171 174 lean banks codes still reading

[Turdle]

ok, so.....all the fuel pressures is right, nothing to do with the fuel, it is the air

brand new upper intake manifold gaskets and i sprayed carb cleaner in front and it died down...wtf....i loosened nuts, retorqued to 17ftlbs and the light still came on

Could it be the lower gasket?
Maybe the manifold is cracked?

 

[REDDY]

was thinking a few options: the manifold became warped, lower intake gasket is gone, or somthing happened during the repair of the upper intaker gasket, or all above

 

[2000StreetRod]

Vacuum tests

My Haynes Repair Manual lists some general type vacuum tests performed with a vacuum gauge.

It states that an average warmed up engine in good condition should produce 17 to 22 inches of vacuum at idle with a fairly steady reading.

A low, steady reading (12 or so) usually indicates a leaking gasket between the intake manifold and cylinder head(s) or throttle body, a leaky vacuum hose, late ignition timing or incorrect camshaft timing.

A low, fluctuating reading (3 to 8 inches below normal and fluctuating) indicates an intake manifold gasket leak at an intake port or a faulty fuel injector.

Unfortunately, since I own a SOHC I'm not very familiar with the OHV.

 

[REDDY]

the new upper gasket could of become pinched somhow over torqued, bad alignment but u just put gaskets in and put manifold back on...idk wtf


24lbs the vaccum test ran today

 

[2000StreetRod]

Borrow a scanner

Before pulling the upper and lower intake manifolds, I would borrow a scanner and confirm what the PCM thinks is happening. I would monitor the following:

Absolute throttle position
Air flow rate from MAF
Engine coolant temperature
Engine RPM
Ignition timing advance
Intake air temperature
Long term fuel trim banks 1 & 2
O2 sensors 1 & 2 banks 1 & 2
Short term fuel trim banks 1 & 2

Your problem could be as simple as a bad ECT sensor but you need more information. A scanner can provide a lot more insight.

 

[blondepms9489]

sounds liek you need an intake gasket, if the idle got rough when you sprayed the cleaner on it then yeah, that is a sign of leakage.

 

[REDDY]

the only thing i can think of is getting new upper gaskets again, try again putting new uppers in again, and if that dont work i think the whole intake manifold would be warped then or somthing.

the X has been hooked up from cheap obd2's, to knock off snap on 1's, to a snap on 1, about 5 different computers

 

[REDDY]

did any1 ever have a problem when they put in new upper intake gaskets and for some reason they wouldnt align right or leak or somthing would be wrong with new gaskets put in

 

[REDDY]

ordered new upper intake gaskets, be in tomorrow, this time i'm not going to push them in all the way and torque down to 17ftlbs and see what happens

the holes u push the gaskets in are alot deeper than the gasket so its possible they slip up in farther than they suppose to so they cant do their job if they aint all the way down

 

[REDDY]

i never never never thought i would have to but brought the truck to a shop, done freezing and hurting and chancing driving around with no inspection, so had to do it

i should know tomorrow what happened with it, will post what was wrong with it for further purposes of people learning

 

[Turdle]

Please do. I am still convinced it is an un-metered air issue. These can be tough to find.

 

[REDDY]

thats what i think also,(extra or just air leaking in some kind of amount it aint suppose to somewhere) it runs fine, as described before reasons why i did bring it, definatly appreciate the help people thanks, i'll get back to u's tomorrow hopefully

 

[REDDY]

171 174 lean bank codes.....ready.....weak coil

after many compression checks, and many times examining the plugs

couple plugs had tiny bit of gas in them

somtimes the compression on couple cylinders would be 125 while rest 155, sometimes they match, weak coil, still doesnt count out couple injectors could be clogged also, have to pay$350 just for injectors, hope its just coil

it was reverse because of computer trying to lean it out


so, switching coils and driving to make sure light dont come on again wont know till tomorrow

 

[REDDY]

it was running 12 degrees advanced timeing, which supposedly aint bad, definatly not good

as 1 good mechanic said, i only thought mercedes computers do such things lol

 

[2000StreetRod]

I don't understand!

