Unique Problem - Bank 1 Overcorrecting (Rich)
They are dead on in vac and in full boost, it only deviates when boost is building. Usually at around 2psi they go apart, then when it levels off at 13/14 psi they are back to .1 a/f difference.
so if i pull back on 1, wouldn't it be off in vac and in full boost causing the same issue in a different area?
I'm confused on why 1 bank would just all of a sudden do this. I'm leaning more towards the way the piping is designed causing an issue but i need to find a way to be 100% sure that it's a "false" lean condition so i don't damage the engine.
Well, we've swapped the O2 sensors, and the problem stayed on the same side, so that eliminates the possibility of it being a bad O2 sensor. And even still, the fact that that it's reading rich (correctly) and still adding fuel is what makes it so strange.
Everything isn't necessarily the same; the intake cam readings are significantly off when the problem is rearing its ugly head. Running theory is that it's a byproduct of the car trying to add more fuel. I went down to Failsafe, and we unplugged the intake cam sensors to see if that would have anything to do with it, and at first it looked like the problem went away, but instead it came right back like before.
Injector pulse widths... not sure if we checked those. I'll have to double-check and get back. I feel like Cipher doesn't provide that option, but I could be wrong.
NEW DEVELOPMENT:
As far as new developments go, while Chris was being awesome and helping me in my quest to figure this crap out, we narrowed down what appears to be a condition under which the AFR imbalance comes back up. At idle, the AFRs are supposed to be steady around 14.7 or thereabouts. If I get on the gas and rev it up to somewhere high and slowly bring it back down, it stays normal. However, if I let off suddenly and trigger the fuel cutoff, it triggers the AFR imbalance issue that's been plaguing me. Bank 1 will drop down to around 13.2 while Bank 2 stays at 14.7'sh and they just hover there for anywhere from 30 seconds to over a minute before suddenly jumping back to 14.7 for both. It's strange.
So I now know of one way that definitely triggers it, and that the condition will disappear over time at random if left alone at idle... only to come back later if triggered again.
So does that mean it's fuel system related? I've cleaned the injectors thoroughly, we've checked the voltages on all of them. I'm thinking about swapping the injectors from one side to the other this week and seeing if that affects anything. I have a feeling, however, that it won't. Any ideas???
Everything isn't necessarily the same; the intake cam readings are significantly off when the problem is rearing its ugly head. Running theory is that it's a byproduct of the car trying to add more fuel. I went down to Failsafe, and we unplugged the intake cam sensors to see if that would have anything to do with it, and at first it looked like the problem went away, but instead it came right back like before.
Injector pulse widths... not sure if we checked those. I'll have to double-check and get back. I feel like Cipher doesn't provide that option, but I could be wrong.
NEW DEVELOPMENT:
As far as new developments go, while Chris was being awesome and helping me in my quest to figure this crap out, we narrowed down what appears to be a condition under which the AFR imbalance comes back up. At idle, the AFRs are supposed to be steady around 14.7 or thereabouts. If I get on the gas and rev it up to somewhere high and slowly bring it back down, it stays normal. However, if I let off suddenly and trigger the fuel cutoff, it triggers the AFR imbalance issue that's been plaguing me. Bank 1 will drop down to around 13.2 while Bank 2 stays at 14.7'sh and they just hover there for anywhere from 30 seconds to over a minute before suddenly jumping back to 14.7 for both. It's strange.
So I now know of one way that definitely triggers it, and that the condition will disappear over time at random if left alone at idle... only to come back later if triggered again.
So does that mean it's fuel system related? I've cleaned the injectors thoroughly, we've checked the voltages on all of them. I'm thinking about swapping the injectors from one side to the other this week and seeing if that affects anything. I have a feeling, however, that it won't. Any ideas???
Has this problem been around since you installed the Mrev or just randomly recent? Its possible you have a small gasket leak in the lower collector gasket(B1)... Try spraying brake cleaner on that gasket...
Also check to see if your O2 sensor heater elements are working correctly...on cold starts and closed loop the O2 heaters kick on(running richer) until the exhaust reaches a certain temperature so that the engine warms up faster(emission reasons). At cruising speeds or moderate/hard acceleration, the O2 heaters should not be on because the exhaust is more than warm enough. Its possible that the ecu sees that the heater is on thinking its a cold start or something along those lines and tries to correct that bank. Sometimes bad O2 heating elements won't throw any codes
Other than that, you've seemed to try everything and I can't think of anything else.
you can check the voltage at the injectors to see if its getting 12 volts, but that won't determine if the injector is bad, just possible wiring issue. You need to check the resistance between the 2 pins on the injector itself. If they are not within factory spec, then you replace that injector and retest
Last edited by allmotorsedan; Aug 19, 2010 at 09:20 PM.
