Potential problem with '04.5 ECU's and F/I systems....
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Joined: Jun 2004
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From: Florida
Originally posted by Speedracer
All I know is that with my HKS F-CON that came pre-programmed with the HKS SC kit, the diagnostics showed the air:fuel ratio on both pre-cat sensors to be 20% richer than the stock "spec" setting. The correctable range for the stock ECU is +/- 12.5%. More than this will trigger an SES. The problem is that neither I nor the Nissan Master Tech who looked at my car had any info on what that actual "spec" A/F is supposed to be for any driving condition. I have contacted HKS and they are looking into it. All their R&D was done on a 2003 model and so the ULEV engine management was not an issue. To their knowledge, I am actually the first person to install the kit on a ULEV spec 350Z.
All I know is that with my HKS F-CON that came pre-programmed with the HKS SC kit, the diagnostics showed the air:fuel ratio on both pre-cat sensors to be 20% richer than the stock "spec" setting. The correctable range for the stock ECU is +/- 12.5%. More than this will trigger an SES. The problem is that neither I nor the Nissan Master Tech who looked at my car had any info on what that actual "spec" A/F is supposed to be for any driving condition. I have contacted HKS and they are looking into it. All their R&D was done on a 2003 model and so the ULEV engine management was not an issue. To their knowledge, I am actually the first person to install the kit on a ULEV spec 350Z.
Im in the same boat.....
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Joined: Mar 2004
Posts: 1,144
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From: West Springfield, MA
Originally posted by Z1 Performance
Also, where in the manual does it say 100% LTFT is fail safe...makes no sense whatsover to me. On every car I have ever datalogged (regardless of maker), 100% stft and ltft corresponded to the car running the way the ecu wants it to. Any number below 100% was the car running slightly richer than stock, any number above 100% was the car running slightly leaner than stock. I remember this from back trying to get my VPC to play nice with my SAFC on my Galant VR4. A stft of 75% would throw a CE light on that car too (it's a '92!), and the car would run like doo doo. If you leaned the SAFC out, you could literally watch stft trim eek back towards 100%.
VJ - try logging just 02, one sensor at a time, one bank at a time, and post here what it does at idle (once the car is warmed up), under cruise and under WOT. Do the same thing for each sensor in each bank and post what you find. Would also be interesting to see what fuel pressure is at idle as well. Remember, the HKS setup has an upgraded pump but no return system
Also, where in the manual does it say 100% LTFT is fail safe...makes no sense whatsover to me. On every car I have ever datalogged (regardless of maker), 100% stft and ltft corresponded to the car running the way the ecu wants it to. Any number below 100% was the car running slightly richer than stock, any number above 100% was the car running slightly leaner than stock. I remember this from back trying to get my VPC to play nice with my SAFC on my Galant VR4. A stft of 75% would throw a CE light on that car too (it's a '92!), and the car would run like doo doo. If you leaned the SAFC out, you could literally watch stft trim eek back towards 100%.
VJ - try logging just 02, one sensor at a time, one bank at a time, and post here what it does at idle (once the car is warmed up), under cruise and under WOT. Do the same thing for each sensor in each bank and post what you find. Would also be interesting to see what fuel pressure is at idle as well. Remember, the HKS setup has an upgraded pump but no return system
It would be REALLY REALLY REALLY great if you could come up next weekend to help figure this all out when we run data on the dyno with several people involved. See what you can do. Isn't there a ferry that will get you pretty quickly to Connecticut?
Also, according to my Fuel Pressure gauge which is located immediately after the fuel damper in the bung that splits off the fuel supply for the auxillary injectors, the pressure is 51-54psi constantly, from idle up to redline at all throttle positions.
Last edited by Speedracer; Nov 27, 2004 at 03:16 PM.
VJ - I will see what I can do. yes the ferry is a quick trip to CT but Wethersfield is far from everyplace 
Plus weekends are family time, so gotta see if I can break free for a day (maybe send her holiday shopping!)
FP is good
Plus weekends are family time, so gotta see if I can break free for a day (maybe send her holiday shopping!)FP is good
Originally posted by techz33
car starts to sputter in 3rd and 4th gear at about 3600-4000rpm
XS engineering is working with me in soliving the problem i will keep you posted on the buff ecu
car starts to sputter in 3rd and 4th gear at about 3600-4000rpm
XS engineering is working with me in soliving the problem i will keep you posted on the buff ecu
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Joined: Mar 2004
Posts: 1,144
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From: West Springfield, MA
Originally posted by Severed Ties
Any new info on this? Was planning to go forced induction in the spring but not if the ECU itself is the problem rather than the tuning???
Any new info on this? Was planning to go forced induction in the spring but not if the ECU itself is the problem rather than the tuning???
Sorry to bring an old thread back to life.
I have HKS GT SC setup with fcon vpr and uprev reflash. My ide is jumpy and I have been throwing p1281 code. I had the driver's side sensor in the manifold replaced, and it went away for awhile. But now I am throwing it again.
Has anyone who has experienced this issue come up with a solution? I don't want to have issues with emissions next time I have to go.
I have HKS GT SC setup with fcon vpr and uprev reflash. My ide is jumpy and I have been throwing p1281 code. I had the driver's side sensor in the manifold replaced, and it went away for awhile. But now I am throwing it again.
Has anyone who has experienced this issue come up with a solution? I don't want to have issues with emissions next time I have to go.
yup yup bringing old thread up again myself. code p1271 and p1281 coming up. we want to head to forged in the next couple of weeks for a tune but want to get the codes cleared first. this has a stillen supercharger on it. so any help would be great.
so your running a stillen supercharger on the stillen box right now? or is it tuned with something else? and based on your codes it sounds like you have 2 bad 02 sensors
Talked to chuck @ stillen he told me to pull the 7th injector and make sure its closing if not I need new injector and it has caused all the sensors to file out. Yes has the black box. I was told the car will not run without the box even with a tuned ecu
Wow to find out after talking with chuck@stillen again. He is telling me the black box is bad. But hey guess what. they do not use the black box anymore. Now they want to sell me a new $900 piggyback I supposed it is. What a crock of crap. So you updated and now the consumer has to pay out the ***? I know you gotta pay to play and glad it is not my car but it is one of my boys and thats just bs. Anyone else out there running the stillen supercharger with a tune and aftermarket injectors to bypass this bs black box??
Wow to find out after talking with chuck@stillen again. He is telling me the black box is bad. But hey guess what. they do not use the black box anymore. Now they want to sell me a new $900 piggyback I supposed it is. What a crock of crap. So you updated and now the consumer has to pay out the ***? I know you gotta pay to play and glad it is not my car but it is one of my boys and thats just bs. Anyone else out there running the stillen supercharger with a tune and aftermarket injectors to bypass this bs black box??
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