Riv Performance
Would you like to react to this message? Create an account in a few clicks or log in to continue.

The 8th Gen Riviera Resource
 
HomeDashboardLatest imagesSearchRiviera Questions & AnswersWrite-Ups IndexRegisterRelated LinksLog in

 

 FAQ: Mass Air Flow (MAF) Sensor Issues?

Go down 
+43
KnottyEagle
matt270avian
charlieRobinson
knuckled1
Karma
robotennis61
BMD
Abaddon
BatMobile
madrivage
Eldo
Mikel
albertj
Tank
Jason
Snowdog
L67
DEMonte1997
Z-type
turtleman
bigriv0
1995 Riv
captshiner
Rickw
curious riv
BKRIV
Chicken
KillaKeninaRiv
Shintsu
rivwilly107
1998 Riv
dreww
98RIV7777
96RivSCMI
54_nailhead
BillBoost37
deekster_caddy
98riv
ibmoses
Mr.Riviera
T Riley
AA
SpaceBar
47 posters
Go to page : Previous  1, 2, 3 ... 8, 9, 10, 11, 12, 13  Next
AuthorMessage
Eldo
Expert
Eldo


Name : Mark
Age : 59
Location : West Salem, Oregon... FINALLY
Joined : 2009-04-09
Post Count : 3174
Merit : 104

FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty
PostSubject: Re: FAQ: Mass Air Flow (MAF) Sensor Issues?   FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 EmptyWed Mar 16, 2011 5:44 pm

Abaddon wrote:
Eldo wrote:

As far as the pressure-regulator goes, how many PSI are there in a 'ton' of fuel pressure? cool

I believe a "ton" of psi's are nothing but a plethora of single psi's, therefore, enough to run the car lmfao

Hmmm - I was thinking that, depending whether it's English or Metric, a 'ton' of fuel pressure would be between 2,000 and 2200 PSI...
jump
Back to top Go down
BMD
Aficionado
BMD


Name : BMD
Location : Canada
Joined : 2009-04-28
Post Count : 1161
Merit : 36

FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty
PostSubject: Re: FAQ: Mass Air Flow (MAF) Sensor Issues?   FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 EmptyWed Mar 16, 2011 5:52 pm

Eldo wrote:
I see that you've covered all the usual suspects but one - have you checked for a 'classic' vacuum line leak? On an open-loop cold start, there's enough enrichment to handle a small vacuum leak; a warm start is leaner... Have you checked all the vacuum hoses with eyeballs and spritzes of carb-cleaner?

As far as the pressure-regulator goes, how many PSI are there in a 'ton' of fuel pressure? cool

Not really basing the "ton" on scientific data, but rather a strong burst of fuel from an ill timed depression of the the fuel rail valve razz ( don't try that at home). As far as vacuum line leaks, we have replaced a bunch of lines, not each and every one, might try the carb cleaner spray trick. But from what I am reading online, a poorly operating Fuel Pressure Regulator can cause this symptom.

EDIT: Sprayed everything down around the intake with carb cleaner, but no change in the idle. Where would one insert a fuel pressure gauge on our cars to check the fuel pressure?
Back to top Go down
Eldo
Expert
Eldo


Name : Mark
Age : 59
Location : West Salem, Oregon... FINALLY
Joined : 2009-04-09
Post Count : 3174
Merit : 104

FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty
PostSubject: Re: FAQ: Mass Air Flow (MAF) Sensor Issues?   FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 EmptyThu Mar 17, 2011 2:40 am

BMD wrote:

EDIT: Sprayed everything down around the intake with carb cleaner, but no change in the idle. Where would one insert a fuel pressure gauge on our cars to check the fuel pressure?

