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Author
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Topic: Anyone efi experts in here?
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steve'66
Gearhead Posts: 8908
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 08-07-2002 07:54 PM
   
I posted this on the SN95 forum, but can any racer help me out with this newfangled computerized car?It's a '95 v-6 Mustang and it is very lazy about returning to idle. Like a sticking throtle body, but it isn't.
The check engine light was on and the OBD-II said it needed a new oxygen sensor on the #1 bank. I changed that and cleared the OBD and the light is now off, but the car will not return to idle for several seconds after lifting the throttle. HELP!! and TIA, SteveW
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pthornton
Gearhead Posts: 606
From: Austin, TX USA
Registered: Jun 99
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posted 08-07-2002 09:38 PM
Sounds like it's stuck in closed loop mode. The car always starts in closed loop mode until warmed up. The idle hangs a long time in closed loop. Once in open loop mode the idle hang is controlled by the dashpot_decay_rate table. My computer is a V so it may be a little different than yours. Not sure what would cause it to stay in closed loop. MAF bad? Could be many things. You would think it would throw a code.
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pthornton
Gearhead Posts: 606
From: Austin, TX USA
Registered: Jun 99
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posted 08-07-2002 09:40 PM
The IAC idle-air-controllers are notorious on these cars. You can clean or replace it.
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steve'66
Gearhead Posts: 8908
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 08-07-2002 09:45 PM
Thanks!What's an idle air controller? SteveW
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Boss302
Gearhead Posts: 841
From: Coleman, Wisconsin
Registered: Jan 2002
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posted 08-07-2002 10:27 PM
quote:
Originally posted by steve'66:
Thanks!What's an idle air controller? SteveW
the silver cylinder bolted to the throttle body with a harness connected to it, i've cleaned mine numerous times and it still won't idle, time for mr mechanic
------------------
Max
-1989 Mustang GT (MaxTang)
225/50R15 tires
BBK Strut Brace
K&N Filter
4 cats, no muffs
180* stat
Member 1,861 "The Horses Shake You Harder Than Sex, the Sounds Ring In Your Ears, Fact Is Your Engines Only on Idle"
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Boss302
Gearhead Posts: 841
From: Coleman, Wisconsin
Registered: Jan 2002
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posted 08-07-2002 10:48 PM
hey steve, if you ever get the car fixed, let me know what the problem was....thanks------------------
Max
-1989 Mustang GT (MaxTang)
225/50R15 tires
BBK Strut Brace
K&N Filter
4 cats, no muffs
180* stat
Member 1,861 "The Horses Shake You Harder Than Sex, the Sounds Ring In Your Ears, Fact Is Your Engines Only on Idle"
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Moneymaker
Administrator Posts: 26242
From: Lyons, IL, USA
Registered: May 99
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posted 08-08-2002 10:38 AM
Also check the TPS (throttle positioning sensor) voltage. It needs to be about 1v.  ------------------
Alex Denysenko
Co-Administrator and Moderator/ non 65-66 Mustang owner sensitivity co-ordinator NHRA/IHRA/SRA member
NHRA and IHRA SS/LA National Record Holder '00, '01, & '02
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28
Part time secret agent license #0089
Professional Manwhore
The Barry of BarrysGrrl
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steve'66
Gearhead Posts: 8908
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 08-08-2002 07:36 PM
Well the check engine light came on again today. So at least I can check the codes again and see what's up. Otherwise Maybe I'll just change parts until it works right.  SteveW
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pthornton
Gearhead Posts: 606
From: Austin, TX USA
Registered: Jun 99
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posted 08-08-2002 11:27 PM
quote:
Originally posted by steve'66:
Otherwise Maybe I'll just change parts until it works right. SteveW
That can get really expensive on these cars. There are lots of expensive sensors under the hood nowadays.
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RickBook
Gearhead Posts: 140
From: Houston, TX
Registered: Apr 2002
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posted 08-08-2002 11:30 PM
I wish I had a nickle for everytime I heard "The problem's in your O2 sensor". I'd be...well..I'd have a dollar and change.As I recall OBDI was almost useless as it provided tons 'o mis-information. The mechanic would seemingly always point to the O2 sensor. After forking over a week's pay to Joe's Garage to have it replaced (only to have the problem re-occur), the next phrase from Joe was something like "Oh yeah, we had to replace the 'fill-in-the-blank-with-anything-electronic' also". ('cha-ching' wav goes here).
