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Old 03-04-2008, 03:10 PM   #1
plugged.in
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Default 99rs wont run with MAF

I have a CAI (by the way) into MRT EL headers, and sti exhaust
only mods.
-----------------------------------
This morning, after i enter onto the whitemud from 159st, I change lanes from middle to left. While doing so I stepped on pedal to make my vaginamatic shift down and speed up. It certainly did shift down. but morelike a dirtbike shifts down into 1st while going down a steep hill. The car slowly went from ~4kpm down to 1, then I came to a stop and the car ishtay off.

I was in the shoulder*ish part of the left lane on the whitemud in between the 2 overpasses.

Car would not stay running for +2 seconds. It will start, idle at 1000 rpm, then die.


I called AMA, and papa bear, they concluded that the car didnt think it was getting air (but you CAN give the car gas...)

So we unplugged the MAF and the car runs in limp mode. WITH [AT OIL TEMP] light CONSTANTLY flashing



Drove home, changed out the MAF to one the dealer gave me on a recall (the dealer installed the new one a while back but the car would stay running, so they just put the old back in and gave me the new one for keeps) and i get the same problem.

I'm not sure if it's a faulty MAF (the new one) or what. I'll go try to exchange for a different one today.



The codes I'm triggering are:
P0170 (Front o2, needs replacing)
and
P0420 (emissions)




any ideas?
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Old 03-04-2008, 03:34 PM   #2
plugged.in
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Now car won't run without MAF
and I get this code:


P0102 Mass air flow sensor circuit low input

Last edited by plugged.in; 03-04-2008 at 04:46 PM.
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Old 03-04-2008, 07:58 PM   #3
RaceFaceXC
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So it ran without the MAF at first but now it wont run without the MAF at all?

maybe the o2 sensor actually is bad and just by coincidence went bad after doing those mods? Try putting anything you changed back to stock? if that doesnt help, id try a new O2 sensor and see what that does. Did this happen just after doing these mods? (intake, headers)
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Old 03-04-2008, 08:33 PM   #4
Tim Sanderson
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You putting oil on your cai filter?
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Old 03-04-2008, 08:52 PM   #5
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how long have you had the intake on for .?
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Old 03-05-2008, 12:21 AM   #6
plugged.in
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I've had the intake on since, october? headers around the same time.

started getting the o2 code about 2 months ago.

been putting it off (i know, i know, stupid...) on the replacement




i haven't been putting oil on the filter no.
and it IS pretty dirty. cleaned today.
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Old 03-05-2008, 12:23 AM   #7
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Quote:
Originally Posted by RaceFaceXC View Post
So it ran without the MAF at first but now it wont run without the MAF at all?

maybe the o2 sensor actually is bad and just by coincidence went bad after doing those mods? Try putting anything you changed back to stock? if that doesnt help, id try a new O2 sensor and see what that does. Did this happen just after doing these mods? (intake, headers)
it takes serious revving to warm the car up to keep it running.


runs in limp mode now without MAF


Its parked (obviously) until i can fix it.
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Old 03-05-2008, 02:57 AM   #8
plugged.in
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99rs btw
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Old 03-05-2008, 12:08 PM   #9
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you're getting an O2 sensor CEl....maybe you should heed the warning and replace it.
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Old 03-05-2008, 12:35 PM   #10
plugged.in
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doing so, tomrorrow.


after I do that, should I reset ecu then try starting car?
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Old 03-05-2008, 06:51 PM   #11
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id try starting it without a ecu reset first.. if it doesnt work, try a reset but a reset shouldn't be necessary to get it running normally.
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Old 03-05-2008, 11:29 PM   #12
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Quote:
Originally Posted by yarrgh View Post
you're getting an O2 sensor CEl....maybe you should heed the warning and replace it.
A pooched O2 sensor will just cause the car to run in open loop and limp mode, it shouldn't have that effect on the car.
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Old 03-05-2008, 11:36 PM   #13
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Quote:
Originally Posted by plugged.in View Post
doing so, tomrorrow.


after I do that, should I reset ecu then try starting car?
yes reset it.
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Old 03-05-2008, 11:53 PM   #14
xilles
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clean the maf with connection cleaner real good
inspect that pcv valve if clogged
replace front o2 sensor(couldve got fouled up bc of the header)
no need to reset ecu but helps, if you reset the ecu it will clear the code and all other learned driving habits, if you replace that o2 sensor without reseting let it run for an hour or 2.
personally i had same problem.mine wouldnt start or go above 4ks mine ended up being both maf and o2. replaced both without reseting ecu drove it around the block a few times actually 12 miles shutting down and restarting the car every so often miles and cel went away...

ps i do have a 07sti and a ej20-ed 99rs.
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Old 03-06-2008, 09:15 AM   #15
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If you've had the MAF out, make sure you didn't put it back in backwards. You can get this code if you do that, too. Just something I've heard....
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Old 03-07-2008, 10:48 AM   #16
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Quote:
Originally Posted by Boxer4Dad View Post
If you've had the MAF out, make sure you didn't put it back in backwards. You can get this code if you do that, too. Just something I've heard....
I'll check on that for him tonight. If that's the case, I am going to slap him
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Old 03-07-2008, 01:20 PM   #17
plugged.in
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that'snot the case.
i dont even think the maf FITS backwards...
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Old 03-10-2008, 02:04 AM   #18
plugged.in
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dealer gave me a faulty MAF...
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Old 03-10-2008, 07:00 PM   #19
RaceFaceXC
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sucks. what are they going to do for all the wasted time and inconvenience?
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Old 03-12-2008, 08:37 PM   #20
plugged.in
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nothing.
they said they didn't install it, so they won't warranty it.


They actually DID install it, but took it out because they couldnt get my car to start with it (defective sensor sounds like the first thing that would pop into my head...) and they handed it to me, threw the old one back in
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