On that schrader valve that you depressed.
Back to top Go down
BMD
Aficionado
BMD


Name : BMD
Location : Canada
Joined : 2009-04-28
Post Count : 1161
Merit : 36

FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty
PostSubject: Re: FAQ: Mass Air Flow (MAF) Sensor Issues?   FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 EmptyWed Mar 23, 2011 8:59 pm

L67 wrote:
Opened up the pins in the connector to get better contact and its working again...cross your fingers boys. P|

I don't know if your around Matt, but can someone tell me how to open up the connector at the MAF sensor to check the contacts?
Back to top Go down
L67
Aficionado



Name : Matt
Joined : 2007-06-05
Post Count : 1125
Merit : 37

FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty
PostSubject: Re: FAQ: Mass Air Flow (MAF) Sensor Issues?   FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 EmptyWed Mar 23, 2011 9:47 pm

BMD wrote:
L67 wrote:
Opened up the pins in the connector to get better contact and its working again...cross your fingers boys. P|

I don't know if your around Matt, but can someone tell me how to open up the connector at the MAF sensor to check the contacts?

Disconnect the plug from the MAF sensor and then use a mini-flathead (or other small poking device) to bend the pins inside the holes of plug upward so that when you plug it back in the pins have more of a contact with the pins on the sensor.
Back to top Go down
BMD
Aficionado
BMD


Name : BMD
Location : Canada
Joined : 2009-04-28
Post Count : 1161
Merit : 36

FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty
PostSubject: Re: FAQ: Mass Air Flow (MAF) Sensor Issues?   FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 EmptyWed Mar 23, 2011 10:33 pm

Okay, thanks Matt. I am still curious if anyone has ever opened up a connector? Are they ruined if they are opened? If you have a bad connector, do you need to splice in a new one?
Back to top Go down
albertj
Master
albertj


Name :
Location : Finger Lakes of New York State
Joined : 2007-05-31
Post Count : 8685
Merit : 181

FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty
PostSubject: Re: FAQ: Mass Air Flow (MAF) Sensor Issues?   FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 EmptyThu Mar 24, 2011 7:46 am

BMD wrote:
Okay, thanks Matt. I am still curious if anyone has ever opened up a connector? Are they ruined if they are opened? If you have a bad connector, do you need to splice in a new one?

If you have the connector kit (I think it's Kent-Moore) it's no problem at all - the factory connectors are intended to be field-repairable. You can find the kits on eBay. They are not cheap BUT if you find one of the sites that is still selling stuff from dealer closings I bet you can find a kit for way cheap. Most people who need such kits (dealers/indie mechanics) have them.

Alternatively you can get most connectors pre-wired in correct wire colors, to splice into the harness, from RockAuto.com or in my case my local NAPA.



Back to top Go down
BMD
Aficionado
BMD


Name : BMD
Location : Canada
Joined : 2009-04-28
Post Count : 1161
Merit : 36

FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty
PostSubject: Re: FAQ: Mass Air Flow (MAF) Sensor Issues?   FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 EmptyThu Mar 24, 2011 1:18 pm

Great info, thanks albert!

My Dads 99 PA just got this code, here is the freeze frame data I retrieved from the car...

Fuel Sys 1            CL
Fuel Sys 2            NA
Calc Load %        2.75
ECT (celsius)       27
STFT B1 %           0.00
LTFT B1 %           16.41
MAP (kpa)             33.00
Eng RPM              1043
Speed (km)          0
MAF ( g/s)             7.67
TPS %                   0.39

Can someone translate this? We are on our second MAF by he way.
Back to top Go down
Abaddon
Expert
Abaddon


Name : Scott
Location : Macomb, Michigan
Joined : 2010-02-24
Post Count : 4315
Merit : 185

FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty
PostSubject: Re: FAQ: Mass Air Flow (MAF) Sensor Issues?   FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 EmptyWed Mar 30, 2011 8:54 am

- in closed loop
- Not applicable
- engine load 2.75% (scanned at idle?)
- coolant temp 27*C
- short term fuel trim 0%
- long term fuel trim 16.41% <--------------buttload off
- manifold pressure (baro sensor) 33kpa
- 1043 RPM
- not moving
- mass air flow 7.67g/sec
- throttle position at .39V (idle)

See if you can scan while driving and see what the short term fuel trim and the MAF is reading.....
Back to top Go down
Mr.Riviera
Expert
Mr.Riviera


Name : Matthew
Age : 38
Location : Florida
Joined : 2007-01-17
Post Count : 4394
Merit : 101

FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty
PostSubject: Re: FAQ: Mass Air Flow (MAF) Sensor Issues?   FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 EmptyWed Mar 30, 2011 11:14 am

Doesnt the ltft peg at 16.4?

