fuel system status


Gobowiec
04-23-2008, 06:06 AM
What describes field "fuel system status"? The value changes from "closed loop" to "closed loop fault" and back. What could cause this? Also what values should I get in the "calculated load value", max what I've observed was 70%.
http://img217.imageshack.us/img217/473/obd2zrzutov1.th.png (http://img217.imageshack.us/my.php?image=obd2zrzutov1.png)

wiswind
04-24-2008, 10:04 PM
I am not at all familiar with the software or setup that you are using.
I only have a scangage....no PC/Laptop setup.
Maybe someone who has such a setup will chime in.

What I CAN tell you is that the windstar OBDII system does NOT monitor fuel pressure or fuel flow.
It also does not monitor barometric pressure.
Does your software setup need to be told this?

One other thing.....my scangauge indicates that the system goes from open loop to closed loop in a fairly short period of time.....the engine does not even register any temperature on the temperature gauge when this takes place.

Gobowiec
05-03-2008, 05:14 PM
what I found is that it goes from open loop to closed as soon as the O2 sensors are heated up. The sensors are heated so it takes really no time to heat them compared to time the engine needs to heat up.
I used other program which gave me this in the logfile:
Fuel System 1 Status, CL-Fault: Closed loop, but fault with at least one oxygen sensor. May be using single oxygen sensor for fuel control., OL/CL, CL-Fault, OL/CL
this is caused by my dead bank 2 O2 sensor. It gives reading 0,05V up to 0,2V. But I also got this:
Fuel System 1 Status, OL-Drive: Open loop due to driving conditions. (e.g., power enrichment, deceleration enleanment), OL/CL, OL-Drive, OL/CL
and with the scanmaster program: "closed loop driving".
I'll like to ask what readings should I get from "Load Value". In the log max what I found was:
Calculated Load Value, 83,92, %, 83,92, %
That was with a "heavy foot" trying to check acceleration. What readings to you get?

tripletdaddy
05-04-2008, 03:30 AM
You might be flying solo there, bud. :(

tripletdaddy
05-05-2008, 05:20 PM
Your software doesn't come with an explaination on this stuff, what these parameters mean, how to interpret measurements and what to do with the info? Does the scan program have a tech support you can contact? As Wiswind pointed out, the OBDII does not measure fuel usage, pressure, flow rate, etc., as it is not part of the federally required parameters used to control emissions. So, I'm guessing some of your measurements, like the FS1 Status, may be fuel dependent, therefore, a meaningless value. The calculated load value sounds like the load of unburnt fuel that the O2 sensors are detecting on the cats. If high or low enough, you would expect corresponding fault codes on your OBDII system. Do you? What was the load value for idle? How does it compare to the hard acceleration? Does it give you a post cat measurement? Do you have a defective O2 sensor? That may be what is giving you loop fault readings. Replacing that may very well fix your problem, though I'd expect to see a big difference in load values from left to right banks right now if that is the cause of your problem. I don't know if one sensor is bad the PCM will then use the other one or default values to determine fuel/air ratio. Hopefully, someone can chime in if this sounds like the PCM needs to be reflashed. Have you tried disconnecting the battery for awhile and have the PCM relearn driving patterns. I think someone on this forum has stated there is a specific procedure for enacting the learning process. Offhand I don't know it.

What specifically are the operation and performance issues you are experiencing, as this would give everyone more of the picture to maybe chime in to make suggestions. Have you done, checked the basics to fix this? Plugs, filters, wires, coil, egr, iac, tps, maf, fuel pressure?

tripletdaddy
05-05-2008, 05:28 PM
What is the exhaust like? Smells like gas and black and sooty. If so, it's running rich, not burning it all and will eventually will overheat the cats and burn them up. If running rough, maybe missing, definitely look into tune up. plugs, wires and coil. The coil has been known to couse this kind of elusive problem.

Gobowiec
05-09-2008, 03:12 AM
I think the I can forget for the moment about fuel status. This is caused by O2 sensor. Spark plugs, wires, coil, MAF, TPS are OK. Some of them where swapped from other Wini for test. ECU (PCM) was reseted and tried all methods of relearning I found on forum. Exhaust is also alright. This is taken from http://findarticles.com/p/articles/mi_qa3828/is_199810/ai_n8813610/pg_1
6. Calculated load. All vehicles must report this parameter as a percentage. This is a very helpfill parameter with MAF-only systems. With a MAP-only system, you can estimate load based on vacuum; on a MAF system, this has to be calculated based on airflow and rpm. This is really the reverse of the speed density calculation. Now for the tricky part: The government required this parameter as a percentage, but it seems that's as far as they went. With most of the OEMs, the idle no-load reading is about 5% to 10%, which seems logical. A Ford, however, will report 25% to 30% under the same conditions. Hmmm.
This didn't make any sense to me until I drove down a big hill, under negative load (compression braking). The Ford load reading dropped to almost zero. So, Ford sets its baseline higher to include negative load conditions in the parameter range. The other OEMs don't read negative numbers, so there's no resolution in their negative load range. This is a central problem with OBD II; different OEMs implement specs in different ways. You can blame the vehicle manufacturer or the government; either way, the responsibility is on you to learn what to do. Remember, OBD II is a work in progress.
Similar link with graph: http://www.dervman.com/obdii.htm#calcload
What I would like to ask if somebody can check their readings MAF-RPM-TPS as I guess this could be useful if I can compare with mine readings. These are mine at idle:
Air Flow Rate from Mass Air Flow Sensor, 0,382283560043211, lb/min, 2,89, g/s
Absolute Throttle Position, 16,078431372549, %, 16,078431372549, %
Oxygen Sensor Output Voltage (Bank 1 Sensor 1), 0,635, V, 0,635, V
Calculated Load Value, 40, %, 40, %
and at acceleration:
Air Flow Rate from Mass Air Flow Sensor, 5,26995745056108, lb/min, 39,84, g/s
Absolute Throttle Position, 47,4509803921569, %, 47,4509803921569, %
Oxygen Sensor Output Voltage (Bank 1, Sensor 1), 0,69, V, 0,69, V
Calculated Load Value, 74,12, %, 74,12, %
The air flow is very low compared to what I found on the net for other engines. I'll try to make a graph next week from all readings.
After taking off the whole intake part of the engine at the garage they told me its OK and engine works fine till first acceleration. Then it looks like something is blocking valve lifters. And this also might be a hint: starting a cold engine after several hours is problem less. Starts at the touch. Almost every next start, especially in a few minuts, is a trouble. Sometimes it needs a second or third try.
I wont have time next few days to make any tests, but if any suggestions can be given I'll try on Monday. Thanks.

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