P0171, P0174 codes

[muddyexplorer]

So an update on my progress...which is none. The dealer replaced the Intake tube (which I had repaired). the Tech said everything was in spec. It wasn't, the LTFT was still in the high 20's and a couple days later the light was back on.

It went back and my wife waited on it while they continued to diagnose it. It took them about 4 hours. They came back with the HP Fuel Rail Pressure Sensor was bad and needed to be replaced. $1200 since it is almost 4 hours of labor. I said no thanks, I can shotgun parts at it myself. I have monitored the pressure in forscan and didn't see what appeared to be any issues, but I don't have mechanical pressure gauge for those pressures to check it. I did find the specs for pressures in the service manual, so I am going to take it out for a test drive to see if it is within spec.
It should be about 220psi at idle and 770psi at 55 mph and KOEO 1120psi.

 

[2016 ExplorerSportCA]

So an update on my progress...which is none. The dealer replaced the Intake tube (which I had repaired). the Tech said everything was in spec. It wasn't, the LTFT was still in the high 20's and a couple days later the light was back on.

It went back and my wife waited on it while they continued to diagnose it. It took them about 4 hours. They came back with the HP Fuel Rail Pressure Sensor was bad and needed to be replaced. $1200 since it is almost 4 hours of labor. I said no thanks, I can shotgun parts at it myself. I have monitored the pressure in forscan and didn't see what appeared to be any issues, but I don't have mechanical pressure gauge for those pressures to check it. I did find the specs for pressures in the service manual, so I am going to take it out for a test drive to see if it is within spec.
It should be about 220psi at idle and 770psi at 55 mph and KOEO 1120psi.

I was able to clear out the Check Engine Light this past weekend. I took it to family mechanic and advised me since I just replaced Throttle Body, MAF sensors on Top of Intake Manifold and Outlet, to drive it to so the PCM can relearn the new Throttle Body and recheck the LTFT. I drove it for about 40 miles round trip this weekend and notice the LTFT going down it went from Bank 1 26% and Bank 2 29% to Bank 1 24% and Bank 2 26% so they are slowly going down. He advised to put a Chevron Fuel System Cleaner and drive it for a week. I am going to recheck the LTFT tomorrow if there have been any changes after driving it this week and see how it does. So far the Check Engine Light as not returned as of now, even after letting it idle for 15 minute to replicate the conditions.

 

[peterk9]

The throttle body was a known issue with the 2016 model.

2016 Explorer Throttle Body Problems

Hello I have a 2016 explorer I've had I'd 5 months it's got 10'000 miles on it currently it's in the shop getting a new throttle bodies the one it had was sticking making the car jump forward at stop lights and go into protection mode .dealership said this was the second 2016 explorer this week...

www.explorerforum.com

Peter

 

[muddyexplorer]

Another update.....a couple weekends go I pulled the intake and replaced the HP fuel sensor, along with the all the O-rings on the intake manifold. and cleaned the TB and intake. I also checked the intake valves to see ow much carbon buildup they had, suprisely 5 of the were not in bad shape, but the furthest one had quite a bit.

Typical of 5 of them.

Furthest from the TB, firewall side.

After putting everything back together and resetting the PCM I took it for a test drive, annnnd.......no changes. After 30 minutes of driving to let the PCM relearn, the LTFT's were back in the high 20's. Everything is still behaving the same, they dip down in the low 20's when doing a lot of driving and when it sits and idles it will creep banck up to 29%. Here's the head scracher though, after 1 1/2 weeks the check engine light hasen't come on. We even got it to pass the emissions inspection, but my mileage has gotten worse.....its in the high14's to low 15's.
Glad I didn't pay the dealer the $1200 to replace the pressure sensor.

 

[tuxedosports]

Another update.....a couple weekends go I pulled the intake and replaced the HP fuel sensor, along with the all the O-rings on the intake manifold. and cleaned the TB and intake. I also checked the intake valves to see ow much carbon buildup they had, suprisely 5 of the were not in bad shape, but the furthest one had quite a bit.

Typical of 5 of them.
View attachment 450406

Furthest from the TB, firewall side.
View attachment 450407


After putting everything back together and resetting the PCM I took it for a test drive, annnnd.......no changes. After 30 minutes of driving to let the PCM relearn, the LTFT's were back in the high 20's. Everything is still behaving the same, they dip down in the low 20's when doing a lot of driving and when it sits and idles it will creep banck up to 29%. Here's the head scracher though, after 1 1/2 weeks the check engine light hasen't come on. We even got it to pass the emissions inspection, but my mileage has gotten worse.....its in the high14's to low 15's.
Glad I didn't pay the dealer the $1200 to replace the pressure sensor.

did you ever figure out what was going on with this?

 

[peterk9]

did you ever figure out what was going on with this?

Welcome to the Forum.
Hopefully, the member is still following. He was last seen here on September 15, 2024.

