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Do you have a scanner to watch the STFT & LTFT? If I’m diagnosing a lean code and with what you already told us, I’d get a can of brake cleaner and spray around the intake manifold where it meets the cylinder heads first. You have to remove both of the intake manifold covers that hide some of the wires and hoses first. Just spray one side at a time and don’t push the sprayer nozzle down all the way to douse it. You’re trying to pinpoint where the vacuum leak is coming from. You are more than likely to have a vacuum leak when the engine is cold first thing in the morning. The 8 individual manifold seals that are supposed to prevent vacuum leaks will be shrunken when cold and expand when up to temperature so I’d do the test when cold while looking at the STFT/LTFT.
The brake booster vacuum tube going to the underside of the throttle body on bank 1 is a very common place for vacuum leaks also.
Do you have a scanner to watch the STFT & LTFT? If I’m diagnosing a lean code and with what you already told us, I’d get a can of brake cleaner and spray around the intake manifold where it meets the cylinder heads first. You have to remove both of the intake manifold covers that hide some of the wires and hoses first. Just spray one side at a time and don’t push the sprayer nozzle down all the way to douse it. You’re trying to pinpoint where the vacuum leak is coming from. You are more than likely to have a vacuum leak when the engine is cold first thing in the morning. The 8 individual manifold seals that are supposed to prevent vacuum leaks will be shrunken when cold and expand when up to temperature so I’d do the test when cold while looking at the STFT/LTFT.
The brake booster vacuum tube going to the underside of the throttle body on bank 1 is a very common place for vacuum leaks also.
I agree that this is likely a vacuum leak issue, and the brake cleaner should find it. I use starting fluid, but same idea. The part load breather tube running from the front of the left cam cover, under the intake manifold, and to the throttle body elbow, is a common place for vacuum leaks. The word “brittle” doesn’t begin to describe that tube, so if you accidentally breathed on it, it’s probably cracked. Only a slight exaggeration there.
Thanks Addicted and Aquifer for the prompt advice.
I tried spraying around with brake cleaner but only the hoses. I didn"t think of a leak at the manifold to head seal. .Ill do that today.
Eric You are not exaggerating. I had to replace that tube earlier. I looked at at it directly and it dissolved. Are there any other similar vulnerable areas in the system?
Addicted, I do have a live data code reader. I know little about fuel trim. I saw some U Tubes about it. What can it tell me?
iTry cleaning the part load breather (small drill; don't go too deep); gently tighten manifold bolts and cam covers; assure the dip stick is sealing (the o-ring fails after years of service). And what year and mileage, please. We really need to know what the LTFT is for the left bank.
Am I missing something, is there another post I didn't see....P0147 is a rear O2 sensor, why the fuss? Anytime you have a lean bank, its almost assuredly an O2.
Potential causes of an P0147 code include:
The Rear Catalyst Monitoring Oxygen Sensor evaluates the rear most Catalytic Converter's emissions-reducing capability in a system with two Catalytic Converters for each bank of cylinders. P0147 is set when the Rear Oxygen Sensor signal does not show closed loop fuel system operation within the required time.
Bad o2 sensor heater circuit
Bad o2 sensor
Wiring harness problems
To meter it out...
Unplug the Bank 1, 3 sensor. With KOEO (key on engine off) use a voltmeter to check for battery voltage present at the o2 sensor connector (PCM side). (You can also do this with a test light. Connect to ground and touch lead to heater circuit supply. Light should illuminate with KOEO) You should have battery voltage present. a. If voltage is present, check the ground side of the heater element also making sure a good ground is present. If it is, check for any faulty connections & then replace the o2 sensor. If you don't have a good ground, then there is an open in the ground circuit somewhere that will need to be repaired. Look for wiring harness contact with exhaust components or broken/missing connectors, etc. b. If battery voltage isn't present with KOEO, check for a blown fuse supplying the heater elements. You may need to get a wiring diagram for this. If the fuse is blown, you'll need to check for a short to ground on the battery supply circuit before replacing the fuse. If you find none, and replacing the fuse re-establishes battery voltage at the o2 sensor connector, then the o2 sensor may have shorted internally, blowing the fuse. Replace it & recheck. (NOTE: it's possible for an o2 sensor's heater circuit to be open/shorted and the o2 sensor to still function). c. If you have no battery voltage present with KOEO and there are no blown fuses supplying the heater circuit, then check for an open on the supply circuit. You can do this by ohming the circuit with the o2 sensor unplugged and the PCM unplugged. Repair and recheck.