_________________
1996 with 254k miles, L32 4" FWI -> ported N* -> Ported Gen V w/3.0" Pulley, Stage 3 Phenolic I/C, ZZP FMHE, 1.84 RR, Headers and 3" pipe to mufflers, F-body brakes, and lowered on Eibachs. -RIP
AMG C400 White on black. Stage 2 w/E30 - 11.9@117 -daily
FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Dsc_0110
Back to top Go down
AA
Administrator
AA


Name : Aaron
Age : 47
Location : C-bus, Ohio
Joined : 2007-01-13
Post Count : 18452
Merit : 252

FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty
PostSubject: Re: FAQ: Mass Air Flow (MAF) Sensor Issues?   FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 EmptyWed Mar 30, 2011 11:29 am

Yes, but I've noticed my scan tool likes certain decimal values. Like it will say 1.8 but never 1.9. Maybe BMD's scanner maxes at 16.41 instead of 16.4? Whatever, it means it's extremely lean - dangerously lean. This happened to me a long while ago. I found two problems: my MAFF translator (AFC) was malfunctioning, and I had a vac leak at the blower. Fixed both and the problem never returned. I'm not sure which one caused the lean condition, or if it was a combination of the two.

I think a failing or dirty MAFF sensor could cause this. If it failed entirely, or were disconnected, should throw a DTC.

_________________
'05 GTO 6.0L • 6-spd • 95k miles • 0-60: 4.8s • 16.9 avg MPG • Nelson Ledges Lap: 1:26

'95 Celica GT 2.2L • 5-spd • 165k miles • 0-60: yes

'98 SC Riviera • 281k miles • 298 HP/370 TQ • 0-60: 5.79s • ET: 13.97 @ 99.28 • 4087 lb • 20.1 avg MPG • Nelson Ledges Lap: 1:30
3.4" pulley • AL104 plugs • 180º t-stat • FWI w/K&N • 1.9:1 rockers • OR pushrods • LS6 valve springs • SLP headers • ZZP fuel rails
KYB GR2 struts • MaxAir shocks • Addco sway bars • UMI bushings • GM STB • Enkei 18" EV5s w/ Dunlop DZ101s • F-body calipers
EBC bluestuff/Hawk HP plus • SS lines • Brembo slotted discs • DHP tuned • Aeroforce • Hidden Hitch

^^^ SOLD ^^^ frown

'70 Ninety-Eight Holiday Coupe 455cid • 116k miles
^^^ SOLD ^^^ frown
Back to top Go down
http://www.cardomain.com/ride/657082/4
BMD
Aficionado
BMD


Name : BMD
Location : Canada
Joined : 2009-04-28
Post Count : 1161
Merit : 36

FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty
PostSubject: Re: FAQ: Mass Air Flow (MAF) Sensor Issues?   FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 EmptyWed Mar 30, 2011 3:31 pm

Thank you guys soooooooo much for responding to this. I don't have an actual scanner, its a code reader that provides freeze frame data as well and yes, we acquired that info at idle in park.

Scott - What should that LTFT reading be at idle?

Aaron - What is a MAFF translator and where is it located? And the blower you are referring to is for the HVAC system, correct? How is that related to engine vacuum?

