2006 Ford Explorer 6 cylinder - No Power When Accelerating - Won't Idle

[rabbit76]

Hi All, I have a 2006 ford Explorer V6 and it has a perplexing problem. Started it the other day and the engine ran rough and threw codes for multiple misfires and an upstream O2 sensor (stuck rich). Needless to say, I replaced the coil, wires, plugs and the bank 1 upstream O2 sensor and the truck still runs bad. It does not want to idle, it shakes at idle and the only way to keep it running is to push on the accelerator pedal. However, once you let off the throttle the truck will eventually start to shake, power down and stall. If you do start it and put it in drive, you would need to mash the accelerator to the floor to go about 5 to 10 miles per hour. If anyone has any clues or idea I am pretty stuck right now. I was thinking maybe the fuel pressure (but I did not see a way to test the pressure on the fuel rail) or maybe the fuel pressure sensor under the manifold? It will start and move, but I would say it is not really drivable. I welcome any thoughts or help.

Also, as an UPDATE. After changing the coil, wires and plugs and the O2 sensor I do not have any misfire codes. I forced the truck to drive yesterday (to try and get the truck to throw some codes) and I got P2196 and P2197. P2196 means bank 1 sensor 1 is stuck RICH. P2197 means bank 2 sensor 1 is stuck LEAN. Why would bank 1 be stuck rich and bank 2 be stuck lean? Also, I replaced the O2 sensor on bank 1 (still got the code).

Thanks!!

 

[410Fortune]

Very likely low fuel pressure
Forget the codes for now, when an engine is running out of gas it will have misfires, and throw a bunch of codes that don’t make sense

Start with the basics
06 explorer 4.0 should have 64 psi rail pressure

Here is a 4.0 sohc engine from a 06 ranger
I circled the fuel rail pressure test port

Let me guess about 150-175k miles?

It’s easy to throw parts at it
We call it loading the parts shotgun
But basic diagnostics is better

Sounds like she’s starving for fuel
I’m not sure but I think a 06 explorer has a fuel pressure sensor? And fuel pump driver module? Regardless you should check your fuel pressure the pump maybe getting weak… with weak pressure it will run but barely
In the old days fuel pumps worked or quit, not these new ones… they will lose their ability to make pressure and still run
Often you can put your ear to the fuel fill and listen to the pump… a strong healthy pump makes a nice quiet smooth noise, a weak failing on usually sounds more like a squeal or “struggling”

I’m only a little familiar with a 06 sploder, I work on the older ones and rangers… but I figured I could chime in and offer some ideas. Others here will know more about the 06 fuel system.. and you can try a search

 

[rabbit76]

Very likely low fuel pressure
Forget the codes for now, when an engine is running out of gas it will have misfires, and throw a bunch of codes that don’t make sense

Start with the basics
06 explorer 4.0 should have 64 psi rail pressure

Here is a 4.0 sohc engine from a 06 ranger
I circled the fuel rail pressure test port

View attachment 462218

Let me guess about 150-175k miles?

It’s easy to throw parts at it
We call it loading the parts shotgun
But basic diagnostics is better

Sounds like she’s starving for fuel
I’m not sure but I think a 06 explorer has a fuel pressure sensor? And fuel pump driver module? Regardless you should check your fuel pressure the pump maybe getting weak… with weak pressure it will run but barely
In the old days fuel pumps worked or quit, not these new ones… they will lose their ability to make pressure and still run
Often you can put your ear to the fuel fill and listen to the pump… a strong healthy pump makes a nice quiet smooth noise, a weak failing on usually sounds more like a squeal or “struggling”

I’m only a little familiar with a 06 sploder, I work on the older ones and rangers… but I figured I could chime in and offer some ideas. Others here will know more about the 06 fuel system.. and you can try a search

All great advise and testing the fuel pressure was on the list of things to do. The problem I had was the fuel rail did not have a schrader valve on it like the engine pictured above. It just has round caps at the end of each one (looks like no port to test on). I did some research and it seems you may have to somehow tap into the fuel line as it comes up the firewall, but I admit I am not sure how to do that yet. I have never had a vehicle act like this. Barely starts, won't idle, you can get it to move........but you need to mash the pedal to the floor and even then the truck is not happy. I also should have mentioned when I pulled the plugs (the old ones) they were very black and smelled like fuel.

