ILOVESUBARU Posted September 24, 2004 Share Posted September 24, 2004 what are the "symptoms" of a dead o2 sensor? also i have two KC Daylighters for sale they both work. 30.00 for the set Quote Link to comment Share on other sites More sharing options...
BobBrumby Posted September 24, 2004 Share Posted September 24, 2004 bad gas milage, rough idle, less responcivness, Quote Link to comment Share on other sites More sharing options...
DerFahrer Posted September 24, 2004 Share Posted September 24, 2004 I think I have O2 sensor issues with none of these symptoms (88 XT EA82 MPFI). Here's my problem: Occasionally while I'm driving, the car will stumble, accelerate awfully slowly if at all, and then wake up and surge forward. Also, if I let the rpm's drop below 1000 while I'm pulling away from a stop, the CEL will illuminate until it hits 2000 rpm, then will shut off. The only code I can pull from that CEL is the O2 sensor code. It's a slight MAF sensor possibility too, but I'm not sure why I'd get an O2 sensor code for a MAF-related problem :-\ Quote Link to comment Share on other sites More sharing options...
rallyruss Posted September 24, 2004 Share Posted September 24, 2004 http://www.ultimatesubaru.org/forum/showthread.php?t=22126 this was a good thread on o2 function. the problem you are refering to sounds like its more MAF related. Quote Link to comment Share on other sites More sharing options...
ILOVESUBARU Posted September 24, 2004 Author Share Posted September 24, 2004 whats the difference of MAF sensor problems and O2 sensor problems...how can i tell them apart Quote Link to comment Share on other sites More sharing options...
pwoens Posted September 24, 2004 Share Posted September 24, 2004 also i have two KC Daylighters for sale they both work. 30.00 for the set i sent you an email. I'll take the daylighters for 35.00 bucks shipped to spokane washington. My email is pwoens1@yahoo.com I also have a spare MAF but its out of an 88 gl10 so Im not sure if its the same on or not?? Quote Link to comment Share on other sites More sharing options...
henrysteele77 Posted September 24, 2004 Share Posted September 24, 2004 have you changed your fuel filter lately? Quote Link to comment Share on other sites More sharing options...
rallyruss Posted September 24, 2004 Share Posted September 24, 2004 whats the difference of MAF sensor problems and O2 sensor problems...how can i tell them apart maf sensor failures usually cause the car to run lean. an o2 failure I belive will run rich. o2 will make it run crappy all the time but still drivable. where a maf failure usually will have pinging/ hesitations. the effect are a bit more harsh but can differ depending on what whent wrong. simply disconnect the o2 and drive it. does it get better? worse? you can clean the hot wire mafs but the flaper style ones are internal contact issues usually. Quote Link to comment Share on other sites More sharing options...
Cliptin Posted September 29, 2004 Share Posted September 29, 2004 If a bad MAF is making it run lean then combined with a bad O2 sensor (or disconnected) is should run reasonably normal but with worse than normal gas milage and emissions, correct? What is the correct way to test the MAF? Quote Link to comment Share on other sites More sharing options...
rallyruss Posted September 29, 2004 Share Posted September 29, 2004 If a bad MAF is making it run lean then combined with a bad O2 sensor (or disconnected) is should run reasonably normal but with worse than normal gas milage and emissions, correct? What is the correct way to test the MAF? look at your wiring diagram and find the signal output wire. the maf should output a linear voltage that coresponds to air flow with out any drop outs. a standard meter may not work if the problem is not severe enough. I would not rely on disconecting stuff as a test method. what maf sensor type are you refering to? flaper or hot wire? Quote Link to comment Share on other sites More sharing options...
Cliptin Posted September 30, 2004 Share Posted September 30, 2004 look at your wiring diagram and find the signal output wire. the maf should output a linear voltage that coresponds to air flow with out any drop outs. a standard meter may not work if the problem is not severe enough. I would not rely on disconecting stuff as a test method. what maf sensor type are you refering to? flaper or hot wire? I'm not sure what type it is; I'm kinda new to this. The vehicle is an '85 MPFI non-turbo 3AT. As for the MAF harness and the wiring diagram, the actual wire colors are different from what is listed in the wiring diagram (Haynes) even thought the pin locations appear to match up. Should I rely on pin location or wire color. Quote Link to comment Share on other sites More sharing options...
rallyruss Posted September 30, 2004 Share Posted September 30, 2004 I'm not sure what type it is; I'm kinda new to this. The vehicle is an '85 MPFI non-turbo 3AT. As for the MAF harness and the wiring diagram, the actual wire colors are different from what is listed in the wiring diagram (Haynes) even thought the pin locations appear to match up. Should I rely on pin location or wire color. pin locations should be acurate. 85 mpfi I would guess you have the flapper style maff. if so you can manualy open the maf "door" while watching the signal voltage(key on engine off). do it really slow and watch the voltage increase nice and smooth. If the singal drops out you have a bad spot in the maf. Quote Link to comment Share on other sites More sharing options...
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