P0171and P0174 CODES CHEVY VORTEC ENGINE.
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- เผยแพร่เมื่อ 27 ก.ค. 2024
- P0171and P0174 CODES CHEVY VORTEC ENGINE.
Ron Williams
Mobile Fix Automotive
26793 Madison Ave Suite 100
Murrieta, Ca. 92562
951-579-7146
Website www.mobilefixautomotive.com/
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Possible cause of P0171 P0174 Lean bank 1 and lean bank 2. Also for power loss when under load.
I'm watching this in 2023! U made it in 2015!! Thank you, it still is helpful to all us backyard heros fixing wife's car, mom's car, neighbors car, oldest daughter car!! With a lil bit of TH-cam love an magic!! We wear our dirty greasy work cloths with pride! Knows BROTHERS IN ARM like yourself are here to help
2024 here
5 years later and still solid video.
Still solid
Excellent video Ron, straight to the point and very informative. People like you us what makes TH-cam great.
thanks. funny thing, i dont use gopro. i use android phone. htc evo 4g lte. lol.
Thank you so much for your help
I fix my suburban thanks to your video
I so a lot of videos and send me for others ways and your video help me a lot...thanks my friend now I'm your fan number one 👍
Great video!! A clear and concise thought process with logical conclusions and no preconceived notions. We DIYers need to know how to fix problems. We are not in mechanics' school seeking a license!! Thank you!!
Thanks Ron for the information ,
6 years later and a still solid video
You are worth every penny you charge to turn a wrench my friend. Great video.
I had the same code p0171 and p0174. And the mass air flow sensor was dirty after i clean it and clean the air filter i was good to go. Check that first. Amigos good luck to all ya
That’s why I read the comments!!! My mf man!! I was about to buy CO2 sensors, fuel injectors or a pump. Saw this and took the MAF off of my Sierra and BOOM!! Feels like a new truck. Good shit Noah.
In your case buddy
Thank you... very informative. Appreciate very much.
Thanks for everything I have to say it was exactly details of my 08 GMC Yukon exactly what you shared code's and all
Thanks brother that was very helpful.👍👍🤙
Man you just made my stress go away thanks brother
Thank God. Feels good to help my brothers
I had a Chevy truck come in with those codes, smoked it, found no vacuum leaks, checked fuel pressure and sure enough was dropping to under 30 pounds, installed a new Delphi pump, ran better, customer took it, it came back about 2 weeks later with same codes, but this time the brake pedal felt weird, harder! Turns out the booster was on it's way out too from the master cylinder leaking brake fluid into it! When I smoked the engine I disconnected the vacuum hose at the booster to introduce the smoke into the intake through there, so was NOT able to see at that time that the booster did have a vacuum leak, it obviously wasn't as bad at the time cause the pedal wasn't hard, but in the two weeks it blew out I guess. After replacing both booster and master cylinder the truck left, hasn't been back in several weeks now, so definitely check the booster for vacuum leaks as well so you don't go through what I went through 🙄
Thank you. To the point with great information
good stuff...thanx...exact issue on my 02 tahoe
Perfect thanks brother mine is running fine now and we passed emissions yes 😀😀😀
Thank you sir very good video you spoke nice and clear so I could understand you thank you
I just got P0101, P0171, and P0174 on my truck today. Seems to drive fine with no idle issues. I have a spare MAF sensor I will try tomorrow and will also check for loose air intake issues. I also have a pressure gauge I can check with. Like the customer in question, I also have to get my emissions tested. Any other suggestions to check for?
Good work Sir
I had this same problem ysdy on a Yukon,, i don't really work on GM products, but the LT fuel trim numbers were around 19%percent with extensive crank time, it took me about an hr to find,, easy compared to the European bolt boxes
After cleaning the MAF sensor, would you say the next smart step before smoke testing for vacuum leaks would be to put a pressure gauge to check for fuel pressure?
Very good videos
Thanks for sharing, I made my diagnosis same of this problem, & the result is fuel pump not working well
Thanks I’m going through the same proven
Good friend in truth perfect that video I have an explorer 2008 and I make that fault I think it is also the fuel pile hurts that here the Venezuelans do not see it as a challenge when there are cars with that fault if not as a crab something that is not You know where it came from thanks for this excellent video
thank you bud
06 silverado 6.0 has lean condition bank one and two. runs and accelerates fine but burns gas crazy fast. idles fine and can't find a vacuum leak. Brand new fuel pump too.
