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p o174

2K views 15 replies 4 participants last post by  M0U35Y's_SS 
#1 ·
i have the above code being thrown. it came up while the car sat in park for a few moments after a short drive. i have previously changed both upstream o2s with the acdelcos from amazon and the exhaust leak was repaired a few months prior. and it has an new egr valve and pcv. i haven't checked for vacuum leaks yet. anything else i should check for. i only have a basic scan tool so all i can see is trouble codes. also, what is the difference between lean and rich?
 
#2 ·
also, what is the difference between lean and rich?
Usually Lean means too much air not enough fuel
Rich means too much fuel not enough air.


i get this confused... is Lean too much air, or is lean not enough fuel...:p

p0174 is bank 2 lean
i am chasing on my car too....:mad:


-ALF out....
 
#8 ·
Usually Lean means too much air not enough fuel
Rich means too much fuel not enough air.


i get this confused... is Lean too much air, or is lean not enough fuel...:p

p0174 is bank 2 lean
i am chasing on my car too....:mad:


-ALF out....
BOTH!

To the OP, make sure you have all of your exhaust manifold bolts and they are tight. Do you hear a spitting or tapping noise while the motor is cold and goes away when hot? If so, exhaust manifold leak of some sort, and this will cause the issue your having. Trust, but verify. you can unplug the o2's and see if the drivability symptoms, if there are any, go away. that would confirm an issue in that area. It will also set more codes, but wont allow closed loop feedback, and thus no fuel trimming. Kind of like a field svc mode. (overly simplified description)

Chris
 
#3 ·
Could a constricted muffler cause this? This is frustrating new o2 sensors amd map clean maf. And checked for intake leakes. Maybe injectors mot flowing? How can i clean those?
 
#4 ·
Since,I'm assuming you have some system scanning capacity. I would be curious if you carefully swap the left & right O2 sensors to see if the problem moves too. I know an exhaust leak can introduce this issue. A minor injector issue can create this condition. A compromised spark plug/wire should be ruled out as well. Use a decent fuel injector cleaner,and verify proper fuel pressure.
 
#5 · (Edited)
scanning meh, its a cheapo just to pull codes and see what emissions system are "on" uhm, yeah ill move the o2s around. i do notice during initial cold start i smell fuel from the passenger exhaust. also the motor runs much smoother until the pcm goes into closed loop. after closed loop it tends to behave more erratically. i am personally leaning injector side because of how long the car sat before i got it. not sure. i would like to clean/replace the injectors. but id rather clean if its cheaper. and i kniw my exhaust system is rather bad. both mufflers are almost rusted through. i can only imagine how bad the cats are. but when i get funds up im replacing the cats with something that flows better.
this problem did seem to coincidentally arise after i replaced my fpr. its a master pro? from orielys. and since i have replaced it i have had had problems starting it and now bank to running lean. i may swap the old (failed) regulator back in to see if my starting issue goes away. idk. i need to get a fuel pressure gauge i know. :p
 
#6 ·
as far as cleaning or replacing injectors, what you guys take? im leaning towards cleaning with this... OTC 7448 Fuel Injection Cleaner : Amazon.com : Automotive
any other better ways?
also i want to remove the intake, clean all the gunk out and add an filter to the pcv vent to prevent future build up. any cleaners/methods of doing said task?
 
#7 ·
I use a quality fuel-injector cleaner (RedLine,or Chevron) in the fuel tank a couple times a year. I installed an oil/vapor separator in the PCV line. Filters quickly clog up,making them useless. I would consider removing the intake to have a shop clean it,if I was having the cylinder heads serviced. Otherwise,I'd leave well enough alone. I mounted the oil/vapor separator on the steering box. One line extends to the PCV,the other goes to the intake. Not a great picture,but the system is highly effective.
 
#9 ·
ok, im gonna try that after i swap o2s n see what happens. or doesn't happen. i went with some lucas injector cleaner. i do have a "tapping" and it does seem to be on the passenger side... but it never goes away. it sounds kinda like the sound my jeep made(4.7 dohc). i have inspected all visible portions of the manifold in question. but not under the heat shield. would it be wise to remove and inspect whats under the heat shield? or leave as is for the moment? i wouldn't imagine this would be a lifter would it?????
 
#11 ·
aight, time to bust out the compaq mirror. and what is the torque spec on the manifold bolts. ive been going with 30 ft lbs. or is it 50? or does it even matter? ive re torqued them twice since i got it back from the shop.
 
#12 ·
ok so i checked all hoses for them there fancy vacuum leaks. and... nada. i listened then sprayed some throttle body cleaner on any and all lines. no change in anything what so ever. i went ahead and took the belt off as to hear better... and the motor ran a little better. maybe the alt is dragging the motor down? also i did notice the ticking only gets quieter as the motor warms up. but doesn't go away. I am going to check the manifold to cat junction when it cools back down. i did mean to unplug the 02s but forgot.
sorry about the long winded post guys.
 
#13 ·
fixed, maybe. i was piddling around just looking for a crack in the manifold when i got the idea to check and see what my plugs looked like. so i pull the boot off the #3? cylinder and the plug was loose enough to be pulled out by hand. as were all the plugs on that side except the first cylinder. tightened them all up and presto, no tick. started right up and ran whisper quite. time will tell if the code stays away.
hth
 
#14 · (Edited)
So to the OP....did you fix it ?

Back in mid Sept i got my custom CAT-Back installed.
Today on about 5 mile in to my 30 mile commute to work the CEL came on. got P0100 and P0174.

Starting to wonder if the cold weather is making this happen ? Or the winter mix of gas ?
I think i will buy a 20gal treatment of Chevron until next oil change to have it looked at again.

1. i need to check if too much oil on my K&N filter EFF-ed up the MAF ?
2. i need to check if i have a broken manifold bolt ?
3. i need to check if my PVC or tubing to it need replacing ?

UPDATE:

just checked my records Jan 30 2013 and Jan 15 2014 I put in 20gal treatment of chevron with techron.
CEL was going on almost daily, since treatment it has tripped P0174 once. (just cruzing highway @70)

-ALF out...
 
#16 ·
So to the OP....did you fix it ?



Starting to wonder if the cold weather is making this happen ? Or the winter mix of gas ?
I think i will buy a 20gal treatment of Chevron until next oil change to have it looked at again.

1. i need to check if too much oil on my K&N filter EFF-ed up the MAF ?
2. i need to check if i have a broken manifold bolt ?
3. i need to check if my PVC or tubing to it need replacing ?

-ALF out...
I replace my pcv valve every other oil change. U may try that.
I don't like oil filters on maf cars. Personnel opinion though. Yes check manifold bolts. And make sure ur o2 connectors are securely seated. Maybe a ground was messed with or an o2 may have been damaged during the exhaust swap.
 
#15 ·
I did fix it. I went through and returned all manifold bolts and through a new intake gasket in the mix. Also went through the entire harness and resecured all ground and checked and rechecked all connectors. Added a few grounds as well. Gas mileage jumped back up and performance was noticeably better. The exhaust ticks went away yea. But now there's a lighter ticking. P rolly just the v alvetrane though. Engine runs so much better now.
 
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