OBDII carries the stigma of its predecessor (IMHO). most "everything" points to a bad O2 sensor....still.
Lots of professional mechanics have made lots of money changing out good O2's over the years - and will probably continue. Only to have mis-diagnosed the original problem to begin with. I actually had a guy tell say to me "You adjusted your O2 sensors too rich". I also got a lecture that I "shouldn't be trying stuff like that" and that I needed to have em replaced - quick - before I'd have to spend even MORE money later on. The problem was a broken #1 spark-plug wire causing an occasional mis-fire.
A sincere 'Good Luck' on your trouble-shooting. It's been my experience that, more often than not, it's a crap shoot.
"Buyer Beware" icon goes here.
Rick
[This message has been edited by RickBook (edited 08-08-2002).]
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steve'66
Gearhead Posts: 8908
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 08-09-2002 01:12 AM
yeah I hear you! I've been had before, that's why I'm not gonna rack up a 500-1000 bill to fix this. It is total b.s. 
I'll figure it out, but I sure do wish it was a holley with an MSD ignition. LOL SteveW
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Moneymaker
Administrator Posts: 26242
From: Lyons, IL, USA
Registered: May 99
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posted 08-09-2002 07:21 AM
LOL  ------------------
Alex Denysenko
Co-Administrator and Moderator/ non 65-66 Mustang owner sensitivity co-ordinator NHRA/IHRA/SRA member
NHRA and IHRA SS/LA National Record Holder '00, '01, & '02
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28
Part time secret agent license #0089
Professional Manwhore
The Barry of BarrysGrrl
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steve'66
Gearhead Posts: 8908
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 08-09-2002 06:02 PM
Well,I f'n give up!  After throwing away a few hundred dollars It's not the o2 sensors or the IAC. This thing's only got 72K miles on it. The code is "it's running lean" Duh, watch it be a clogged fuel filter or something really stupid. I don't have the gauge to check fuel pressure. So it's off to the friendly Ford dealer. SteveW
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JAAZZY
Gearhead Posts: 777
From: Bay Area, CA
Registered: Apr 2001
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posted 08-09-2002 06:30 PM
My Explorer loved the firendly Ford dealer. It was like it was built with an internal clock. I had the extended 75K warranty and it ran great until 76K miles. It was so expensive to keep up and needed so many major repairs that by 100K I just traded it for half of it's value. I just didn't have the heart to sell it to somone myself and if I told them what was wrong I doubt I could have found a buyer. If I really had a heart I would have taken it out back and torched it!
quote:
Originally posted by steve'66:
Well,I f'n give up! After throwing away a few hundred dollars It's not the o2 sensors or the IAC. This thing's only got 72K miles on it. The code is "it's running lean" Duh, watch it be a clogged fuel filter or something really stupid. I don't have the gauge to check fuel pressure. So it's off to the friendly Ford dealer. SteveW
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Buster
Gearhead Posts: 1447
From: Hurricane alley
Registered: May 2002
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posted 08-09-2002 08:37 PM
What code are you getting?btw, check the brake booster & vacuum leaks. Sometimes you have both, lean & rich, problems. Once you fix one the other shows up.... Example. Say your EGO was not working. That will make the engine go rich most of the time, reporting to the processor less then .5 volts, over .5 is rich and under .5 is lean. So, the engine runs rich and fuel will get into the oil, getting past the rings. The EGO will pick up the fuel vapors from the PCV. Now you can get a rich code, until you change the oil. If you have a DVOM you can watch the EGO work.... EEC systems are in Open loop cold and closed loop, getting feed back from the EGO, once the EGO is over 650* [This message has been edited by Buster (edited 08-09-2002).]
