When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I purchased a 2010 4.0 ranger about 2000 miles ago with about 61k miles on it. Since I can’t be sure about the maintenance I’ve been running through list of things with the goal of getting all the maintenance items done that should get done around the 60k mark.
Poking around under the truck I notice that all 4 of the o2 sensors have been unplugged. Strangest thing is that it isn’t throwing a code or running all that rough at all. Gas mileage has sucked but I chalked that up to being a ranger. Idle was a little choppy but wasn’t anything that deterred me from buying it.
Anyway, working my way through getting them plugged back in over the course of a couple of days and I have both bank 2’s plugged in and b1s2 plugged in and the truck is running great. Gas mileage and power was much improved. Idle has improved quite a bit and I figure it’ll get right where it needs to be when I get b1s1 plugged in. Battery unhooked and engine cold I get the connectors together. I let it sit for an additional 20 mins before hooking the battery up. I start it and let it run for 2 mins and head down the road for a test drive.
It ran great up until the engine got almost all the way warmed up. Just cruising along at 55 with steady throttle off cruse control it lost all power. It didn’t shut off but lost all power. I blipped the gas pedal a couple of times and then the engine came back. It did that weird power cut a couple times every mile until I got home.
I have a look at the o2 sensors with my torque app and they are doing exactly what they need to do with their voltages. No flatlines, no high voltage, no low voltage. Nice easy waves up and down. I pull the battery connection and unplug the b1s1 because it was running fine before that. Let it sit for about 10 mins, hooked the batter back up and went out for a drive. Ran great, no shutoffs or power kills. I get home, unplug the battery, and hook b1s1 o2 back up and get a mile down the road and same thing is back. power cut to 0 and I have to blip the gas pedal before it comes back. I pull into my driveway and let it sit idling. It only gets a few mins before a complete engine stall. It’s immediate like the fuel gets cut.
I run to the local parts store to pick up a brand new motorcraft o2 sensor and throw that in thinking that although the wave pattern looks good maybe there is something off with it that is screwing the fueling up. Same thing…. In a mile or so it’s a power cut to 0 and I have to blip gas pedal to get it back (gas pedal blip works going down the road but in the driveway it just dies either way power cut or die it’s sudden with no sputtering).
Right now I’m waiting for the engine to cool down before I unplug b1s1 o2 sensor again and I’ll bet it runs smooth with no shut offs. It’s very surprising but the fuel trims look nearly perfect running it without it plugged in. I can provide some graphing from the torque app.
So in a nutshell it dies when b1s1 o2 sensor plugged in (even with replacement) and runs about 98% fine without it….No check engine light or codes get generated.
Unplug the MAF sensor and see if it sets a code for MAF and IAT(air temp) sensors
If so reset and unplug Throttle sensor(TPS) and see if it sets a code
Just doing a "sanity test" on the PCM
Each O2 has 2 parts, the sensor and the Heater, so you should get TWO codes for each O2 that's unplugged
Unplug the MAF sensor and see if it sets a code for MAF and IAT(air temp) sensors
If so reset and unplug Throttle sensor(TPS) and see if it sets a code
Just doing a "sanity test" on the PCM
Each O2 has 2 parts, the sensor and the Heater, so you should get TWO codes for each O2 that's unplugged
I’ll get out there this morning to try these things. It’s about 20f right now but at least the wind isn’t blowing and it’s sunny. I’m also going to unplug the b1s2 and b2s2 sensors and leave b1s1 and b2s1 plugged in to see if that lets it run right. If it does then I’ll call it a day.
So I ran through some of the suggested steps and all I got it to report was a U2510. That was with no check engine light on. I tried to isolate it by unplugging maf, iac, egr, tps, etc. These either graph in or not graph in torque depending on if they are or are not plugged in. never get a cel when they are unplugged.
With any particular sensor or a combination of them unplugged either it wouldnt run or it would run and still power cut going down the road or die all together if idling in the driveway. Also can confirm that it is 100% associated with engine temp. It was 20f this morning and it ran fine with everything plugged in with no issues until it is at or close to operating temp. I also tried to run with the b1s2 and b2s2 (downstream) unplugged with leaving b1s1 anad b2s1 (upstream) plugged in and still power cuts.
At the end of it all I left b1s1 unplugged and the rest plugged in and it runs about 98% as good as it does with all 4 plugged in (in between power cuts) with no issues and +20 mpg.
Last edited by msmith3331; Apr 16, 2022 at 12:56 PM.
Here is a little graphing through the torque app while sitting in the driveway. You can see the o2 sensors with the fuel trims. This is with all the o2 sensors plugged in.
Last edited by msmith3331; Apr 16, 2022 at 01:13 PM.
