98 4.0 ohv help

[NoDangerIfItsARanger98]

Hello I'm new here but have lurked for a long time. I have a 98 Single cab long bed Ranger with the 4.0 ohv in it. It's my daily driver and I love it. Its a rust free southern truck I bought out of Texas with 200,000 plus on it. The truck made it 10,000 miles for me before the engine developed a severe knock. Pulled it apart and could tell right away it had been abused all it's life. Long story short I bought a long block with all new internals and rebuilt the rest myself. New injectors, gaskets, the works. I followed the break in process to a T and everything ran fine when I first got it back on the road. Changed oil after the first 500 miles then again at 1,000 and switched to a heavier oil since the oil pump doesn't like the thin stuff. Anyhow after a few days in it felt sluggish so I checked the air filter and low and behold the mice chewed it to pieces. It sat out behind my place of work for a month while i waited on parts so I should have known better but I was just happy to have it up and running again. So changed that and the changed plugs as they were fowled pretty bad from the lack of air for a proper mixture and didn't have an issue. A month or so later I developed the same miss or more so like a lag or lope. Checked everything again and all was fine. Decided to check the cats and the first cat was melted 3/4 of the way shut and the second was plugged almost solid with soot. So for a quick fix I( dun dun dun) removed them and instantly gained my throttle and power back. I only drive it to and from work maybe 8 miles a day. Didn't have any issues again for a while. Now this thing has had O2 sensor issues from when I bought it and even after I rebuilt it it's always throwing a lean code for one bank and rich for the other. I've changed sensors and used cleaners and seafoam and the whole 9 yards but it always only works for a short time. I can not keep spark plugs in the thing and the O2 sensors are always bad. Just a week or so I again developed a miss or more so like something is restricted, like it's taking in all the air it can but there is no power in the the throttle. I also found the hose coming off the intake to the what I'm assuming is some form of vacuum canister or something with the egr was collapsed and as soon as I opened the hose it almost stalled itself out before regaining idle speed. I guess my overall question is where do I go from here? I'm not looking to make my ranger into some hotrod power demon, I just want it to run as best as possible for what it was designed for. Light duty work, 4x4 for the winters and the occasional offroading and overall smooth running engine performance. So questions are do I put a new cat on and change the O2s and hope for the best? Different muffler for better flow? Fuel system upgrades? or is there another issue with the egr and vacuum systems? Are there any things you all would recommend or suggest? Thanks for your time and I hope I haven't rattled on to long ?

 

[RonD]

Hello I'm new here but have lurked for a long time. I have a 98 Single cab long bed Ranger with the 4.0 ohv in it. It's my daily driver and I love it. Its a rust free southern truck I bought out of Texas with 200,000 plus on it. The truck made it 10,000 miles for me before the engine developed a severe knock. Pulled it apart and could tell right away it had been abused all it's life.

Long story short I bought a long block with all new internals and rebuilt the rest myself. New injectors, gaskets, the works. I followed the break in process to a T and everything ran fine when I first got it back on the road. Changed oil after the first 500 miles then again at 1,000 and switched to a heavier oil since the oil pump doesn't like the thin stuff.

Anyhow after a few days in it felt sluggish so I checked the air filter and low and behold the mice chewed it to pieces. It sat out behind my place of work for a month while i waited on parts so I should have known better but I was just happy to have it up and running again. So changed that and the changed plugs as they were fowled pretty bad from the lack of air for a proper mixture and didn't have an issue.

A month or so later I developed the same miss or more so like a lag or lope. Checked everything again and all was fine. Decided to check the cats and the first cat was melted 3/4 of the way shut and the second was plugged almost solid with soot. So for a quick fix I( dun dun dun) removed them and instantly gained my throttle and power back.

I only drive it to and from work maybe 8 miles a day. Didn't have any issues again for a while. Now this thing has had O2 sensor issues from when I bought it and even after I rebuilt it it's always throwing a lean code for one bank and rich for the other. I've changed sensors and used cleaners and seafoam and the whole 9 yards but it always only works for a short time.

I can not keep spark plugs in the thing and the O2 sensors are always bad. Just a week or so I again developed a miss or more so like something is restricted, like it's taking in all the air it can but there is no power in the the throttle. I also found the hose coming off the intake to the what I'm assuming is some form of vacuum canister or something with the egr was collapsed and as soon as I opened the hose it almost stalled itself out before regaining idle speed.