+Frank Castle
Check for air leaks in intake gaskets usually the center area on both sides. The easiest way is with a scanner looking at the short-term fuel trim spray carburetor or brake cleaner through a straw at the center of the intake manifold with the engine running and look and see if the fuel trim changes. If it's truly running lean the short-term fuel trim is going to be reading positive numbers probably up in the 15 area. It should actually be showing positive to negative 3 back and forth. If you have access to a smoke machine those are actually the best at finding all the leaks
I just bought a 2003 Tahoe Flex Fuel 5.3L and I first tested fuel pressure after P0174 and P0171 had pulled and it was down around 20 psi. I changed the fuel filter and now it is reading about 40 psi but my freeze frame fuel trim %'s are way higher than before I replaced the fuel filter. my freeze frame data is showing Calc load is 17.6% and the temp at 192.2 @ 1839 RPM and 13 MPH and both bank 1 and bank 2 readings are exactly the same and pretty excessive in my opinion. The STFT for both banks is reading 39.8% and LTFT for both banks is reading 25%... Since it is showing these conditions under load and not at idle i am assuming it is still a fuel pressure issue... So should I start with replacing the fuel pump or what should my course of action be? Thanks
I'm trying to narrow down my issue. I'm getting the p0171, p0430,p0332,and p2a01 on a 06 GMC 5.3l and my truck has long tube headers and no cats so idk wtf is going on. Recently had my air filter let some unfiltered air by it,have since replaced the air filter. Im going to check my fuel pressure. I'd appreciate any input. Thanks for the great video
Thanks
Hey run I’m experiencing this same problem but I’m also experiencing my 2006 Silverado engine shuts off when I turn on the ac or heater you think is because is to much overload
thnks man..im running the same code but i dnt have a hard start, but my codes do come back really fast after resetting them. im having the manifold gasket change because tht gives the same code with a blown gasket. my truck runs fine other the idle at cold starts. whn my mechanic finds the prob i will let u know
Hello I have the inline 6cly engine and I'm getting that lean bank one it has good power its a 06 Chevy trail blazer I bought a smoke machaine but have not smoke the intake yet any ideals
Thats my issue I think! I thought it was a TPS or IAC, so I replaced both. Still running goofy Idle. Took it to Chevy dealer. They said bad intake Manifold gasket. Hat that done. Still doing it, they said fuel pressure was reading what the 5.3 should be not 6.0 also gave codes p0171 and p0174 and said the fuel trim was all over the place on the computer. Now it will barely climb hills
Did you ever fix your problem?
What if truck is cranking, but not starting at this point ? This started a couple of months back where it wouldn't rev in gear, but it would idle and rev out of gear....later it guilt on the road I had it towed to home....need some help here.
Ok i have an 1999 chevy Silverado that has the lean bank 1,2 plus pu 300 starts on first key turn runs good keeps up and sometimes idles rough the check engine light flashes then pauses what can i do to fix it
I have a 2004 do I g same thing as your truck hard to start at time I put the fuel gage on it I had 55psi and at idle 62 I should of tested the fuel pressure wen it was hard to start see what it was then my fuel trims are high as well I smoke it no leaks any were
Preciate it!
Same engine. Just p0171. Any suggestions? No vacuum leaks. Used a smoke machine. LS swap.
I replaced my pump it drove great that evening ever since a mechanic tuned my tahoe it stalls when taking off, also my pressure when running is 60 and bouncing a Lil bit.. now when I drive it flexes bad but stays at 69 just flexes really bad I also do have knock sensor codes too
Having issues finding my problem, truck turns on fine no problems with driveability I don't know maybe injectors? O2 sensors bad?
I have 99 z56 Tahoe. Same issue too lean on both banks. Rough idle. Stumbles on acceleration at stop 🛑. Stft @50 ltft @25. Unplugged maf. Engine idled better and trim numbers decreased by half. I’m 🤔. Plz help
I have an 06 savana 4.8 with both those codes I wonder if it's the same problem.