The two S1 O2s are looking normal
The two S2 O2s are very low, expected with working Cats is 0.7-0.8volts, Cats burn up most of the Oxygen so S2s see "rich" exhaust, very little oxygen
B2S2 is steady as expected but low voltage, so maybe no Cats, i.e. hollowed out???
B1S2 is low and jumping around which may be because of B1S1
The computer will cycle the fuel mix lean and then rich every few seconds to test S2 O2 sensors for a response to see if Cat converter are working, your S2s should set a code
What the history on this vehicle, looks like someone may have changed the software to "fake" sensor inputs so it won't set a code because sensor is never unhooked, not even sure if that is possible
But, with the absence of code setting I would say its a computer issue, for sure, seems to be a wonderful failure but a failure none the less, lol
Here is where I was graphing with all the o2 sensors plugged in. I was also tracking maf along with fuel flow. As you can see, whe the power cuts hit o2 sensors bottom out while fuel flow and maf nearly do but not completely. The engine is still running but drops to idle rpm and then comes back.
The two S1 O2s are looking normal
The two S2 O2s are very low, expected with working Cats is 0.7-0.8volts, Cats burn up most of the Oxygen so S2s see "rich" exhaust, very little oxygen
B2S2 is steady as expected but low voltage, so maybe no Cats, i.e. hollowed out???
B1S2 is low and jumping around which may be because of B1S1
The computer will cycle the fuel mix lean and then rich every few seconds to test S2 O2 sensors for a response to see if Cat converter are working, your S2s should set a code
What the history on this vehicle, looks like someone may have changed the software to "fake" sensor inputs so it won't set a code because sensor is never unhooked, not even sure if that is possible
But, with the absence of code setting I would say its a computer issue, for sure, seems to be a wonderful failure but a failure none the less, lol
Not sure the history on it. I know it was an elderly farmer that really didnt drive it much. The software part that you mentioned is what I'm a little worried about. I know it can be reflashed by the dealership if it was changed and ultimately I might have them check. Carfax showed a replaced coil pack about 4k miles ago and I kindof wonder if that was the beginning of it all. Hope not and its a genuine issue but you never know with people. Everything that can be graphed seems to respond and react to throttle input so at first glance everything seems to be performing correctly
I have an upcoming appointment at the dealership to have the airbag recall done and maybe I'll have them dig into this while its there. Bummer too I just bought a nice reflex site for my g19 and had to take it back for a refund in anticipation for the shop bill.
Dealer shop should be able to "talk" to the computer on a deeper level to see what it has to "say for itself" as far as not setting codes
There is Forscan software you can use, its like OBD+ in that there are more options to "talk" with Ford computers and you can change some parameters
Its not an expensive software but you do need the OBD cable that can hookup to laptop or tablet that's running the software
Dealer shop should be able to "talk" to the computer on a deeper level to see what it has to "say for itself" as far as not setting codes
There is Forscan software you can use, its like OBD+ in that there are more options to "talk" with Ford computers and you can change some parameters
Its not an expensive software but you do need the OBD cable that can hookup to laptop or tablet that's running the software
I bought the forscan software from the play store. 6 bucks to get a different view is pretty inexpensive. As luck has it I had already bought the compatable bluetooth adapter years ago when I bought torque so good to go there. Went out this morning to do some quick checks and I'm pretty impressed. I have a lot more pids I think than torque but not sure which ones would be useful in this case. Maybe one or more voltages when the power cut happens?
Would it be useful to perform a pcm or gem module reset/re-learn after plugging in b1s1 or is a battery unplug and wait for about 15 mins accomplishing the same thing?
Ultimately its probably a dealership level issue but i'll still try some things not to have to pay that bill.
Forscan Forum is a good place to read up on all the options
Yes, as long as the dealer price is not too outrageous on "talking to" the PCM, then they will be the best bet
Ford Mechanics have access to Ford "forums" and data bases that have "posts/reports" from all the other Ford Mechanics
So a lot of been there/done that/fixed this info on all things Ford and Ranger
Quick update but not the end of it. The ford dealership I took it to to do the maintenance is saying that the rear cassette is worn and is causing a contribution problem in cylinders 1 3 and 5 due to timing being off. They explained that when b1s1 is unplugged the computer falls back on a default mode of operation which is masking the timing issue caused by the worn cassette. Plug in b1s1 and everything starts talking to each other and then it knows it has a problem. It won’t know it has a problem and act on it (power cut) if you take out some of the info as in this case removing signal from b1s1.
Their fix..You guessed it, pull the motor and replace all the chains and cassettes. $3500 quote. Now that’s a bit suspect to me to have that kind of wear on a motor that has 61k on it and a 2010 as well. As far as I know the 2010’s were pretty solid. Anyway something’s up with it still. Someone unplugged the o2 sensors to mask an issue. Either it was the seller to the dealership or the dealership to me.
