You keep mentioning a Baro sensor. You do mean the MAF sensor just above the air filter, right? Or is there a separate baro sensor I dont know about?

I did see your threads about cleaning the spark plug well and where it makes contact with the head. Makes sense to me.

 

Looks to me thats a very minor misfire but you can achieve no counts by a good hosp clean job . clean cop contacts ,replace any connector not locking on by soldering new one in . Replace all boots on plugs .Use very little dielectric grease .yes clean spark tip well area with carb cleaner,that carbon breaks plugs going in and out . .

 

I had to do quarter turn tighten followed by third turn loosen even after a healthy carb cleaning job but I'm a scally wagger and didn't replace plugs for 100k miles I ran plus who knows how long plugs hadn't been changed before I bought truck

 

Well, ya got me! Egg on my face "Two-point-oh-one". Now, I am going to learn something else - with you (or from you).

Yea, I been talking about this mystical barometric pressure sensor for a long time. /// I have always believed there was one - SOMEWHERE?, but admittedly didn't know exactly where it was - so I sat out to find the little bugger.///

The origin of my misguided belief was the fact that there are TWO (2) OBDII PIDs listed as BARO(). First one is PID 0x0033. This PID does NOT respond on my Truck. ?? (i discounted that as just another one of those many inconsistencies in OBDII assignments between models.) Then there is PID # 0x1127 that responds nicely with a nice clean value --- that 'by the way' converts perfectly to barometric pressure in inches of mercury by applying the one byte 0-Five volt A/D convertor formula (byte value * 0.13107). I 'erroneously' thought that was a voltage reading from a sensor being presented on port 1127 by the PCM.

We often tend to 'FORGET" all OBDII readings are NOT actual sensor outputs - but are filtered through software in the PCM before being posted on an OBDII port. It turns out (based upon additional research --because of YOU) that this BARO() is a 'calculated' value by the PCM: based on Throttle Position, Engine Displacement, Mass Air Flow, Engine RPM, IAT, and hell knows what else. The software engineers, (for whatever reason) decided to present the value in standard A/D converter counts to represent a range of ~ 25 to 33 inHg with the 255 possible counts in a binary byte.

I also learned (thanks to YOU) that the large part of the BARO() formula is from MAF input, and a LOW BARO() can occur because of a contaminated MAF element.

This ALL relates to my recent efforts to develop a Torque Pro formula for a gauge to display "Volumetric Efficiency" in relation to understanding the CMCV / IMRC valve. That formula uses many of the same inputs. And NOW I find that SO DOES the "ENGINE LOAD".

"ENGINE LOAD" is a federally mandated OBDII value for all OBDII compliant vehicles and has to be presented at PID # 0x0004, and thus should be highly reliable. It's formula is VERY similar to Volumetric Efficiency, with the minor exception that the formula is designed to max out at 100% - (based on WOT at MAX LIMITED RPM). Whereas Volumetric efficiency can potentially exceed 1:1 ratio under certain conditions.

BUT -- What all this means. You might watch ENGINE LOAD in your quest to find lost power. MAF [and/or BARO()] producing a low reading would depress ENGINE LOAD reading. Maximum load (100%) is generated when MAXIMUM air is being aspirated for a given throttle position and RPM while in closed loop with fuel/air ratio at stoichiometry (perfect air/fuel ratio).

Bottom line. There is NO barometric pressure sensor on our trucks. _B U T_. The the PCM calculates the value relying heavily upon the MAF sensor - and it's internal intake air temperature sensor.

 

Cool. I thought I was crazy. I've cleaned my MAF and no change. But again, first the misfires need addressed. Still waiting on an OTC 6900 socket...

I do think my MAF is functioning properly. I've read on here that a good baseline number for air intake is 1 g/s per engine liter size. Mine is consistently around 5.5 to 6 at idle. I think I've seen yours is around there also on one of your posts.

To your point about baro being calculated out of multiple inputs, this is what led me earlier in this thread to think my bank 2 cat was going out. FordTechMakuLoco on youtube has several videos showing just that (and others showing how the baro gets messed up by other problems).

On a separate note, where do you get all your PIDs for everything? I do pretty complex math for a living and could geek out on my torque pro app.

 

Have You watched this video PhilG?

 

I have. My misfires are across multiple cylinders, though I just tried to shimmy my injectors last night to see if the orings were bad. I didn't notice a difference in the idle. That guy's videos are super helpful.

 

From numerous different sources and lots of hacking my truck with Torque Pro and matching things up with a FULL Torque Pro scan of all possible OBDII ports that respond on my truck.

Sounds like you are enough of a geek to get some benefit out of it. PM me an email address and I'll send you my Excel Spreadsheet. Sounds like you might benefit a lot from it. You might help me create some Torque formulas. Torque Pro is phenomenal in its equation parser. It supports pretty much all math functions and you can create 'psuedo' PIDs and use them like 'local' or 'global' memory variables and include values from other PIDs within a formula. As I mentioned, a present effort is trying to work out a formula for calculating Volumetric Efficiency - THE Torque Pro PID so named does not work on MY Truck. I presume there is some OBDII parameter difference on mine that it can't get a value from. ???

