabe just a little?

Are your spark plug wires on fully?

Did you (Plug) a spark plug while cleaning them?

Check your wires mabe you shorted one (If they're old)

Check the Dist. Cap mabe you pulled a wire off

And Check around for and wire harness that may have let go while you were doing your spring cleaning.
 
F

Fastvette86

Guest
Unplug the MAF and start your engine. If its runs smoothly, then you have a bad MAF. With the MAF unplugged the engine runs on the internal fuel/air map in the computer - limp home mode, which doesn't give you the best performance, but it will idle well and get you home.

Dennis
 
O

OSO86

Guest
Thanks for the ideas and info. I took the MAF off again and looked at it and all of the fine wires are intact, I reconnected it and started up the car and the "Check Engine Soon" light did not come on, it also idles fine now. Who knows, maybe one of those things. One thing that does still happen which is unrelated is that sometimes after driving the car for awhile the "Check Engine Soon" light comes, but after shutting off the engine and restarting the light goes off. It does this occasionally especially if I drive over 75mph for a sustained time. The car runs great apart from this.
:w
 
F

Fastvette86

Guest
OSO86

You should check the codes in your computer. Check out your manual to see how to get the codes out of it. Using a alligator clip jumper is the simplest and cheapest to jump the two terminals on the ALDL that's just under the dash to the right of the steering wheel.

I love these cars because with the computer codes they'll tell you why they are sick.

Dennis
 
E

Eagle85C4

Guest
Mine did the same...check engine comes on then goes away after restart. Codes say problem is with knock sensor....sensor is good, problem was loose connector to sensor. Cleaned and tightned it up...no more light.
 
Joined
Oct 30, 2001
Messages
2,273
Location
Glen Burnie, MD, USA
Corvette
1986 Bright Red Coupe
86! Good year :).

Definitely see what your check-engine code is. Procedure is simple - take the cover off the ALDL connector (as someone said, under the dash between the steering column and the center console) and with the key OFF, put a piece of wire between the upper right two connectors. Then turn the key to RUN, but don't start the engine. Your check-engine light will flash once, pause, twice, long pause, and repeat two more times. This is a "12", meaning you're in diag mode. After the three "12" sequences, the next flashes will be the numeric codes. It's always 10's place, pause, 1's place, long pause, repeat twice. When it's done, it'll spit out another three "12"s. Then turn the key off, take the wire out, and disconnect your battery for 10 seconds to clear the codes (unless you want your mechanic to verify them). Post the codes here or look them up (I think there's a section in the Knowledgebase that lists them).

I just read a 42 and 43 from mine today - the 42 was probably from setting the timing, but the 43 is pointing to the knock sensor.
[RICHR]
 

Paul G

Well-known member
Joined
Aug 27, 2001
Messages
200
Location
Griffith, IN, USA
Corvette
96 CE LT4 Convertible
I had a similar problem with my MAF sensor. Code 34 I believe. MAF was fine. The plug conection was dirty. Take some contact cleaner and spray the contacts in both plugs. You can get it at radio shack. Clean the wire side and the MAF side. Use some rags to catch the overspray and drips. Dont let it get on paint or other plastic parts. Then when you plug the MAF back in give the conectors a nice firm wiggle home to be sure the contacts are seated together well. Should take care of the problem if it is just dirty conections.

Good luck.
 

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