I wanna help my Dad out here, he has already spent a pretty penny on a new MAF sensor ( returned for a second...) and a new IGN module for his no start condition, now this. Any info will be greatly appreciated.
Back to top Go down
Mr.Riviera
Expert
Mr.Riviera


Name : Matthew
Age : 38
Location : Florida
Joined : 2007-01-17
Post Count : 4394
Merit : 101

FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty
PostSubject: Re: FAQ: Mass Air Flow (MAF) Sensor Issues?   FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 EmptyWed Mar 30, 2011 3:57 pm

LTFT should be 0 all the time. plus or minus 5 is pretty normal though. this just means the car is trying to pull fuel or add fuel.
When it starts to get outside the +-5 range it may be you need a tune up or to tune for the mods you have added.

The AFC is something aftermarket AA added to help adjust the A/F for his car

the term "blower" usually refers to the supercharger.


_________________
1996 with 254k miles, L32 4" FWI -> ported N* -> Ported Gen V w/3.0" Pulley, Stage 3 Phenolic I/C, ZZP FMHE, 1.84 RR, Headers and 3" pipe to mufflers, F-body brakes, and lowered on Eibachs. -RIP
AMG C400 White on black. Stage 2 w/E30 - 11.9@117 -daily
FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Dsc_0110
Back to top Go down
BMD
Aficionado
BMD


Name : BMD
Location : Canada
Joined : 2009-04-28
Post Count : 1161
Merit : 36

FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty
PostSubject: Re: FAQ: Mass Air Flow (MAF) Sensor Issues?   FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 EmptyWed Mar 30, 2011 4:10 pm

Thanks Mathew,

Mr.Riviera wrote:
the term "blower" usually refers to the supercharger.

Shoulda realized that one. oops

Well hes got new.... IGN module, plugs, MAFF, IAC, TPS, oxygen sensor, fuel filter, coolant sensor, we cleaned the throttle body, checked and replaced vacuum lines... the only thing left that I can think of aside from getting the injectors checked is the Fuel Pressure Regulator. In my FSM it says that "If the fuel pressure is too low, poor performance and a DTC P0171, could result" But his car drives really smooth and strong????
Back to top Go down
Mr.Riviera
Expert
Mr.Riviera


Name : Matthew
Age : 38
Location : Florida
Joined : 2007-01-17
Post Count : 4394
Merit : 101

FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty
PostSubject: Re: FAQ: Mass Air Flow (MAF) Sensor Issues?   FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 EmptyWed Mar 30, 2011 4:12 pm

The 96 rivs have a lot of vac lines. Sure all of them were replaced? Some of them are not even avail from the dealer anymore.

Edit: sorry i went back to your original post that this is for a park ave not your riv.

What is the mileage on the PA, is it the L67 ultra or something else?

_________________
1996 with 254k miles, L32 4" FWI -> ported N* -> Ported Gen V w/3.0" Pulley, Stage 3 Phenolic I/C, ZZP FMHE, 1.84 RR, Headers and 3" pipe to mufflers, F-body brakes, and lowered on Eibachs. -RIP
AMG C400 White on black. Stage 2 w/E30 - 11.9@117 -daily
FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Dsc_0110
Back to top Go down
BMD
Aficionado
BMD


Name : BMD
Location : Canada
Joined : 2009-04-28
Post Count : 1161
Merit : 36

FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty
PostSubject: Re: FAQ: Mass Air Flow (MAF) Sensor Issues?   FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 EmptyWed Mar 30, 2011 4:37 pm

Yeah his car is a Supercharged L67 with 130000 miles . Not every vac line has been replaced. The vac lines we did replace we did with vac hoses, very tight fit.
Back to top Go down
Abaddon
Expert
Abaddon


Name : Scott
Location : Macomb, Michigan
Joined : 2010-02-24
Post Count : 4315
Merit : 185

FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty
PostSubject: Re: FAQ: Mass Air Flow (MAF) Sensor Issues?   FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 EmptyWed Mar 30, 2011 4:37 pm

BMD wrote:
Thank you guys soooooooo much for responding to this. I don't have an actual scanner, its a code reader that provides freeze frame data as well and yes, we acquired that info at idle in park.

Scott - What should that LTFT reading be at idle?

Aaron - What is a MAFF translator and where is it located? And the blower you are referring to is for the HVAC system, correct? How is that related to engine vacuum?

