need help solving lean condition

[HACK BLOCK]

i'm trying to get to the bottom of my super bad mpg (150-180 a tank) and p0171 and p0174 codes. at first i took it to a shop to be looked at and i was told i had 3 bad injectors and they wanted to charge me around $750 for 8 injectors and labor. but after changing my evap purge valve my check engine light went away and i figured they was trying to **** me over. i ended up buying an al619 scan tool to figure out why my abs light was on and noticed my LTFTs were super high between 18% and 25%. after some reading online i came to the conclusion that i have a fuel delivery problem. but something i did notice is that my LTFTs are less than 10% when cold and rise has the car gets closer to operating temps. i have not checked my plugs yet and what should i check before i start dumping money into it

 

[swathdiver]

Vacuum leaks and your PCV system. Can you test each injector and coil with your scan tool? How old are your O2 sensors?

 

[HACK BLOCK]

Vacuum leaks and your PCV system. Can you test each injector and coil with your scan tool? How old are your O2 sensors?

from what I read online I don't have a vacuum leak because if my LTFT got better when I raised the rpm then that would indicate a vacuum leak but mine pretty much stays the same no matter the rpm. I don't think I'm able to test the injectors with my scan tool and I bought the truck about 2 months ago so as far as I know it's original

 

[HACK BLOCK]

from what I read online I don't have a vacuum leak because if my LTFT got better when I raised the rpm then that would indicate a vacuum leak but mine pretty much stays the same no matter the rpm. I don't think I'm able to test the injectors with my scan tool and I bought the truck about 2 months ago so as far as I know the o2 sensors are original

 

[Scottydoggs]

sounds like a large vac leak to me. spray the top of the engine down with carb cleaner, if the idle jumps up you found the leak area.

when cold they run richer so it adds fuel to make it run at that higher idle till it warms up some. once the idle drops the trims go back to normal. in your case real high. thats gonna hurt your mpg too.

 

[HACK BLOCK]

I'll check but like is said before I don't think it's a vacuum leak cause my fuel trim doesn't change when i Rev it and my car idles steady at around 550rpm.

 

[Scottydoggs]

if it stays pegged @+16 or higher, you have a vac leak.

ltft should move when you give it gas. scan for codes, you might have a pending lean code. drive it for a bit, then scan it running, turning it off can clear a pending code.

 

[iamdub]

... but something i did notice is that my LTFTs are less than 10% when cold and rise has the car gets closer to operating temps...

What do you mean by "as the car gets closer to operating temps"? You mean the LTFTs are low after a cold start? This particular point may not even be a consideration since the PCM is operating in open loop prior to operating temp. Then again, maybe it could help to diagnose the cause since the PCM is ignoring many sensor inputs during open loop. As it transitions to closed loop, it begins reading and responding to the input of those sensors. Check out a live data stream.

 

[HACK BLOCK]

when the car is cold the fuel trims are normal but as the car warms up the fuel trims get higher and higher. when cold. both trims are less than 5%, but the time the temp is around 195 the trims are anywhere between 18% and 25%. the screen shots below are what I've been going by when deciding if it's a vacuum or fuel problem

 

[Scottydoggs]

all i know is a pegged ltft of +16 is a vac leak 100% of the time.

can you scan bank one and bank two ltft's with the scanner you have? that would narrow it down to what side is having a issue.

 

[HACK BLOCK]

both are about 2% of each other

 

[Scottydoggs]

sounds like intake gaskets maybe to me. pretty common for them to fail. not the worst job to do really. at least theres no coolant to spill when you pull the intake off.

and you said it idles at 500 rpm? thats low. should be up around 700. in gear 650 ish at idle.

 

[HACK BLOCK]

here's the data from idle

 

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one more

 

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and here's the date from 1500 rpm

 

[HACK BLOCK]

more

 

[Scottydoggs]

this one is up there but not real bad.

this one at idle looks ok to me really.

mine stock was leaning out to +8 or so wot in the higher rpm. stock tune kinda sucks. they run em lean for some reason.

just holding the rpm's in park is not the same as being under load driven, just noticed no mph showing.

over all thats not horrible. not great either tho.

you in NYC or one of the boroughs? im about 5 miles from the GWB down rt 80. if you want to come by i can run my hpt scanner on it and see a host of crap and know better whats up with it.

 

[bottomline2000]

Have you tried cleaning the MAF sensor and another thought is testing the fuel pressure to make sure you don't have a clogged fuel filter or weak pump. These are some less than $5 options to start with since you rent the fuel pressure tester for free from most automotive shops.

 

[HACK BLOCK]

this one is up there but not real bad.

this one at idle looks ok to me really.

mine stock was leaning out to +8 or so wot in the higher rpm. stock tune kinda sucks. they run em lean for some reason.

just holding the rpm's in park is not the same as being under load driven, just noticed no mph showing.

over all thats not horrible. not great either tho.

you in NYC or one of the boroughs? im about 5 miles from the GWB down rt 80. if you want to come by i can run my hpt scanner on it and see a host of crap and know better whats up with it.

yea that's the thing, at idle the numbers are good. once I start to give it gas the ltft start going up. I'm getting about 7 city and 11 highway. I'm in Queens about 5 minutes from jfk so we can definitely organize something just let me know when is good

 

[HACK BLOCK]

Have you tried cleaning the MAF sensor and another thought is testing the fuel pressure to make sure you don't have a clogged fuel filter or weak pump. These are some less than $5 options to start with since you rent the fuel pressure tester for free from most automotive shops.

I cleaned the maf when I changed my intake 2 months ago and I'll see about the pressure tester later today or tomorrow