5k rpm studder with UTEC
Originally Posted by BSREVOLUTION
my tuner also said something about how my larger injectors are dumping to much fuel when he would step on the gas. im going to see if he can come online and explain more.
Yeah there are several possibilities.. OLF/CLF transition (Fuel dump), Improper scaling, Fuel cut (in Closed loop) tuning could also have been in the wrong load cell for that RPM..
There could be a problem, but at 4000rpm thats a bit unusual unless there's just SO much fuel added, or SO much fuel removed, that it cuts out or quenches the ignition.
I don't really want to say much more until you post a log of what is happening and the map.. also its important to know what some of your settings are, such as if your using the flat shift feature, what your RPM limit is set for, what your OLF MAP and MAF cut value are, etc..
There could be a problem, but at 4000rpm thats a bit unusual unless there's just SO much fuel added, or SO much fuel removed, that it cuts out or quenches the ignition.
I don't really want to say much more until you post a log of what is happening and the map.. also its important to know what some of your settings are, such as if your using the flat shift feature, what your RPM limit is set for, what your OLF MAP and MAF cut value are, etc..
Evolving Member
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What I have noticed that most of these 780cc injectors respond so slow that it's pretty much useless to use the injector scaling feature. Alot of the time i don't waste my time scaling them cause it makes the 0 percent too lean and causes headaches everywhere.
I'd love to see the maps and parameters though. It's hard to make a speculation as people always do without having facts to make assumptions from.
Thanks,
Jermaine@turboxs.com
I'd love to see the maps and parameters though. It's hard to make a speculation as people always do without having facts to make assumptions from.
Thanks,
Jermaine@turboxs.com
Hey guys,
Thought I'd chime in. First and foremost, we are very familiar with the UTEC over here - I've been tuning with them since there inception. Second, I've tuned many many EVOs with the UTEC, so this is nothing new.
The UTEC was properly setup in OLF. I played with a number of different setting in order to get tip-in enrichment (accel fueling) to work properly. While I was able to fix this, it resulted in even more stumbling at 4k.
The problem is duty cycle related. As the car approaches 4k, it transitions through the 20%/30%/40% columns very quickly. For whatever reason, it was nearly impossible to get a smooth increase in duty cycle through this area - resulting in a lean/rich/lean stumble.
I spent a great deal of time trying to find a proper balance for the troubled area - including multiple from-scratch fuel maps. The behavior persisted and eventually we decided it would be better to fix the problem before spending anymore time or money on the dyno.
It is possible that it is UTEC related - but I wanted to rule out the possibility of injectors first. These injectors were purchased used, the manufacturer and specification was unknown, and this is the first I've seen of this problem after tuning well over 100 UTECs on WRX, EVOs, and STIs.
My recommendation was to move to a more standard injector such as a Greddy to elimate any other possibility. These are the injectors we tune most often and I always have great results whether using UTEC, AEM, Autronic, etc.
Regards,
Thought I'd chime in. First and foremost, we are very familiar with the UTEC over here - I've been tuning with them since there inception. Second, I've tuned many many EVOs with the UTEC, so this is nothing new.
The UTEC was properly setup in OLF. I played with a number of different setting in order to get tip-in enrichment (accel fueling) to work properly. While I was able to fix this, it resulted in even more stumbling at 4k.
The problem is duty cycle related. As the car approaches 4k, it transitions through the 20%/30%/40% columns very quickly. For whatever reason, it was nearly impossible to get a smooth increase in duty cycle through this area - resulting in a lean/rich/lean stumble.
I spent a great deal of time trying to find a proper balance for the troubled area - including multiple from-scratch fuel maps. The behavior persisted and eventually we decided it would be better to fix the problem before spending anymore time or money on the dyno.
It is possible that it is UTEC related - but I wanted to rule out the possibility of injectors first. These injectors were purchased used, the manufacturer and specification was unknown, and this is the first I've seen of this problem after tuning well over 100 UTECs on WRX, EVOs, and STIs.
My recommendation was to move to a more standard injector such as a Greddy to elimate any other possibility. These are the injectors we tune most often and I always have great results whether using UTEC, AEM, Autronic, etc.
Regards,
Last edited by Harman Motive; Jan 7, 2005 at 11:03 AM.
Originally Posted by Harman Motive
Hey guys,
Thought I'd chime in. First and foremost, we are very familiar with the UTEC over here - I've been tuning with them since there inception. Second, I've tuned many many EVOs with the UTEC, so this is nothing new.
The UTEC was properly setup in OLF. I played with a number of different setting in order to get tip-in enrichment (accel fueling) to work properly. While I was able to fix this, it resulted in even more stumbling at 4k.