Having this issue throwing p0300 and p0701 or whatever for lean and misfire done coils etc all the vacuum testing the FP has been weak for a while now
I have exact situation, cept my fuel pressure is steady at 43. I can’t find spec for my ‘02 Tahoe, but I did see 55 somewhere and you said 50. Is 43# insufficient? I’m about to drop the tank as we’ve replaced everything else…..I mean everything!
i have the same codes, but i got a new fuel pump and erase the code but it came back on, could it be something else?
My man I got p0171 and p0174 codes on my 03 suburban after replacing my fuel pump.. what do you think the issue is?
What is the pressure supposed to be
99 Sierra 1500 5.3
Getting both of these codes. Already replaced FPR and fuel filter. Replaced one fuel injector. Changed all these parts because it was misfiring. When I changed all those parts I checked fuel pressure. It was lower than 55. I don't remember what it was, but for sure lower than 55. Has a hard time with cold starts. Not like in your video, but it's noticeable.
Fuel pump it is?
You need fuel pressure above 50/55 psi. Hard starts are often caused by the fuel pressure check valve which is located inside the tank on the fuel pump assembly. it can only be replaced by servicing the entire fuel pump assembly in most cases. It bleeds off inside the fuel tank where you cant see it.
Also, if your fuel pump is running and fuel pressure is low then remove fuel pump and check the hose between the fuel pump and the steel line inside the fuel tank. I have seen these come loose/hole or loose clamps.
Im having an issue with my 2004 chevy silverado 4.8l ive checked for vacuim leaks cant find and im getting just the p0174 code along with a p0300 code im lost on what to look for also my fuel gauge just stopped working i dont know what to do anymore
+ryacline89 the gauge is probably bad. A scanner that can perform a gauge sweep will tell you for sure.
The p0174 is the computer telling you there is a lean condition on bank 2. (Drivers side) if a smoke test on the intake manifold shows negative results then I would check the fuel injectors on the driver side cylinder head. It's very difficult to give advice without seeing a vehicle
Sir, my 4.8 has Gibson shorty's and cold air intake. the headers have no egr location so I just made a mount and simply plug the egr back in. I have a new fuel pump, could the bolt ons be causing these two codes as well, with the egr not operating? 180k on the truck starts just fine no problem there....Thank you in advance...HAPPY New Year!
Sorry e delay, I was on vacation. When you refer to egr I am assuming you mean oxygen sensors? If so they have to mounted inside the exhaust to operate properly. Just bolting them on and letting them hang is not going to work. You should be able to stop by your local exhaust shop and have them weld in the collars that the o2 sensor screw into.
Ron Williams thanks for the reply, I'm on vacation as well. we got dad a scan tool for Xmas and I've been doing o2 live readings and the o2s are in and reading at warm temp .600 to .900 volts with egr unplugged with it plugged in its reading from .100 to .850 volts giving the lean code on both banks was told .500 and up should be a rich o2 reading. and sorry for th e confusion the egr is just sitting on a custom mount and not hooked up was just plugged in.
What if I just put a knew filter in. And would a hole in the tank restrict pressure
I have a 4.8 litre that has 50psi at the fuel rail but it still idles rough and says bank 1 is to lean help me please
Which delphi pump would you go with. Rock auto list 2 pumps..?
I dont buy from Rock. But there should only be one Delphi make. The difference should be which connector you have. When I purchased Delphi pumps unless I already have pump out I order both and return the wrong one.
Same for the 4.3L V6?
I have an 02 blazer with the 4.3 vortex. I have the same codes. Hooked up a fuel pressure gauge, and pressure is 55psi at idle. Also did a smoke test and could not find a vacuum leak. Been trying to solve this issue for over a year. Anything else in need to know before I rip off the plenum and replace the original $400 spider injectors?
Hi . did u figure out your problem
@cj reyes did you ever find the problem have the same codes and been thinking of changing the spider injector as well but I am trying to make sure before I do it
It was indeed the injector assembly. I got the updated one that is now MPI.
