Hello,
So when I connect my OBDII into the truck and open it on my android (Torque Lite) I don't get any readings from any of my O2 sensors; voltage stays at 0.
I know it is not my app since I have used the OBDII in another vehicle which gives me readings without any issues.
I am getting lean codes and I would be interested in seeing these readings.
I have already tested both upstream sensors with a voltmeter and they seem to be working fine. I even bought a new sensor from Autozone and installed it. Still, no readings on their voltage.

Anyone have any ideas what may be going on? Where should I start looking for issues?

Thanks in advance!

 

Welcome to the forum

O2 sensors needs to be at 650degF to start working, this is why they are heated, so it takes about 5 minutes for then to start working, from cold start, just a minute or 2 from warm start

What is the code number
Lean code is about fuel injector open time, which can be cause by failing O2 sensor but there should also be another code "O2 not switching low voltage-lean", which is not a "lean" code even though it has the word lean in it, lol

O2 voltage is .1 to .9volts, so narrow range

They use a Chemical reaction to Generate their own voltage, so the .1-.9 volts is from the reaction of the chemical to Oxygen in the exhaust, and that can only happen above 650degF

 

This is all true!
I recently bought a new o2 sensor from autozone and as soon as I installed it, the engine started to have a rough idle and the obd2 gave me a code about the o2 sensor. In frustration I left to bed.
The next day the truck was working just fine and that code was gone.

The only two codes that I am now having say that There is a rich mixture in chamber 1 and 2.
I believe the codes are p0172 and p0175.

I cant seem to find the reason of this and I have tried many things.
MAF sensor works fine, according to my voltimeter readings.
TPS maay be a bit off as it sometimes gives a jump between .10-.30 volts while slowly accelerating from the throttle body. But it comes and goes, so I guess thats working ok ish....

I am running out of ideas.

 

Thinking those are the codes is useless information.

Someone goes to all the trouble to help with those codes only to find out YOU were wrong and all the help they gave you is also wrong and a waste of their time.

Get the correct codes and post them.

 

bloody hell matey, yes, the codes are correct. take a chill pill.

 

The computer can use the O2 sensors for the first 5 minutes or so from cold start
So O2 sensors can't cause and running issue for the first 5 minutes or so of driving, computer is in Open Loop

If the engine runs poorly at this time then it isn't an O2 issue

Could be ECT(engine coolant temp) sensor, not related to ECT SENDER, which is for the dash board temp gauge
ECT sensor is only used by the computer
When ECT sensor shows temp under 140degF then computer will run Choke Mode, runs the engine richer with higher idle(1,100rpms or so)

Does engine idle higher when cold started, and does idle drop as engine warms up?
These are signs the ECT sensor is working

If ECT sensor is show "cold temp" all the time then computer will run engine in Choke mode all the time
So check TEMP with the ODB reader when cold and when warmed up, 175+ degF

 

Hello,
I wanted to update my case.
I still dont have O2 readings, but at least I managed to fix the code. I had a short on the downstream O2 sensor. So I bought a new one and everything is working.

Anyways, another problem that I had is that my ranger would have a very high idle and would rev up sometimes all the way up to 3000+ RPMs while shifting. It would also stay accelerated while cruising, kinda like if it had a cruise control.

I managed to fix this by disconnecting the sensor on top of the rear axle (Manual transmission).
The idle has been fixed by disconnecting this sensor, so I guess I will have to change the sensor for a new one.

 

What year Ranger?

The ABS sensor, rear axle sensor, should cause ABS light to come on if its not working or unplugged

High idle or REVing when shifting can be IAC(idle air control) Valve is sticking, not hard to clean and test this valve

Read here: https://www.explorerforum.com/forums...-w-pics.84220/

 

The rnager is 1998 XLT 4x2 3.0
I have tried everything, EVERYTHING that has to do with the IAC. I even changed it, cleaned the Throttle body etc etc etc.
Nothing fixed it. There are dozens of threads on the internet of people going through the same.
I don't know what the ABS sensor has to do and I am still perplexed. But I disconnected it the problem has been solved... I will be changing the sensor for a new one in the next couple of hours.