 

[410Fortune]

Yep
On some 4.0 the shcrader valve is on passenger side rear of the rail, near the firewall… worth a check
If it doesn’t have one then they expect you to read the pressure with your scanner
Or
Plumb in a manual gauge with a tee fitting…. Not easy when the fuel line comes up the back of the engine on the spine of the transmission…… and not easy when we are dealing with 64 psi and spring lock fittings

The engine is fitted with a fuel pressure sensor… so the scanner will show the pressure
Now these trucks also have a fuel pump driver module, which basically turns the pump on and off or regulates its rpm to provide only pressure when needed

Injectors require like 64 psi in order to atomize the fuel properly and spray it into the combustion chamber. If pressure is low it will literally dribble out the end of the injector and not fire off with the spark, can explain flue soaked plugs

How many miles?
I did a quick search on YouTube and many videos showed up… you may find one that details all of this properly for your 06

 

[rabbit76]

Yep
On some 4.0 the shcrader valve is on passenger side rear of the rail, near the firewall… worth a check
If it doesn’t have one then they expect you to read the pressure with your scanner
Or
Plumb in a manual gauge with a tee fitting…. Not easy when the fuel line comes up the back of the engine on the spine of the transmission…… and not easy when we are dealing with 64 psi and spring lock fittings

The engine is fitted with a fuel pressure sensor… so the scanner will show the pressure
Now these trucks also have a fuel pump driver module, which basically turns the pump on and off or regulates its rpm to provide only pressure when needed

Injectors require like 64 psi in order to atomize the fuel properly and spray it into the combustion chamber. If pressure is low it will literally dribble out the end of the injector and not fire off with the spark, can explain flue soaked plugs

How many miles?
I did a quick search on YouTube and many videos showed up… you may find one that details all of this properly for your 06

I would like to say thank you. I really appreciate your knowledge and experience and taking the time to respond. To answer your question, the truck has 127,000 miles on it. It ran perfect with no issues to this point. Worked in the morning when I took the kids to school. Gave me all these symptoms I am describing in the afternoon when I went to pick them up (absolutely no warning or engine codes in between that time). Everything you are saying makes sense and I am thinking since I replaced the coil, wires, plugs and an O2 sensor (tune up items), maybe I should just go ahead and pick up a fuel pump and fuel filter and give it a go (also tune up items)? The fuel pump seems logical.

 

[410Fortune]

You are welcome!!

20 years and 125k miles is a lot to ask of a fuel pump especially these new ones that run on and off on and off

However as a mechanic I hate to throw parts at anything without first seeing it with diagnostics
It is the last part you buy that fixes the issue


If you do replace the pump use oem quality
Cheap pumps will have you doing it twice
I use Bosch pumps and strainers, Wix or
Motorcraft filters

I’ve never worked on a 06 explorer except to crush it and steal the engine and seats lol

But I do a lot of ranger stuff up to 2011
Shame on ford for getting rid of the fuel pressure test port
This is common throughout it the industry as they try to
Keep their dealerships alive they have made it harder and harder for us YouTube mechanics to work on things

Does your code reader have the ability to see fuel pressure?

 

[rabbit76]

You are welcome!!

20 years and 125k miles is a lot to ask of a fuel pump especially these new ones that run on and off on and off

However as a mechanic I hate to throw parts at anything without first seeing it with diagnostics
It is the last part you buy that fixes the issue


If you do replace the pump use oem quality
Cheap pumps will have you doing it twice
I use Bosch pumps and strainers, Wix or
Motorcraft filters

I’ve never worked on a 06 explorer except to crush it and steal the engine and seats lol

But I do a lot of ranger stuff up to 2011
Shame on ford for getting rid of the fuel pressure test port
This is common throughout it the industry as they try to
Keep their dealerships alive they have made it harder and harder for us YouTube mechanics to work on things

Does your code reader have the ability to see fuel pressure?

I think so. I went out there just now and I saw a description on the scanner that said FRP (kPa) (I assume fuel rail pressure). I looked at that and it said 273.97 kPa. I am pretty sure when I did the conversion that this translates into 39.73psi. To be clear, all I did was turn the key to the start position (I did not start the truck) and that is what I got. Any thoughts? I included a picture from the scanner below.

Also, I forced the truck to start and read the live data. It ranged from the high 250's (kPa) to about 284 (kPa). This was mostly with my foot on the accelerator trying to keep it running. When I took my foot off the accelerator, the truck would hold for a little while around 270 (kPa), then eventual it would start to shake and the kPa would drop to 260's 250's and stall out.

 

[rabbit76]

As an update if anyone is following this, I have replaced the fuel pump and the fuel filter this weekend (Bosch Fuel Pump) and Motorcraft fuel filter. Unfortunately the problem I have still exists? As mentioned, I have replaced the coil, wires, plugs, 02 sensor, fuel filter, fuel pump and this issue is not resolved. I will say that using my scan tool and not starting the truck (just turning the key forward), the FPR (or fuel rail pressure) seems to be closer to 500 (as opposed to the 273 mentioned above. However, when I start the truck and look at the live data, the fuel pressure per the scan tool seems to drop to 260 / 250 kpa and will only run if I step on the accelerator? The only other thing I can think of is the fuel pressure sensor? I am pretty stuck here so if anyone has any ideas, please let me know. I can use the help. Also, there are no other codes (which is not helping either).

 

[410Fortune]

Very good work!
I’m so sorry throwing fuel parts at it is now helping dang
Not easy to change fuel pumps

I’m going to do some research about the fuel sensor and your readings will report back (this system still new to me)

Could the engine have jumped time?
Could the exhaust be plugged?
Could the intake / airbox be plugged up?

