How’s it going,

I’m new to these trucks. This is my grandpas dirty farm rig with over 300,000 miles. It had a problem of no crank originally, and a really terrible idle.

Long story short, I had a million codes, and I fixed all of them but 2. P1137 KOER: Lack of (HO2S12) Switch Sensor indicates Lean

P1131 KOER: Lack of (HO2S11) Switch Sensor Indicates Lean

It CURRENTLY starts a little rough, but once it idles, it does it perfectly, for as long as you want it to idle. However, as soon as you put it in drive with your foot on the brake, or reverse, it dies. Basically stalls under any sort of load on the engine. Even turning the wheel tight can make it sputter. Other than that, runs great, once idling.

There is perfect fuel pressure. Fuel pressure Vacuum regulator works properly. zero vacuum leaks now. (Smoke tested). And Throttle body cleaned


Everything replaced thus far:
Starter Solenoid
CHT Sensor
IAC Valve
TPS
PCV Valve
EGR Valve
Fuel Filter
MAF Sensor

The Truck is very rusty, and has always had a tick, of which I don’t know where from, and nobody on the farm has ever cared about. This relates to my next discovery, possibly, or maybe unrelated and just valvetrain.

On the passenger side, I found both exhaust studs on the rear flange snapped off, and signs of a leak. I haven’t tested how big the leak is, but I’m about to, because I don’t know if this is the cause to my problem. From what I’ve read, my 2 codes from the O2 sensors are on the passenger side, where the exhaust leak is also.

Would the exhaust leak cause that big of a running, starting, and drivability problem? It seems like there’s more too it. Let me know your thoughts. I suppose I’ll replace both passenger side O2 sensors, but first I’d have to take off the manifold, unless you think it could be something else.

Thanks





Update #1
It definitely leaks on the passenger side around the flange where the studs are snapped off. However, the biggest leak is coming from seemingly 2 places on the drivers side catalytic converter. The drivers side cat shouldn’t be a problem for my issue would it? Would you say it’s still the passenger side exhaust leak?

Also, Yes, the tick most definitely comes from that exhaust leak on the manifold.



Update #2
I found a fuel leak on the return line coming from the passenger side. Fixed it. I took the Manifold off and removed the snapped studs, a pain. I replaced the gasket, and put in new hardware. I replaced the downstream passenger side O2 sensor also. Guess what, truck still does the same thing, and shows the same codes.


B1S1 on the O2, has zero volts, and B1S2 has .040 and varies but very small volts, is that okay? B2S1 and B2S2 have around .4-.6 volts I believe, I forget as I’m righting, but bank 1 is definitely lower on voltage.

 

Intake manifold plenum might be leaking
That is the plastic piece on the bottom of the intake manifold down in the valley
Check that intake plenum and the intake gaskets for a leak by either smoke testing or spraying some Brakleen down there
With the engine running you see if the idle changes as you spray the sauce
Check your fuel trims with your scan tool in live data or freeze frame data section
Your injectors might be failing
One test for those is to monitor the fuel pressure while you manually fire each one, one at a time
You watch the fuel pressure drop as you fire the injector and listen for the click from the solenoid
A few might not click = BAD and a few might not drop any fuel pressure, also bad
Good luck, have fun with Grandpas truck

 

there’s zero air leaks, but I’ll try and mess what the injectors or whatever

 

My injectors at least work to some extent, not very scientific, but I used a stethoscope to hear them ticking, they all do, and speed up ticks when I rev.

My Short and long fuel trims seem to be correct. The longs stay at about 3.7% or so if I remember; and the shorts can go from -3% to 4%.

what’s not normal is my voltage that I get to the B1S1 and B1S2 O2 sensors (Passenger side). On B1S1 (Upstream) I get zero volts when running, no matter the rpm. I verified for battery voltage to the sensor via my repair book. It gets a battery signal voltage when the key gets turned to ON. I have not replaced the Upstream sensor yet. I have replaced the downstream O2 sensor with a Motorcraft one, which is apparently the correct one for my vehicle and position (although the connector seemed different, it still plugged in). It’s weird because I replaced this downstream one, and it gets incredibly low, out of acceptable range voltage, like .040 volts, where it’s supposed to get .1 to .9 volts. The drivers side has correct voltage. And yeah, the upstream passenger one gets zero volts. These low to zero volt numbers on the B1S1 and B1S2 make sense as to why it runs lean, and is possibly my entire problem.

But why don’t they get proper voltage? Also, could I have gotten the wrong one that I replaced.

 

Well, back in the good ole days you couldn't plug a rear HEGO into the front wiring circuit
The connectors were different, and the sensors were different
Now days, Ebay and Rock Auto and the boys have been selling 4 of the supposedly same sensors for both front and rear
The sensors always were supposed to be the same anyway, IIRR, they just sold front ones and rear ones
So, last ones I bought for a 04 F150 came with 4 sensors for way cheap (less than 50 bucks from China) (Motorcraft sensors, knockoffs most likely)
*That rear HEGO SHOULD stay around 1/2 volt (so yours reading mostly .4 volts is okay)
Upstream passenger one reading zero volts (or real low voltage) is an indication of a very lean condition or a faulty sensor
THe front ones need to switch above and below 1/2 volt quick
The rear ones should not fluctuate much but they will some

 

I went ahead and replaced the B1S1 O2 sensor as it was reading zero volts

I now have voltage to it when running, but significantly lower voltage still, just as the downstream one that I previously replaced (B1S2)

So, The Oxygen sensors must be good, but they’re getting low voltage and therefore throwing the lean codes.

Could this be PCM problems? Could my injectors be bad even though they all tick? What would be the reason for the signal of low voltage.


As you see, B1S1 and B1S2 are getting low voltage, but they are operating correctly, just getting a lean signal for some reason.

 

I replaced the check valve on the brake booster as it wasn’t working. It now seems that the truck runs a tad better, and dies a little bit less when in drive or park compared to previous, but it’s still stalling and running rough. So I scanned it again, and to my surprise, my O2 sensors were now sending normal voltage. The bank 1 moves up and down in voltage fast, and more, like it should. Then I saw my bank 1 fuel trims way too rich.

Long term I got about 25%

Short term it ranged from 13% to 30%

This is definitely too rich, and the bank 2 side looks normal like the bank 1 side used to look like.

Why would it be forcing bank 1 so rich. Could my fuel injectors be dirty or something like that

I did have them out to check that they all sprayed decently earlier, they did, and I’ve had them out to make sure they don’t leak when pressurized. Keep in mind these tests I just took the fuel rail and injectors out and left everything hooked up to test, it’s not like I used a machine. The injectors also have in spec resistance.