LEAN AFR - Possible Injector issues?
LEAN AFR - Possible Injector issues?
tuners and anyone that might have any educated guess at whats happening, pls chime in...
Basically i've been struggling w/ an odd lean spot at WOT between approximately 5200rpm - 6500rpm. It runs just fine at 11.0 AFR up until it hits this area and then it instantly goes lean to about 12.0+. Another weird thing is that right after 6500rpm it goes back to normal at around 11.0.
At first we thought maybe the flash was mapped too lean, since it was my first wideband reading.. but TTP graciously provided me w/ 2 richened maps and it still did not change the AFR in this section from going lean. So we have ruled out that it is the map. (richening the fuel map does nothing..) Then i datalogged it w/ EvoScan and the INJECTOR DUTY CYCLE also dips immediately at the SAME rpms. The Injector Pulse Width also drops here too. SOooo.. i figure im going lean as a direct result of both inj duty/pulse going down. Ive got that part. The odd thing is that its doing this against what the Fuel Map is telling it to do... therefore im thinking it has to be something else. ANYONE have experience w/ this?? i did trigger an INJ CIRCUIT code once, but it hasnt come back. The injectors are ticking as usual...
i can't seem to attach the logs... so if anyone is interested in looking at them, i can email them to you.
Basically i've been struggling w/ an odd lean spot at WOT between approximately 5200rpm - 6500rpm. It runs just fine at 11.0 AFR up until it hits this area and then it instantly goes lean to about 12.0+. Another weird thing is that right after 6500rpm it goes back to normal at around 11.0.
At first we thought maybe the flash was mapped too lean, since it was my first wideband reading.. but TTP graciously provided me w/ 2 richened maps and it still did not change the AFR in this section from going lean. So we have ruled out that it is the map. (richening the fuel map does nothing..) Then i datalogged it w/ EvoScan and the INJECTOR DUTY CYCLE also dips immediately at the SAME rpms. The Injector Pulse Width also drops here too. SOooo.. i figure im going lean as a direct result of both inj duty/pulse going down. Ive got that part. The odd thing is that its doing this against what the Fuel Map is telling it to do... therefore im thinking it has to be something else. ANYONE have experience w/ this?? i did trigger an INJ CIRCUIT code once, but it hasnt come back. The injectors are ticking as usual...
i can't seem to attach the logs... so if anyone is interested in looking at them, i can email them to you.
anyone? well, i have no idea how the electronics for our fuel systems work... but im venturing to guess it has something to do w/ the injectors or whatever is sending the signal to them etc... i don't think its the flash or fuel maps etc. Is there anything else that goes between the injectors and ECU that could possibly fail and cause this odd problem?
If it was mine, I would try two things right off the top of my head. First, I'd swap the stock air intake system back on. Then, secondly, if that doesn't work, I'd swap in a new Walbro. Of course, maybe someone else has a better idea. Good luck
EDIT: The reason I suspect the HKS RS, is because I had a similar problem after adding a SAMCO MAF pipe and a foam pod filter. My car went way lean beween 4000-6500 RPM. We had to add a ton of fuel to the table.
EDIT: The reason I suspect the HKS RS, is because I had a similar problem after adding a SAMCO MAF pipe and a foam pod filter. My car went way lean beween 4000-6500 RPM. We had to add a ton of fuel to the table.
Last edited by sparky; Oct 1, 2007 at 11:35 PM.
Email me your logs updoc21@hotmail.com so I can take a look.
And FYI, I wouldn't go calling this a "lean spot" so much since it is almost 1500rpms long. That is a long time for the car to experience such lean A/F ratios on pump and I would bet you are knocking.
For now I wouldn't go swapping any hard parts yet. First, try turning the boost down slightly to 17-19 psi. Take the car back out and log it. I have a sneaking suspicion that your problem will go away. Be sure to send those logs to me as well.
I have encountered a problem like this before and I have yet to figure out what is the root cause. If it is the same as what I have seen, you are definately knocking and turning the boost down is a good idea for the preservation of your engine.
I will review your logfiles when you send em and get back to you but int he interim turn that boost down!
And FYI, I wouldn't go calling this a "lean spot" so much since it is almost 1500rpms long. That is a long time for the car to experience such lean A/F ratios on pump and I would bet you are knocking.
For now I wouldn't go swapping any hard parts yet. First, try turning the boost down slightly to 17-19 psi. Take the car back out and log it. I have a sneaking suspicion that your problem will go away. Be sure to send those logs to me as well.