I drove straight from that dealership that performed the service to the dealership I purchased it from with the printout of the diagnosis and talked it over with them. They are going to have a look at it tomorrow as a second opinion. Ultimately I think it’s going to be on the dealership that sold it to me with disabled/tampered emissions components. Pretty sure in the state that I bought thats a big no no for a dealership to do that and they can be fined. If it is the timing chain I’m going to push for a buyback because I’m just over it.
Last edited by msmith3331; Apr 21, 2022 at 07:06 AM.
But I am still at a loss with the No CEL and No Codes
How did Dryer explain that?
Sure pulling out ANY engine and rebuilding it is never a bad idea, IF YOU ARE NOT PAYING FOR IT, I get that part, lol
"Ashtrays dirty, buy a new car", sure why not, for sure fixes the problem and any other problem with the dirty ashtray car
Noisy cassette might cause Knock sensor issue
The 1997-2003 4.0l SOHC did have timing chain issues..................and not once have I ever read about unplugging any or all O2 sensors to help out, not even off-hand comments, there is no connection
I am certainly not an expert in Ford Computerese, but I do know how systems work and interact, so I would have to call BS on the timing chain O2 sensor connection
But the big thing, in my opinion, is the NO CODES, I want to know how I can disable code setting in my computers, lol, that's some good info there
I agree 100% on the check engine light. I’m going to leave that up to the dealership it’s at right now to figure out. I guess I should have asked when I picked it up from the dealership that I have do the work but I guess I was just in shock. Seems pretty dumb in hindsight not to have asked. I’m going to make sure that I get a good answer for that while it’s at the current dealership (The one who sold it to me). I do remember getting a U2510 code once and that boils down (I think) information received not information expected so maybe that’s the tip of the iceberg.
Have the day off and the truck goes in at noon so I figured I’add to the posts. Here are some of the printouts from the dealership that was troubleshooting for me (not the one I purchased it from)
Top one is a cylinder contribution test and the bottom one is a compression test. Supposedly the numbers are down due to the worn rear guides/chain. I wasn’t familiar with this method of troubleshooting this particular issue and my experience with compression is a sealing issue with either the valves, head, or rings. But..they are all uniformly down on that right side so that is suggesting a commonality to me. Normally there is a bit more variance on the numbers and these are strangely pretty close to each other. Contribution as far as I know can be many things not necessarily sealing related like spark, injectors, etc. But all pretty much uniformly on the right side as well.
I guess I never mentioned this either. I don’t get that start up rattle that is all over youtube. It’s starts up just fine with no noise. I changed the tensioners out of a regular maintenance a couple hundred miles ago but they weren’t noisy before either. I’d be curious if anyone else has had these tests done after they changed their tensioners as well.
More to come as I hear more.
Last edited by msmith3331; Apr 21, 2022 at 05:51 AM.
Yes, those tests speak volumes
You are correct one bank is effected so mechanical issue
The Cams on each head are not "keyed", they use "friction fit" to hold the timing, i.e. the shaft has a taper as does the gear, so the force of tightening the gear to shaft holds the timing
This is quite common now on all engines, woodruff keys and slots are very 20th century, lol, it does cut down on manufacturing cost quite a bit so I get it, but I still like the idea of a key and slot to ease my mind
So..........reason I mention it is because without the "rattle" noise I would tend to think a gear has slipped on one bank not bad cassette, and the cams can be re-timed without engine removal, need to take valve covers off so not simple but for sure do-able
But I get why they recommended pulling the engine for the repair, its the "dirty ashtray" thing, worse case is its not just the cam gear that has slipped, so once valve covers are off to reset the gears another issue comes up so....................customer gets mad because engine now has to be pulled so cost skyrockets
Mechanics do have to quote worse case, and its not their money
Update on the truck. The dealership I bought it from confirmed what the other dealership found..Or at least they confirmed that the timing was off. They then proceeded to say that other people have been into the engine since I bought it from them so most likely they are to blame and not them. I reminded them that all the work has been done by the other ford dealership in town and they bit on that to say well, when they replaced the tensioners they knocked it out of timing. I told them BS and that was impossible to do. I think they are confusing the guides/cassettes with the tensioners.
I went round and round with them about fixing it on their dime or buying the truck back and they stated they would be doing neither. So I’m making call after call getting as much info as I can to get them to fix it or buy it back. Probably not going to be able to do anything about it short of talking to a lawyer that handles this stuff for the date of minnesota but it’s a distraction for me for now.
If anyone knows if it is illegal for a minnesota dealership to sell a truck with a disabled emissions system I’d like to know.
I don't know who would be the equivalent to contact in your state, but if this happen to me in California, I would be contacting California Air Resources Board and EPA. They carry a lot of weight when it comes to pollution control. I recently had a issue with a major company that would not honor the warranty on their after market catalytic converter system. It tool a while but C.A.R.B. applied enough pressure to get it taken care of.