Do you know What the recommended fuel pressure is for a 1998 GMC K1500 SL/SLE ( V8 ) 305 5.0 liter auto 4WD when the engine is off with key on and with the engine running ?
all details would be appreciated thanks :-)
Also what fuel pump would you recommend ?
i had a loos air intake hose
I have same problem PO171. And PO174 there is no air leak I've checked I checked my fuel pump it's at 40psi off an engine on it stays at 50 psi so I don't know I guess I'll change the fuel pump because I'm out of options
Ever figure out what the issue was?
Could this be the reason for my passenger side spark plugs looking like charcoal?
Hey Ron I have a 06 Silverado with a O2 code and a 300 code how can I contact you to get some info
I had the same problem on mine no vac leaks the problem was the front o2 sensors
Got an 08 5.3l flex fuel. p0174 only with misfire codes 02 sensor? new injector coil is good new plugs. intermittent at idle.
which misfire codes did you get?
question, I have a 02 GMC YukonXl Denali 6.0, 1500. I used the gumout fuel treatment in my truck let it sit for a while. when I got ready to drive it was ok for a few feet before my truck stalled and the check engine light came on.
I filled up my tank with gas drive back home. the next day I let it run for over 30 minutes. later that day I drive to Beverly hills on the fwy, no problem. get all the way back to L.A., it cuts of before I get off the fwy.
the code I got was P0174 only. I changed the fuel filter it drove lovely, next day got on the fwy it cut off. now I changed the MAF sensor, then it wouldn't start at all. later that night it start right up. But press the gas and it cuts off. I'm still thinking it's the fuel pump.... But not exactly surewhat's going on...
what is the fuel pressure reading?
truthfully I don't know, I don't have the tools to check it. My needle is jumping all over the place though.
I got a 08 6.2 with this code it shut off on my mechanic has put all types of parts on it chuld this be my issue
Dam my boss is like it was running fine I changed the last exhaust bolt and had idling 10min then put put put and yes I was scratching my head and mad I told him just a coincidence shit I could of put air in the tires and it would of happened lol
My truck starts strong. Not lazy so to speak. Got the 5.3l vortex and no vacuum lost,
Round 4000rpm cel flashes as if cat being damaged.. what else could it be.
Red Cap the code only comes on for me at low rpm/ idle
What kind of gauge is that you are using to check fuel pressure
+Dickey Moore its a old actron gauge i had for years. Unfortunately i lent it out and it came back broken and they dont make tgem anymore
i have a 99 gmc sierra. the code p0171 showed up a week ago. then it started to shift very hard. and when i get up to 60mph when i punch the gas it stahls for 3 seconds,, shifts real hard, then revs real high. usually when i punch it, it rev high immediatly and i go fast. but also while im going 60mph, if i just give it normal gas it starts to sputter.any ideas?
Your going to need a good scanner that can read freeze frame data for that one most likely unless you just start throwing parts at it. I would start with checking fuel pressure while driving, if you get a p0171 code only without the p0174 code at same time most likely bank 1 sensor 1 is weak, since both heads share same intake manifold air.
The shifting hard and reving could be transmission ,solenoid, or ecm, that one is a little difficult to help with here. Too bad i couldn't see it in person.
Wiggy McCrackin I had the same problem but it was right after I put in a new fuel pump, and fuel filter. Now I’m getting those two codes and it’s doing what your truck is doing. Idk why it just decided to start driving this way literally right after I put in a new pump. I hope it’s not the transmission or ecm. Hope it’s something simple. Don’t have the money to throw parts at it.
I have a 2001 Silverado 1 ton with the 6.0 liter.Im getting the same codes.I haven't checked the fuel pressure.The truck has 2 gas tanks.Is there a fuel pump in each tank?
+clint polcare yes
+clint polcare some of the gm trucks with duel tanks have 2 pumps. But only the forward tank supplies pressure to engine. The rear pump only transfers fuel to the forward tank on these vehicles. Weird set up in my opinion.
I took a look at the truck.The front tank was totally out of gas and the rear tank was full.I don't know why the rear tank didn't pump into the front tank.This has been doing this for quite some time.the truck has 160,000 miles on it.
I have an 02gmc Sierra 2500hd with the 6.0 throwing the same codes....i tested the pressure and I'm shocked that it even runs, my pressure reads between 10-15lbs. Standard is 55-65 I was told it's my pump but I was also told maybe a bad ground or power source to the pump?? I'm clueless. The truck runs and drives but has no power :( a new pump would fix my issue?
