Also the two pre cats are much worse when it comes to the disintegration, had to stop here for now but more pics of those to come.

Thanks,
RT

 

Alright, I have replaced the cats!

The good news is the truck drives much better. The bad news is I am still throwing lean codes after a KAM reset, some time in a warmup drive, and some time here idling.

There does seem to have been an improvement though, as instead of LTFT being at 30.5 no matter what RPM, I now see different LTFT per RPM. Before, no matter what my LTFT would be 30.5 (and maybe this will go back to being how it is after enough driving but we will see).








Drive-ability has definitely improved and I can actually hear the engine now standing at the back of the truck, so this is good progress.

Back to the drawing board on the P0171 & P0174 however!

Still trying to figure out if it’s a fuel issue (maybe injectors dirty still after a tank or two of fuel system cleaner?) or perhaps still a vacuum leak (even though the old IAC trick seems to indicate it may not be? If I unplug that IAC it will stall or drop from 750ish RPM to 500).





Off to bed for the night, take care!

Thanks,
RT

 

No vacuum leak

Engine temp must be above 160degF for O2s to give proper feedback, so running for at least 4 min, then look

Can you see the voltage on the downstream(After Cat) O2 sensor, Bank 1 Sensor 2(B1S2), should be 0.75v-0.85v and fairly steady compared to upstream O2s voltage
STFT is based on O2 voltage on that bank
LTFT is based on voltage from all 3 O2s

 

Hey Ron!

Alright here is what I see with running for around 5 mins, engine reaches temp, for both B1S2 and B2S2.





This is at idle by the way, so no throttle load. This is the after cat sensors.

I can also make graphs that match pre and post cat O2’s.

And there’s something interesting here it seems:


Bank 1 sensor 1 and sensor 2

Bank 2 sensor 1 and sensor 2

As you mentioned, it seems that o2 voltage for bank 1 sensor 2 stays steady at .6v and bank 2 sensor 2 jumps up and down between 0.1v and 0.6v.


Could the Bank 2 Sensor 2 be a dud?

Thanks,
RT

 

For what it’s worth, both downstream sensors are brand new “Walker” brand (O’Reillys $24.99 options). If I had to hedge bets on the o2s being defective vs the magnaflow cats being defective… I’d bet on the walker being defective every time.

Also they are easy enough to switch, so I can rotate them and see if the low voltage follows the sensor that is currently in B2S2.

Let me know what you think and I can try it tomorrow after work!

Thanks,
RT

 

You don't have Bank 2 sensor 2, well the computer doesn't, so ignore that

Bank 1 sensor 2 is a bit low, you want at least 0.8v average with new Cats

O2s can only see Oxygen not fuel
O2 volts
0.1v = high oxygen(lean)
0.9v = low oxygen(rich)

Good air/fuel engine burn should average 0.4v, that's the oxygen left in exhaust manifolds, upstream O2s see that, and STFT is based on that, lower that 0.4v = higher STFT, higher than 0.4v = lower STFT
Cat converters use the remaining oxygen to Burn Up pollutants so should average 0.8v, so low oxygen level is expected at the downstream O2

 

Okay good deal!

I have a spare NGK o2 sensor that I bought a few weeks back. When I bought the cats I ended up picking up the two Walker o2 downstream sensors at the same time just to start fresh with it all.

Today I will plug in the 2-3 week old NGK O2 sensor for Bank 1 Sensor 2 and we will see if it goes a bit higher up to .8v, or if we get the same result.

So the current thought process is:

• according to the bank 1 downstream o2, we have an excess of oxygen so the fuel trim must be increased in order to heat up the cats so it may use that oxygen to burn.
• If bank 1 sensor 2 was reading .8 (or perhaps closer to it), fuel trims should correct themselves based on both 1st position sensors reading up to .8v, and the b1s2 sensor reading closer to .8v in a more steady manner.
• The cause of the low reading would either be: a) the catalytic converter honestly not doing its job, or b) the o2 sensor not doing its job.

Let me know if that thought process is right on the money.

Also, we can say that the upstream o2 sensors look good, because they are see-sawing up to the right voltage.

It’s good to know the ranger ECU doesn’t use that B2S2 sensor in this regard, and also good to know the downstream are used in fuel calculations in this manner too.

At this point if the P0171 & P0174 was resolved, we wouldn’t be having this much fun chasing it down

As a side note, and to further validate the idea of vacuum not being an issue, last night I took the upper intake manifold off for fun to inspect it.




