Hi all... today i had my first test run after the engine rebuild drove the freeway fifteen miles ok coming back check engine light... all these codes related to the 02 sensors PO136...PO1131...P1000 ... the 02 sensors are new motocraft ... only thing different is the front cat was gutted by the PO rear one intact..

Or should i drive it more until the PO 1000 clears

 

Quick update i cleared the codes and drove 12 freeway miles ...no light ...stopped engine 1/4 mile from home went to post office.... re started pulling away the check engine light came on same codes
So by the codes its running lean, everything is new on the engine except for the injectors, i did replace the O rings .. no vacuum leaks .. that leaves the fuel pump pressure or injectors?? engine runs smooth .. i added 2 cans of seafoam to a full tank of gas... anyone any ideas ...

 

2003 3.0l Ranger

Should always include that

P0136 02 Sensor Circuit Malfunction (Bank I Sensor 2)
P1131 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 1

P0136 is a wiring issue on the downstream O2 so check wires for damage, and check connector, unplug it and plug it back in

The computer can "see" if O2 sensor has a full circuit with key on but will wait until O2 sensor is fully warmed up before setting a code


P1131 means Passenger side upstream O2 voltage is 0.0 which is "lean" and its not changing when computer adds more fuel to that bank, i.e. "lack of switching"
Computer didn't use P0171 System too Lean (Bank 1)
Its not a "circuit code" but could still be a wiring issue or connector issue so have a look

You could swap around Upstream O2s and see if code changes to P1151 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 2
If so that O2 sensor is bad

 

Thanks for that tip Ron it worked.. lower 02 unplugged cleaned plug connector now no PO 136 will do the same with the front......... both 02s are new.....The PO replaced the rear 02 i kept it as its not old i will fit that in the front, whats the chance a new 02 is bad.......if i still have PO1131 after road test i will be leaning towards the fuel pump pressure i will pick one up tester gage from harbor freight.
After run out still get 1131 update to follow lol

 

A fuel pressure issue or upper vacuum leak or MAF sensor issue would all cause BOTH upstream O2s to show lean, not just one bank

P1131 is a "lack of switching" this means the Voltage on that O2 is not changing at all.................so not really an air/fuel issue, its a sensor or wiring issue

I have yet to find ANYTHING that's is 100%, works every time
While a new O2 should be fine, "should" is the word, not 100% for sure

 

Ron i have the 98 2.5 now i lost the 3.0 in march ... 2.5 has only one upstream 02 before the cat but the front cat is gutted....when i first took the ranger out for run after rebuild it bogged down at full throttle, the MAF did not look very old but the two fine wires were dirty cleaned them off the the MAF spray.. full throttle was ok... i tested the output voltage of the MAF steady voltage from idle and increase with the rpm no sticking or jumping...12 volts at the 02 sensor, no vacuum leaks
Will post fuel pressure results Sunday... driving me nuts... so you think it could be a sensor or wiring issue ?

Going back to my bosch scanner i was looking at the data and the 02 was in open loop, i forgot about that, never closed ..ok does that mean the 02 is not getting hot enough to go to closed... dam the front cat is gutted, is that my problem

 

Yes, the 4cyl matters, lol

What was the engine temp showing on the OBD Reader, that's what sets Closed loop, above 150degF

O2s have heaters to warm them up faster, computer is the ground for the heater, so it will set a O2 heater circuit Code if that part is not working
But yes, if O2 sensor is under 600degF it will not work, and code P1131 could cause computer to stay in Open Loop

Closed loop means computer can/is adjusting air/fuel mix based on feedback from the O2 sensor, so "no switching" would be the O2 sensor is not working so Open Loop only

When engine coolant passes 140degF computer will then start to use all sensors, like the O2s, at that point if it "sees" questionable data from an O2 it will go back to open loop

Do you have another O2 to swap in, even an older one

 

I did swap 02 but same problem... this morning i went to the big multi pin con and cleaned the pins hoping that was my problem.... started cold engine looking at data ..i was so pleased to see it go into closed loop after a few minutes as it warmed up closed loop kept rpm under 2k... then rpm changed and went back into open loop?... does this look like the 02 is not getting 600 degrees and i need to replace the front pipe.. it has front and rear cats

 

What was the upstream O2 showing for voltage?

