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        General >> Problems >> "Open loop" fuel system status
        
(Message started by: Ivan Pevnitsky on Jul 30^th, 2009, 3:42pm)

Title: "Open loop" fuel system status
Post by Ivan Pevnitsky on Jul 30^th, 2009, 3:42pm

Hi there again!

I've got an error P0171 System too lean, and my car is working in "Open loop" mode (i don't know what exactly it is, but I know it's not good ;))

I was told by a mechanic that there's no second lamda sensor somewhere either after catalyst or before -i don't remember. But he meant not the one under the hood.

Here my results from ScanXL ELM (click to view fullsize image):
http://ipevnitsky.fromru.su/Fuel/o2sensors_preview.png (http://ipevnitsky.fromru.su/Fuel/o2sensors.png)

Note that it shows me 2 sensors: bank1 sensor1 (that works) and bank1 sensor2 - that is always 0V. And that is why I think my system works in "open loop" mode.

And I think the reason is abroken lambda sensor. Am I correct?

Thanks

PS: don't pay attention to "Taurus 3.0" at the bottom. It's because the program doesn't support Scorpio, so I had to select another car.

Title: Re: "Open loop" fuel system status
Post by Gazza_UK on Jul 30^th, 2009, 4:13pm

???
How can it work ?

It cant its looking for features on your car that dont exist ? Like bank 2?

What I mean is it was set up for a 3lt by the sounds of it and yours is a 2.3
To be honest all the readings could be wrong

Title: Re: "Open loop" fuel system status
Post by scorpio_man on Jul 30^th, 2009, 4:20pm

hi there

i'll jump about a bit with my answer.

no, you only have 1 (pre cat) lambda sensor.

how long was the car running before doing the scan? the car needs to be running for 180 seconds before the lambda controls the fueling (closed loop).

your long term fuel trim is high at 18%.

was it really warm outside when you ran the scan, as your intake air temp sensor is at 46oC! remember the intake can get warmer than outside temp (maybe +10 oC).

at a quess, i'd think you have a air/vacuum leak somewhere (egr pipework?).

hth

Title: Re: "Open loop" fuel system status
Post by tlundkvi on Jul 30^th, 2009, 7:07pm

on 07/30/09 at 16:13:02, Gazza_UK wrote:

There is one bank and two sensors mentioned in the post. Sensor 2 is mounted after the cat and should show a steady line between 0.4 and 0.5 Volt, used for monitoring only. If jumping => bad cat. Reading of 0V suggests a bad lambda sensor, but still the sensor 2 only monitors. Ivan, are there any other error codes? Have you done an exhaust test?

I believe the Taurus 3.0 was needed to setup the right communication protocol. I may be wrong, but I believe the ODB-stuff can query which sensors and codes exist (like plug & play). My 24V could be scanned with the settings for a 2.0 which is different too, and yet codes & info about second bank lambdas was readily shown.

Title: Re: "Open loop" fuel system status
Post by scorpio_man on Jul 30^th, 2009, 9:36pm

hi there

as i said earlier, the 2.3 DOES NOT have a 2nd lambda, only a PRE cat lambda.

the 'reading' is at 0 volts as it's not there.

hth

Title: Re: "Open loop" fuel system status
Post by Gazza_UK on Jul 31^st, 2009, 12:20am

on 07/30/09 at 19:07:36, tlundkvi wrote:

Sensor 2 is mounted after the cat.

Not on a 2.3 ;D

Title: Re: "Open loop" fuel system status
Post by tlundkvi on Jul 31^st, 2009, 8:31am

Sorry, my mistake :)

Title: Re: "Open loop" fuel system status
Post by Ivan Pevnitsky on Jul 31^st, 2009, 6:12pm

Sorry me, guys :)) It was an old info about the problem.
I have recently changed EGR pipe (http://www.fordscorpio.co.uk/cgi-bin/yabb/YaBB.pl?board=Advice;action=display;num=1247934406) (because it's been broken), and idle revs became stable. But I believed that P0171 stayed.

Today I checked my car again. And there were no P0171 code (there're only gearbox related ones)
And here's a pic (click on it to enlarge):
http://ipevnitsky.fromru.su/Fuel/RPM_on_Idle2_preview.png (http://ipevnitsky.fromru.su/Fuel/RPM_on_Idle2.png)

Forget to check fuel system status though, but i think it should be ok! Will check it later.