Have you found / looked at my Torque Pro "Misfire Dashboard" that uses Mode $06 calls to pick up values from the PCM's misfire counters by cylinder. Best place to get it from is here: https://torque-bhp.com/forums/?wpfor...opic&t=10826.0 That link has a 'CSV' file with all the relevant PIDS so you don't have to key them in.

The individual cylinder misfire PIDs do not work on many of our vehicles.

 

I had not seen your misfire dashboard. I'll take a look. I realized I could log data from torque pro. I looked at the log from yesterday and watched what else was happening when the truck logged a misfire. It looks like it happens when the timing advances, although my VCTerrors (per your formula) don't correlate. I have a longer drive to make today and will collect that entire log. With all that data, I can actually do some statistically analysis on the output to verify if the misfires do signficantly correlate to the timing advanced value. Yeah, I am a geek - by day I'm a computational chemist. On the weekend, I just want some more performance out of my truck to pull my trailer.

I"ll send you a PM to get your sheet. I don't have a tremendous amount of free time, but would love to learn and help where I can.

 

So I finally got spark plugs replaced. After getting them out, the previous owner had replaced them with SP515s, but they were due to be changed. The good news is that none of them broke.

The back to cylinders were not torqued correctly. It almost looked like there was oil on those threads, but the wells are clear, so I don't think it's a valve cover leak. Could have been gas creeping up the threads and mixing with dirt, copper anti-seize, etc. Any way, got them installed correctly and torqued down right.

The misfires persist across all cylinders though. The good news is that between the spark plugs and putting new foam weather stripping around my air filter tray (the old stuff was flaking away). My baro reading is consistently up to 14.5 now. I am thinking the misfires are associated with the classic timing problems associated with these engines. I definitely have some timing chain slap happening (probably from blown tensioners). I want to drive this truck until the wheels fall off, so I think I'm going bite the bullet and do the whole thing - phasers, solenoids, a melling 10341 oil pump, etc. I need to fix the chain slap anyway, so I might as well only take the front cover off once.

I'm going to try a few other small things in the meantime (throttle position sensor, clean the throttle body, take a look at the fuel pump driver module) before I spend the $1000-$1500 on parts for the timing job.

 

Glad the Baro() reading improved. That ECU does some magical math, so that suggests 'something' was improved in the right direction.

Another small - but important - item you didn't mention that I'd recommend doing in the meantime: If you don't have an after market Oil Pressure gauge, throw one in the list. If it is too low, might change the whole equation. Just my .02 c

 

I can certainly check the oil pressure. At baseline I just assume the oil pressure is low given the quality of the oil pump on these things and the fact I do hear some chain slap on start up. So even if my pump is good but I'm bleeding off pressure to the VCT system, then I have to take the front cover off anyway, so I'm only going into there one time.

 

The oil pressure gauge suggestion was based elsewhere - and is contrary to your assumption that oil pressure is low, quote: "given the quality of the oil pump on these things and the fact I do hear some chain slap on startup." The two are _almost_ totally unrelated.

There is a hydraulic physics 'disconnect' between oil pressure in the HEADS as compared to that read at the cheap-*** sending unit (s 5-7 lb switch). This is the 'restrictor' in the oil galley entry point into the heads. Due to this restriction, oil pressure 'IN THE HEADs' (and available to roller/followers, phasers, tensioners etc) is NOT directly indicated by Oil pressure at the oil pressure sending unit. How much restriction, and thus pressure drop, the restrictor presents is unknown to me. But pressure in the head is something 'less'. How much less must be surmized, guessed, estimated by timing system symptoms - such as your chain slap or timing failure DTCs. /// BUT Also - chain slap can occur due solely to simple chain stretch that can (and often does) exceed the tensioner's maximum plunger travel, and broken guides - without even having blown tensioner gaskets ///.

Oil pressure read at the sending unit represents 'PRIARILY' lower end pressure (subject to normal loss in valve train / timing components downstream from the restrictors). If THIS reading is significantly low - it would indicate failed thrust bearing or worn main or rod bearings in the lower end. NOT problems in the upper end. Both conditions that could impact the wise course of action. HOWEVER it will result in identical symptoms as problems in the timing system. Lower end oil pressure simply provides one inexpensive additional indicator.

When my timing problems became severe at 212k miles (rough idle / dieing at stop signs etc) I exhausted all the typical efforts you read about on the forums - I had a mechanic shop install a temporary mechanical Oil pressure gauge and test "FULL OPERATING TEMP" oil pressure. It would idle 585 RPMs in drive, A/C on at around ~15 to 16 lbs. I judged the lower end was healthy enough to give more useful life.

Increasing the oil pump volume (and thus pressure) is a very worthwhile part of the job. It will help both lower and upper end going forward. I used the Melling 10340 and am very happy with pressure and performance.

 

Excellent write up F150TORQUED

 

Still working on this. I ended up getting some O2 sensor spacers/defoulers. My downstream O2 sensors were consistently at 0.6-0.65 V. Looking at a few other resources, they should be up around 0.8 to 0.85 V. With the spacers, they are more consistently around 0.7 to 0.75 V. This has me thinking again my cats are reaching their end of life.

The odd shape of my upstream sensor voltages coupled with my random misfires has me thinking thr cats could be partially clogged and the back pressure is causing the misfires. Going to get a pressure gauge to fit into the O2 ports to check before and after the cats.

I'm also starting to acquire all the timing job parts.