+corey green there is a rubber hose that goes from the top of the fuel pump to the bottom side of the fuel pump assembly at the top of the tank. It is inside the fuel tank. That's usually the most common problem that I see when there's low fuel pressure. There are occurrences where the fuel pressure regulator if it has one on the fuel rail goes bad but mainly it's the fuel pump. The only way you're going to know is if you take the tank down and pull the assembly out and look at the rubber hose and see if it has a split in the side
Thanks man will have to check that! Luckily I do not have to drop my tank ;p I cut the whole in my bed lol
did you change fuel filter as wel
+clownguy101 fun always change fuel filter. Some fuel filters are integrated into fuel pump
Hello Ron, could you please tell me what the part is that's on top of the intake right behind the throttle body? mine is hissing really bad. And I have both them codes. I filled up with gas and the light went away for a day, but the next day it popped back on. Thanks in advance.
+Edward Thayer are you referring to the plastic cylinder standing up its the evap purge solenoid..
Ron Williams yes, mine is constantly hissing, is that normal?
no. its not. replace it. your Shure that's the source?
I spelled sure wrong. LOL
Ron Williams no I'm not sure. that thing is definitely hissing. but i have both bank lean codes. I filled up with gas and the light went out. the next day it came back on!
Thanks so much for your time and help. I greatly appreciate it!
I currently own a 1996 chevy truck with a 5.7 engine, my engine light is on and I pulled codespo171,po420, and po102. I just replaced my fuel pump a week ago, and my mass airflow sensor is fairly new also. The 420 and 171 have been on for probably 3 years at least but I haven't had any problems until recently I went through 2 fuel pumps in a month. They po102 code is new I'm just wondering what could cause these codes to go off my truck does have over 360 thousand miles on it just not sure what to try next Thanks.
Its interesting you don't have a p0174 code? That means there is probably a vacuum leak on the drivers side of the engine only, or a possible bad o2 sensor! The p0102 is a mass air flow code, If the mass air flow was not an AC Delco or Delphi unit it may still be the reason for the code. Only performing pin tests will tell without replacing with a "known good part". The p0420 is a bad catalytic converter. I almost never get a 420 code to go away without changing the Cat unless its setting because of a defective downstream o2 sensor. I only install DELPHI fuel pumps. I had way to many warranties with aftermarkets.
thanks Ron Williams
Hi great video, I have a question I have a 2001 Chevy Suburban k1500 5.3L as I was driving from a long trip on the freeway all of a sudden I started losing power & felt like it was going to shut off, I pulled over the engine idled fine, I turned it off for a few minutes & it starred right up. I drove it home then hooked up my obd2 scanner & got p0171 & p0174 codes, then after a while the check engine light came on. I put in a new fuel filter a few months before any of these symtoms started happening just as maintenance since it had never been changed, It starts up within seconds even when the engine is cold can it still possibly be the fuel pump? I cleaned the maf sensor reconditioned the K&N FIPK filter & reoiled it with K&N oil, checked for exhaust leaks, put water around the intake manifolds, but didn't find or hear anything out of the ordinary. Thanks in advance if you're able to answer my question.
+armandomrgl85 what is your fuel pressure at when engine is idling?
Ron Williams I need to go to an Autoparts store to see if I can rent a pressure tester, if I understood correctly it's suppose to be at 50psi correct?
+armandomrgl85
Yes, 50 to 60 psi. Make sure that you check the pressure at idle and also while you're pushing on the gas pedal to see if it drops. Then report back to me
Sorry for the late response, finally got time to check it, haven't driven it since problem started. I don't have pressure when I turn the key to start, then turn it over it starts fine the fuel pressure is at 45psi at idle, needle jumps back & forth between 45 & 47psi, I rev it up & it stays consistent on 45psi. Thanks in advance
Did you ever finger it out I got the same problem
How do u replace the fuel pump or filter....thanks. great video, you should definitely make more....those go pro cameras are great for them....
Fuel pump is in gas tank. fuel filter is on left side of frame under drivers seat. pretty easy to remove fuel tank if you siphon fuel down to lighten tank. also, newer model trucks/suburban have fuel filter built into fuel pump. so if you dont see one inline like i said earlier thats probably why.
