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Fuel Injector Sizing

Peak to Peak

That sounds like a possible solution. I will give it a try.
I am going to try a 10% adjustment first though.
According to some reliable sources that factory narrowband O2 sensor uses a range of 0 -.9 volts, and yesterday I did a manual amplitude test on the O2 sensor by pumping the pedal a few times and it did hit a max of .9 so I know the sensors are still good. 20% had some of the values over the .9 max of an O2 sensor so I will try 10%. If that looks promising I may just try the 20%.

I must say that it is not really amplitude the PCM is having a problem with, it is frequency. Check out this statement on the test.
The HO2S is also tested functionally. The response rate is evaluated by entering a special 1.5 Hz. square wave,
fuel control routine. This routine drives the air/fuel ratio around stoichiometry at a calibratable frequency and
magnitude, producing predictable oxygen sensor signal amplitude. A slow sensor will show reduced amplitude.
Oxygen sensor signal amplitude below a minimum threshold indicates a slow sensor malfunction. (P0133 Bank 1,
P0153 Bank 2). If the calibrated frequency was not obtained while running the test because of excessive purge
vapors, etc., the test will be run again until the correct frequency is obtained.

It seems that my truck just tries and tries to run the test, never setting a code, this makes that last statement ring loud in my mind. Right before that it states that if the amplitude is below minimum it sets a code (PO133 or PO153). I will also note that I did try shutting off the canister purge two years ago, I may try that again just for giggles.
 

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HEGO Test

Here is the other information on the HEGO test.
What I think we really need access to is the commanded frequency and desired result of the HEGO test, in our tunes. Maybe that is just asking too much.
 

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HEGO Test

Typical HO2Sresponse rate malfunction thresholds:
Voltage amplitude: < 0.5 volts

Maybe I should try 20% decrease.
 












first make sure you have your fuel dialed in, verify the lambses are switching at 1.000 during all conditions, otherwise the lambses will have to over compensate to reach stoich and make the hego switch

that sounds like its your problem, injector swap alone will not affect the test at all
 






voltage swing

It says that a malfunction is when the voltage swing is less than 0.5 volts. That's why you should increase the magnitude of the voltage swings.

The swing is over .5v on bank 1
 






lambses

first make sure you have your fuel dialed in, verify the lambses are switching at 1.000 during all conditions, otherwise the lambses will have to over compensate to reach stoich and make the hego switch

that sounds like its your problem, injector swap alone will not affect the test at all

My fuel is dialed in.
Look at the screenshot, fuel trims are about 1.00 + or - .03
That is for both STFT and LTFT
 












O2 Sensor Amplitude

Good argument.
I was looking at that too.
However the two arrows facing up would not be included since they are 2 of the low peaks and not high ones (for lack of better terminology.
The arrows facing down sure do indicate a lower than normal amplitude, especially the last one.
Let me introduce this next picture and a couple thoughts.
If it is an amplitude problem it will set a code PO133 or PO153. The sensors as they wear loose the ability to reach a higher voltage. Manually pumping the throttle three times fast triggers the accelerator pump function through the TPS to the PCM and causes a rich mixture. If the voltage reaches .8 or higher the sensor is said to be capable of reaching it's rich threshold. I tested the truck with these injectors in and the O2 sensors are capable of hitting .9

Also "A slow sensor will show reduced amplitude" quoted from the OBD information, but my O2 sensors are not slow. The sensors work just fine with the pressure at 39.15 and the injector data entered accordingly and MAF dialed in. (they were brand new Motorcraft sensors 2 years ago when I first encountered all the same responses when datalogging, been about 5,000 since then).

The best argument that it is a frequency issue, not amplitude, is that in the screenshot below of about 12 or more seconds, the peak voltages never went below .5 volts and it still never was able to pass/complete. The test only has to run/pass for 4 seconds. I couple that with the statement "If the calibrated frequency was not obtained while running the test because of excessive purge vapors, etc., the test will be run again until the correct frequency is obtained." If I get the vehicle in the right conditions to run the test again it tries and tries, never is able to complete, and never sets a DTC.

I seriously am thankful for any and all input and arguments on this matter, it makes you think harder and see things from different perspectives. I am still going to try different tunes with different peak to peak settings, different injector data, and fuel pressures. I have the tunes on my X4 and am waiting to get a chance to use them.
 

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Defining the problem

I guess the way I see it is this
The amplitude within the frequency is what is messed up.

What I mean is that if the voltage was just not hitting a high enough point everytime, (lets say .8 and it was just hitting .7 instead) then maybe adjusting the Peak to Peak swing a little higher might make it be able to hit that .8 and pass the test.
The fact that it hits peaks of .8 and valleys of close to 0 but very randomly, makes me believe that it is a precision issue not a volume or range of voltage. But maybe adjustments to peak to peak will make them more refined. I guess I should spend less time typing and go out there and test it, but it is cold!
 

