ECU pulling timing, bad fuel economy and performance

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Tytanium

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2018 SHO non-PP @ 55k miles
EPP CAI
Gearhead AO tune package with 170* tstat, 0.028 gapped plugs, 3 bar map
MSD coils (switching back to Motorcraft after one of these failed and hearing terrible things about the quality of these)
Running 92 octane from Costco gas

I've been having issues with mileage (steady cruise highway mileage dropped from about 25-27mpg to about 20-21mpg) and some other noticeable drops in performance.

Data I've found:
No DTCs
+15-17% LTFT in both banks at idle, +7-9% under steady RPM. Bank 1 typically reads higher than bank 2 by about 5-6%
+3-6% STFT in both banks at idle, closer to +/- 1 under steady RPM
OAR is currently sitting at about -0.76 (was -1.0 a year ago with the same equipment and gas)
OBDII datalogger shows knock sensor pulling timing under load. Individual knock sensor PIDs show a readout I don't really understand (usually about 75-80 at idle, with a difference of 4-6 between sensors). Goes up to about 200-250 under load. Like I said, I have no idea what these numbers mean and I can't find any information about it.
Individual cylinder knock count did not show anything for any cylinder.

Diagnosis questions I have:
Is there a way to check the wideband O2 sensor voltages in a datalogger? I just want to verify that they are switching correctly or if there's anything else weird going on.
I did not notice any wire chafing on the knock sensor. Is there anything else I should be concerned about, sensor-wise?
IAT and MAP sensors are clean. I have not checked for boost/vac leaks yet, or exhaust leaks, but I'm definitely leaning more towards a sensor issue than a leak.

I'm open to any other suggestions! I had done a seafoam treatment at the throttle body a few weeks ago but didn't notice any improvement and I'm not sure if there's a lot of carbon buildup in the intake valves.
 
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rubydist

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Sounds like the knock sensor is thinking there is knock when there is not really knock. This can happen from loose parts rattling on the engine, like a loose cover or a hard line not secured properly etc.

It seems to me that the long term fuel trims are more than they should be. That is often caused by oxy sensors going bad. How old are the sensors?
 

SeanDev

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Good call in my opinion on the MSD, dealer blamed my ECM failure on those coils while I also had a leaky injector to fix. Here is a video of what this guy thinks of MSD and he has been posting great videos on the Ecoboost for years.

 

Tytanium

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I finished swapping all of my coils back to Motorcraft ones and rigged up a DIY smoke tester to check for boost leaks. Only one I found was naturally at the noisemaker

Unnamed

I have an EPP noisemaker delete pipe on order now. Would this by itself cause the excessively high fuel trims? I would understand if this were a MAF system but as it's not, I'm curious what else could be an issue. After reinstalling the noisemaker I started getting intermittent misfires on cylinder 1. I'm going to go through and double check all the plug gaps as there's only about 20k on these colder plugs.
 

Tytanium

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Sounds like the knock sensor is thinking there is knock when there is not really knock. This can happen from loose parts rattling on the engine, like a loose cover or a hard line not secured properly etc.

It seems to me that the long term fuel trims are more than they should be. That is often caused by oxy sensors going bad. How old are the sensors?
As far as I know, all sensors are original to the car (bought it used) except for the 3bar map.
 

SeanDev

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I finished swapping all of my coils back to Motorcraft ones and rigged up a DIY smoke tester to check for boost leaks. Only one I found was naturally at the noisemaker

View attachment 86019

I have an EPP noisemaker delete pipe on order now. Would this by itself cause the excessively high fuel trims? I would understand if this were a MAF system but as it's not, I'm curious what else could be an issue. After reinstalling the noisemaker I started getting intermittent misfires on cylinder 1. I'm going to go through and double check all the plug gaps as there's only about 20k on these colder plugs.
Any boost leak is bad, the engine is expecting a certain amount of air and fuel, if one is out, you'll get rich or lean fuel mixture. Bad thing with misfires is it hits the cylinder that is firing at that millisecond. I had a bad injector, I would get one cylinder or a bank, and would skip from bank 1 to 2. Cylinder 2 had the bad injector yet was the only cylinder not to throw a misfire code. The quirks of Ford's.
 