I wanna help my Dad out here, he has already spent a pretty penny on a new MAF sensor ( returned for a second...) and a new IGN module for his no start condition, now this. Any info will be greatly appreciated.

The LTFT basically tells you how the car has been running, and the STFT tells you how it's running right now. Based on what the front 02 is saying, the PCM will add/subtract fuel accordingly. This is reflected in the STFT. If the STFT remains high (+), the LTFT will go up and up until it can't go any higher. P0171 is the result. Basically, LTFT makes coarse adjustments in order to get STFT as close to zero as possible.....got me?

If you've replaced everything that you have, and you're convinced that you have no vac leaks and what-not, I'd be looking at the 02 sensor for a skewed reading. The fuel trims are directly affected by the 02 reading......
Back to top Go down
Karma
Aficionado
Karma


Name : Andrew
Age : 40
Location : Ontario, Canada
Joined : 2008-01-14
Post Count : 1949
Merit : 123

FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty
PostSubject: Re: FAQ: Mass Air Flow (MAF) Sensor Issues?   FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 EmptyWed Mar 30, 2011 4:45 pm

I haven't really been looking closely at this thread, but..
have a look and make sure one of you rear plug wires is not touching the 02 sensor wire. Its been known to cause all sorts of funny things if it is...

_________________
Warning!
Back to top Go down
BMD
Aficionado
BMD


Name : BMD
Location : Canada
Joined : 2009-04-28
Post Count : 1161
Merit : 36

FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty
PostSubject: Re: FAQ: Mass Air Flow (MAF) Sensor Issues?   FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 EmptyWed Mar 30, 2011 4:50 pm

Abaddon wrote:
The LTFT basically tells you how the car has been running, and the STFT tells you how it's running right now. Based on what the front 02 is saying, the PCM will add/subtract fuel accordingly. This is reflected in the STFT. If the STFT remains high (+), the LTFT will go up and up until it can't go any higher. P0171 is the result. Basically, LTFT makes coarse adjustments in order to get STFT as close to zero as possible.....got me?

If you've replaced everything that you have, and you're convinced that you have no vac leaks and what-not, I'd be looking at the 02 sensor for a skewed reading. The fuel trims are directly affected by the 02 reading......

dunce Let me see if I got this straight, so the PCM takes the O2 info and adjust the fuel mixture accordingly to keep the STFT as close to zero as possible by adjusting the LTFT, even if its to its detriment?

@ Karma, will do, thanks.
Back to top Go down
Abaddon
Expert
Abaddon


Name : Scott
Location : Macomb, Michigan
Joined : 2010-02-24
Post Count : 4315
Merit : 185

FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty
PostSubject: Re: FAQ: Mass Air Flow (MAF) Sensor Issues?   FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 EmptyWed Mar 30, 2011 5:07 pm

Well, yes and no. If the PCM reads lean, it will continue to add fuel until it's no longer lean (STFT as close to zero as it can). I believe P0171 sets when the LTFT reaches about +12 to +13%. It can only add so much fuel......so really, it's not to it's detriment, but merely trying not to blow holes in your pistons lol

EDIT: just add to Mr Riv.....yes, LTFT "pegs" at about 16%, and STFT "pegs" at about 20%.
Back to top Go down
AA
Administrator
AA


Name : Aaron
Age : 47
Location : C-bus, Ohio
Joined : 2007-01-13
Post Count : 18452
Merit : 252

FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty
PostSubject: Re: FAQ: Mass Air Flow (MAF) Sensor Issues?   FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 EmptyWed Mar 30, 2011 5:28 pm

I've never had a DTC for LTFT, reaching as high as +16.4 on my Riviera. It may be supposed to set the P0171, but it didn't actually happened in my experience.