I actually just got this code today. The car has been running for over 400 miles without codes and today after shutting it off (driven before shutoff so it was completely warmed up) and then turning the car on literally about a minute later the code came on upon startup. I cleared it and will see if it comes back up. Sometimes i step on the gas slightly when car is warm to start it up easier, maybe that caused my problem.
I wonder if the rear O2 sensors (sensor 2) are causing the problem... You threw codes for them. I'm not sure how they interact with sensor 1 to regulate fueling, if at all. Swapping those side to side might be worth a try though.
Im still trying to get rid of this code and wonder if a bad hfc might be giving me this problem (maybe clogged hfc?). Going pull the hfc's off this week and see what comes up. OP are you running cats, hfc, or test pipes?
Tomci08,
what are your mods??
Also, there is this thread here :
https://my350z.com/forum/maintenance...-ses-code.html
Same issue on my car.keep the updates coming!
what are your mods??
Also, there is this thread here :
https://my350z.com/forum/maintenance...-ses-code.html
Same issue on my car.keep the updates coming!
Im hoping it is the HFC's but after reading all of the other threads about this i doubt it is, yet still keeping my fingers crossed. Also was wondering if this could be cause by a cracked header?
Well its def not the HFC's as those are still good. Im tempted to yank that damn o2 out and place it right next to the o2 sensor after the cat so it doesnt keep coming up haha. Anyone else have any solutions to this yet?
Thread Starter
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Joined: May 2008
Posts: 548
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From: Tulsa, OK
Well, I had my short block replaced per the infamous 2006 Rev-Up oil consumption problem, but the error code has come back, and the same symptoms have been observed in Cipher just as they were before. This is getting stupid. But at least I now know it's not a problem in the lower half of the engine, right?
Thread Starter
Registered User
Joined: May 2008
Posts: 548
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From: Tulsa, OK
I've just gone ahead and roughly chronicled the entire saga that hunting this gremlin has become - complete with point-by-point details of the problem and every major test that has been conducted with their subsequent results. It's all organized nicely in the attached Word document for anyone that is interested in helping me solve this problem.
I'm serious about this: I am going to give $200 to whoever successfully identifies what is causing all of this and leads me to the solution.
I'm serious about this: I am going to give $200 to whoever successfully identifies what is causing all of this and leads me to the solution.
i didnt read the whole thread, but i did read the entire word document. so, did you have o2 sensor bungs welded into each bank's exhaust sides for wideband purposes?
check for pinhole leaks on any bung welds, might be hard to see with them on the car. i dont think this is the case though, because a pin hole next to the wideband would max out the A/f ratio at idle. it happened to me, idle a/f just read 22. as soon as any throttle was applied, it jumped down to a normal reading, so i doubt that is your problem.
check for pinhole leaks on any bung welds, might be hard to see with them on the car. i dont think this is the case though, because a pin hole next to the wideband would max out the A/f ratio at idle. it happened to me, idle a/f just read 22. as soon as any throttle was applied, it jumped down to a normal reading, so i doubt that is your problem.
Thread Starter
Registered User
Joined: May 2008
Posts: 548
Likes: 2
From: Tulsa, OK
i didnt read the whole thread, but i did read the entire word document. so, did you have o2 sensor bungs welded into each bank's exhaust sides for wideband purposes?
check for pinhole leaks on any bung welds, might be hard to see with them on the car. i dont think this is the case though, because a pin hole next to the wideband would max out the A/f ratio at idle. it happened to me, idle a/f just read 22. as soon as any throttle was applied, it jumped down to a normal reading, so i doubt that is your problem.
also, are you sure its a b1 rich problem and not a b2 lean problem?
check for pinhole leaks on any bung welds, might be hard to see with them on the car. i dont think this is the case though, because a pin hole next to the wideband would max out the A/f ratio at idle. it happened to me, idle a/f just read 22. as soon as any throttle was applied, it jumped down to a normal reading, so i doubt that is your problem.
also, are you sure its a b1 rich problem and not a b2 lean problem?
On the second, yeah. Seeing how how 1) the correction factor shows b1 adding 15% more fuel while b2 stays the same and 2) the actual air-fuel ratios reflect those changes, I feel pretty confident that that's the case. B2 seems to go later on the in process and to a later degree - more of the appearance of an effect than a cause, you know?
If something is fooling the O2 sensors, could it be related to a true dual setup vs. a y-pipe>midpipe>axleback muffler?
Has anyone thrown the code with a single exhaust? I don't think I've seen this problem with such a setup yet.
Has anyone thrown the code with a single exhaust? I don't think I've seen this problem with such a setup yet.