I have encountered a problem like this before and I have yet to figure out what is the root cause. If it is the same as what I have seen, you are definately knocking and turning the boost down is a good idea for the preservation of your engine.
I will review your logfiles when you send em and get back to you but int he interim turn that boost down!
At a guess your using calculated load?
If you want to post the logs or email them to me I can can tell ya whats happening for sure. See if the AFR map drops a bit in that spot.
If you want to post the logs or email them to me I can can tell ya whats happening for sure. See if the AFR map drops a bit in that spot.
After reviewing your logs, this is exactly what I have seen before. No knock, but the MAF signal is capping out at the exact same value of 1603.95hz. At the same time your load and duty cycle on the injectors is dropping but not as intense as a fuel cut state.
The thing I dont understand is the MAF should count well over 2500hz and I see no reason why this is happening. The "work arounds" that I have seen somewhat allieviate this effect are
1) Lower the boost slightly
2) Add meth injection
3) Race gas
Believe it or not, and I still dont understand why, but when we were trying to fix this issue on my buds car, when we added c16, we saw the MAF count rise up to 1840 some hz. Its like the car is knocking, not registering it and limiting the air signal to compensate somehow.
This doesnt make an ounce of sense to me since, at that point, I would think the car should dump extra fuel to help preserve the engine, but it dsoesn't, it does the opposite and pulls fuel.
Im sorry I cant help more but AI would definately get on the phone with your chip flashing tuner since they have to have seen this before.
The thing I dont understand is the MAF should count well over 2500hz and I see no reason why this is happening. The "work arounds" that I have seen somewhat allieviate this effect are
1) Lower the boost slightly
2) Add meth injection
3) Race gas
Believe it or not, and I still dont understand why, but when we were trying to fix this issue on my buds car, when we added c16, we saw the MAF count rise up to 1840 some hz. Its like the car is knocking, not registering it and limiting the air signal to compensate somehow.
This doesnt make an ounce of sense to me since, at that point, I would think the car should dump extra fuel to help preserve the engine, but it dsoesn't, it does the opposite and pulls fuel.
Im sorry I cant help more but AI would definately get on the phone with your chip flashing tuner since they have to have seen this before.
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After reviewing your logs, this is exactly what I have seen before. No knock, but the MAF signal is capping out at the exact same value of 1603.95hz. At the same time your load and duty cycle on the injectors is dropping but not as intense as a fuel cut state.
The thing I dont understand is the MAF should count well over 2500hz and I see no reason why this is happening. The "work arounds" that I have seen somewhat allieviate this effect are
1) Lower the boost slightly
2) Add meth injection
3) Race gas
Believe it or not, and I still dont understand why, but when we were trying to fix this issue on my buds car, when we added c16, we saw the MAF count rise up to 1840 some hz. Its like the car is knocking, not registering it and limiting the air signal to compensate somehow.
This doesnt make an ounce of sense to me since, at that point, I would think the car should dump extra fuel to help preserve the engine, but it dsoesn't, it does the opposite and pulls fuel.
Im sorry I cant help more but AI would definately get on the phone with your chip flashing tuner since they have to have seen this before.
The thing I dont understand is the MAF should count well over 2500hz and I see no reason why this is happening. The "work arounds" that I have seen somewhat allieviate this effect are
1) Lower the boost slightly
2) Add meth injection
3) Race gas
Believe it or not, and I still dont understand why, but when we were trying to fix this issue on my buds car, when we added c16, we saw the MAF count rise up to 1840 some hz. Its like the car is knocking, not registering it and limiting the air signal to compensate somehow.
This doesnt make an ounce of sense to me since, at that point, I would think the car should dump extra fuel to help preserve the engine, but it dsoesn't, it does the opposite and pulls fuel.
Im sorry I cant help more but AI would definately get on the phone with your chip flashing tuner since they have to have seen this before.
Oddly the Maf scaling pulls back the amount of air that it says the car is being fed and it probably just stays at that value once it passes that point. This probably has something to do with the restrictive intake the car has in its stock form.
oh wow... so then not everyone maxes out at 1603.95 hz? for some reason i thought that is where it maxed out at or something... Hmm, strange. The good thing is that the car stopped knocking all the sudden. i have no clue why, but im welcoming it! the only thing i have been changing is the gas. BUT the fuel dip and lean spot hasnt changed... i still need to figure that out. But at least its not registering knock anymore. I am going to use a piggy back HKS AFR to dump more fuel in (easier to control while im making numerous passes) and see if it corrects the lean mixture. Would it be somewhat possible that i may have a defective MAF? and how would i prove that to the dealer anyways? i have no codes thrown..