171 174 lean bank codes.....ready.....weak coil

after many compression checks, and many times examining the plugs

couple plugs had tiny bit of gas in them

somtimes the compression on couple cylinders would be 125 while rest 155, sometimes they match, weak coil, still doesnt count out couple injectors could be clogged also, have to pay$350 just for injectors, hope its just coil

it was reverse because of computer trying to lean it out


so, switching coils and driving to make sure light dont come on again wont know till tomorrow

I think you're saying the mechanic's explanation is that the ignition coil pack was weak and that the PCM was trying to compensate for it by changing the timing which resulted in a lean condition.

Is the explanation that the timing change resulted in more complete combustion which the O2 sensors detected as a lean condition? A timing change causing lean DTCs seems unlikey to me.

Is the mechanic saying that there also is the possibility that some of the injectors are clogged resulting in less fuel injected? That seems like a plausible explanation but it would have to be at least one injector in each bank. The PCM would try to compensate for the detected lean condition by increasing the injector pulse width. Once the limit is exceeded the code gets set.

 

[2000StreetRod]

Injector cleaner?

it was running 12 degrees advanced timeing, which supposedly aint bad, definatly not good

as 1 good mechanic said, i only thought mercedes computers do such things lol

My timing varies from 15 to more than 40 DBTDC depending on engine conditions.

Have you tried a bottle of fuel injector cleaner in the tank?

 

[REDDY]

computer trying to compensate and thats why it reads lean, the o2 sensors are fine so its not telling to dump more gas in 4cylinders, and the fuel pump has no shorts or over pressure to shoot extra gas through injector

i think both coil and injectors are gone dont know just yet....

inside the injector is the(forgot name) it opens and closes letting fuel in, if its clogged it wont shut all the way leaking gas in.

hope alot of people learn from this

 

[REDDY]

so switched coils from other explorer i have same year engine, brand new coil on that last nite while the other one was in garage so its switched and seeing if my coil on that truck makes light come on, if it dont its injectors but still could also be coil for both could be wrong

was also just thinking should replace fuel filter, i ran injector cleaner 7months ago in it

115,600 miles on the problem truck, 85,000 on other

 

[REDDY]

worst news i heard yet, the heads on these trucks are starting to crack, leaking antifreeze, would be like leaking around 1gallon of antifreeze every 3kmiles and the sparkplugs might have some stuff on it, i guess the heads are starting to be a problem on these trucks....not on my truck yet

 

[2000StreetRod]

computer trying to compensate and thats why it reads lean, the o2 sensors are fine so its not telling to dump more gas in 4cylinders, and the fuel pump has no shorts or over pressure to shoot extra gas through injector . . . inside the injector is the(forgot name) it opens and closes letting fuel in, if its clogged it wont shut all the way leaking gas in. . . .

As I stated in a previous post:

Fuel Monitor Operation:
DTCs0171 Bank 1 Lean, P0174 Bank 2 Lean
Monitor Execution:continuous while in closed loop fuel
Monitoring Duration:2 seconds to register malfunction

Typical fuel monitor malfunction thresholds:
Lean malfunction: Long Term Fuel Trim > 25%,
Short Term Fuel Trim > 5%

If an injector won't close then it would inject more fuel than the PCM demands. The O2 sensors would detect a rich condition and the PCM would try to decrease the pulse width. When the PCM hits the established limit, a too rich DTC would be set - just the opposite of what you're experiencing. If the injector is your problem, I think it's because it's clogged and not allowing enough fuel into the port. The O2 detects a lean condition and the PCM increases the pulse width. When the PCM hits the limit, it decides that it is trying to increase the richness more than should be necessary for normal wear and sets the too lean DTC.

Either way, the solution would be to clean or replace the faulty injectors. Ford says to replace the fuel filter every 30,000 miles. The main reason is to prevent injector contamination. It's on my list of things to do in the near future.