Open Loop issues- which sensors - Ford Mustang Forum
Like Tree5Likes
Reply
 
LinkBack Thread Tools
post #1 of 196 (permalink) Old 11-19-2018 Thread Starter
SHELBY GT 350 Member
 
90lxwhite's Avatar
 
Joined: Aug 2011
Posts: 5,874
           
Open Loop issues- which sensors

Are there any particular sensors to look at when trying to diagnose a problem once it’s in open loop? Especially when it comes to not wanting to idle unless I give it gas. It idles real well in closed loop, and it will drive in open, it just doesn’t want to idle.
For example, what would be more suspect, the o2’s or the MAF? Or both and it’s a crap shoot? It seems in the past when I had a bad MAF or o2 (different vehicles) it would run real bad like it was missing, and it would hardly idle warm or cold.
Anything else y’all can think of?

90lxwhite is offline  
Sponsored Links
Advertisement
 
post #2 of 196 (permalink) Old 11-19-2018 Thread Starter
SHELBY GT 350 Member
 
90lxwhite's Avatar
 
Joined: Aug 2011
Posts: 5,874
           
Do I have my loops right?
It’ll idle when cold. Not at operating temp.
The exhaust smells like a gas pump


Last edited by 90lxwhite; 11-20-2018 at 08:27 AM.
90lxwhite is offline  
GT Member
 
wbrockstar's Avatar
 
Joined: Aug 2013
Location: Nashville
Posts: 2,179
 
Open loop= cold start/warmup mode/wot...
Closed loop= engine at operating temp with o2 sensors used...

(Strategies Used For Every Running/Driving Mode Link)
http://web.archive.org/web/201208082...index.php?p=64

1991 Mustang lx
D.S.S. 342ci {10.5:1}
TFS 190cc + track heat
Lunati 61011 .549".565"
Pro-M 76mm maf
Jetronic 30lb inj
QA1 Coilovers
17" Weld ProStar XP's
wbrockstar is offline  
 
post #4 of 196 (permalink) Old 11-20-2018 Thread Starter
SHELBY GT 350 Member
 
90lxwhite's Avatar
 
Joined: Aug 2011
Posts: 5,874
           
Quote:
Originally Posted by wbrockstar View Post
Open loop= cold start/warmup mode/wot...
Closed loop= engine at operating temp with o2 sensors used...

(Strategies Used For Every Running/Driving Mode Link)
http://web.archive.org/web/201208082...index.php?p=64
Thanks man. So I have closed loop issues then.
90lxwhite is offline  
Apprentice
 
imps's Avatar
 
Joined: Jul 2017
Location: Mohave County
Posts: 153
 
Similar Problem

Quote:
Originally Posted by 90lxwhite View Post
Thanks man. So I have closed loop issues then.
'94GT, 5-speed, no CEL, high fuel consumption, stinks a lot idling cold or hot, runs perfectly fine.

Many new parts taken from spare brand new 5.0 Engine, injectors, TB, new HO2S, ECT, MAF, PCM. Nothing changed.

My Foxes got at least 20 mpg normal rural/town driving, mid-20s highway, consistently. This thing bests at 15.0, same driving conditions. Seems to make plenty of power, no cat restrictions.

How might one determine if closed-loop operation is being attained. No stored codes. Thanks!
imps is offline  
post #6 of 196 (permalink) Old 11-21-2018 Thread Starter
SHELBY GT 350 Member
 
90lxwhite's Avatar
 
Joined: Aug 2011
Posts: 5,874
           
Quote:
Originally Posted by imps View Post
Quote:
Originally Posted by 90lxwhite View Post
Thanks man. So I have closed loop issues then.
'94GT, 5-speed, no CEL, high fuel consumption, stinks a lot idling cold or hot, runs perfectly fine.

Many new parts taken from spare brand new 5.0 Engine, injectors, TB, new HO2S, ECT, MAF, PCM. Nothing changed.

My Foxes got at least 20 mpg normal rural/town driving, mid-20s highway, consistently. This thing bests at 15.0, same driving conditions. Seems to make plenty of power, no cat restrictions.