 

In 1998-2000 Rangers that ABS sensor on the rear axle also runs the speedometer so your speedometer should also be off with it unplugged

Because this sensors is the only Speed sensor(1998-2000) the computer also uses it to control the IAC valve
When "speed" is under 5MPH computer will set the low idle via IAC Valve
When "speed" is above 5MPH then computer sets high idle, 1,000-1,200rpm for lower emissions

With this sensor unplugged you are always under 5MPH so lower idle

But there should be a Check engine light on, with P0500 code set, no speed signal at computer
Also the ABS light should be on

If your speedometer has been having problems recently then yes it could be the ABS sensor, and easy enough to replace

If IAC Valve has been cleaned and tested then Computer is setting the higher RPMs which could be from incorrect speed sensor or failed software in the computer
You can use your VIN and call a Ford Dealer to see if there was a TSB about a software update needed, although they may not have that info after a vehicle is 15 years old or older

 

I am so frustrated again..
I replaced the ABS sensor and soon enough, the high idle has returned. Mind you, not as strong as before. But it is still there.
Goes over 2k while shifting and stays at a steady 1.5k - 2k while cruising. Honestly, I want to give up this is costing me too much money.

When I turn the engine on, revs go up and then hover at a little over 1k while idling, but as soon as I hit the pedal and give it a quick rev, the RPMs stay at 1.5k steady.
I don't know where else to look. IAC is new.
I also disconnected the battery for 40 minutes and the problem persists.

 

After engine is fully warm up and idling
Unplug the 2 wire connector on IAC Valve, it will close and RPMs should drop to 500 or engine may even stall either is GOOD, it means no vacuum leaks
(IAC Valve is computers ONLY control of RPMs)

If RPMs do not drop then you have a vacuum leak somewhere, leave IAC Valve unplugged, and start removing vacuum hoses on upper intake and put finger over open port, if RPMs drop then that hose or its device is leaking.
Start with PCV valve hose, this valve and hose are common leaks
Power brake booster hose next

Another reason for higher RPMs with IAC Valve unplugged is that throttle plate is not closed enough, there is an adjustment screw on it, an anti-diesel screw, someone may have thought is was an idle screw and messed with it
With engine warm and IAC Valve unplugged that screw should be set so engine barely idles, 500rpm or so

Also check throttle cable make sure it or Cruise cable is not holding throttle open a bit, manual try to pull throttle close, if RPMs drop then most like throttle spring is broken and can't pull throttle plate closed against the 20+" of vacuum trying to suck it open

 

I've checked for vacuum leaks before with carburator cleaner and nothing has been found.
Whenever I disconnect the IAC, RPMs drop, but nowhere close to 600-650. It hovers around 900.
I will do it like you are saying... and report back with any updates.....

 

Unless throttle plate is open too far then there is a vacuum leak if RPMs are at 900 with IAC Valve unplugged
If RPMs do not change when adjust that screw then stop and put it back where it was, its not the problem

May have to get a Cigar and do a Smoke test, don't forget the whisky, can't do a valid smoke test without a beverage :)

 

I did some testing and swapped some vacuum hoes for new ones.
The revs seemed to get down at first (750-800) and was very excited. However, after idling for a few minutes and reving the engine, RPMs went back up to 850-900...

Also, when connecting the IAC revs go to 900+ and wont come down....
Should I keep swapping hoses?

 

If engine idles at 900 without IAC valve powered up then IAC valve can only make it higher that 900 not lower

Thats why without IAC valve powered up the idle should be 500-600 so the IAC CAN set a 750-800 idle by opening a little

 

yes I connect the IAC and it goes up.
But disconnecting the IAC doesnt get me no where near to 500-600....

 

And did you try to pull throttle closed manually?

Or try to adjust the anti-diesel screw?

 

Yes, the throttle cable was even lose and I also manually made sure the throttle was closed while the engine was running. Also adjusted the screw. Its almost all the way up.

 

Then its a vacuum leak