2002 Explorer Sport Code P0174 (Lean Bank 2) - SOLVED

[Danno54]

Hi Everyone. I'm new here but a long time car guy and mechanic (mostly older collector cars). I thought I'd ask for opinions on where to start with this repair. My brother gave me a 2002 Explorer Sport with less than 60,000 miles. It sat for 4 years because it had a bad fuel pump. I installed the new fuel pump and it started up fine but ran a little rough. It got a little smoother as it warmed up and then the check Engine light lit up... only one code is present P0174.... lean bank 2. Live data long term fuel trim shows a 25 for bank 2 and bank 1 is within normal range. I think I hear hissing behind the alternator so hooked up a vacuum gauge and it's at a steady 18 inches vacuum at idle. That leads me to believe it's not a vacuum leak. Could it be a bad injector? I'll attach some photos of the data. The first 2 are freeze frame for the P0174 and the others are the live data. Any ideas what could be causing this. Thanks.

 

[410Fortune]

Lean in one bank is usually a weak or bad injector

Vacuum leak or intake plenum gasket leak effects both banks

0174 means the computer has seen a lean condition and dumped as much fuel as it can to compensate and still the lean condition exists

 

[410Fortune]

Lean in one bank is usually a weak or bad injector

Vacuum leak or intake plenum gasket leak effects both banks

0174 means the computer has seen a lean condition and dumped as much fuel as it can to compensate and still the lean condition exists

Check fuel pressure at the rail if possible some 2002 sohc engines have a schrader valve on the back of the fuel rail near the firewall passenger side, it’s a blue cap on the end of the rail

 

[Danno54]

Lean in one bank is usually a weak or bad injector

Vacuum leak or intake plenum gasket leak effects both banks

0174 means the computer has seen a lean condition and dumped as much fuel as it can to compensate and still the lean condition exists

Check fuel pressure at the rail if possible some 2002 sohc engines have a schrader valve on the back of the fuel rail near the firewall passenger side, it’s a blue cap on the end of the rail

Thanks, I do see the schrader valve on the fuel rail and a pressure test is on the agenda. I've also read that someone fixed a P0174 code by cleaning the MAF sensor. It puzzles me how that could affect only one bank but I'll do that later today. Can't hurt to clean it.

 

[410Fortune]

Likely an injector

If you run it through some more drive cycles more codes may appear, especially a misfire code for a specific cylinder

I would run it, goose the throttle then shut down
Pull spark plugs and see if you can determine which cyl is having issues
Pulling plugs on a sohc engine sucks! I know I had to do it like 4 times in the last couple of weeks lol

 

[410Fortune]

114 degrees intake air temp?? Seems pretty high must be like 90 outside!

 

[Danno54]

114 degrees intake air temp?? Seems pretty high must be like 90 outside!

Yeah, I don't understand why it's so high. It was about 70 degrees F outside.

Likely an injector

If you run it through some more drive cycles more codes may appear, especially a misfire code for a specific cylinder

I would run it, goose the throttle then shut down
Pull spark plugs and see if you can determine which cyl is having issues
Pulling plugs on a sohc engine sucks! I know I had to do it like 4 times in the last couple of weeks lol

Thanks. That all makes a lot of sense. I was thinking of pulling the connector on the individual injectors to try to locate the culprit but that looked pretty difficult. Plug wires are much easier.... I think I'll pull them at the coil.

 

[410Fortune]

With a mechanics stethoscope you
Can reach most of them to hear them
Clicking
As these trucks get older I see more and more bad injectors, usually one at a time.

But we have to rule everything else out like fuel pressure and gasket leaks, dirty mas, slow 02 sensors etc

I don’t believe the iat temp maybe need a new iat sensor should be just a bit above ambient temp with a factory airbox and “warm” engine

 

[C420sailor]

Mine gets that hot when idling on a warm day. Gets hot under there

 

[Danno54]

Update - Running great... fuel trims are all good... no codes. I took the intake manifold off, installed new gaskets and 6 new fuel injectors. It must have been a clogged injector or two on bank two. The original intake gaskets looked like they were sealing just fine. Not that difficult of a job... at least not as bad as I expected. Thanks for the assistance!

 

[C420sailor]

Well done

those gaskets are essentially preventative mx on these engines…and eventually the injectors are too

 

[410Fortune]

Lots of injectors going south last couple of years it’s just age me thinks maybe some ethenol but mostly age they are tough little buggers from Bosch!

 

[C420sailor]

Mine are all original at 338k. Very well made for sure