Correct, no MAF = Open Loop

 

ok well last night it started to run like crap and stalled even with the MAF unplugged. But before it also would run like crap unplugged until warmed up, which then it would hold an idle and drive. Might this suggest it not being the o2 sensor then?

 

So I took off the o2 sensor to look and it and have it ready to replace when it comes in the mail tonight. Ordered the MAF too so I'll get that Monday. I'm getting MAF codes 157 and 158. Sometimes 158 and 159. It's suggesting the voltages are above and below normal. I'm hoping replacing these 2 parts will fix it even though the MAF looks fine... it is a remanufactured one

 

Get a Volt Meter and test the voltage, cheapest way to work on newer vehicles

 

hey I ended up throwing on an o2 sensor. Didn't expect it to fix the problem but more than likely needed it. And just now put on a new refurb MAF. Runs and drives now. Holds an idle. Drove around town for a bit no problems yet. I'm hoping this MAF won't crap out anytime soon. I will keep you posted. Thanks for the help RonD. If this crap comes back I'll test everything with a volt meter

 

O2 sensor shouldn't effect cold engine, it is ignored until it warms up.

But overtime failing O2 sensor can effect Long term Fuel trims which does effect Cold engine operation

 

well it was giving me lean o2 codes before that I couldn't figure out and wanted to replace it. Everywhere only had Bosch so hopefully it'll work good on this Ford

 

hey RonD everything's ran great for about 4 days. Just now before I got done driving to work it started surging and almost cutting out at idle. Right before it did it felt like I was giving it gas when I wasn't. Then it stalled down the road after that. Started right back up, then kept feeling like it was dying at idle, causing the electrical gage to almost go down along with the oil level gage. When it would almost cut out it would almost make those gages go down like it was about to cut out. Gonna scan it later when I'm home after work... this is stressful idk what to do to this truck.

 

Check battery voltage after it sits for a few hours, key off
12.8v is new battery
12.5volts is 2 to 3 year old battery
12.3v is 5-6 year old battery and time to replace it

Start engine
Battery voltage should now be 14.5v-14.9v, Recharge voltage
After engine runs for a few minutes voltage should drop down to 13.5v-13.8v, keeps battery charged but doesn't cook it.
Turn on all lights, leave door open, put heater fan to High
Voltage should drop while turning everything on but then come back up to 13.5v at least
If lower than 13.5v then raise RPMs, if it comes back up to 13.5v or higher then you have a failed field in the alternator.

The lower voltage at idle can cause lower fuel pressure, less spark, and as RPM gets even lower battery tries to take over but after a few days it doesn't have enough juice left either
While it is called a 12volt system it really isn't, lol, everything is designed to run at 13.5 to 14.5 volts, because that is the normal running voltage, engine can start with 12volts but often can't run very long if system stays at 12volts

If alternator tests bad then battery might be OK just drained, so replace alternator and see if battery voltage comes back up after sitting over night, or at least a few hours

 

Ok I'll check that tonight and reply with my findings. Thanks!

 

Also my battery is 7 years old. From 9/10. Got it tested and it still has use in it. Think it had 400 cca and it's a 500 or 550 cca. The guy at the battery shop said it's enough to start my truck still so I shouldn't replace it.

 

So if my voltages drop lower that those readings you gave me, will that mean my battery is bad or my alternator is bad and isnt charging enough. Im very confused because I watched 2 videos by the same guy, explaining how to test a battery and an alternator and they were done the exact same way I think. Watched the videos twice and cant tell how you can tell the difference between knowing if its the battery or the alternator. Can you tell me how to test the alternator, if that way you told me was how to test the battery exclusively

 

If battery voltage, AT REST, is 12.3v or lower then replace it, period
AT REST means after it has been sitting for a few hours, testing battery voltage just after shutting off the engine will show a false higher voltage

Batteries store energy via chemical reactions, each time you start the engine some of the chemicals are moved from one "plate" to another "plate" in the battery
When battery is changed the reverse happens, one "plate" back to the other "plate"

Each time this happen battery loses a bit of chemicals and storage places on the "plates".

Eventually battery loses enough capacity to hold a high enough charge/voltage, that is the 12.3v mark, this usually happens at 5 to 7 year mark with average use, it depends on the size, number and thickness of the plates inside, cheaper batteries have less plate surfaces, so cheaper to make and don't last as long.