Peter

 

[tuxedosports]

Welcome to the Forum.
Hopefully, the member is still following. He was last seen here on September 15, 2024.

Peter

i knew it was an old thread but i should have looked at when he was last seen around here.. thanks! hate to be the new guy that brings up old threads.

 

[peterk9]

i knew it was an old thread but i should have looked at when he was last seen around here.. thanks! hate to be the new guy that brings up old threads.

It's no problem to bring up old threads since there is always the possibility that someone who hasn't seen them may have an answer.
Good luck.

Peter

 

[muddyexplorer]

did you ever figure out what was going on with this?

No I have not. The check engine light stayed off through the Summer and Fall, but the LTFT's were still in the lower 20's and the fuel milage was still bad.....13-14 around town and only 16 on long trips. I knew long term that I might eventually mess up the cats. I was very much considering taking it to Brian at BSG Automotive @FordTechMakuloco ouside of Chicago since he is the Ford guru. Never got around to it and this December the Check Engine light came back on for the same issue but there now is a pending P0420 code for cat inefficently and the exhust smells rich. On top of that the rear driveshaft seal on the PTU started leaking pretty bad, so we have temperally parked it so we dont burn up the PTU. We picked up a 2022 F-150 with the 3.5 Ecoboost (I know, I have a problem!) to replace my 2000 F-250 and the wife hase been driving that to work.

I still want to get the issues resolved to return it to commuter status, because even though it has 250,000 miles on it everythong else is in good shape and I honestly love driving it, and the dealer was only willing to give me $500 for trade-in.

 

[tuxedosports]

No I have not. The check engine light stayed off through the Summer and Fall, but the LTFT's were still in the lower 20's and the fuel milage was still bad.....13-14 around town and only 16 on long trips. I knew long term that I might eventually mess up the cats. I was very much considering taking it to Brian at BSG Automotive @FordTechMakuloco ouside of Chicago since he is the Ford guru. Never got around to it and this December the Check Engine light came back on for the same issue but there now is a pending P0420 code for cat inefficently and the exhust smells rich. On top of that the rear driveshaft seal on the PTU started leaking pretty bad, so we have temperally parked it so we dont burn up the PTU. We picked up a 2022 F-150 with the 3.5 Ecoboost (I know, I have a problem!) to replace my 2000 F-250 and the wife hase been driving that to work.

I still want to get the issues resolved to return it to commuter status, because even though it has 250,000 miles on it everythong else is in good shape and I honestly love driving it, and the dealer was only willing to give me $500 for trade-in.

wow thanks for responding.. i have a 14 sport ive done all kinds of stuff too i smoked it put new injectors in it and it still shows 20-30% fuel adding.. today in the am when it was 18* out i sprayed brake cleaner around the intake to head mating surface and the fuel trims went down.. i pulled the intake and didnt see anything odd so i put rtv down on the head surface and am waiting for it to cure some before i fire it up.. i installed new intake orings when i did the fuel injectors.. this one seems to only throw the engine light when its idling in gear for a while because thats when the trims are the worst.


here is me spraying it while its running and scan tool showing trims changing.. brake clean dont work when the engine is hot because it evaporates

 

[tuxedosports]

I figured mine out it was the fuel rail pressure sensor.. first pic is just putting the sensor in trims went to a corrected state... then i reset kam.. and they stayed in a -trim state.. looks to be fixed but i just did this and ran it for about 20 min no driving yet. but its looking positive!

 

[muddyexplorer]

Hope that works for you! I replaced mine from the diagnosis from the dealer. It helped some....just enough to bring the LTFT's down just enough to keep the light off. After about 6 months they were back up.

What led you to determine the issue was the pressure sensor?

 

[tuxedosports]

Hope that works for you! I replaced mine from the diagnosis from the dealer. It helped some....just enough to bring the LTFT's down just enough to keep the light off. After about 6 months they were back up.

What led you to determine the issue was the pressure sensor?

did you install an oe ford sensor? my trims instantly went negative from the ltft's when i changed it.. drove it around quite a bit so far and trims are staying down.. this one is my wifes she even noticed the throttle responds is better.

i read on a focus ST/RS page they were having tons of issue with them.. but also were getting a p0087 code.. but not always... it was basically the last choice for me.. or the lp fuel pump.. ive changed everything else.. i figured wth give it a shot.. crazy it didnt fix urs..

 

[muddyexplorer]

did you install an oe ford sensor? my trims instantly went negative from the ltft's when i changed it.. drove it around quite a bit so far and trims are staying down.. this one is my wifes she even noticed the throttle responds is better.

i read on a focus ST/RS page they were having tons of issue with them.. but also were getting a p0087 code.. but not always... it was basically the last choice for me.. or the lp fuel pump.. ive changed everything else.. i figured wth give it a shot.. crazy it didnt fix urs..

It was not OE, I believe it was a Bosh from NAPA.