How might one determine if closed-loop operation is being attained. No stored codes. Thanks!
I’m just assuming I’m stuck in “warmup loop” because I let it idle the other day and idled great until it reached operating temp and died.
90lxwhite is offline  
GT Member
 
wbrockstar's Avatar
 
Joined: Aug 2013
Location: Nashville
Posts: 2,179
 
Quote:
Originally Posted by 90lxwhite View Post
I’m just assuming I’m stuck in “warmup loop” because I let it idle the other day and idled great until it reached operating temp and died.

@ 90lxwhite & imp

When the ecm is running in open loop mode,o2 sensor voltage will remain at a fixed value. Once it switches to closed loop mode,o2 sensor voltage will begin fluctuating constantly.On an engine with heated o2 sensors,closed loop begins once the engine reaches operating temp & the o2 sensors reach 625+°.
higher reading= rich 450-900mv
lower reading= lean 100-450mv

Im not 100% sure about the 94-95 models,but the 86-93 models have a 20ga blue fusible link on the gray/yellow wire that passes over the pass strut tower in the main harness.Make sure the gray/yellow wire has 12+ volts or battery voltage with the key on.Make sure the orange o2 sensor ground wire is good too.Its attached to a lower intake bolt (rear) or the cylinder head (rear) If either of these circuits don't pass,the o2's wont work correctly.

1991 Mustang lx
D.S.S. 342ci {10.5:1}
TFS 190cc + track heat
Lunati 61011 .549".565"
Pro-M 76mm maf
Jetronic 30lb inj
QA1 Coilovers
17" Weld ProStar XP's
wbrockstar is offline  
post #8 of 196 (permalink) Old 11-21-2018 Thread Starter
SHELBY GT 350 Member
 
90lxwhite's Avatar
 
Joined: Aug 2011
Posts: 5,874
           
Quote:
Originally Posted by wbrockstar View Post
Quote:
Originally Posted by 90lxwhite View Post
I’m just assuming I’m stuck in “warmup loop” because I let it idle the other day and idled great until it reached operating temp and died.

@ 90lxwhite & imp

When the ecm is running in open loop mode,o2 sensor voltage will remain at a fixed value. Once it switches to closed loop mode,o2 sensor voltage will begin fluctuating constantly.On an engine with heated o2 sensors,closed loop begins once the engine reaches operating temp & the o2 sensors reach 625+°.
higher reading= rich 450-900mv
lower reading= lean 100-450mv

Im not 100% sure about the 94-95 models,but the 86-93 models have a 20ga blue fusible link on the gray/yellow wire that passes over the pass strut tower in the main harness.Make sure the gray/yellow wire has 12+ volts or battery voltage with the key on.Make sure the orange o2 sensor ground wire is good too.Its attached to a lower intake bolt (rear) or the cylinder head (rear) If either of these circuits don't pass,the o2's wont work correctly.
Thanks man
90lxwhite is offline  
Rookie
 
Kaili919's Avatar
 
Joined: Dec 2014
Location: Nanaimo
Posts: 38
 
Garage
I don't know if it's exactly the same as chev, but i once had a lumina and the complaint was it was really stinky, almost like rotten eggs and it turned out to be MAP sensor...
Kaili919 is offline  
Apprentice
 
imps's Avatar
 
Joined: Jul 2017
Location: Mohave County
Posts: 153
 
Quote:
Originally Posted by wbrockstar View Post
@ 90lxwhite & imp

When the ecm is running in open loop mode,o2 sensor voltage will remain at a fixed value. Once it switches to closed loop mode,o2 sensor voltage will begin fluctuating constantly.On an engine with heated o2 sensors,closed loop begins once the engine reaches operating temp & the o2 sensors reach 625+°.
higher reading= rich 450-900mv
lower reading= lean 100-450mv

Im not 100% sure about the 94-95 models,but the 86-93 models have a 20ga blue fusible link on the gray/yellow wire that passes over the pass strut tower in the main harness.Make sure the gray/yellow wire has 12+ volts or battery voltage with the key on.Make sure the orange o2 sensor ground wire is good too.Its attached to a lower intake bolt (rear) or the cylinder head (rear) If either of these circuits don't pass,the o2's wont work correctly.
@wbrockstar This is the kind of info I need! Thanks! The '94 still uses EEC-IV level of EFI, has only 2 HO2S, each with 4 leads, two of which feed the heater. I can check schematics for a fusible link. My '04 Explorer 4.0 uses standard fuses to feed O2 heaters. imps
imps is offline  
post #11 of 196 (permalink) Old 11-22-2018 Thread Starter
SHELBY GT 350 Member
 