Running a car type battery down, under 12volts, damages the plates, so they lose surface area that can hold a charge, so shortens life of battery.
Over charging a car battery does the same thing, damages the plates


Alternator needs to keep battery voltage at 13.5v to 13.8volts with ALL electrics in the vehicle on, and at any RPM from 650 to 6,500.
Just after starting engine battery is drained by starter motor, so voltage regulator will increase alternator voltage up to 14.9v, over 15volts will damage battery, so bad alternator.
After 2 to 3 minutes of 14+ volts, no more than 5 minutes, voltage regulator should drop alternator voltage to 13.5 to 13.8volts, if not alternator is bad(voltage regulator is inside alternator)

If engine running voltage is under 13.4volts at any time then alternator is bad

 

Ok at rest it's 12.52
runningg with heat fan music and lights it's 14.62
and no codes with the odb1 reader
even though it will flash when it almost cuts out really quick. Sometimes the CEL sometimes the battery light and sometimes neither flash

 

12.5v is good

14.6v is OK if engine was just started

So not a voltage issue

 

Getting code 10 still which says in my book cylinder 1. 10 is 1, 20 is 2, ect ect
Maybe I'll compression test the cylinder when I got time on my day off. Any idea what the pressure should be at before I look it up? May not be the problem but worth looking into.

But no other codes is giving me nothing to work with. Just drove fine now all night after stalling once after work.

And it wasn't just started it ran for a while and I drove it and it stayed right at 14.52

 

Hey so it's been running great all month until today it stalled. Mechanic couldn't figure it out just gave me new plugs and forgot to plug one in too....

odb1 won't let me read codes. Running or not, just won't start the test. I got it starting now but it won't go over 30 mph, doesn't want to shift gears. It's an automatic. Exhaust smells bad. CEL. Idk what to do Ron. My code reader just won't connect

 

Also. It picks up speed better when I'm not flooring the pedal. When I floor it. It doesn't go fast at all. It'll slow it down

 

when I do floor it down a hill and it allows it to gain speed I hear a couple or a few pops or knocks coming from under me or behind me. Possibility the exhaust pipe backfiring

 

Over 14volts after 10 minutes of driving either means battery is old and needs to be replaced or voltage regulator in alternator is bad.
Could also mean volt meter is off, check it on another source, car or even 9volt battery

Compression on any vehicle gasoline engine should be above 140psi

But yours now reads like either fuel pressure or computer has failed
There is a fuel pressure test port on the engine, 30-40psi is expected, 20-25psi with engine off and sitting for a few hours
And while watching fuel pressure gauge run engine up to 2,5000RPMs and hold it there for 30 seconds of so to see if pressure is slowly dropping

 

Ok so I think it may be the computer. Because now whenever I plug in my ODB1 it wont read. Key on, engine off, and engine on wont allow me to run the test.

 

I was also thinking the CAT is clogged because it caused the pipe was glowing red. And backfired through the air intake

 

Cat getting too hot can mean Rich fuel mix as well, Cat is there to burn any excess fuel

You can test for clogged exhaust with vacuum gauge

 

Hey so I got it running couldn't pull codes. Let it run for 15 minutes. Idle changed. Was able to WOT. Drove for a while no CEL. Came back on. Ran codes. Got the lean mixture code again. Not sure if it's my MAF I replaced or the o2 I replaced. I'm thinking o2 since the light comes on after driving it for 5-10 min. But when it wouldn't start for those few days on a cold start and made a funny sound I was thinking MAF.

Bosch o2 sensor btw...

I'm so lost with this truck

 

MAF and O2 both wouldn't set lean code until engine was warmed up.
Computer has no way to test MAF until O2 sensors come "on line" after engine gets warm

Lean code is from computer having to add more fuel, injectors need to be opened longer, than it calculated based on O2 data and MAF data.
So either could cause it

But so can any air leak from MAF to intake valves, which includes vacuum leaks but not limited to vacuum leaks

And so can Lower fuel pressure than computer expects

An exhaust manifold leak can also cause lean code, but in this case a false lean so engine would run Rich, Cats would get very hot