NAPA has vacuum hose and connectors. That's what I did on my '06. I think I spent less than $15for the parts.
Burning smell, light smoke from engine bay
- Thread starter theophile
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NAPA has vacuum hose and connectors. That's what I did on my '06. I think I spent less than $15for the parts.
theophile
Well-Known LVC Member
::sigh:: Another evening spent troubleshooting unsuccessfully. I bought some braided vinyl tubing for a temporary replacement of the broken plastic flex line I discovered yesterday. A lot of the vacuum hoses look new (or at least "newer"). They tend to flex better and don't seem to be as dirty as some of the others.
Anyway, I traced the lines over and checked every one I could see, but so far no more apparent cracks or splits or breaks. I've also done the TB cleaner test (a third time) with no hot spots.
I cleaned the MAF with MAF cleaner. No effect.
The sound I referred to earlier as a hissing sound is still present, though I've been listening to intently for so long that I'm able to convince myself it's all sorts of things (coolant flowing through the t-stat housing, etc.). I've made 2 more videos, this time while moving my phone around various parts of the engine bay in the hopes the microphone would be able to capture sound from places I couldn't safely stick my head.
I can now definitely hear the sound LSFrank was referring to. It does sound like it's coming from the TB area. Anyway, videos here:
https://drive.google.com/file/d/0B0Z0bpkQXwBFMTVsSXZZU0xkdVk/view?usp=sharing
https://drive.google.com/file/d/0B0Z0bpkQXwBFRWNGWDhZSlNuMGc/view?usp=sharing
I'm trying to stay positive but frustration is starting to take its toll. I think the next step will be to buy a vacuum pump and gauges and start testing these components (EGR valve, EGR pressure solenoid, DPFE, Evap purge solenoid, etc.) one by one to see if the components are damaged. I'm also about ready to make one of those redneck smoke machines. And because it seems like you can never really rule out COPs and plugs, if I can't find a vacuum leak, I guess the next step will be to swap all COPs and plugs to the opposite side of the engine.
I swear, when I finally find the culprit, it's going to end up being a hose or a plug I didn't reconnect or something stupid like that...
Anyway, I traced the lines over and checked every one I could see, but so far no more apparent cracks or splits or breaks. I've also done the TB cleaner test (a third time) with no hot spots.
I cleaned the MAF with MAF cleaner. No effect.
The sound I referred to earlier as a hissing sound is still present, though I've been listening to intently for so long that I'm able to convince myself it's all sorts of things (coolant flowing through the t-stat housing, etc.). I've made 2 more videos, this time while moving my phone around various parts of the engine bay in the hopes the microphone would be able to capture sound from places I couldn't safely stick my head.
I can now definitely hear the sound LSFrank was referring to. It does sound like it's coming from the TB area. Anyway, videos here:
https://drive.google.com/file/d/0B0Z0bpkQXwBFMTVsSXZZU0xkdVk/view?usp=sharing
https://drive.google.com/file/d/0B0Z0bpkQXwBFRWNGWDhZSlNuMGc/view?usp=sharing
I'm trying to stay positive but frustration is starting to take its toll. I think the next step will be to buy a vacuum pump and gauges and start testing these components (EGR valve, EGR pressure solenoid, DPFE, Evap purge solenoid, etc.) one by one to see if the components are damaged. I'm also about ready to make one of those redneck smoke machines. And because it seems like you can never really rule out COPs and plugs, if I can't find a vacuum leak, I guess the next step will be to swap all COPs and plugs to the opposite side of the engine.
I swear, when I finally find the culprit, it's going to end up being a hose or a plug I didn't reconnect or something stupid like that...
FDR
Dedicated LVC Member
Maybe try this? The cigar vacuum leak method https://www.youtube.com/watch?v=zMok2y05jNE
Your first video gets right into the TB area and you can hear the pulsing tick/gurgle I was referring to. I inquired about it because I have a similar noise that creates an audible tick in the cabin. Is THAT normal?
Your first video gets right into the TB area and you can hear the pulsing tick/gurgle I was referring to. I inquired about it because I have a similar noise that creates an audible tick in the cabin. Is THAT normal?
Telco
Dedicated LVC Member
What a good idea, never even considered using a cigar for finding a leak before. My daughter's car has a leak somewhere that I've not been able to track down. Guess I'm off to the cigar shop myself. I've only ever tried the propane method as an external aid and it's never worked very well for me.
theophile
Well-Known LVC Member
I may try the cigar technique. I'm actually a cigar guy anyway and with all the frustration this is causing, it would be nice to relax and diagnose the problem at the same time.
