1993 4.0l ohv running like crap

[firemanst13]

I recently put a new long block in my 1993 Ford Ranger XLT 2wd 4.0 l V6. when I first put it all together and tried to start it for the first time it fired right up, no hesitation or anything. Still today is starts right up but runs like you got 3 spark plug wires off. It jerks, it has no power, I might go 100 miles on a half of a tank or gas. I have replaced everything, plugs, wires, core, MAP sensor and so on, if you have a question on something just ask, I can recall all of them. New fuel injectors also. No smoke coming from tail pipe. I bought a OBD1 checker, and I am getting codes 172 and that seems to mean it is running lean, and code 177 which is running rich. I am at a loss to what to do to it, I have checked for vacuum leaks by pulling the hoses and checking for any holes, tears, or brittle hoses, and then I took Carb cleaner while it was running and sprayed it in every nook and cranny I could find, all the hose ends, the length of the hose and around every gasket I could find and reach, and nothing. I can usually find the problem on stuff, but this thing is whooping my behind, nothing I do makes it worse or better. I am just ready to get it running correctly. Please any advice ideas, you know exactly what my problem is just any help will be greatly apricated. I just want to thank everyone who takes the time to read this. Please help

 

[RonD]

Stop replacing things, it just adds to most problems

New, now-a-days, means NEVER EVER TESTED, so unreliable, no longer means "it works"


Code 172 means Lean on Right side/bank of engine, passenger side
177 mean Rich on Left side of engine, drivers side

This happen to me when a shop installed a new clutch and REVERSED the O2 sensor plug ins, yes there is a left and right O2 and they have exactly the same connector
Just on speculation I would locate both O2 connectors at the top back of the engine and reverse them, 4 wire, Round connectors

Only 1 wire color is different, red/black wire is LEFT side(drivers side O2)
Grey/blue is Right side O2
The other 3 wires on each connectors are the same colors

That should clear up most of your running issues
You will just have to run it for a bit to see
O2s are not used on start up or for the first few minutes of cold engine driving, which is why engine can run OK then, just FYI

Unhook the battery while locating and swapping connectors, over 5min and when you reconnect power the computer will have erased previous "learned" fuel trims, so it can start fresh with correct O2 sensor feed back


Also its most likely time to change the 3 capacitors in the computer, after 20 years they will leak and cause running issues
Under $5 to replace them, but only if there is another issue

 

[firemanst13]

OK, I did replace the O2 sensors, and my wife went to buy them. The guy at the parts store did tell her that the same part number should work on both sides. He did say she could bring them back if they didn't work, I just need to look at the wire colors and see which side I have and replace it. As far as the capacitors in the computer, I put a new remanufactured one in it, so capacitors, the one in it was a remanufactured one and I opened it and it had a bad spot on the board. I will go look and see if I can find the correct O2 sensor, thank you and pray these fixes it, I am about to just get rid of it and I don't want to.

 

[firemanst13]

OK, I am trying to find a left and right O2 sensor. Can you please give me the part numbers? Which part number is the left and which is the right? Thank you

 

[RonD]

Sorry, there is no left and right O2 sensor as far as the device, the sensor itself

There is a left and right PLUG-IN on the wiring harness, one wire color is different on the Rangers harness side, O2s will both have same color wires on their harness, so no help there, have to look at the truck side of the harness
Or in this case just reverse them

You have the left side O2 plugged into the right side plug, and visa versa
So computer is going "nuts"
Lean on one side, Rich on the other

It would be like following directions to someones house and all the left and right turns were reversed...........you would be LOST pretty quick, lol, the computer is "lost"

Engine computers for V6 and V8 engines run each side/bank of the engine on its own, adjusts the air/fuel mix for best power and MPG
If its getting the wrong feedback from wrong O2 sensor then you get what you got, Lean on one side and Rich on the other

 

[firemanst13]

OK, that makes me feel better, thought I was going crazy looking for 2 different O2 sensors, I am going to do that real fast and try it, I just hope the wires are long enough to switch them around. Thank you again and thank you for clarifying for me.

 

[RonD]

Wires will be long enough, both O2 connectors are next to each other at the top rear of the engine which is why they can be reversed

 

[firemanst13]

Hey RonD, if you ever get married, you let me know because I will sing at your wedding for free. Someone must have messed with them before I got it because while taking the harness out, I marked all the wires and the one I had on the driver's side said driver's side. I switched those bad boys and it started up and was purring instead of coughing and bouncing. I really do thank you a lot for the help, I was ready to give it, runs like a sewing machine now and not only is the long block new, heck fire all the major and minor parts are all brand new, hope to get many many enjoyable miles out of it.

 

[RonD]

Good work

And thanks for the kind words

 

[firemanst13]

OK, hate to bother you again, but my truck ran great all day long yesterday, I left this morning looking for some 14-inch tires for it, no one around here has them, have to order them. But the last place I went to when I began to leave, I started it up and bam, it was doing the same thing as before. I brought it home but never got a check engine light and even ran a test with my OBD1 tester and it didn't find anything. So, I decided to take the negative battery cable off and let it sit for a while, it did nothing this time, still no power and jerking. It is not as bad as it was before but bad enough, I don't want to drive it, got me any more advice?

 

[RonD]

4.0l OHV rarely had spark issues, but it does "wear them out" fast, lol

Lack of computer codes points to computer
Unplug the MAF sensor and see if it drives OK and SETS a MAF sensor code, sanity test for computer

Could be dirty fuel filter, or Leaking Fuel Pressure Regulator(FPR)check the vacuum hose on the FPR, for signs of gasoline inside it

 

[firemanst13]

OK, I unplugged the MAF sensor and yes it ran worse, check engine light came on as soon as I unplugged it. I took the fuel filter off and that bad boy is not dirty at all, took it off from the engine side and got gas everywhere, yes even my mouth, I recheck the Fuel Pressure Regular and it is dry as a bone. I ran a scan on it, and it gave me 157 I think, it did say it was the MAF and something about not enough volts. I guess tomorrow I will pull and clean the plugs if it is needed. I have no idea what is up with this truck, takes me about a month to get it running right, you have me switch those wire and it runs like a brand-new truck for a day and a half. Maybe I need a priest come do a cleanse on it. Please don't give up on me. I did take the negative battery cable off and will try again tomorrow after checking the plugs.

 

[firemanst13]

Ok, today, I took every plug out and you couldn't ask for it to be running any better by reading the plugs. They all looked brand new and no richness or lean on any of them. I bought a new positive battery cable and put on it just because I hadn't changed it yet. Drive it and the same old story, the more load there is the more the jerking. I double checked the fuel pressure regulator and still no gas or wetness on or near or in the vacuum tube. I am back a square one, running like crap and I have nowhere to turn or anything, please help. I wish I had one friend close by that worked of stuff like this that could give me a hand, but I never get any hands-on help with anything.

 

[holyford86]

Have you checked your fuel pressure?

 

[firemanst13]

Yes, the pressure seems to be fine, I am lost, the check engine light is not coming on now so I don't even get a hint from the truck with what could be causing it.