Ron Williams ok thanks for the info.
I have a PO15B reading can u tell me what it is!
Joseph Ensign 02 sensor code.
What could it be if the the pump is at 48 psi and I only get the lean code for bank one ??
The oxygen sensor replace it and check engine will go away
Ron Swanson?
And if the truck won't start? Then the fuel pump is shot?
How do I distinguish between bad fuel and bad fuel pump? Would I still get low fuel pressure with bad fuel?
+PedalTheGlobe typically bad fuel will not cause low pressure. No mater the BTU of the fuel the pump should still maintain correct pressure
Ron Williams If the FPR is bad will I still get high fuel pressure but just more fluctuation?
Ssilverado 97 5.7 had error code PO134 that is for o2 sensor bank 1 sensor 1, so i move it to bank 2, and bank 2 to bank1 now shows code PO174 the code now is for bank 2. sensor 1. I believe is a bad o2 sensor. toughts?
would make sense. if error switches sides thats a good sign of possible defective part
@@SandCarServices
Hi Ron I just subscribed I'm going to get my fuel pressure checked on my 2000 GMC Sierra 4.8.
I actually had to replace the fuel pump five six years back maybe seven.
Not fun. My truck does start good though it doesn't seem like the lazy fuel pump but I guess you never know nowadays. I'm going to keep digging perhaps at some other type of vacuum leak or something.
Keith Kuhn
Already did that, on my 2003 Chevy Tahoe 4.8, new fuel pump, fuel filter and regulator, still acting like it wants to die when I put on Drive or when I come to a red light, any thoughts
I'm getting these codes and a po300 also I have a small amount of black smoke coming out the tailpipe. Truck starts fine, what could be my issue?
WHAT KIND OF TRUCK DO YOU HAVE?
Ron Williams it's a 2002 Silverado 5.3
I recommend having a smoke test done on intake manifold. The 5.3's are known for the rubber seals on the intake manifold gaskets leaking. If you don't have access to a smoke machine hook up a scanner that can read PID list. (what the sensors are reading) and look at short term fuel trim (STFTRM) If you are truly running lean It should read above 15.
If it reads -5 to -20 its not running lean.
while watching the short term fuel trim take a can of brake cleaner with a straw and spray the base of the intake manifold on both sides and watch the PID. If the gasket is leaking the readings will switch to a number with a - symbol in front of it. (be careful with brake cleaner, if you have a leaking spark plug wire and you spray it with a flammable substance there is a chance of it lighting the brake cleaner spray on fire.) Safety first.
The black smoke almost sounds more like a leaking fuel injector tip. That test is a little to difficult to explain But lets start there.
So I hooked up a scanner fuel trim bank 1 and 2 were +20 I sprayed into the intake and it made no difference
ok, whats fuel pressure at? +20 means the computer is adding 20% more fuel than required normally. Which means its running lean.
mine did that and it was the fuel pressure regulator and I have replaced the fuel pump and still get the lean codes
Do a smoke test and see if you have a vacuum leak. I thought mine was fuel pump but I found a leak in intake manifold. It caused my o2 sensors to read wrong.
This not the only cure. This was just 1 stubborn problem I found that is rare but for people to keep an eye out for
Po138 p0300 p0171 chevy silverado 2005 all the codes come at the same time I can’t find the solution any suggestions
working on tahoe 5.3 vortec and it was multiple missfire and too lean bank 1 and bank 2. changed spark plugs that were gaped at .60 and the pregapped were .35 ? anyways missfire is gone (i think) hahaha anyways too lean bank 1 popped up again. and the abs!!!! son of a ***** hahahaha well i guess my next test is to check fuel pressure
one abs sensor was broken so i replaced it but didn't take the abs light off. next I'll be testing the other sensor. my main comcern is the lean condition. i also removed the air filter because it was plugged with dirt. will be replacing tomorrow.
My 04 Yukon SLT has same exact codes
Idles good, runs good unless you mash on fuel hard n starts to spit n sputter. Only does it occasionally, does it worse when hot. Doesn’t want to pull steep grades, and barely able to run at 40mph little alone above it. Have to barley lay foot on fuel pedal and if it hesitates ease off a little and it goes on.
