running lean

91cobra5.0 · January 21st, 2008, 12:41 AM

ok so i had to leave off the pipes and run headers until this wed. (ran out of time at the shop and had to get the car home so i didnt get the pipes back on) well now its running lean and i was just curiouse as to why that was happening, is it becuase that there is no back pressure?

White Thunder · January 21st, 2008, 12:58 AM

im guessing but something with the o2 sensor...i might be really wrong so flame away

91cobra5.0 · January 21st, 2008, 01:23 AM

yea i was thinkin that too, that becuase the sensors arent there that the computer is sending the car into a safe mode.

Tony_90fox · January 21st, 2008, 01:42 AM

Off topic but what color is your car? Specific name if you got it.

SALIV8 · January 21st, 2008, 11:09 PM

without o2 sensorsthe stock ecu is setting a preprogrammed "tune" it is in open loopwithout feedback from the sensors

91cobra5.0 · January 22nd, 2008, 01:38 AM

i dont know specific color but its 2 tone silver, a darker silver on top with obviously lighter on the bottom

91cobra5.0 · January 22nd, 2008, 01:40 AM

Originally Posted by SALIV8

without o2 sensorsthe stock ecu is setting a preprogrammed "tune" it is in open loopwithout feedback from the sensors

if i just plug the sensors back in withought the pipes would it fix the no feedback? i mean the engine light will still come on but maybe it wont run lean

JBIGBOOTSY · January 22nd, 2008, 03:43 AM

How do you know it's running lean?

Goblin · January 22nd, 2008, 11:13 AM

Originally Posted by JBIGBOOTSY

How do you know it's running lean?

This is also the question i have.

Iwannagofast · January 22nd, 2008, 11:54 AM

Originally Posted by 91cobra5.0

i dont know specific color but its 2 tone silver, a darker silver on top with obviously lighter on the bottom

i hadnt even noticed the two tone.....but it looks nice

91cobra5.0 · January 22nd, 2008, 11:27 PM

Originally Posted by JBIGBOOTSY

How do you know it's running lean?

air-fuel guage

SALIV8 · January 23rd, 2008, 06:58 PM

Originally Posted by 91cobra5.0

if i just plug the sensors back in withought the pipes would it fix the no feedback? i mean the engine light will still come on but maybe it wont run lean

o2 sensors needs exhaust to give the ecu the correct voltage. it will stay that way until they're in the exhaust

ryans88gt · January 23rd, 2008, 07:04 PM

A wide band O2 or an autometer guage? the autometer gauge reading off of stock O2 sensors is next to meaningless.

I tried using mine to tune my nitrous once. It actually read leaner when I fattened up the fuel jets...

BTW I ran my 88 without O2s for about 3 years with no ill effects other than having shitty fuel economy and it running rich below 2000 rpms. The O2 sensors don't really have much effect above 2500 rpms

91cobra5.0 · January 24th, 2008, 12:04 AM

its a autometer guage but i dont know if it runs off the o2 sensors and i put th pipes back on and the guage reads fine

jam77 · January 24th, 2008, 12:36 AM

i wouldn't trust that gauge

91cobra5.0 · January 24th, 2008, 02:47 PM

should i re rout it or something?

Goblin · January 24th, 2008, 02:54 PM

Ditch that gauge, and get a good wideband o2 meter. This is ofcourse, if you can afford it. With the gauge you have now.. if your running on the lean side of stoich, the gauge will tell you your lean.. even though you may only be lean by .02:1 With the o2 sensors disconneted, the car will actually run slighty rich. With the exhaust being disconnected, that doesnt effect the A/F ratios, unless you take the o2s off.

ryans88gt · January 24th, 2008, 02:57 PM

Well, if you didn't have any O2 sensor...think about this...how did the guage now you were running lean??

lol...no O2s means no sensor sending unit.

91cobra5.0 · January 24th, 2008, 06:05 PM

true, but still is the whole guage inacurate or just how it was installed?

Goblin · January 24th, 2008, 06:12 PM

The gauge just isnt accurate.

January 21st, 2008, 12:41 AM	#1
91cobra5.0 Hardcore Enthusiast 91 mustang 266 ftlbs 191 hp (15.138 @92.91) @5000ft elevation Join Date: Jan 2008 Location: colorado springs Posts: 1,500	running lean ok so i had to leave off the pipes and run headers until this wed. (ran out of time at the shop and had to get the car home so i didnt get the pipes back on) well now its running lean and i was just curiouse as to why that was happening, is it becuase that there is no back pressure? __________________ Fender well cold air intake, 3:73's, eibach springs, 65mm TB, electric fans, 3g upgrade, smog delete, advanced timing, MSD cap and rotor, ford racing 9mm plug wires, 75mm Pro-M MAF, flowmaster sieres 40 delta flows

January 21st, 2008, 01:23 AM	#3
91cobra5.0 Hardcore Enthusiast 91 mustang 266 ftlbs 191 hp (15.138 @92.91) @5000ft elevation Join Date: Jan 2008 Location: colorado springs Posts: 1,500	yea i was thinkin that too, that becuase the sensors arent there that the computer is sending the car into a safe mode. __________________ Fender well cold air intake, 3:73's, eibach springs, 65mm TB, electric fans, 3g upgrade, smog delete, advanced timing, MSD cap and rotor, ford racing 9mm plug wires, 75mm Pro-M MAF, flowmaster sieres 40 delta flows