And thank you for the info that there's only one lambda sensor. I can sleep calmly now :))

Title: Re: "Open loop" fuel system status
Post by scorpio_man on Aug 1^st, 2009, 7:56am

hi there

that scan seems far better.

are you running a induction kit on the air filter? your intake air temperature is still quite high (or is it really warm outside).

also, your MAF readings are a wee bit low. maybe run a scan on just that and check the readings throughout the rev range? :-/

hth

Title: Re: "Open loop" fuel system status
Post by Ivan Pevnitsky on Aug 2^nd, 2009, 10:05am

I don't know what is the induction kit.
The air temperature was about 23° Celsuis with almost no wind. How much should be IAT? Where's the temperature IAT sensor?
How much should be MAF data? I have recently changed air filter and cleaned the MAF. I'll try to test it on higher revs, and even while driveng

Thanks

Title: Re: "Open loop" fuel system status
Post by scorpio_man on Aug 2^nd, 2009, 11:21am

hi there

the clear air filter and MAF will explain the lower readings.

an induction kit is something like using a K&N cone instead of the filter box.

the IAT sensor is underneath the air tube to the throttle. you can give it a clean with carb cleaner.

hth

Title: Re: "Open loop" fuel system status
Post by Gazza_UK on Aug 2^nd, 2009, 2:47pm

on 08/02/09 at 11:21:10, scorpio_man wrote:

the IAT sensor is underneath the air tube to the throttle. you can give it a clean with carb cleaner.

hth

Please show by Pic if possable as Im curios on this and what it does ( see im still learning as well )

Title: Re: "Open loop" fuel system status
Post by scorpio_man on Aug 3^rd, 2009, 11:11am

hi there

http://www.fordscorpio.co.uk/16vcomponents.htm

hth

Title: Re: "Open loop" fuel system status
Post by Gazza_UK on Aug 3^rd, 2009, 4:28pm

Is there any info on what theses all do ?

EDIT

the ones I DONT know and what they do are

A
B
C
D
I
J

Title: Re: "Open loop" fuel system status
Post by scorpio_man on Aug 3^rd, 2009, 4:45pm

hi there

a= idle by pass valve.
b= throttle postion sensor.
c= only on the 2.0 16v and 2.9 24v engines.
d= camshaft sensor.
i= engine coolant temperature sensor.
j= intake air temperature sensor.

http://www.fordscorpio.co.uk/ccmonitor.htm

hth

Title: Re: "Open loop" fuel system status
Post by Ivan Pevnitsky on Aug 3^rd, 2009, 10:25pm

why the letters on the picture end with H, J, K . while the description ends with H, I, J

Title: Re: "Open loop" fuel system status
Post by Gazza_UK on Aug 4^th, 2009, 10:39am

Well spoted just noticed that my self ???

Title: Re: "Open loop" fuel system status
Post by Gazza_UK on Aug 4^th, 2009, 10:58am

on 08/03/09 at 16:45:48, scorpio_man wrote:

hi there

http://www.fordscorpio.co.uk/ccmonitor.htm

hth

Yes thats what Im after . . .
now it can make some sense to me ;)
Right with that Info I'm off to mates garage to play with is Snap On ETHOS

Title: Re: "Open loop" fuel system status
Post by Ivan Pevnitsky on Aug 8^th, 2009, 3:52pm

Took a diagram while 10 minutes driving:

http://ipevnitsky.fromru.su/Fuel/RPM_driving_preview.png (http://ipevnitsky.fromru.su/Fuel/RPM_driving.png)

2scorpio_man: see that IAT's falling down from 50° to 23° while driving (the outer air temperature was about 13.5°).

Why the MAP is alwas 0? Is it failed MAP signal?

There're no MAP-related errors in my DTCs, they are only gearbox-related:
P0732 Gear 2 Incorrect Ratio
P1756 Shift Solenod B Performance
P1761 Shift Solenod C Performance

Title: Re: "Open loop" fuel system status
Post by Tompion on Aug 8^th, 2009, 7:00pm

Assuming the MAP referred to is a sensor then there isn’t one, it was superseded by the MAF.
See first paragraph here:
http://www.fordscorpio.co.uk/cleanmaf.htm