However, I'm beginning to think that maybe the lean code is more related to the fuel supply than the air supply. Earlier in this thread, after I had replaced the COPs/plugs/VCGs, I started the car up and found it idling/driving roughly and throwing a cylinder 6 misfire code. It turned out I had accidentally unplugged the #6 fuel injector. After plugging it back in, the idling/driveability did not change at all, but the code switched from #6 misfire to bank 2 lean condition. I feel like there has to be a connection between the two. Maybe the #6 injector was negatively affected in some way by having the fuel rail pressurized without the injector plugged in? Or maybe some debris was inadvertently introduced to the fuel line during the time it was disconnected and that debris is now clogging one or more of the injectors on bank 2?
My instinct is to disconnect the injectors on bank 2 one by one and see what changes are observable during idle. If one of them causes a lesser change than the others, I would assume that's the one that needs to be addressed.
However, I'm beginning to think that maybe the lean code is more related to the fuel supply than the air supply. Earlier in this thread, after I had replaced the COPs/plugs/VCGs, I started the car up and found it idling/driving roughly and throwing a cylinder 6 misfire code. It turned out I had accidentally unplugged the #6 fuel injector. After plugging it back in, the idling/driveability did not change at all, but the code switched from #6 misfire to bank 2 lean condition. I feel like there has to be a connection between the two. Maybe the #6 injector was negatively affected in some way by having the fuel rail pressurized without the injector plugged in? Or maybe some debris was inadvertently introduced to the fuel line during the time it was disconnected and that debris is now clogging one or more of the injectors on bank 2?
My instinct is to disconnect the injectors on bank 2 one by one and see what changes are observable during idle. If one of them causes a lesser change than the others, I would assume that's the one that needs to be addressed.
theophile
Well-Known LVC Member
I got a subscription to AllDataDIY, which describes a diagnostic procedure to help determine whether the P0174 code is being caused by too much air (vacuum leak) or by not enough fuel. It involves monitoring the short-term and long-term fuel trim values for each bank at idle, and then increasing the engine RPM to 2500 for 10 seconds and again monitoring the short-term and long-term fuel trim values. If the total fuel consumption (sum of the sort- and long-term trim values per bank) is 15% of greater, that means there is a vacuum leak.
I just performed this test twice, and both times the difference in fuel consumption per bank was well within the 15%. In fact, the values on bank 2 (where the code indicates the problem is) didn't change at all.
According to the service manual, the next step is to perform a key-on, engine-running (KOER) self-test. The first step of that procedure says:
"Disconnect fuel vapor hose from intake manifold and plug fitting at intake manifold."
However, there is no diagram and I have been searching for over an hour trying to figure out what "fuel vapor hose" I am supposed to disconnect. There's the purge line from the EVAP canister, but that connects to the throttle body, not the intake manifold. Does anyone know what hose this refers to and where it is?
Thanks.
I just performed this test twice, and both times the difference in fuel consumption per bank was well within the 15%. In fact, the values on bank 2 (where the code indicates the problem is) didn't change at all.
According to the service manual, the next step is to perform a key-on, engine-running (KOER) self-test. The first step of that procedure says:
"Disconnect fuel vapor hose from intake manifold and plug fitting at intake manifold."
However, there is no diagram and I have been searching for over an hour trying to figure out what "fuel vapor hose" I am supposed to disconnect. There's the purge line from the EVAP canister, but that connects to the throttle body, not the intake manifold. Does anyone know what hose this refers to and where it is?
Thanks.
theophile
Well-Known LVC Member
Without knowing what the "fuel vapor hose" is, I decided to take a break from hunting down vacuum leaks and switch back to checking the ignition system. With the engine running, I started disconnecting and reconnecting the electrical connectors on the COPs one by one, starting on bank 2. On cylinders 5, 7, and 8, when I disconnected the COPs connector, the engine stumbled noticeably before recovering. When I plugged it back in, the idle increased momentarily before recovering. But with (the infamous) cylinder 6, there was no apparent change when I unplugged and replugged the COP connector.
So I removed all 8 COPs and all 8 plugs, checking the gaps of all the plugs. One thing I noticed immediately is that the ceramic insulator around the electrode was white for 7 of the 8 plugs (they are pretty much brand new plugs) but it was a greyish tan on the plug from cylinder 6. I'm not quite sure what this means, as most of the diagnostic photo arrays indicate that grey/tan insulator means normal operation, but these are not worn plugs. (My hunch is that it means it's saturated in gasoline because the cylinder isn't firing.)
Anyway, I placed all the COPs and plugs on a sheet of cardboard with each plug/COP pairing arranged according to where they were in the engine. Then I turned the cardboard around 180 degrees and put them all back in. So the plug/COP that had been in cylinder 1 swapped with the ones that had been in cylinder 8, 2 swapped with 7, 3 swapped with 6, and 4 swapped with 5. I made sure everything was seated properly and that all the COPs were pressed down firmly to ensure that the springs were seated on the plugs.