90lxwhite's Avatar
 
Joined: Aug 2011
Posts: 5,874
           
Quote:
Originally Posted by Kaili919 View Post
I don't know if it's exactly the same as chev, but i once had a lumina and the complaint was it was really stinky, almost like rotten eggs and it turned out to be MAP sensor...
No MAP sensor on the mass air mustangs. Mine doesn’t have the rotten egg smell. It’s more gassy. It runs like a lawnmower engine with the choke on. Good when warming up but I think “the choke” is still on after it’s warm and it’s flooding it out. When I open the throttle I think enough air gets in to keep it running.
90lxwhite is offline  
post #12 of 196 (permalink) Old 11-22-2018 Thread Starter
SHELBY GT 350 Member
 
90lxwhite's Avatar
 
Joined: Aug 2011
Posts: 5,874
           
Pmas MAF

I’m not exactly ready to throw parts at it yet, but this 80mm MAF from Pmas be the way to go if it comes to that. I probably don't need an 80mm, but the price isn’t too bad for a new non-reman. http://www.pmas-maf.com/product/mh80...jectors-black/
90lxwhite is offline  
GT Member
 
wbrockstar's Avatar
 
Joined: Aug 2013
Location: Nashville
Posts: 2,179
 
If you do decide to purchase a maf sensor from pmas,I would call the company directly to order,so you can talk to the tech dept first to make 100% sure you get the correct sensor for your application.
Dont you run 24lb inj,an Anderson Power Pipe & a conical filter now or no?? I know the filter setup is important when they do the calibration to the sensor electronics, so its information they need to know when they're recommending which maf you need.
That link you posted is a 80mm maf
w/19lb calibration w/stock airbox for a Ford thats currently running a 80mm maf.
So you might need a maf with a cai or conical filter calibration,but they're the experts that can tell you that.
There are several other mafs listed specifically for 94-95 models.The only ones I listed below are the black finish mafs.

MH80FB-24
80mm/24lb/stock airbox/with a flanged 70mm maf installed currently/94-95 Mustang


MH80FB-24CA
80mm/24lb/cold air intake/with a flanged 70mm maf installed currently/94-95 Mustang


MH80FB-19CA
80mm/19lb/cold air intake/with a unflanged 55mm maf installed currently/94-95 Mustang


MH80-FB-19
80mm/19lb/stock airbox/with a flanged 80mm maf installed currently/Fords
**The description for the maf above stated to use part number MH80-19 if you are running a conical filter,but that number maf isnt shown at all on the site.
Numbers like MH80A-19/MH80B-19/ MH80FA-19/MH80FB-19 are shown,but no MH80-19**

I would definitely call them.

1991 Mustang lx
D.S.S. 342ci {10.5:1}
TFS 190cc + track heat
Lunati 61011 .549".565"
Pro-M 76mm maf
Jetronic 30lb inj
QA1 Coilovers
17" Weld ProStar XP's
wbrockstar is offline  
post #14 of 196 (permalink) Old 11-23-2018 Thread Starter
SHELBY GT 350 Member
 
90lxwhite's Avatar
 
Joined: Aug 2011
Posts: 5,874
           
Quote:
Originally Posted by wbrockstar View Post
If you do decide to purchase a maf sensor from pmas,I would call the company directly to order,so you can talk to the tech dept first to make 100% sure you get the correct sensor for your application.
Dont you run 24lb inj,an Anderson Power Pipe & a conical filter now or no?? I know the filter setup is important when they do the calibration to the sensor electronics, so its information they need to know when they're recommending which maf you need.
That link you posted is a 80mm maf
w/19lb calibration w/stock airbox for a Ford thats currently running a 80mm maf.
So you might need a maf with a cai or conical filter calibration,but they're the experts that can tell you that.
There are several other mafs listed specifically for 94-95 models.The only ones I listed below are the black finish mafs.