Quote :
Let me see if I got this straight, so the PCM takes the O2 info and adjust the fuel mixture accordingly to keep the STFT as close to zero as possible by adjusting the LTFT, even if its to its detriment?
That shouldn'tt happen, because LTFT typically follows STFT's lead. If you are really maxed out lean at +16.4, your STFT should not be 0. Your scan might have been taken too soon, before the LTFT learned. If you can scan again, see if the situation has changed. Usually, if STFT is zero, LTFT will soon try to match it.

_________________
'05 GTO 6.0L • 6-spd • 95k miles • 0-60: 4.8s • 16.9 avg MPG • Nelson Ledges Lap: 1:26

'95 Celica GT 2.2L • 5-spd • 165k miles • 0-60: yes

'98 SC Riviera • 281k miles • 298 HP/370 TQ • 0-60: 5.79s • ET: 13.97 @ 99.28 • 4087 lb • 20.1 avg MPG • Nelson Ledges Lap: 1:30
3.4" pulley • AL104 plugs • 180º t-stat • FWI w/K&N • 1.9:1 rockers • OR pushrods • LS6 valve springs • SLP headers • ZZP fuel rails
KYB GR2 struts • MaxAir shocks • Addco sway bars • UMI bushings • GM STB • Enkei 18" EV5s w/ Dunlop DZ101s • F-body calipers
EBC bluestuff/Hawk HP plus • SS lines • Brembo slotted discs • DHP tuned • Aeroforce • Hidden Hitch

^^^ SOLD ^^^ frown

'70 Ninety-Eight Holiday Coupe 455cid • 116k miles
^^^ SOLD ^^^ frown


Last edited by AA on Wed Mar 30, 2011 5:34 pm; edited 1 time in total
Back to top Go down
http://www.cardomain.com/ride/657082/4
Mr.Riviera
Expert
Mr.Riviera


Name : Matthew
Age : 38
Location : Florida
Joined : 2007-01-17
Post Count : 4394
Merit : 101

FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty
PostSubject: Re: FAQ: Mass Air Flow (MAF) Sensor Issues?   FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 EmptyWed Mar 30, 2011 5:30 pm

BMD wrote:
Abaddon wrote:
The LTFT basically tells you how the car has been running, and the STFT tells you how it's running right now. Based on what the front 02 is saying, the PCM will add/subtract fuel accordingly. This is reflected in the STFT. If the STFT remains high (+), the LTFT will go up and up until it can't go any higher. P0171 is the result. Basically, LTFT makes coarse adjustments in order to get STFT as close to zero as possible.....got me?

If you've replaced everything that you have, and you're convinced that you have no vac leaks and what-not, I'd be looking at the 02 sensor for a skewed reading. The fuel trims are directly affected by the 02 reading......

dunce Let me see if I got this straight, so the PCM takes the O2 info and adjust the fuel mixture accordingly to keep the STFT as close to zero as possible by adjusting the LTFT, even if its to its detriment?

@ Karma, will do, thanks.

STFT= short term fuel trims
LTFT= long term fuel trims

how long is long, and how short is short i dont know.

the O2 sensor adjusts the fueling and the fuel trims change as a result. STFT changes fast and may not be at 0 all the time. LTFT is like an averaged value of the STFT that shows how the air/fuel has been over time.
For purposes of tuning i look at LTFT more than STFT

AA, i have never had the code set either and as much as i screw with my car i'm at 16.4 or -22 pretty often when i start changing stuff around.

_________________
1996 with 254k miles, L32 4" FWI -> ported N* -> Ported Gen V w/3.0" Pulley, Stage 3 Phenolic I/C, ZZP FMHE, 1.84 RR, Headers and 3" pipe to mufflers, F-body brakes, and lowered on Eibachs. -RIP
AMG C400 White on black. Stage 2 w/E30 - 11.9@117 -daily
FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Dsc_0110
Back to top Go down
BMD
Aficionado
BMD


Name : BMD
Location : Canada
Joined : 2009-04-28
Post Count : 1161
Merit : 36

FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty
PostSubject: Re: FAQ: Mass Air Flow (MAF) Sensor Issues?   FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 EmptyWed Mar 30, 2011 8:08 pm

