O2 Sensor Voltage Question
09-02-2016, 10:34 AM
#21
My first inclination was that it had to be a leaky injector, but now it may very possibly be a leaking turbo leaking oil into the exhaust. I hope to do some investigating this weekend. I'll update everyone as soon as I get time to remove my stock downpipe.
09-09-2016, 01:49 PM
#22
Update for anyone that cares: This will be a little lengthy.
After doing days of driving and watching sensors, let me throw out a plausible situation, and I feel like I may be onto something as everything I've checked has came up negative. I've got the service manual, and I have went through every single test/symptom chart in there. All came back negative findings.
I've been driving around on the stock tune for about a week I guess. After blowing the soot out of it a few times I've got my readiness check to pass. Emissions passed to my surprise (not that I really care, but I was using that as a parameter that my sensors were failing, etc.). I'm still getting a little erratic sensor readings, but I feel like my sensors are working correctly and something is causing it. After I figure this out 100% I still plan on doing a down pipe more than likely.
Anyways, in short, my truck is sensing a slightly "rich" condition at all times, and calling for an average of 5-7 negative long term fuel trim. While I'm driving, short term trim is negative 4-8% at times and maybe 1-2% positive depending on load. This is all within spec, and 100% of the dealers out there would send me home saying my truck is perfectly fine. However, the truck is feeling sluggish, very actually compared to 50k miles. All parameters are in check.
What got me thinking about this is I pulled my MAP sensor out of the intake to clean it because I have never cleaned it (115k miles). I failed to take a picture of his sensor, but it was very tar like colored/brown and almost black really when it should be a pearly white color (the sensor in front of throttle body is pearly white). It had a very thick and sticky coating of oil/tar-like stuff. This has been covered and talked about on here numerous time, but I never really gave it serious thought until now. I have the stock PCV system on the truck. Actually, I swapped the PCV valve out to the new updated one at 100k miles. No catch can, or anything like that.
Now... my hypothesis. Carbon buildup on the intake valves. After thinking about it, it makes sense to me. Carbon build up around the valves, effectively reducing the opening allowing slightly less air into the cylinders. Injector injects amount of fuel per volume of air the truck is reading (from all the sensors that have been found to function correctly) and compares it to the O2 sensor readings. Senses rich, thus, calls for negative fuel trims 100% of the time. It may be far fetched, but I've personally seen what carbon buildup on a VW CC looked like at 130k miles and holy cow, that's what got me thinking.
If all goes well. I've got the instructions printed out and I'm hoping to yank off the intake manifold tonight or tomororw and report back, or at least try to scope it and see what I'm up against. Intake manifold removal looks to be fairly straightforward and simple.
I've researched ways on cleaning the valves, so that might be my next step. What do you all think? Far fetched??
After doing days of driving and watching sensors, let me throw out a plausible situation, and I feel like I may be onto something as everything I've checked has came up negative. I've got the service manual, and I have went through every single test/symptom chart in there. All came back negative findings.
I've been driving around on the stock tune for about a week I guess. After blowing the soot out of it a few times I've got my readiness check to pass. Emissions passed to my surprise (not that I really care, but I was using that as a parameter that my sensors were failing, etc.). I'm still getting a little erratic sensor readings, but I feel like my sensors are working correctly and something is causing it. After I figure this out 100% I still plan on doing a down pipe more than likely.
Anyways, in short, my truck is sensing a slightly "rich" condition at all times, and calling for an average of 5-7 negative long term fuel trim. While I'm driving, short term trim is negative 4-8% at times and maybe 1-2% positive depending on load. This is all within spec, and 100% of the dealers out there would send me home saying my truck is perfectly fine. However, the truck is feeling sluggish, very actually compared to 50k miles. All parameters are in check.
What got me thinking about this is I pulled my MAP sensor out of the intake to clean it because I have never cleaned it (115k miles). I failed to take a picture of his sensor, but it was very tar like colored/brown and almost black really when it should be a pearly white color (the sensor in front of throttle body is pearly white). It had a very thick and sticky coating of oil/tar-like stuff. This has been covered and talked about on here numerous time, but I never really gave it serious thought until now. I have the stock PCV system on the truck. Actually, I swapped the PCV valve out to the new updated one at 100k miles. No catch can, or anything like that.
Now... my hypothesis. Carbon buildup on the intake valves. After thinking about it, it makes sense to me. Carbon build up around the valves, effectively reducing the opening allowing slightly less air into the cylinders. Injector injects amount of fuel per volume of air the truck is reading (from all the sensors that have been found to function correctly) and compares it to the O2 sensor readings. Senses rich, thus, calls for negative fuel trims 100% of the time. It may be far fetched, but I've personally seen what carbon buildup on a VW CC looked like at 130k miles and holy cow, that's what got me thinking.
If all goes well. I've got the instructions printed out and I'm hoping to yank off the intake manifold tonight or tomororw and report back, or at least try to scope it and see what I'm up against. Intake manifold removal looks to be fairly straightforward and simple.