January 22nd, 2008, 01:38 AM	#6
91cobra5.0 Hardcore Enthusiast 91 mustang 266 ftlbs 191 hp (15.138 @92.91) @5000ft elevation Join Date: Jan 2008 Location: colorado springs Posts: 1,500	i dont know specific color but its 2 tone silver, a darker silver on top with obviously lighter on the bottom __________________ Fender well cold air intake, 3:73's, eibach springs, 65mm TB, electric fans, 3g upgrade, smog delete, advanced timing, MSD cap and rotor, ford racing 9mm plug wires, 75mm Pro-M MAF, flowmaster sieres 40 delta flows

January 22nd, 2008, 03:43 AM	#8
JBIGBOOTSY Hardcore Enthusiast 1990 LX hatch Join Date: Aug 2006 Location: Hobart Indiana Posts: 2,066	How do you know it's running lean? __________________

January 23rd, 2008, 07:04 PM	#13
ryans88gt MM Fanatic Join Date: May 2007 Location: Bloomington, IL Posts: 3,769	A wide band O2 or an autometer guage? the autometer gauge reading off of stock O2 sensors is next to meaningless. I tried using mine to tune my nitrous once. It actually read leaner when I fattened up the fuel jets... BTW I ran my 88 without O2s for about 3 years with no ill effects other than having shitty fuel economy and it running rich below 2000 rpms. The O2 sensors don't really have much effect above 2500 rpms __________________ 89 LX 515 hp 497 ftlbs 11.3 @ 125 mph 88 GT 11.4 @ 118

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January 21st, 2008, 11:09 PM	#5
SALIV8 Enthusiast Join Date: Dec 2006 Location: Lookin' at you in my rearview Posts: 519	without o2 sensorsthe stock ecu is setting a preprogrammed "tune" it is in open loopwithout feedback from the sensors

January 24th, 2008, 12:04 AM	#14
91cobra5.0 Hardcore Enthusiast 91 mustang 266 ftlbs 191 hp (15.138 @92.91) @5000ft elevation Join Date: Jan 2008 Location: colorado springs Posts: 1,500	its a autometer guage but i dont know if it runs off the o2 sensors and i put th pipes back on and the guage reads fine __________________ Fender well cold air intake, 3:73's, eibach springs, 65mm TB, electric fans, 3g upgrade, smog delete, advanced timing, MSD cap and rotor, ford racing 9mm plug wires, 75mm Pro-M MAF, flowmaster sieres 40 delta flows

January 24th, 2008, 12:36 AM	#15
jam77 Enthusiast 1987 Mustang GT Join Date: Apr 2007 Location: IL Posts: 685	i wouldn't trust that gauge __________________ 87 GT, typhoon upper and lower,70mm tb, 90mm maf, bbk shorties, bbk x-pipe, flowmaster cat back, 3:73 gear, pro 5.0 shifter, novi blower,afm power pipe, load IO, Trick Flow heads, Anderson B-31 cam, Anderson PMS, 42 lb injectors, t-rex fuel pump.

January 24th, 2008, 02:47 PM	#16
91cobra5.0 Hardcore Enthusiast 91 mustang 266 ftlbs 191 hp (15.138 @92.91) @5000ft elevation Join Date: Jan 2008 Location: colorado springs Posts: 1,500	should i re rout it or something? __________________ Fender well cold air intake, 3:73's, eibach springs, 65mm TB, electric fans, 3g upgrade, smog delete, advanced timing, MSD cap and rotor, ford racing 9mm plug wires, 75mm Pro-M MAF, flowmaster sieres 40 delta flows

January 24th, 2008, 02:54 PM	#17
Goblin Hardcore Enthusiast Secret In The Works Join Date: Apr 2007 Location: Relocated Back To Tucson, Arizona Posts: 2,038	Ditch that gauge, and get a good wideband o2 meter. This is ofcourse, if you can afford it. With the gauge you have now.. if your running on the lean side of stoich, the gauge will tell you your lean.. even though you may only be lean by .02:1 With the o2 sensors disconneted, the car will actually run slighty rich. With the exhaust being disconnected, that doesnt effect the A/F ratios, unless you take the o2s off. __________________ Definition of Fast? I'd say thats good enough. NMRA Outlaw 10.5 Season Opener 2008 Photo courtesy of - Yours Truly

January 24th, 2008, 02:57 PM	#18
ryans88gt MM Fanatic Join Date: May 2007 Location: Bloomington, IL Posts: 3,769	Well, if you didn't have any O2 sensor...think about this...how did the guage now you were running lean?? lol...no O2s means no sensor sending unit. __________________ 89 LX 515 hp 497 ftlbs 11.3 @ 125 mph 88 GT 11.4 @ 118

January 24th, 2008, 06:05 PM	#19
91cobra5.0 Hardcore Enthusiast 91 mustang 266 ftlbs 191 hp (15.138 @92.91) @5000ft elevation Join Date: Jan 2008 Location: colorado springs Posts: 1,500	true, but still is the whole guage inacurate or just how it was installed? __________________ Fender well cold air intake, 3:73's, eibach springs, 65mm TB, electric fans, 3g upgrade, smog delete, advanced timing, MSD cap and rotor, ford racing 9mm plug wires, 75mm Pro-M MAF, flowmaster sieres 40 delta flows

January 24th, 2008, 06:12 PM	#20
Goblin Hardcore Enthusiast Secret In The Works Join Date: Apr 2007 Location: Relocated Back To Tucson, Arizona Posts: 2,038	The gauge just isnt accurate. __________________ Definition of Fast? I'd say thats good enough. NMRA Outlaw 10.5 Season Opener 2008 Photo courtesy of - Yours Truly

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