But when I started the engine, there was no change from before. The idle is still rough, it still throws the P0174 code almost immediately, and I still get the same behavior with cylinder 6, where unplugging the COP connector does not appear to make any noticeable difference in the idle.
So I removed the pins from the connector again to make sure the wires hadn't disconnected from the pins somehow. Then I took the plastic connector off #5 and swapped it onto the #6 wires and vice versa. Still no difference.
Now, I have read that a cylinder not firing can cause a lean code, so I unplugged a COP on bank 1 to watch how the sensors reacted. The bank 1 O2 sensor 2 showed a dramatic dip, but then it came back up to normal levels after the PCM adjusted the ratio. So running a cylinder short on bank 1 doesn't produce the rock-bottom O2 sensor readings I'm getting on bank 2.
I'm about out of ideas here. I bought a vacuum pump/tester to rule things out, which I plan to do tonight. I haven't tried swapping O2 sensors yet because everything I've read is that the downstream O2 sensors are for monitoring only and don't cause the PCM to change running conditions. So a bad downstream O2 sensor shouldn't be causing a rough idle. Also, while a vacuum leak is usually the cause of these kinds of error codes, I cannot understand how a vacuum leak would cause this issue only on bank 2 and not on bank 1. Same goes for EGR/DPFE problems. I don't see how such a problem would affect only one side of the engine but not the other.
I'm running out of ideas here...
So I removed all 8 COPs and all 8 plugs, checking the gaps of all the plugs. One thing I noticed immediately is that the ceramic insulator around the electrode was white for 7 of the 8 plugs (they are pretty much brand new plugs) but it was a greyish tan on the plug from cylinder 6. I'm not quite sure what this means, as most of the diagnostic photo arrays indicate that grey/tan insulator means normal operation, but these are not worn plugs. (My hunch is that it means it's saturated in gasoline because the cylinder isn't firing.)
Anyway, I placed all the COPs and plugs on a sheet of cardboard with each plug/COP pairing arranged according to where they were in the engine. Then I turned the cardboard around 180 degrees and put them all back in. So the plug/COP that had been in cylinder 1 swapped with the ones that had been in cylinder 8, 2 swapped with 7, 3 swapped with 6, and 4 swapped with 5. I made sure everything was seated properly and that all the COPs were pressed down firmly to ensure that the springs were seated on the plugs.
But when I started the engine, there was no change from before. The idle is still rough, it still throws the P0174 code almost immediately, and I still get the same behavior with cylinder 6, where unplugging the COP connector does not appear to make any noticeable difference in the idle.
So I removed the pins from the connector again to make sure the wires hadn't disconnected from the pins somehow. Then I took the plastic connector off #5 and swapped it onto the #6 wires and vice versa. Still no difference.
Now, I have read that a cylinder not firing can cause a lean code, so I unplugged a COP on bank 1 to watch how the sensors reacted. The bank 1 O2 sensor 2 showed a dramatic dip, but then it came back up to normal levels after the PCM adjusted the ratio. So running a cylinder short on bank 1 doesn't produce the rock-bottom O2 sensor readings I'm getting on bank 2.
I'm about out of ideas here. I bought a vacuum pump/tester to rule things out, which I plan to do tonight. I haven't tried swapping O2 sensors yet because everything I've read is that the downstream O2 sensors are for monitoring only and don't cause the PCM to change running conditions. So a bad downstream O2 sensor shouldn't be causing a rough idle. Also, while a vacuum leak is usually the cause of these kinds of error codes, I cannot understand how a vacuum leak would cause this issue only on bank 2 and not on bank 1. Same goes for EGR/DPFE problems. I don't see how such a problem would affect only one side of the engine but not the other.
I'm running out of ideas here...
theophile
Well-Known LVC Member
NAILED IT!
It was indeed a problem with cylinder 6. Evidently, when I reconnected the fuel injector harness that had slipped free from the #6 injector, one of the pins in the connector pressed out of the connector, far enough that it wasn't connected but not far enough that I could see it. I pressed the pin back into the connector and verified it was seated properly, and now the engine is running perfectly. The O2 and fuel trim readings on bank 2 are back within spec, and the CEL is off.
Maybe this thread will be useful to others searching in the future.
Thanks everyone for all the input and suggestions.
It was indeed a problem with cylinder 6. Evidently, when I reconnected the fuel injector harness that had slipped free from the #6 injector, one of the pins in the connector pressed out of the connector, far enough that it wasn't connected but not far enough that I could see it. I pressed the pin back into the connector and verified it was seated properly, and now the engine is running perfectly. The O2 and fuel trim readings on bank 2 are back within spec, and the CEL is off.
Maybe this thread will be useful to others searching in the future.
Thanks everyone for all the input and suggestions.