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steve'66
Gearhead Posts: 8908
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 08-09-2002 09:02 PM
Buster,Thanks for the help. The code is 0174 same as last time. The symptoms are lack of power and it won't return to idle between shifts. It's a pain to drive cause it keeps accelerating after you lift. SteveW
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Buster
Gearhead Posts: 1447
From: Hurricane alley
Registered: May 2002
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posted 08-09-2002 09:19 PM
Steve, let me know if the brake booster is ok and no vacuum leaks. There are a few ways to check the booster. Pinch off the vacuum line is one way. And here is another way: Run the engine and place your foot on the brake peddle semi lightly. Then shut the engine off... If the peddle pushes up on your foot the booster is leaking.
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steve'66
Gearhead Posts: 8908
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 08-09-2002 09:36 PM
Buster,The booster is fine. Tested it both ways including a test drive with a very hard brake pedal just now. I've been scratching my head all day wondering how it can get air with the throttle closed and a good IAC. The old IAC had black soot in it, is that a clue? How about the egr? SteveW
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Boss302
Gearhead Posts: 841
From: Coleman, Wisconsin
Registered: Jan 2002
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posted 08-09-2002 09:39 PM
how exactly can i tell if theres a vacuum leak?? i pulled the tube off the throttle body or whatever that thing is, and i couldn't feel any sucking/blowing. and my dad checked another line and there was nothing. is this normal?------------------
Max
-1989 Mustang GT (MaxTang)
225/50R15 tires
BBK Strut Brace
K&N Filter
4 cats, no muffs
180* stat
Member 1,861 "The Horses Shake You Harder Than Sex, the Sounds Ring In Your Ears, Fact Is Your Engines Only on Idle"
IP: Logged |
Buster
Gearhead Posts: 1447
From: Hurricane alley
Registered: May 2002
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posted 08-10-2002 10:45 AM
quote:
Originally posted by Boss302:
how exactly can i tell if theres a vacuum leak?? i pulled the tube off the throttle body or whatever that thing is, and i couldn't feel any sucking/blowing. and my dad checked another line and there was nothing. is this normal?
Well, my wife is an RN and I use her stethoscope... but you can use a vacuum line or even fuel line. Hold one end up to your ear and the first place I go is the vacuum tree. Place, your make shift stethoscope, on each vacuum line. If one of the lines are louder the the others, bingo. Also, go to the intake manifold where it meets the head. You would be surprised what you can find that way.
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Buster
Gearhead Posts: 1447
From: Hurricane alley
Registered: May 2002
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posted 08-10-2002 10:55 AM
quote:
Originally posted by steve'66:
Buster,The booster is fine. Tested it both ways including a test drive with a very hard brake pedal just now. I've been scratching my head all day wondering how it can get air with the throttle closed and a good IAC. The old IAC had black soot in it, is that a clue? How about the egr?
SteveW
Steve, if the EGR were not closing properly you would have a low engine idle. Something is causing the lean condition, if not a vacuum leak then I would say a sensor, map & mas air flow are the most dominant mixture sensors. The problem with checking a MAP sensor is it converts a DC voltage to an RF signal and you would need a special tester for that. A cracked exhaust manifold or air getting into the exhaust would cause a lean code as well. One other thing to check is the vacuum signal to the inside of the vehicle. If you have a leak, say vacuum can, when you accelerate hard, the blower will switch from the vents to the defroster. Also, have you changed the PCV? I have seen parts stores sell the wrong PCV, one the flows to much and cause the same problem. If its the old one Make sure it didn't come apart. [This message has been edited by Buster (edited 08-10-2002).]
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cpmaverick
Gearhead Posts: 1666
From: Santa Clarita, CA
Registered: Jan 2000
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posted 08-10-2002 07:52 PM
Steve-Sounds like either a MAF sensor or a vacuum leak. Make sure, in addition to checking the intake manifold, that you have no leaks downstream of the MAF sensor. If you have a multimeter, tap into & check the output wire of the MAF (it will be one of the end wires on the plug). It should read between .8-1.1 V at idle. It varies between cars so it's best to find the spec for your application, but should be in that range regardless. ------------------
-Charlie Ping
1970 Maverick Grabber
[email protected] with AC and overdrive.
http://www.maverickgrabber.com
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Glens67
Gearhead Posts: 477
From: Petaluma
Registered: Mar 2002
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posted 08-11-2002 02:46 AM
Steve
Bring her by. I can fix it in about .002 or .003 seconds. Just got a new supply of C-4.
