I have a 1997 Ford ranger ext cab with the 2.3 liter engine. Just recently my check engine light came on. It was for an EVAP leak and both of my O2 sensors. I fixed the EVAP leaks and replaced both of the O2 sensors and the check engine light keeps coming back on after I reset it. Since then, when I'm driving down the road sometimes, it seems like my truck is gummed up, or acting like there is something holding it back. Any ideas as to what this can be or if it might be O2 sensor related?

 

Can anyone help me diagnose this/these problems? Even if its just one at a time.

 

What did you fix for the EVAP? Are you sure you got the right type of O2 sensors?

Check all fuses both in the cab and under hood in PDB. To clear codes and reset PCM pull battery cable and leave disconnected for at least 30 minutes then re-test. If the check engine light comes back on, pull stored codes and post them back here.

 

I brought it to my buddy's shop, where we ran a smoke test. His mechanics fixed my evap leaks. I replaced the sensor's with the correct ones. Its the second time I've had to change them since I've owned the truck. I replaced them with the bosch sensors. Fuses were all fine, both in the cab and in the PDB. I pulled the battery cable this time, instead of using the computer to turn it off. I will run it tomorrow morning to see if anything changes. Thank you for your reply.

 

Ok, so I found out why the O2 sensor read may have been going off. The mechanic that installed it didn't tighten it all of the way! That guy may not have a job tomorrow... Anyways so after I fixed that, I still got the reads for bank 1 sensor 1, bank 1 sensor 2, and another EVAP leak. We ran the smoke through the lines and fixed all of the leaks last time. I'm not sure what else to do besides keep throwing new parts into it until the check engine light goes off. The error codes that came up are P1443, P0141, and P0135. Any suggestions?

 

I don’t think one of the sensors not being fully tightened would cause these problems.

To start you’ll need to do some functional tests. So lets start with the O2 heater circuit first. At each sensor connector (chassis harness side) you’ll find four wires. The ones you’ll be looking for are as follows:

Sensor 1 Bank 1: Light Blue with Orange stripe (connector pin 1 engine side of harness Power supply). The other is Red with White stripe (connector pin 2 engine side of harness to PCM pin 93 ground control).

Sensor 2 Bank 1: Light Blue with Orange stripe (Power supply). The other is White with Black stripe (PCM pin 95 ground control).

Using a DVM set to read 12V and both connectors disconnected turn the ignition switch to the run position but do not start the engine.

Next, insert the red probe from your DVM to sensor 1 bank 1 connector pin 1. Connect the black probe to a known good ground. You should read 12V (or battery Voltage). Do the same thing at sensor 2 bank 1 connector pin 1. Again you should read 12V.

If you don’t read 12V at either connector you’ll need to check the HEGO fuse 20 (15AMP). If you only read 12V at one, you’ll need to trace the wiring to find the open circuit and repair it.

Next you’ll need to check the ground side. Set your DVM to read Ohms. Insert one probe in sensor 1 bank 1 connector pin 2 and the other to a known good ground. You should see a reading of less than 2 ohms (note some systems pulse the ground circuit for duty cycle so you may see the meter jumping between 1 ohm to infinity. This is normal). Someone else may have more definitive information on this aspect of the ground circuit operation.

Next do the same at sensor 2 bank 1 connector pin 2.

If your meter indicates no reading (infinity) you’ll need to trace the wiring back to the PCM looking for an open circuit.

Next,you'll need to test the actual sensors heater element in the O2 sensor. Utilizing the connector from the sensors pigtail, identify the corresponding pins 1 & 2. Using your DVM set to read Ohms, insert one probe in pin 1 and the other in pin 2. Your meter should read between 2 – 2.5 ohms. If lower than 1.6 ohms or greater than 2.8 ohms, you’ll need to replace the sensor.

Also, if you have a scan tool, what is your engine coolant temperature sensor reading (not the temp gauge on dash) when the check engine light comes on?

 

Thanks for the help Rev. I appreciate it. The truck is running, and its the last weekend of hunting season right now so I'm going to be in the woods all weekend, but as soon as I get back I'll be back on it.

 

Okay, so Just got done messing around with the truck in the shop. Its raining here, so I couldn't paint it any more :-(, but I did figure out the O2 sensor problems. I checked the wiring, and followed it all the way back to the fuse box. It was perfectly fine. We ran the bulldog PC on it. Found that the spark plug wires could cause the O2 sensors to fail. Its the only other thing on the list. So tomorrow's job is spark plugs and wires... Yay.. Looking forward to taking that intake manifold off.

Any suggestions as to what spark plugs I should run? I was thinking the Iridium's but I'm not sold 100% yet.

As far as the EVAP leak goes, we will clean the carbon off of the EGR while we have the intake off, and it could also be the fuel hose gasket. Does anyone know the best/easiest way to change that?

 

Put new plugs and wire in it today. I ran the autolite iridiums. Took the O2 sensor codes off, but not the p1443. I think it could be the fuel purge solenoid. What do ya'll think?

 

i am almost in the same boat as you, im pulling the p0141 and p1443 codes. i recently got a whole new exhaust put on my 97 ranger and before i dropped it off i had no CEL and after picking it up i have a "bad" o2 sensor behind the cat and purge malfunction. but both purge pieces are new the valve and solonoid and i dont know what to do. the solonoid took the CEL off a week ago but not anymore. it has a strong vaccum. im lost.

 

So its been almost 2 months since I've gotten another chance to look at my truck. Work has bogged me down so much...

Any who, overall, I have replaced the O2 sensors, changed the spark plugs and wires, changed the vacuum lines, replaced the purge valve and solenoid, cleaned the fuel system, and cleaned the throttle body. My truck is still throwing the P0141 and P0135. The O2 wires have power, but now my truck has a rough idle at times. We thought it could be the fuel lines or the throttle, so we cleaned those, but it hasn't helped much.

Also, when I turn my A/C on now it will sometimes blow out of the top of the dash (like the defroster) instead of through the vents, and my windshield wipers have gotten a mind of their own, and turn on spastically sometimes while I'm driving.

Could any of these problems be solved by simply changing the PCM? I'm not sure if the A/C and windshield wiper problem will change, but if it will fix my predicament with the engine running bad, I can overlook the other minor problems.

 

You'll need to conduct the tests listed above to verify proper operation of each O2 sensor heater circuit.

The A/C issue sounds like you have a vacuum leak. The wiper problem sounds like it might be a bad multifunction switch.

 

regarding the p1443 code, if you replaced the purge valve and solenoid and there are no leaks in the lines back to the tank you might want to check your gas cap. i have heard a bad seal on the cap could throw the code.
having said that on mine the code cleared without a pressurized gas tank as the filler hose was leaking at the time...