I ask because you are with the vehicle and may have insight

 

[Turdle]

Might not help, but I'd like to see throttle position sensor data if possible. Off, idle and throttle input

 

[rabbit76]

Very good work!
I’m so sorry throwing fuel parts at it is now helping dang
Not easy to change fuel pumps

I’m going to do some research about the fuel sensor and your readings will report back (this system still new to me)

Could the engine have jumped time?
Could the exhaust be plugged?
Could the intake / airbox be plugged up?

I ask because you are with the vehicle and may have insight

Hey, no issues. I don't mind doing the work as it is somewhat "tune-up" type items. I am just more confused now because ignition should be fine and fuel delivery to some extent has been "resolved". The only other things I can think of are 1) maybe the fuel pressure sensor (maybe sending bad readings)?, I thought about jumping time as I had a different explorer that did that and it wound up junk. To test that I will try and do a compression test on both banks to see what I get (I know they have plastic timing guides that fail). Airbox is clear (had that off changing the passenger side plugs). I plan to do the fuel rail pressure sensor (which requires me to take the manifold off). I will get new gaskets and make sure nothing is plugged up. It's weird because I am not getting any additional codes? Also, as a side thought.......if it jumped time wouldn't I get a bunch of codes?

 

[rabbit76]

Might not help, but I'd like to see throttle position sensor data if possible. Off, idle and throttle input

Hi, yes......I will try and get you those. I am at work now, but will try later today / tonight. I am running out of ideas here.

 

[motormanforsure]

I am going through the same journey as you. I inherited this 2007 4.0L XLT Explorer with the unable to idle, hard to crank, sometimes not start at all issue. I now have a starts up but idles rough Explorer. I started with the fuel filter and the fuel pressure sensor, it was the least painful to change as compared to the fuel pump. Then I realized I would have to change the fuel pump. Once I changed the fuel pump it would start but idled like crap. So I changed the MAF, I did have a MAF trouble code I don't remember what it was. It Idled a little better still a bump or something a little rough about the idle still and no Trouble codes. I change the plug wires, the spark plugs looked ok, I checked all my vacuum lines, no indication that they are the culprit. So I took it for a test drive, While driving above 1800 RPM or so the engine would misfire some and It did not have any top end speed over twenty miles an hour or so and would lose speed. So I searched around the interwebs and came to the conclusion that the catalytic converters were stopped up. So I pulled it off and it was in fact clogged up. Once I replace the cats, I now have top end but still a semi rough idle and a little popping when accelerating, no trouble codes though. So now I am going to change my intake manifold gaskets pull the battery cables off while I do it in hopes that it reset the ECU. If this doesn't fix it I can try changing the coil and the spark plugs. I will also go through and check all of my electrical connections.

 

[rabbit76]

I am going through the same journey as you. I inherited this 2007 4.0L XLT Explorer with the unable to idle, hard to crank, sometimes not start at all issue. I now have a starts up but idles rough Explorer. I started with the fuel filter and the fuel pressure sensor, it was the least painful to change as compared to the fuel pump. Then I realized I would have to change the fuel pump. Once I changed the fuel pump it would start but idled like crap. So I changed the MAF, I did have a MAF trouble code I don't remember what it was. It Idled a little better still a bump or something a little rough about the idle still and no Trouble codes. I change the plug wires, the spark plugs looked ok, I checked all my vacuum lines, no indication that they are the culprit. So I took it for a test drive, While driving above 1800 RPM or so the engine would misfire some and It did not have any top end speed over twenty miles an hour or so and would lose speed. So I searched around the interwebs and came to the conclusion that the catalytic converters were stopped up. So I pulled it off and it was in fact clogged up. Once I replace the cats, I now have top end but still a semi rough idle and a little popping when accelerating, no trouble codes though. So now I am going to change my intake manifold gaskets pull the battery cables off while I do it in hopes that it reset the ECU. If this doesn't fix it I can try changing the coil and the spark plugs. I will also go through and check all of my electrical connections.

Wow, those problems you are having sound very familiar. Yes, probably tomorrow I will change the fuel rail pressure sensor as well as the intake gaskets. The only thing I have not messed wit was the catalytic converter. Perhaps I should look there as well. Please let me know what other progress you make. This information was very helpful as well. Thanks for sharing!

 

[rabbit76]

Ok All, I have another update. Based on my suspicions that the truck jumped time, I did a compression test over the weekend. It would appear that the drivers side bank had good compression (all cylinders were around 175-180psi). However, when I got to the passenger side all of the cylinders were in the 80psi range. So to me, the problem has been solved. It would appear the truck jumped time. Now I need to bore scope those cylinders to see if the pistons kissed the valves and bent them (i.e. what is the extent of the damage). I am guessing if it is not too bad I can pull the engine and replace all the timing components (and check the oil pickup for timing cassette parts). If it is real bad, then I may need to replace the passenger head as well as the timing components. Just thought I would let everyone know what happened. I am open to any thoughts, suggestions should anyone have any. Thanks!!