I have completed the Lifter change, on the 67. Will Fire on Sunday. Still looking for the Coil. Got distracted after I pulled it, Nancy wanted something, set it down now I can't find it. You know I kind of like hiding my own easter eggs.
 ------------------
Glen
67 GT 390
65 Galaxie 500 XL 4 Speed
It was not a Red Light they gave me a Slow Tree [This message has been edited by Glens67 (edited 08-11-2002).]
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steve'66
Gearhead Posts: 8908
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 08-11-2002 06:21 PM
Sounds good Glen!It is insured, so maybe the c-4 is the answer. I'm crossing my fingers for you on the lifter swap. SteveW
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Dusty Kiser
Gearhead Posts: 171
From: Bethel,Oh USA
Registered: Mar 2002
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posted 08-11-2002 09:37 PM
Buster is giving you lots of good info, but beware of trying to test circuits unless you know exactly what you're doing. On the logic circuits ( any sensor ) you must have a 10 megohm tester. Most digital multimeters are ok. Also, unless you have the correct data to compare your readings with, you're pissing in the wind anyway. Sounds like a vacuum leak to me. I usually start by pinching off one vacuum hose at atime and watch RPM and manifold vacuum. Then if needed wil spray some WD40 or carb cleaner around intake gaskets and other potential leak sites still watching for RPM change and manifold vacuum. By the way, vac should be around 21 inches. I suspect your engine should be equipped with HEGO's ( heated exhaust gas Oxygen sensor ) and is probably OBD1 which is early EEC V and a PIA. Even if you choose not to work on it yourself, a good engine performance repair manual is worth the money, so at least you can follow what your mechanic is saying and determine if he's BS or for real.
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Buster
Gearhead Posts: 1447
From: Hurricane alley
Registered: May 2002
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posted 08-14-2002 07:14 AM
Any luck Steve?
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steve'66
Gearhead Posts: 8908
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 08-14-2002 10:04 AM
Buster,It's at the Ford Dealer today being looked at by a "drivability tech".
SteveW
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steve'66
Gearhead Posts: 8908
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 08-15-2002 11:07 PM
This story is finally over!It turns out the MAF sensor was faulty. And for only $500 it runs like a champ again. Basically it thought it was running in 10,000' of air when it was really at sea level. WTH, it's only money. LOL The next person that suggests putting a efi motor in a classic is in trouble. SteveW
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steve'66
Gearhead Posts: 8908
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 08-15-2002 11:55 PM
Update:The check engine light is back on! The car still runs well, but it's going back to the dealer in the morning. SteveW
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steve'66
Gearhead Posts: 8908
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 08-15-2002 11:57 PM
Anyone have some extra vaseline? SteveW
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steve'66
Gearhead Posts: 8908
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 08-17-2002 12:39 AM
OK,An update for anyone that cares, the latest trip to the FoMoCo garage yielded a faulty HO2S, the only one of the 4 that I didn't replace. Another $344 and it's on the road again. This has been a $1000 experience.
I sure hope the light doesn't come back on for a while. SteveW [This message has been edited by steve'66 (edited 08-17-2002).]
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Boss302
Gearhead Posts: 841
From: Coleman, Wisconsin
Registered: Jan 2002
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posted 08-17-2002 03:48 PM
i think it would cheaper to disconnect the idiot light, then u wouldn't know when something was wrong. lol ------------------
Max
-1989 Mustang GT (MaxTang)
225/50R15 tires
BBK Strut Brace
K&N Filter
4 cats, no muffs
180* stat
Member 1,861 "Look Into Those Eyes So Deep In-Love, and Drink It Up, 'cause Thats the Good Stuff"(for spenc)
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steve'66
Gearhead Posts: 8908
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 08-17-2002 04:49 PM
Max,I'd change your MAF sensor, all the HO2S's then disconnect your battery to clear the 'puter. You can do all that for only $400 or so.  SteveW
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