I guess my overall question is where do I go from here? I'm not looking to make my ranger into some hotrod power demon, I just want it to run as best as possible for what it was designed for. Light duty work, 4x4 for the winters and the occasional offroading and overall smooth running engine performance. So questions are do I put a new cat on and change the O2s and hope for the best? Different muffler for better flow? Fuel system upgrades? or is there another issue with the egr and vacuum systems? Are there any things you all would recommend or suggest? Thanks for your time and I hope I haven't rattled on to long ?

Welcome to the posting side of TRS


Paragraphs man, paragraphs

Anyway I think your upstream O2 sensor plug ins are reversed, that causes lean and rich codes at the same time

O2 sensors use universal connectors, so left or right side have exactly the same plug in
Computer runs the fuel mixed based on left side and right side O2 sensor data, if It see lean burn on drivers side it adds fuel just to the drivers side injectors, if O2 still show lean it add more, but if its actually seeing the Passenger side O2.................well doesn't wok out well, lol

You have to look at the truck side/harness side wire colors to see which is drivers side and which is passenger side connector
So find the drivers side O2 connector in the harness first

Each O2 has 4 wires

All 3 O2s will have an Orange and a Light Blue/Orange stripe wire, these are the 2 common wires

The drivers side O2 will have yellow/blue stripe and a Red/black stripe

Passenger side O2 will have a red/white stripe and grey/blue stripe

Rear O2, behind cats will have white/black, red/green but its connector is usually too far back to get confused with the 2 upstream O2s

 

[NoDangerIfItsARanger98]

Hello and thanks for the quick reply. Paragraphs got it.

When I pulled the motor out to put the rebuilt in I discovered that the driver's side O2 connecter had come off it's clip and had half melted to the exhaust pipe. I wire tied it back together and had no issue.

A few weeks later it acted up again and I discovered that inside the rubber grommet that holds the wires into the plug was broken off and all green and nasty inside. I found a new plug and changed the end and the issue went away. I made sure and connected each wire to the new plug as it came out of the old so that everything was the same.

I didn't think it was possible to plug in the sensors backwards since the one runs up one side and the other up the opposite side as my harness Ys off behind the motor. I will definitely check that and check that the correct wires are going to the correct side. I never considered that but it's possible. I'll start there!

 

[RonD]

A shop did that(reversed O2s) on my 4.0l Ranger when they changed the clutch

Driving it home, after it warmed up and started to using the O2s, its started running poorly and Check engine light(CEL) came on, never ever had a CEL on that Ranger before
Had a hill on the way home so floored it and engine started running great, but as soon as throttle wasn't at WOT it ran bad

Got home and codes were Lean bank 1/Rich bank 2 WTF??? ,lol

Checked everything I could think of and nothing seemed to matter, it ran fine cold, but not warm

Woke up that night to the thought "what isn't used cold or at WOT(wide open throttle)?"
O2s are not used
Both O2s failing at the same time..........................too long of odds on that
Checked the wire colors..................reversed plug ins

Called the shop just to give them the heads up, "oh we would never do that", lol, mechanics, can't help stupid sometimes

 

[NoDangerIfItsARanger98]

I just checked the wiring for the O2 plugs and they are on the correct sides. One thing I forgot to mention is that when I let off the gas pedal and the RPMs drop down to between 1000 and 2000 the truck and RPM gauge jump up and down between 1200 and 1500 until I press the gas then it goes back to normal.

I plugged the the scanner in again and the codes I'm getting are as follows

P0155 HO2S Bank 2 Sensor 1 Heater Circuit Fault

P1132 HO2S BANK 1 SENSOR 1 RICH

P1151 HO2S BANK 2 SENSOR 1 LEAN

P1138 HO2S12 SENSOR RICH

Also in the GEM (which was a bitch to get figured out as mine quit and I had to get a rebuilt one because Ford said pound salt and then week later my local dealer calls and says hey we got that GEM after all ?)

B1302 Accessory Relay Coil Circuit Fault

B1398 Left front window 1 touch down relay circuit fault (but this is a single cab with crank windows?)