MH80FB-24
80mm/24lb/stock airbox/with a flanged 70mm maf installed currently/94-95 Mustang


MH80FB-24CA
80mm/24lb/cold air intake/with a flanged 70mm maf installed currently/94-95 Mustang


MH80FB-19CA
80mm/19lb/cold air intake/with a unflanged 55mm maf installed currently/94-95 Mustang


MH80-FB-19
80mm/19lb/stock airbox/with a flanged 80mm maf installed currently/Fords
**The description for the maf above stated to use part number MH80-19 if you are running a conical filter,but that number maf isnt shown at all on the site.
Numbers like MH80A-19/MH80B-19/ MH80FA-19/MH80FB-19 are shown,but no MH80-19**

I would definitely call them.
I actually emailed them earlier today.
I’m using Vortech’s induction setup and 19#’’ers. The filter attaches to the MAF w a clamp and there’s a collar that slides over that attaches to the stock maf’s flange.
I’m assuming I want their cone filter style maf. I guess/hope the flange the where it bolts up is the same size as the stock one.
I wonder if the difference in calibrations between the air box style and cai type are in the electronics or the housing? I hope their “19# calibrations” aren’t too far off from stock to where it causes tuning issues. Seems like the maf’s should be/would be pretty much stock like. I didn’t see a 75mm, I think that size would be better suited for my asthmatic top-end. The stock maf is 70mm and the opening on the intake manifold is 60mm or less. BBK and others have 75mm I know, but I’m not paying $250+ for a maf. What makes the Pmas look attractive is the price. It’s $109, a new Duralast is $85, and a reman is $65. I’m not really expecting any more power out of the deal. But surely it’d be of better quality than the parts store stuff. I just hope the whole calibration thing works out right since it’s been dyno tuned.
I see that the one for a cai is unflanged. I need a flange, I think? Or maybe it’ll work if I don’t use the collar the flange goes to.
*Edit*
I’m going to call them, but I think this is the one I might need. It’s the 80mm for 19’s and cai. The description says it doesn’t have a flange but the one in the picture has one. I think I’ll be able to use one with or w/out one though. I’m going to wait and I get any cold hard cash for X-mas this year before making a purchase.
http://www.pmas-maf.com/product/mh80...-intake-black/
Attached Thumbnails
Click image for larger version

Name:	14E7BEEC-651D-43FB-AC34-7DA3DC4025E7_1542951807519.png
Views:	40
Size:	185.5 KB
ID:	607061   Click image for larger version

Name:	CD6BA977-8611-4B06-9596-39D1F6CFB64A_1542952176084.png
Views:	42
Size:	150.1 KB
ID:	607063  

Last edited by 90lxwhite; 11-23-2018 at 04:55 AM.
90lxwhite is offline  
GT Member
 
wbrockstar's Avatar
 
Joined: Aug 2013
Location: Nashville
Posts: 2,179
 
One thing I found odd was that they listed the MH80FB-19CA for a 94-95 Mustang, but yet its supposed to replace a unflanged 55mm maf,which is the size of the maf that came on the 89-93 Mustang.
I would have thought their maf thats made for a 94-95 model would have been
listed as replacing a 70mm maf,not a 55mm,so thats a little odd.Another one was the part number you originally listed thats supposed to replace the 80mm maf
on Fords already using that size.Why would someone replace their maf with the same size maf,but I guess someone could use it as a direct replacement if something happened to their stock maf.It would allow them to buy a new maf to replace their stock maf instead of buying a reman unit.
It looks like one calibration is for use with a stock airbox & one is for a cai and/or conical filter?? Its a good point you bring up about whether the calibration is in the electronics or housing.I don't think youll have an issue with a new maf since you're still running 19lbers.On a na setup,its usually a good idea to size the air intake components to where it funnels the air
into the intake (i.e.- going from slightly larger pipe down to smaller/identical size pipe as the throttle body/egr spacer,so that airflow can build up speed and make a smooth transition into the intake. However on a boosted setup,since you're forcing that air into the engine,artificially speeding it up,pipe size might not be as important?? The main thing is to not have the air hit an obstruction,like using a 75mm tb when the intake opening is only 60mm or having 60mm pipe size meeting a 75mm tb.It creates turbulence.


1991 Mustang lx
D.S.S. 342ci {10.5:1}
TFS 190cc + track heat
Lunati 61011 .549".565"
Pro-M 76mm maf
Jetronic 30lb inj
QA1 Coilovers
17" Weld ProStar XP's
wbrockstar is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Ford Mustang Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a VALID email address for yourself, otherwise you will not receive the necessary confirmation email needed to confirm, validate and activate your new AFM member account.

Failure to provide a VALID email address, will result in the cancellation of your new AFM member account registration.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome
 


Search Engine Friendly URLs by vBSEO 3.6.1