For a detailed layout of changing O2's, read this. It also shows which sensor plugs are upstream and downstream.
You need to watch those short term fuel trims as you spray around the engine compartment. You won’t hear much of a change but you’ll see it on the live data. That’s the only way to do it
Some folks use a propane torch (no flame, please), to watch the fuel trims move. But your long term trims don't look that bad. Maybe just a fuel system cleaner (BG44K or GUMOUT's best).
Inside the ⭕️, these are the 2 that you need to clean out real good. It’s sorta hard to tell if they’re clean or dirty sometimes so you’ll need to look at them prior to cleaning and of course afterwards and see if they appear different. Don’t be afraid to blow it out real good because they’re pretty robust.
STFT will constantly move around within the -10% to +10% range on a completely issue free engine.
LTFT will adjust much slower than STFT within the -10% to +10% but, -5% to +5% is preferred. However, as the engine ages, seals & gaskets don’t hold their tension as well as many other components aren’t as efficient like they used to be, the LTFT will be in the higher +/- 10% range and not display a too rich or too lean code.
Engine vacuum I believe will be around 18”. This is also on a fully warmed up engine at idle.
Your photos you submitted the other day, what was the temperature outside and what was the engine coolant temperature at? Do you recall? Outside temperature can play a big part also.
Last edited by Addicted2boost; 03-16-2021 at 05:14 AM.
So far so good, 300 miles and no check engine light. But, I've been here before.
I Replaced lower part load hose.
New o rings in upper PCV hose, (valve covers to throttle body) (300 to buy new so I just replaced o rings)
Cleared and sealed upper part load nipple (on the valve cover by the timing chain) with a small drill bit.
Sealed both ends of brake booster hose, on booster and Throttle body, with high temp sealer. (red)
Removed and cleaned MAF sensor, especially the little resisters.
I checked the torque on the manifold bolts, one was a little loose.
i replaced (with a used hose) the right side breather hose (valve cover by timing chain to main air snorkel ) and tightly wrapped it with electrical tape
I re re re inspected every vacuum hose I could get to.
The fuel trim aspect of this is way beyond my compression. Lots to learn .
The Car is running great BTW.
Hopefully P0174 is gone and I will pass MD emissions.
I’d strongly recommend replacing the full load breather tube vs repairing it. Repairing those is ok until the new one gets delivered to your home. Oil vapor passes through that tube and will swell up that hose and leak right on by the electrical tape.
Why $300? Because they can??
I wouldn’t bother with that hose unless it’s trashed. BTW, the testers will want to see a “P1111” code stored in your ECM to prove that it ran all the necessary emissions tests and passed. If you take it to get inspected and they see a “P1000”, I’m fairly confident that’ll be an instant fail. If you do see that “P1111” code, DO NOT clear it because it’ll have to start allll over again. If I were you, I’d drive as much as possible between now and test time to get that P1111 up and stored. Search on here “drive cycles” and there should be some tips on getting that P1111 code in your ECM.
The ABS module has a power and a ground that needs reflowed. When drilling into the case (or whatever your method for access), just be cautious about drilling too far as you’ll likely ruin the electronics board. I wouldn’t try to remove the entire front panel of the module as it’s bonded to the backside. I know there’s many threads related to the ABS repair if you search for it on here.
For drilling the case, find yourself a 3/4 or 7/8 holesaw. Go to Lowe's or Home Depot and pick up a plastic hole plug the size of the saw. Take the pilot bit out of saw and cut your hole carefully using just the saw barrel.
The plastic case cuts pretty easy, so don't get froggy and push to hard or spin the barrel too fast. After re-soldering the 2 points, just put the plug in about half way and take a lite bit of clear silicone (30 minute stuff works great) and go around it and put it the rest of the way in for a good seal.
03-08-2021, 06:45 PM
The dreaded P0147, bank 2 Lean