I think I get it now. Learning new things is the one upside of having car trouble wink . In any case, as far as repairs go, I think I'll put my Dads, old O2 sensor back and see if that code re-appears, thanks guys, I'll update when I get more info. By the way Karma, O2 wires and spark plug wires were not touching one another.
Back to top Go down
Abaddon
Expert
Abaddon


Name : Scott
Location : Macomb, Michigan
Joined : 2010-02-24
Post Count : 4315
Merit : 185

FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty
PostSubject: Re: FAQ: Mass Air Flow (MAF) Sensor Issues?   FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 EmptyThu Mar 31, 2011 9:42 am

AA wrote:
I've never had a DTC for LTFT, reaching as high as +16.4 on my Riviera. It may be supposed to set the P0171, but it didn't actually happened in my experience.

There are 15 conditions that need to be met in order for P0171 to actually set. Tuning and playing around for a day or two is more than likely not going to throw the code.

FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 P0171

If any one of these don't get met, P0171 won't set.........
Back to top Go down
AA
Administrator
AA


Name : Aaron
Age : 47
Location : C-bus, Ohio
Joined : 2007-01-13
Post Count : 18452
Merit : 252

FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty
PostSubject: Re: FAQ: Mass Air Flow (MAF) Sensor Issues?   FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 EmptyThu Mar 31, 2011 9:58 am

I drove around for a couple weeks with LTFT pegged at 16.4. It wasn't from experimenting, my AFC had gone haywire, and I had a major vac leak. No P0171 code, nor any code was set.

Most of those 'conditions' are irrelevant. They occur whenever the car takes a trip. The only ones that matter (assuming everything else is in order) are LTFT & STFT. I cannot remember if my STFT was maxed at +20, but I know LTFT was +16.4.

It would seem that if STFT is not maxed, the system is not actually lean by the PCM's definition. This could explain why BMD, Mr.Riviera and myself didn't get the code?

_________________
'05 GTO 6.0L • 6-spd • 95k miles • 0-60: 4.8s • 16.9 avg MPG • Nelson Ledges Lap: 1:26

'95 Celica GT 2.2L • 5-spd • 165k miles • 0-60: yes

'98 SC Riviera • 281k miles • 298 HP/370 TQ • 0-60: 5.79s • ET: 13.97 @ 99.28 • 4087 lb • 20.1 avg MPG • Nelson Ledges Lap: 1:30
3.4" pulley • AL104 plugs • 180º t-stat • FWI w/K&N • 1.9:1 rockers • OR pushrods • LS6 valve springs • SLP headers • ZZP fuel rails
KYB GR2 struts • MaxAir shocks • Addco sway bars • UMI bushings • GM STB • Enkei 18" EV5s w/ Dunlop DZ101s • F-body calipers
EBC bluestuff/Hawk HP plus • SS lines • Brembo slotted discs • DHP tuned • Aeroforce • Hidden Hitch

^^^ SOLD ^^^ frown

'70 Ninety-Eight Holiday Coupe 455cid • 116k miles
^^^ SOLD ^^^ frown
Back to top Go down
http://www.cardomain.com/ride/657082/4
Sponsored content





FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty
PostSubject: Re: FAQ: Mass Air Flow (MAF) Sensor Issues?   FAQ: Mass Air Flow (MAF) Sensor Issues? - Page 9 Empty

Back to top Go down
 
FAQ: Mass Air Flow (MAF) Sensor Issues?
Back to top 
Page 9 of 13Go to page : Previous  1, 2, 3 ... 8, 9, 10, 11, 12, 13  Next
 Similar topics
-
» mass air flow?
» o2 sensor trouble w/ high flow catalytic converter
» FAQ: P0341 Camshaft Position Sensor (Cam Sensor / Timing Chain)
» Cam sensor and air intake sensor bad = bad ground?
» MAF sensor and crankshaft sensor

Permissions in this forum:You cannot reply to topics in this forum
Riv Performance ::   General Tech :: Care & Maintenance-
Jump to: