Explorer 4.0 OHV - system too lean banks 1 & 2 Please HELP!!! | Ford Explorer Forums - Serious Explorations

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Explorer 4.0 OHV - system too lean banks 1 & 2 Please HELP!!!

stikz

New Member
Joined
December 10, 2010
Messages
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City, State
Pittsburgh, PA
Year, Model & Trim Level
'99 4.0 ohv 6 cyl
ok I have a 1999 Explorer OHV 4.0. I bought it in november of last year. Since i purchased the vehicle the check engine light has been on with various codes.

for a while it would run ok but occaisionally get a rough idle.
Then my fuel filler pipe broke. At first due to limited funds i used a washing machine rubber hose duct taped inside the fuel filler hose to fill it with gas- eventually it started to run horrible- and would stall out at idle- whether park, or neutral or at stops- eventually i got a used pipe at a junkyard and installed it- then the filler nozzle on the tank broke off- so i JB welded it back on and now i have no gas leaks-but still running bad- I found some bad plug wires that arc'd thru the insulation and replaced them with older wires in better condition. for about a day it ran perfect.


Then it started stalling out and would not run unless my foot was on the accelerator. while driving if i took my foot off the gas pedal the RPMs would drop and the truck would stall out- So since i needed to get to work i kept my foot on the brake and gas pedal simultaneously while driving. 2 days after i started it up to see the O/D light flashing. I've heard this is usually related to the torque converter or solenoids on the transmission.

The next day i put in all new plugs and wires- This brought power back to my acceleration but did nothing for the rough idle/stalling problem.

Now i just chkd the diagnostics and im getting system lean bank 1 & 2- o2 sensor 2


and 2 no definition codes- not sure of the numbers

my truck seems to push and pull in a hesitant manner when down shifting.
and the RPMS drop slightly at times even when my foot is consistent on the gas pedal.


when warm sometimes the truck will idle without stalling- and i can let my foot off the pedal without it stalling sometimes as well too but not often


Since i bought it i replaced

the DPFE sensor- (July '10)
both Pre cat O2 sensors
Plugs and wires TWICE most recent was november '10 a few days ago
Mass Air sensor (October '10)
Transfer case (july '10)
Fuel Filter (October '10)
Air Filter (May '10)



I cleaned my IAC
Sprayed carb cleaner around all of my vacuum lines and the idle stayed the same


From what i understand the prob could be intake gaskets, fuel pressure (pump or regulator), coolant temp sensor, cam sensor, crank sensor, Vacuum Leak, PCV valve, EGR Valve, Tranny Solenoid Pack, Torque Converter


so being that my finances are low i was hoping that some experience mechanics or 4.0 ohv drivers could point me in a good direction for low cost/free diy testing/fixes

or other possible problems


thnx
 



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Probably intake gaskets and possibly bad iac valve on top of that problem.
 












i ran a ohmeter across my IAC and it reads fine......


seems like a vacuum leak or fuel pump problem.

Today while sitting idle to warm it up- i was holding my foot on the gas at about 2000 rpms- i noticed the idle shot up t about 4000 while i maintained consistent pressure on the pedal.... I also noticed an extreme power loss while driving home
 






I vote gaskets, I did all the same things you did any the only thing that fixed was the new gaskets!
You need the codes if they are p0171 & p0174 i'm gonna say do the gaskets and be done with it.
 






I had the same problem and code one time and it ended up being the Mass Air Flow sensor. All it took was a can of MAF Cleaner from Autzone, 10 minutes and a heavy dose of the cleaner and everything worked perfectly.
 






check the pressure at the fuel rail. just push the valve in.if its not a big spary (lots of pressure like a bike tire) go to the fuel pump. Just did mine and the codes went away.
 






I had the same problem and code one time and it ended up being the Mass Air Flow sensor. All it took was a can of MAF Cleaner from Autzone, 10 minutes and a heavy dose of the cleaner and everything worked perfectly.

I replaced the Mass air sensor already
 






check the pressure at the fuel rail. just push the valve in.if its not a big spary (lots of pressure like a bike tire) go to the fuel pump. Just did mine and the codes went away.

where is the fuel rail?
 






just found that my passenger side pre cat o2 sensor is bad- how in less than a year tho?.... anywayz i'll try replacing it this week- also going to get a vacuum gauge kit- then fuel line gauge kit after that- i really hope it isnt my torque converter
 






Intake Gaskets

Not sure if your OHV is the same as my 4.0 SOHV, but I just replaced my upper and lower intake manifold gaskets yesterday and it got rid of the rough idling. Had a P0147 lean code pulled up at Autozone, the guy tried to sell me an O2 sensor but I declined. Replace the original PCV valve, cleaned the MAF and IAC too. But the ( lower ) gaskets were leaking bad. It purrs now. $24 total. I've got 154,000 miles on it.
 






Definitely check the fuel pressure first. I just went through this, and luckily I was able to read all the sensors real time, so I didn't throw parts at it. The 99 should be an SOHC, and should have 62 psi on the rail (front left of the motor). The regulator on the 99 is in the tank, just above the tank. Not fun, but instant fix to all my codes and rough idle.
 






also check that the intake it self is not leaking, mine did it was like it was comig apart at the seams, jbweld does wonders
 






fuel line pressure at 60lbs puts more fuel in then at 25lbs. if you dont have 60lbs orso the computer spits out a lean condition. and you will chase problems all day long.IMHO
 






likely a vaccum leak or............>>>

vacuum leaks are a high possibility,

my check engine light came on and diagnostic codes P0171 & P0174 lean bank 1, lean bank 2, i was told it could be my oxygen sensors so i replaced all four at $300.00 after two gas refills the check engine light came back with same codes as before, im a do it yourself type of guy, i don't trust mechanics here in new York, anyway i did some research online to find possible cause, which varies as listed below.

1. faulty or just dirty mass air flow sensor
2. dirty iac
3. fuel filter
4. faulty pcv hose
5. vaccum leak. coming from faulty manifold gaskets, valve cover gaskets, or throttle body.

PS: when those two codes P0171 & P0174 are set together it is highly unlikely it is the oxygen sensor, possible but highly unlikely. i feel i wasted $300 replacing mines add it did not solve my problem, but hey live and learn :)

Everyones possible solution varies. in my case i went to ammoco and they suggested to do a vacum leak test by smoking my engine at a price of $129.99, low and behold i had a faulty throttle body, it had a vaccum leak, i fixed and all is well now, hope this helps someone. by the way you can save yourself money by building your own smoke machine, go to youtube and search for homemade engine smoke machine or you can go to party city or any party store and buy a fog Machine average $30. along with a hose that will fit your manifold, and duct tape, you can find these at home depot. good luck everyone :)

follow up: its now 3 days after i posted this and the check engine light came back on and same two codes came back P0171 & P0174, i replaced the mass airflow sensor, and so far so good, at dealer it cost $275. bought one at my local autozone for $93. will post back if problem persist. this site has saved me thousands of dollars in repairs just on information alone, I will contribute info as well :)

its been a few days now and check engine light came back on along with same two codes, this time different mechanic said my manifold gaskets need to be changed, cost $190 for diagnosing and changing the gasket, will post again if problem persist

WOO HOO!! its 3/14/13 over a month now and all is good, the problem was the manifold gasket causing a vaccum leak.. hope you don't have to go thru all the crap i went thru to finally diagnosing the actual problem,,, good luck to everyone :)
 






falla no CE

afirmativo, cambie mi ETC y todo trabaja muy bien!
 












Same issue's

I have the same damn issue's, my normal mech moved to a smaller shop and he doesn't have the tools to do everything. He changed the MSC that didn't work, he changed the gas filter, that didn't work.... i went to a different shop and they smoked my truck 2 of the tubes had holes i asked if this solved the problem and it didn't, when i started the truck up i felt it was still the same. The check eng came on again, so i went back and the error was P0174, i paid 134 for the smoking and changing the tubes. I am getting about 5miles pre, they told me that doing a tune up will prob solve this... They all want to screw you for money.

You changed the Intake Gasket and it solved it? Please let me know (fulbldital@hotmail.com)
 






Change the upper intake gaskets and orings!
 



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