I did find there that it appears my thermostat housing is leaking coolant, so I’ll be chasing that down soon and cleaning things up.

The plastic manifold itself was in seemingly good condition, no cracks, gaskets were ok enough to put them back on (but going to order some fresh gaskets for it when I need to come back this weekend and do the thermostat and housing etc.

Question for you: since I’m in there and going to have easy access to it… I saw in some other threads along the way that the Engine Coolant Temp sensor plays a role in the air/fuel calculations… is that malarkey?? Or is there some truth to it?

If so I will add the ECT to this weekends parts list. Honestly I can probably read the temperature PID as well and get a sense of it being good or not…. But on the instrument cluster temp gauge I am always running a bit cooler than half on the gauge.

Let me know your thoughts, and I will update later with the NGK o2 readings in b1s2!

Thanks,
RT

 

Yes, your thought process seems to be on track

Your Bank 1 sensor 1 and Bank 2 sensor 1, the upstream O2s, looks like a good average but STFT are still a bit high at +10
Idling doesn't count for any O2 sensor voltage, same as engine being cold, at idle computer has to run the engine richer to prevent overheating

 

Alright here is todays information:

What I did today:

• Removed B1S2 Walker o2 sensor, replaced with NGK (NTK) o2 sensor.
• Replaced the B2S2 sensor with the B1S2 that was removed in the first step (why not).

Here is the data:

For the first test, I simply warmed the truck up and watched it idle. Here is the new NGK sensor shown below with its B1S1 sensor right above it. NGK B1S2 is the bottom graph. Cleared the KAM and it crawled back up on fuel trims. The good news is resting o2 voltage is around 0.7.



Bank 1 Sensor 1 and Bank 1 Sensor 2 Idle test


The second test is raising the RPMS TO 1500-1700-2000 rpm to simulate getting out of idle, and holding it across those RPMs. In this instance, B1S2 does reach moments of .8v as seen below:



Bank 1 Sensor 1 and Bank 1 Sensor 2 - 1500-2000 rpm

For fun in the same tests, here is bank 2:



Bank 2 Sensor Group idle



Bank 2 sensor group rpm 1500-2000


Would you say it’s possible that o2 performance for Bank 1 looks acceptable at this point? We seem to be seeing good voltages. Fuel trim still did work it’s way back up to 30.5 on both banks LTFT and 10ish STFT both banks, when adding RPM the short term does go up as well.

Let me know your thoughts, and have a good evening!

Thanks,
RT

 

So today I cleared the KAM memory and started the scanner KOEO, got my fuel trims on display and started it up. Basically from cold start, it was rough idle at 0.0% trim and slowly walked its way up to 50% trim, where things became much more steady and what I am used to with regard to idle.

With new magnaflow cats all around and new o2 sensors, I am feeling like the readings I am seeing (lean) are true, and feel to me like a fuel delivery problem.

The thing is I do have 65 psi to the rail, but I pulled off the bank 1 injectors today just to get a look at what’s going on.





I also have an Amazon fuel injector tester that can pulse and with the hookup for the fuel injector spray can as well to build pressure to test with.

Using this method I found that all three bank 1 injectors had a decent spray pattern, as it was misting correctly, however when I had them out, I did soak them fuel rail side down in a small cup of fuel injector cleaner while doing things, and I was finding that doing this was freeing up a bunch of particulate that was caught inside the injectors and unable to be pushed through the injector nozzle.




This cup was clean when I started - you can see the flakes in there. I also used a carb brush / pipe cleaner ring kit to try and dig around through the fuel rail side of the injector and managed to get a few more flakes out of there on each one, but I doubt that I did get everything completely cleaned.

I also found that one of the bank 1 injector casings were cracked, it’s not leaking fuel but I suppose it could begin to leak at any moment.




At this point, between the flakes in the cup and the cracked casing, I ordered 6 new injectors to try to finally rule out the fuel system.

I am internally justifying this by thinking of how going to WOT - the fuel trim increases correspondingly. Also doing a bit of looking on the web in other places folks seem to say that sudden WOT should flood the o2’s rich, but mine floods lean/low voltage. This would be an actual fuel delivery issue right?

Thanks,
RT

 

Another thing I would like to do over the next few weeks is to completely rule out the MAF. I have replaced it three times so far to be sure, once with Standard ignition brand, twice with Motorcraft (was in town so did a warranty replacement on the Motorcraft MAF for the second time since it was in stock.