The problem is duty cycle related. As the car approaches 4k, it transitions through the 20%/30%/40% columns very quickly. For whatever reason, it was nearly impossible to get a smooth increase in duty cycle through this area - resulting in a lean/rich/lean stumble.
I spent a great deal of time trying to find a proper balance for the troubled area - including multiple from-scratch fuel maps. The behavior persisted and eventually we decided it would be better to fix the problem before spending anymore time or money on the dyno.
It is possible that it is UTEC related - but I wanted to rule out the possibility of injectors first. These injectors were purchased used, the manufacturer and specification was unknown, and this is the first I've seen of this problem after tuning well over 100 UTECs on WRX, EVOs, and STIs.
My recommendation was to move to a more standard injector such as a Greddy to elimate any other possibility. These are the injectors we tune most often and I always have great results whether using UTEC, AEM, Autronic, etc.
Regards,
Thought I'd chime in. First and foremost, we are very familiar with the UTEC over here - I've been tuning with them since there inception. Second, I've tuned many many EVOs with the UTEC, so this is nothing new.
The UTEC was properly setup in OLF. I played with a number of different setting in order to get tip-in enrichment (accel fueling) to work properly. While I was able to fix this, it resulted in even more stumbling at 4k.
The problem is duty cycle related. As the car approaches 4k, it transitions through the 20%/30%/40% columns very quickly. For whatever reason, it was nearly impossible to get a smooth increase in duty cycle through this area - resulting in a lean/rich/lean stumble.
I spent a great deal of time trying to find a proper balance for the troubled area - including multiple from-scratch fuel maps. The behavior persisted and eventually we decided it would be better to fix the problem before spending anymore time or money on the dyno.
It is possible that it is UTEC related - but I wanted to rule out the possibility of injectors first. These injectors were purchased used, the manufacturer and specification was unknown, and this is the first I've seen of this problem after tuning well over 100 UTECs on WRX, EVOs, and STIs.
My recommendation was to move to a more standard injector such as a Greddy to elimate any other possibility. These are the injectors we tune most often and I always have great results whether using UTEC, AEM, Autronic, etc.
Regards,
Well here's a fix. At that 4k point, you are adding +3.2 percent of fuel right before and right after that you're taking away -4.2. I know on the utec any drastic changes may cause stumbling. Smooth it out and tell us what happens.
Mind posting your maps so i can take a look at them?
Mind posting your maps so i can take a look at them?
Here a digital pic of the dyno sheet, im having the paper scanned later. im working on putting the maps online in a bit.
widebandphillip, thanks for the help.
http://www.we-todd-did-racing.com/we...ZmQzMXk1NDE%3D
http://www.we-todd-did-racing.com/we...ZmQzMXk1NDE%3D
http://www.we-todd-did-racing.com/we...ZmQzMXk1NDE%3D
My first ran was 261whp and the final was 271whp
3 big-ones down the drain.
widebandphillip, thanks for the help.
http://www.we-todd-did-racing.com/we...ZmQzMXk1NDE%3D
http://www.we-todd-did-racing.com/we...ZmQzMXk1NDE%3D
http://www.we-todd-did-racing.com/we...ZmQzMXk1NDE%3D
My first ran was 261whp and the final was 271whp
3 big-ones down the drain.
If these injectors are "questonable" I would throw them out. The last thing you want to happen is be WOT and have a injector fail and lose a cylinder. Really if you want to skimp. Skimp on a blow off valve or something smaller. But injectors are one of the most important things in your motor.
Also I notice around the area you say you are having the problem your MAF Hz decreases this is not uncommon with the evo but it does seem to jump from 574 Hz to 946 Hz. And you can see the stock car wants to jump from 800 to about 900.
And also at RPM 3871 the Hz decrease again while the stock wants to increase slightly.
I wonder what is cause this to happen. What intake are you running?
I think what we need is a log(hopefully including a AFR but it doesn't look like you have a WB and were just using the dynos WB. Your map, and a list of your mods. With all this information and i pretty sure someone here can get the problems pinned down.
Ben
Also I notice around the area you say you are having the problem your MAF Hz decreases this is not uncommon with the evo but it does seem to jump from 574 Hz to 946 Hz. And you can see the stock car wants to jump from 800 to about 900.
And also at RPM 3871 the Hz decrease again while the stock wants to increase slightly.
I wonder what is cause this to happen. What intake are you running?
I think what we need is a log(hopefully including a AFR but it doesn't look like you have a WB and were just using the dynos WB. Your map, and a list of your mods. With all this information and i pretty sure someone here can get the problems pinned down.
Ben