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EGO monitor description

At one time it probably worked as follows:

"During normal operation of the vehicle, the EGO monitor will follow the following execution sequence:
I. Test is enabled from the Diagnostic Executive.
II. Local entry conditions are satisified.
III. High frequency fuel modulation begins.
IV. After a number of engine revolutions, sampling of the upstream EGO sensors starts occuring every 16 milliseconds. Upstream EGO sensor voltage and frequency statistics are computed.
V. After a number of commanded LAMBSE cycles occur, high frequency fuel modulation is disabled, and 16 millisecond sampling is disabled.
VI. EGO signal amplitude and frequency response is calculated for each of the upstream sensors. These statistics are compared to calibrated limits and a decision is made as to the health of the upstream EGO sensors.
VII. The voltage envelope of the downstream EGO sensors is checked, and if it not sufficently large because a minimum rich voltage on bank 1 or a minimum lean voltage on bank 2 has not been observed, then the fuel control is forced into open loop and a rich A/F ratio is commanded for bank 1.
VIII. After the calibrated number of seconds times out or the required rich voltage is seen the rich A/F excursion is discontinued. If a required minimum lean EGO sensor voltage has not been seen up to this point then the fuel control is forced into open loop operation and a lean and A/F ratio is commanded for a calibrated number of seconds for the appropriate bank.
IX. After the calibrated number of seconds times out or the required lean EGO sensor voltage is seen, the lean A/F excursion is discontinued.
X. A decision is made on the relative health of the downstream EGO sensors based on the voltage envelope attained on the downstream EGO sensors.

Simultaneously to all of the above, whenever an overvoltage condition occurs on any EGO sensor, a malfunction will be identified to the diagnostic executive and no further testing of the malfunctioning sensor will take place.

Also, the EGO heaters will be tested by rapidly turning them on and then off and then back on again and recording the activity on the OSM (output state monitor) input for each of the EGO heaters. Malfunctions will be identified to the diagnostic executive when a faulty heater is found.

In order to ensure EGO tests can be included/excluded as required to match the particular application a set of configuration switches are made available to the calibrator. "

It may no longer be that way in your strategy. The criteria for pass/fail are calibration constants that I don't have access to in Advantage III even with "Calibrator" status.
 






Peak to Peak

Here are the datalogs of raised and lowered Peak to Peak.
The raised one definitely looks better compared to the lowered one, it was only 10% increase.
I will try 20% added instead of 10%, to see if it gets better or worse.
The second picture is with 20% removed, definitely worse. You can see how the amplitude shrunk through most of the pattern.
 

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headers?

The O2 sensors' range is electrically limited so increasing the deviation range in the table will not affect the peaks once they are achieved. However, it should increase the slope because the PCM "thinks" there is a larger range. That's why I suggest increasing it until the O2 values are clipped. HHO users have devices that alter the outputs of the O2 sensors to fake out the PCM. I think "tweaking" here and there will avoid the need for such a device.

I can't remember if you still have the stock exhaust manifolds. Here are the transport delays for my stock tune.
O2TransportDelay.jpg

I think when the HEGO test is running the PCM is in open loop. If so, do the STFTs reflect commanded lambda? Can you tell if shifting the O2 responses relative to the commanded change would decrease the response time? I wonder if aligning the injector pulse leading edge with the O2 sensor response would help things.

EDIT: By the way, have you turned off the IMRC switch? If not, turning it off will save your PCM a little processing time.
 






O2 sensors

Increasing the range until the O2's clip sounds promising, I am looking forward to testing with 20% increase to the table. Then 30% or more if needed.

I do have JBA headers, and have thought about transport delay, most things I have seen with transport delay issues are from long tube headers so I didn't think it to be a necessary change. But who knows, maybe scaling back or forth may just be that edge needed to get the Test to run and pass.

IMRC is turned off since that is long gone. I some how felt that something from it is left behind that I can not access though. What made me think so was how the STFT does not show commanded Lamda at WOT, it seems to start that way and then goes to .8 something. I have commanded set to .784
 






Switch to Force Open Loop?

. . . IMRC is turned off since that is long gone. I some how felt that something from it is left behind that I can not access though. What made me think so was how the STFT does not show commanded Lamda at WOT, it seems to start that way and then goes to .8 something. I have commanded set to .784

I had the same problem. I finally determined that having the Switch to Force Open Loop being equal to the stock value of 1 was the cause of the problem. With it set to 0 the STFT when the PCM is in open loop matches the BFT value throughout the entire engine operating range.
 






20% Peak to peak

Here is the screen shot for 20% increase in Peak to Peak amplitude for closed loop. Did not turn out like I hoped.
Then I tried these two switches. (primary O2 sensor test switch 2 and 3)
Turning these two switches off made the OBD tests, never try the O2 sensor tests.
At least I can drop the fuel pressure back to 39.15 and get it through inspection with these 47lb injectors.
I may just try a set of Injector Dynamics ID725's. $720.00 though.
 

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Passed HEGO monitor with 43.5 psi

Finally got the Hego test to pass with fuel pressure at 43.4
I am kicking myself for this one.
When I went to jack up fuel pressure I noticed it was at 36.15 instead of 39.15.
I took mental note of it but still increased the fuel pressure to 43.5
So instead of an approximate 4 psi of change it was 7.
It was in the back of my mind the whole time, should have known better.
I rescaled the injector data with my new number calculated by the larger fuel pressure change and it worked.
So I need to pay attention to the amount of pressure change exactly, which fuel pressure gauges I have are calibrated correctly, and battery voltage when adjusting fuel pressure.
 

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Congratulations! talking about a fine adjustment to have that test pass. Wow.

How does the head room look now? Is lowering pressure going to be an issue at wot?
 



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Fuel Pressure

I didn't lower the pressure. I rescaled the injector data.
Raising the pressure lowered duty cycle to 80 something when it was hitting 90% with the pressure at 39.15.
Still need to raise it more, will have to be careful rescaling injector data and retest with each pressure increase to see if it will still go through the HEGO test afterwards.
Wondering where a good safe duty cycle should be, need room for increased airflow down the road.
 






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