**FIXED!!** 2000 Ford f550 chassis with 6.8 no codes, wont pass obd monitors

Have a 2000 Ford chassis motor home with a 6.8 litre v10. Unit has no active codes other than p1000. Has new ho2 sensors but will not pass the monitor for the sensor or the heater. Could really use some help. Need to pass the monitors to get it smogged

I found this on the web:

The P1000 DTC code is a manufacturer specific trouble code. In the case of Ford & Jaguar vehicles, it simply means that the OBD-II monitor testing is not complete.

There are only 3 things that I can think of that would cause the monitor tests to never complete:

1. The power is fluctuating in the vehicle, resetting the computer constantly
2. Two full drive cycles have not been completed
3. The ECU/PCM is faulty

For item 2 to happen at least 2 things have to happen

1. The conditions for a drive cycle to happen must be presenst
The best way that I've found to do this is to fully warn the vehicle up, then drive it down the highway at highway speed with the cruise control on for about 10 miles. That will complete 1 drive cycle. Then shut it off, let it completely cool down ( for an hour ) and do it all again. That will complete 2 drive cycles.


2. The ECU/PCM has to know that those conditions are present
If you have something ( like an incorrect coolant temp sensor, no codes will be set, but also the engine will always think that it never warmed up.
In that condition a drive cycle will never complete.

Use a scanner the can read live data and make sure that what all of your sensors are telling is correct

There’s many other things that can cause monitors to not set. Focus on your inputs. like ECT sensor, MAF, Map.

I’ve seen each of the above 3 cause monitors not to set.

I have no experience with Diesel engines but the same should still apply for emissions monitors

That's kinda my issue. I spend 90% of my time on diesels and I'm not too familiar with these gas emmisions systems

Just buy, rent or borrow a basic scan tool that does live data.

• Check your TPS ( Throttle Positions Sensor ) <-- Check for smooth linear operation as you slowly press the throttle pedal to the floor. This can be done Key On, Engine Off Also note the max and min readings

Fully warm the engine up, then check the following:
[hr]

• MAF (Mass Air Flow) You can use the volumetric efficiency formula to tell if this reading is normal or not. You'll have to Google it
• MAP (Manifold Absolute Pressure) at idle along with RPM's <-- normal MAP reading at idle is between 17 to 22"mg.
• ECT ( coolant temp sensor ) <-- should be around 185 - 200DegF at full engine warm up, depending on your thermostat and cooling system health.
• IAT ( intake Air temp sensor ) <-- should be warmer than outside air temp be a good 10 to 20DegF because of the hot engine bay
• STFT ( Short Term Fuel Trims ) <-- in a perfect World it would be 0%... but LTFT+STFT should be between +10% and -10%. That is the extreme limit of "ok"
• LTFT ( Long Term Fuel Trims ) <-- in a perfect World it would be 0%... but LTFT+STFT should be between +10% and -10%. That is the extreme limit of "ok"
• Fuel System Status ( You want to see "Closed Loop" )
• Check your primary O2 sensors. They should switch between rich(above 0.6v) and lean (below 0.6v) atleast once every 2 seconds
• Spark Advance should be around 10 deg BTDC at idle and should advance up toward 30 deg BTDC as you increase RPM's toward 5k
• Check your I/M monitor status. It will tell you specifically which monitors are complete and which ones are not

If all that check out and looks sane, then perform the 2 drive cycles that like I listed above.
let us know how it turns out.

i recently had an 08 silverado that wouldn't run O2 or O2 heater monitors & found ECT was 11 degrees F different than IAT before cold start (SI states needed to be within 5 degrees). Replaced ECT & monitors ran through in 4 miles. I would recommend reading drive cycle criteria for your specific make/model/year & check all applicable scan data.

I forgot to mention spark advance. I added that to my list above.

Have you had any luck with it?

Spark advance is around 20 degrees at idle and the o2 seems to be switch between rich and lean fairly steady. Mad gm/s is around 9.02 at idle . Stftrim is around 4 at idle on bank 1 and 3-8 on bank 2. If I. Not mistaken isn't there a correlation between maf and engine displacment. Would that mean I should see a maf reading closer to 6.8m

The MAF reading that high is something to really think about. I would expect something around 7.5 gms/s

Though I would expect your fuel trims to be

www.otctools.com/ve

I don't quite understand volumetric efficiency. What will I be looking for when I get it

Volumetric efficiency is at 17

Sorry that was at idle actual reading was 65

Spark advance is around 20 degrees at idle and the o2 seems to be switch between rich and lean fairly steady. Mad gm/s is around 9.02 at idle . Stftrim is around 4 at idle on bank 1 and 3-8 on bank 2. If I. Not mistaken isn't there a correlation between maf and engine displacment. Would that mean I should see a maf reading closer to 6.8m

1. Spark advance: 20 deg BTDC
2. Primary O2 sensor is switching
3. MAF: 9.02 g/sec
4. STFT B1: 4%
5. STFT B2: 3% - 8%

There is still a lot of information missing... like:

• engine RPM <-- what RPM does it idle at?
• Long term fuel trims
• Coolant temp <-- before engine start up and after full warm up
• Intake Air temp <-- before engine start up and after full warm up
• Throttle position <-- what is the throttle position at idle?

We need all of the stuff from my original list.

You'll have to do the test again to re-check the info with the complete list.

Based on your MAF and Spark advance readings, I'm guessing that your idle is higher than it should be... but there is no way to know without all of the data. There is no way to tell if your engine is idling high, or if there is some other problem because we don't know the engine RPM.

Idle was 800, ect before warmup was 68 after warm up was 192-197. IAT was 72 after warmup was 70. And long term fuel trims we're at 0

Think I figured it out. It's a heavy duty chassis with no after cat o2 sensor. I believe it falls under obd 1 emissions. So the monitors are irrelevant. Should find out tomorrow for sure.

I doubt that is the case. Every vehicle sold in the USA that was manufactured on or after 1996 is required to use OBDII.
Yours was made in 2000

It was the case. It passed smogg without those monitors being set due to the gvwr. It's tested as obd 1

Thanks for the follow up!

I had no idea that there was a weight clause in the Clean Air Act of 1986.
I'll definitely have to look into that.

Yeah I think what it is is if over 14000 gvwr if can fall under obd1.

We should mark this thread as Fixed.
I don't know how to do that, but I know that it can be done.
It really helpful for future people who search the forum with various problems.
It always good to know which threads ended with an actual solution.