Runs 53 lbs of pressure at idle, 50 lbs at 3000 rpms, 45lbs 4500 rpms, from 5000 and above it falls off to 20lbs psi, engine starts sputtering, but doesn’t die. Just put a new acdelco fuel pump in, in July it’s under warranty, but don’t want to drop tank and replace if it isn’t my problem, any ideals? This one has me stumped
New mass air flow sensor, also. It starts great. But out on the road is dangerous.
If fuel pressure drops below 45psi then i suggest replacing regulator. If it still drops there is a restriction in lines possible
How do I test the regulator
I’m assuming just by unplugging the vac line off, if engine dies, it’s bad, if not it’s good.
I though the same, I can’t even find the regulator on this thing, and the filter is in the pump housing inside the tank.
So I ran some fuel cleaner/injector cleaner through it along with some cfoam through the throttle body and it straightened up a little for a day or two, but today it’s back
i have a malibu maxx 3.5L, with a 22 PSI. Car runs good at low rpm, at high rpm pedal to the floor car will not accelarate that quick.
Got a 01 Yukon p0174.p0171 replaced maf,fuel pump,both upstream sensors,New gaskets,fuel regulator lol it also hesitates it jerks 221k miles while driving and sometimes on start up ...any other ideas ???...thanks ron
+Marcos Moreno check for restricted exhaust. Possible plugged catalytic converter
had same issue turn out to be the distributor
+jesus martinez this engine does not have a distributor! Thanks
fuel filter had the same issue. couldnt blow air through the old one i removed
You probably put a cheap Dorman maf sensor
Mine was injectors, apparently they werent installed correctly or arent the correct size
What yr model is that chevy
You guys still in elsinore I'm in perris and I got the p0171, truck runs fine but you can hear the fuel pump sometimes
I'm in Murrieta now. address is at Mobilefixautomotive.com
I have both the same codes po171 and po174 po102 and po440 and I can’t figure out if I have a gas leak or not cause usually I put 20 bucks in my tank and that last me about four or five days sometimes and this week I just put in 20 bucks for the third time this week I need help
The 440 code is a leak detected in the evap/fuel system.
Since the 171 and 174 codes are accompanied by a 102 code I would test/replace the mass air flow sensor.
Did it not have a Delphi pump in it to begin with. You said those have a problem. Would it be better to install a aftermarket quality brand. Please let me know what u think
My truck misses while cold warms up and runs fine I think it's the intake gaskets not fuel pump
That's why diagnostics are so important.
Fuel tank needs to be dropped to replace fuel pump, its inside tank. not to difficult after you remove fuel from tank to lighten it up. fuel filter will be inline on frame under drivers seat. newer chevys dont have filter, its built into tank.
+Ron Williams what about on the 2005 chevy trailblazer 4.2 vortec ive replaced the fuel pump around a year ago so the pump is still considered new i threw p0171 bank 1 code too lean
I hope You can help. I installed a new motor in My 96 Astro 2 years ago, I used all of the old external parts on the new block. the only fuel related items I replaced was the idle air control and the fuel regulator. I had had a few emission related problems which I fixed. I have the code p0171 and I can`t seem to find the problem. I replaced a bad o2 sensor and the code cleared. But came back on later. This engine runs great with the exception of one problem. Sometimes when I take off from a stop the engine just stumbles and shudders like there is no fuel but if you accelerate hard it finally takes off and runs great at other speeds any help would be appreciated. Thank, Joe
+Joe Hammock check fuel pressure at the rail. It should always be above 50 psi when accelerating. If so smoke check intake manifold for leaks.
Let me know results.
Hello Ron I did the pressure check and it is as specified also I`ve been to the moon and back and never found a vacuum leak, it just stumbles intermittently at take off like its not getting fuel? It doesn't do itt all the ttime, thanks
+Joe Hammock do you have another mass air flow sensor you can swap out and test with.
I`ll look into it. What puzzles Me is the old engine ran find till I burnt a bearing, All I did was install a new rebuilt block. If the mass is bad would it cause this intermittent problem? I know You`re busy, thanks for Your help
Joe Hammock check your mass air flow sensor
I have the p0174 code but have 0 problems starting it turns right over