I've researched ways on cleaning the valves, so that might be my next step. What do you all think? Far fetched??
Last edited by PSI-FX4; 09-09-2016 at 01:51 PM.
09-10-2016, 03:30 AM
#23
Senior Member
Yea, I think carbon building on the intake valves is a little far fetched. Fyi just because the LTFT are calling for more fuel at certain rpm's, doesn't mean you're running rich. That's just the correction the pcm makes based on the o2's desire to keep the air/fuel ratio at 14.7:1.
09-10-2016, 10:20 AM
#24
Right. But what comparing those readings to my explorer sport. The LTFT is zero, and short term bounced from negative to positive a few percent.
Mine is -5-7 and short term is calling for -3-6 almost 100% of the time. This is why I'm thinking something is up. My O2 sensors are acting 100% the same as the explorers while running the same tests on both vehicles. That is what help me determine that my sensors are actually functioning properly.
I just know something isn't right. It literally feels like I'm towing my bass boat 100% of the time, and back when the truck was new I would get 12mpg towing it. I'm not towing anything and I'm getting 12mpg.
When I go WOT, it feels like I'm hooked to a sled and the truck doesn't have smooth power, it's almost erratic. While I agree, the carbon buildup is out there comparing to the number of ecoboost owners that have ever had serious issued ever arise from it (zero from what I can find), I will still investigate it just so I can eliminate it.
My aunt had pretty severe issues with her VW at 130k miles. Had a rough idle, and drove very sluggish, but she had misfire codes. When I took the intake off holy cow it was insane.
Mine is -5-7 and short term is calling for -3-6 almost 100% of the time. This is why I'm thinking something is up. My O2 sensors are acting 100% the same as the explorers while running the same tests on both vehicles. That is what help me determine that my sensors are actually functioning properly.
I just know something isn't right. It literally feels like I'm towing my bass boat 100% of the time, and back when the truck was new I would get 12mpg towing it. I'm not towing anything and I'm getting 12mpg.
When I go WOT, it feels like I'm hooked to a sled and the truck doesn't have smooth power, it's almost erratic. While I agree, the carbon buildup is out there comparing to the number of ecoboost owners that have ever had serious issued ever arise from it (zero from what I can find), I will still investigate it just so I can eliminate it.
My aunt had pretty severe issues with her VW at 130k miles. Had a rough idle, and drove very sluggish, but she had misfire codes. When I took the intake off holy cow it was insane.
09-16-2016, 01:32 PM
#25
Senior Member
You ever get around to pulling the intake manifold? I might do that this weekend but I also have to do brakes and my blend door so not sure if I will get to it
09-29-2016, 10:54 AM
#26
I have not had the time to pull the intake off yet. Been swamped with home improvements and traveling on the weekends. That is still on my next to do list. Actually, when I do it, I'm going to have new gaskets ready, and plan on cleaning the valves with brushes, etc. so it will be an all day event for sure.
I'm still running the stock tune. Truck runs great now, sluggish slightly still but I think it's just because it's stock shifting. With my tune, and now stock tune, I can't really tell any difference in power, only sluggish stock shifting. I ran it HARD for a couple tanks on stock tune, and the MPG has jumped 1-1.5mpg from previous. Four tanks in, and I haven't seen below 13.8 mpg (was 12.5 before). Odd really.
I'm wanting to try another tuner, maybe something was going on with my old tune/tuner, although I have ran that tune for 75,000 miles, lol. There is no support for that tuner now that I have (H&S mini-max with KEM Nutty Professor tune for Ecoboost). Maybe try and call up MPT or Livernois to see what they can do for me. May go ahead and get an off-road pipe when I do that just for giggles (or turbo whistle? haha).
I'm still running the stock tune. Truck runs great now, sluggish slightly still but I think it's just because it's stock shifting. With my tune, and now stock tune, I can't really tell any difference in power, only sluggish stock shifting. I ran it HARD for a couple tanks on stock tune, and the MPG has jumped 1-1.5mpg from previous. Four tanks in, and I haven't seen below 13.8 mpg (was 12.5 before). Odd really.
I'm wanting to try another tuner, maybe something was going on with my old tune/tuner, although I have ran that tune for 75,000 miles, lol. There is no support for that tuner now that I have (H&S mini-max with KEM Nutty Professor tune for Ecoboost). Maybe try and call up MPT or Livernois to see what they can do for me. May go ahead and get an off-road pipe when I do that just for giggles (or turbo whistle? haha).
09-29-2016, 09:52 PM
#27
Senior Member
I was curious about pulling mine and seeing if the gasket is leaking while its pressurized. That's the one thing I have had through all this is a loud air leaking noise, like air getting let out of a tank, over approx 8 psi boost. That could make it run rich. Otherwise it has to be the ecu venting it because the timing is off with my phasers/chain. I dunno yet, if I keep having a good year I am thinking of having the dealer do my chain again with phasers this time as a shot in the dark.