Admittedly I did not record readings or differences between each, but I would like to know what the readings should be in order to mainly rule out damaged wiring for the harness there (as you can see I am grasping at straws but, I have had damaged wiring throw sensor CELs in the past of course).

I have set up a few dashboards using sensor voltage as well as some of the Ford PCM PIDs to check that and I’ll start collecting that data tomorrow.

One day I will crack the code here!

Thanks,
RT

 

Call up MAF sensor on OBD2 display change it to show grams/second, gr/sec

Rule of thumb at 800rpms-1,000rpms you should see engine liter displacement, i.e. 3 liter engine 3, 4 liter engine 4, 5 liter engine 5, so easy to remember

MAF is measuring the WEIGHT of the incoming air, not the amount of air, computer already knows/was programmed for, the size of the engine, so it already knows how many liters of air are coming in an any RPM, its just math
What it doesn't know is how much that air WEIGHS
Air at 5,000ft elevation(Denver) weighs A LOT LESS than air at sea level
Hot air, 90degF, weighs A LOT LESS than air at 40degF

Gasoline air/fuel ratio is 14.7/1
And its a WEIGHT RATIO
14.7 pounds of air to 1 pound of gasoline
14.7 grams of air to 1 gram of gasoline
Weight ratio
That's why fuel injectors are labelled as 14 pounds an hour(14lb/hr), or 20 pounds an hour(20lb/hr), ect................

 

That’s great information!

I will try the g/s measurement today, just on the way to drop the kids off at school this morning and I caught a few captures of WOT looking to accomplish a Volumetric Efficiency test with the dashboards I set up yesterday:




Using some of those values I tried to line up the run at the peak of 5170 RPM (and do note some of the graphs are a little “off” because of the editing map being a drag and drop style map, so for some reason graph alignment is an issue in some data sets lol).

Then I plugged approximate values into the volumetric efficiency calculator here:




And we get 78% VE - which is acceptable for what I understand assuming all things were measured correctly.

Next step while waiting for the injectors will be to further rule out the MAF, including the g/s measurement and maybe just bench testing the sensor.

If I could find out the correct voltages at the harness itself coming from the PCM, I will try and check those as well and see if anything is afoot.

Thanks,
RT

 

Checking in tonight,

Using a different scanner app and I think it is pretty nice, I have MAF g/s and rpm, intake temp here, and short term trims:




Seeing about 3.2 sometimes up to 3.4 at idle around 750-800 rpm.

Is this high enough to be an issue I wonder, or is this close enough to 3.0 to make sense?

Fuel injectors say they get here tomorrow, I will certainly try to replace them if I get the chance in the evening. I did a bit of a test today regarding the MAF:

- I warmed up the truck with the MAF plugged in, ran it around the house a bit, saw my usual fuel trims high.

- Unplugged the MAF and saw the fuel trims roll back down to 0.0, it would idle but not run very well. This is the first time I have tried this test with the new cats. Little power, in fact even without the MAF I saw it have to trim up 10% to get the truck to accelerate at WOT.

This is making me hopeful about the new injectors coming in. Either way I will continue to test and discover!

Thanks,
RT

 

The 3.2 to 3.4 is fine

 

Alright! The new injectors did NOT solve for the trim issue.




At least they are in there now and I can finally rule them out. Here is the march from 0.0 up to 50% trim on a clear KAM startup.



That is within seconds of starting the engine.

Back to the drawing board again tomorrow, but at least I can rule out injectors as the cause here.

Thanks,
RT

 

One interesting graph to show is this one, engine RPM is the bottom most graph. You can see when I hit the throttle, all sensors react, then the cats level out at about 0.8v for b1s2 and about 0.6v for b2s2.



Onward to more research on to how this could be!

Thanks,
RT

 

I think Ford switched to 21lb/hr from the earlier 14lb/hr injectors in 2001 so they could use the same injectors in flex and non-flex 3.0ls
E85 requires higher fuel use than Regular(E5 or E10) so needed a higher flow injector, 24lb/hr, in the earlier Flex Fuel engines
If you were running 14lb/hr injectors you would get higher fuel trims on a 2001+ computer because its expecting 21lb/hr flow

Or could just be a computer issue in general, it shouldn't have adaptive software to run Flex Fuel, but Ford was never forth coming about any proprietary software