 

Started cold engine in the afternoon 75f out... it stayed in open loop for five minutes never changed... turned key off unplugged the multi pin connector again and pushed it back in tightening the ten mil bolt, dont know if this has anything to do with it ... restarting engine after one minute back to closed loop, this lasted for about three minutes, back to open....
.
Fuel pressure KOEO 60psi KOER 64psi so the fuel pump is ok, who knows it might have been replaced

 

O2 11 is stuck at 0v, upstream

O2 12 should be at 0.7 to 0.8v, downstream, Reads if Cats are working

You can check fuse 13 in engine bay fuse box, 15amp, that's for the O2 heaters, but also power EVAP so if it was blown there would be EVAP code as well

Engine is not actually running Lean or you would have complained about pinging/knocking full time
Open loop prevents it from running Lean

No exhaust manifold leaks right?
If idles at 750-800 so no vacuum leaks

Both O2s are showing HIGH oxygen levels or the wiring is bad.........or computers O2 section is bad
Its a puzzler

 

Ron no exhaust leaks, all new gaskets... Cats are not working i would bet on that, with the California regulations they have it covered, i am sure, tampering with the cats brings on check engine light...the rear one must be oil fouled as the truck was burning oil plus blowing it out lol.... front 02 not getting hot enough to work......I have the chance of buying the front pipe/2 cats for $300 California compliant CARB half the price of new one... do i cross my fingers on this one.. i will post update later this week..........

 

I picked up the new front pipe today never been used two cats... could not wait to get it on . starting up and waiting for temp to get over 150 scanner hooked up open loop wtf.... did not go to closed ,...dam.... so i unplugged the square multi pin connector again sprayed it with cleaner, re fitted and started up after a few minutes it went to closed loop, lasted a few minutes in that time nothing from 02s.... then back to open.... i am lost what to do.... will the p1000 not clear until the problem is fixed..

 

P1000 will not clear until closed loop is stable

If you think all the wiring for O2s is OK then you will need to try another Computer
Pull computer and inspect it first

 

Yes i think your right on the computer, i pulled it and took a look inside no bad solder connections i did notice just outside the ecu in the harness two black wires to ground bit dirty, cleaned it up ... one more thing i need to check is the Ground / open in the RED/WHT 02 wire to the ecu ..... thanks

 

Only getting .032 volts doing the test between 02 red/white to ECU should be 12v ...needle in haystack lol

I pulled the ECU wires from the connector finding the red white wire from 02 .. no breaks in wire ..so it looks like the ECU is at fault

 

O2s have 4 wires
One should be 12v with key on for the heater

On a 2.5l I show a red/white wire as the GROUND for the O2 heater NOT the 12volts, so unplugged it wouldn't have 12volts

The Light blue/orange wire is the 12v wire on either O2 sensor in 1998

The attached O2 sensor's 4 wires usually have just 3 colors
2 are the same color, they are for the heater, no polarity, as long as one is 12v and the other a ground heater works
The 2 other colors are for the sensor part of the O2, these usually have no polarity either since the Sensor generates it own voltage as it heats up, 0.1 to 0.9volt

Generally speaking O2 makers follow this chart: https://i.pinimg.com/originals/0a/42...f87d9d5523.jpg

 

Sorry Ron i worded it wrong this is the test i used ..could be for another model but it did not work

1. Locate the upstream oxygen sensor and disconnect it from its harness connector.
   
2. 2Locate the RED/WHT wire of the engine wiring harness oxygen sensor connector.
   
3. 3With your multimeter in Volts DC mode, probe the RED/WHT with the black multimeter test lead.
   
   Ground the red multimeter test lead directly on the battery's positive (+) terminal.
   
4. 4Your multimeter should register 10 to 12 Volts DC if Ground is prese
5. 
   

 

Well was i going in the wrong direction last ditch effort before i jumped into getting a ECU so i have new 02s in there changed the front one..... say chance its bad, used a spare good one ...same problem... when i got the new front pipe it came with new 02s for the heck of it i put it in the front... bingo it worked closed loop.... Dam

 

So it was a "new" O2 sensor issue, good to know, and hopefully that solves the issue

 

After run out no check engine light but i do have a code pending PO171 .. gosh what next... the DPFE sensor EGR differential pressure sensor, i will test that next bet its as old as the truck

 

I have a 2006 ranger 4.0 came home from work to a dead fuel pump replaced the whole assembly started up great check engine light came on Bank1 and bank2 rich and a p1000 new fuel injectors 1year old checked EGR has vacuum and is working MAF sensor is working and checked live data running the right amount of grams checked purge valve solenoid it clicks to open and holds vacuum no fuel smell in the oil changed one o2 sensor the rest are 1 year old at a loss of what could be wrong any help would be appreciated

 

I have a 2006 ranger 4.0 came home from work to a dead fuel pump replaced the whole assembly started up great check engine light came on Bank1 and bank2 rich and a p1000 new fuel injectors 1year old checked EGR has vacuum and is working MAF sensor is working and checked live data running the right amount of grams checked purge valve solenoid it clicks to open and holds vacuum no fuel smell in the oil changed one o2 sensor the rest are 1 year old at a loss of what could be wrong any help would be appreciated