SM105K

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The MSD's have gotten a bad rap. There is a bunch of us on here that bought them in a big group buy. We are a good test/control group. I have them on my car, and I haven't really heard of any of ours failing here.
 

Tytanium

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The MSD's have gotten a bad rap. There is a bunch of us on here that bought them in a big group buy. We are a good test/control group. I have them on my car, and I haven't really heard of any of ours failing here.
I was in the group buy as well!
 

Tytanium

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So I've reset the ECU (as much as you can from a negative battery cable pull) and the LOR/OAR is now at -1.0 and has held there. I double checked all the plug gaps with a feeler gauge and all were at about 0.025, so I increased it to 0.028 as specified on the GH site. I'm getting intermittent misfires on cylinders 1 2 and 3, fuel trims are slightly better at idle but still around +7-10% and even higher under load.

Intake gasket leak? Fuel injectors?.
 

SHOWNF

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I have msd coils. No issues so far, knock on wood. I believe yaycandy had a similar issue of timing being pulled and he replaced his fpcm behind the back seat to fix his issue. He had stated he wasn’t sure how but it did fix his issue. Worth a shot as it’s an inexpensive quick replacement. Hope this is helpful
 

Ta2dResqr

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What are you using for data logging/code reading? Can you see fuel pressures? Lean fuel mixture can cause knocking. If your pump or controller is getting weak, this could explain the fuel trims and the knocking under load. As mentioned above, the FPCM is a known problem on these vehicles. The Dorman OE Fix part is $40 on RockAuto. For some cheap insurance, that would be a good start. From there, I would start checking LPFP pressure and rail pressure. It sounds like something system wide as you are seeing fuel trim issues on both banks.
 

Tytanium

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What are you using for data logging/code reading? Can you see fuel pressures? Lean fuel mixture can cause knocking. If your pump or controller is getting weak, this could explain the fuel trims and the knocking under load. As mentioned above, the FPCM is a known problem on these vehicles. The Dorman OE Fix part is $40 on RockAuto. For some cheap insurance, that would be a good start. From there, I would start checking LPFP pressure and rail pressure. It sounds like something system wide as you are seeing fuel trim issues on both banks.
I have an OBDLink SX cable and a tablet with OBD Fusion. I haven't looked at fuel pressures, mostly just been looking at O2 and A/F graphs. The O'reilly by me has the Dorman FPCM for a little more money, I'll just grab that when I'm out today just in case.
 

Tytanium

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So I've installed the noisemaker eliminator pipe and did some intensive pressure and smoke testing today and was not able to find anything. Using about 10psi with my air compressor, i did hear a noise around the back of the motor but wasn't able to pinpoint a leak, and did not sound like hissing. Assuming that it's probably leak-by in the motor?

Reset adaptive tables and took it for a 20 minute test drive, idle trims are better but still high, between 8-12% for both banks. Misfires still show up on random cylinders, but never more than 5 or 6 instances per cycle.

IAT1, IAT2 and CACT temps all look normal to me. Cleaned both MAP sensors, but not sure what normal idle vacuum should look like. Fuel rail pressure looks good and low side fuel pressure looks good too.

At this point, I'm thinking the next thing to check out are the wideband O2 sensors? Outside of pulling the upper intake and checking the injectors and the state of the intake valves, I'm out of ideas.
 

Tytanium

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I was adding more PIDs to my dashboard and finally figured out how to convert inHg to PSI in the datalogging portion. Today, the KOEO barometric pressure was indicated at 13.8psi (about 28inHg) when the actual barometric pressure was 14.8psi (~30.3inHg). Would this incorrect reading have an effect on air/fuel calculations?
 

stripSHO

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I was adding more PIDs to my dashboard and finally figured out how to convert inHg to PSI in the datalogging portion. Today, the KOEO barometric pressure was indicated at 13.8psi (about 28inHg) when the actual barometric pressure was 14.8psi (~30.3inHg). Would this incorrect reading have an effect on air/fuel calculations?
If your "actual" barometric pressure came from a weather report then it's not the actual barometric pressure but the  corrected barometric pressure. You need  uncorrected, from a place like www.airdensityonline.com

I suspect bad iniector(s) or broken ring(s). I would definitely do a compression test before throwing any parts at it.
 

autoteleology

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Did this issue ever get solved? It sounds extremely similar to what my car was doing before it stopped running.
 

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