I cant get past about 19 psi on my setup. I am running the MAF pro tuned at around 11.5 afrs at wide open throttle. I am running a GT4082 turbo, and all the supporting mods-but cant tune out fuel cut. I heard something about a hertz cut that you can program into the MAF pro (I am running v 4.4, I like that one)-but I cant find any more info on it. I dont want to run a FCD, but I do want to run about 25 psi at around the 11.5 afr mark. Anyone have any ideas( yes, i have checked for boost leaks and all the normal). If it helps, I am running a Greddy profec b spec 1 boost controller with the gain set about halfway. Playing with the gain does help a tad, but kills responsiveness. Thanks for any help, and yes-I have searched with not too much luck...
Fuel cut!
- Thread starter polobai
- Start date
It would be helpful if you could post a bin and a data log for us to look at. At least post up all your settings in text.
ok update-now my cd that I have that came with my MAF Pro wont even load tuner pro RT. It just keeps crashing when i open it. I downloaded the free version, but I want the one I am supposed to have. Can anyone send me the Tunerpro RT version to polobai@aol.com? I dont feel like paying $30 for something I should already have...still working on the bin by the way...
It only comes with the free version, as far as I know. I had to buy the full version in addition to the MAFT unit, anyway.
The versions mine came with are:
SetupTunerProRT_v413 generic.exe
SetupTunerProRT_v414.exe
Don't remember anything about either though.
EDIT:
Well, I just installed both of the versions on the disk that came with my MAFT Pro and neither is a registered copy.
SetupTunerProRT_v413 generic.exe
SetupTunerProRT_v414.exe
Don't remember anything about either though.
EDIT:
Well, I just installed both of the versions on the disk that came with my MAFT Pro and neither is a registered copy.
Same problem but Im running gt40/88 turbo with the maft pro and 550cc injectors would raising fuel pressure help get rid of fuel cut? Im hitting fuel cut at 17psi or would I be better off just getting FCD ?
Adjuster
Supramania Contributor
I don't have a running version of the Translator Pro myself, so take my advice/opinion for what it's worth.. LOL BUT, I've been looking into this for a long time, and have run 440's, 550's and now trying to get 780's to work on the 7MGTE.
I've run the Eman Blue, and the Lexus meter... air screw backed all the way out, and flowing as much "leaked" air as possible, and was able on WOT could see 25psi with no fuel cut, but if I tried to floor it in a lower gear, and loaded up the engine, it would instantly hit boost cut. (Not that on bad fuel, I melted a piston with a spike to 28psi.. but on good fuel, it would boost at 21 to 25 psi and was a hoot to drive.. At that time, I was running 30% Toulene most of the time.. and for some reason, the 3psi spike change was the point of no return for the stock pistons... Coated forged ones might hold up better, but there are no absolutes in this world, especially with engines and parts, so tune/push at your own risk.)
Now, I had the Hz signal going to the TCCS clamped at 1450Hz. (The TCCS calls for fuel cut at Hz levels of 1500 or more.) I've read many posts by guys like Jet Jock and others who have much more knowlege on the stock TCCS than I do, but there are more parameters than just the Hz rate that causes fuel cut.
So, here is what I've come to think.
The larger you go fuel injector size wise, the more Hz rate you pull from the signal being "fed" to the TCCS by the piggyback computer.
This can cause problems at high boost, as the lower Hz rate is interpeted as less airflow, and the TCCS assumes the engine is stock.. so it keeps the same spark advance as a stock engine running 440's at a given RPM rate and TPS signal. (Please correct me if I'm wrong, I'm not sure the TPS signal has a role to play here? Thanks in advance.)
So, in theory, if you put 880cc injectors, the engine would only need to see half the "stock" Hz rate to run at the same air fuel ratio. BUT the spark advance table/setting might be way off. Example would be an engine running 4000rpm with 440's would "see" the same air flow Hz rate as one running 2000rpm on 880cc injectors.
Now, I'm only guessing here, but I'd bet that the spark advance for 2000 rpm is much more agressive than the one for 4000rpm when the turbo can be building boost at that point. (So, if due to your larger injectors, you are building boost at 4k, but your TCCS is being fed the airflow Hz rate for 2000rpm, that would be bad for the motor, as too much advance can cause detonation..)
So along comes the Translator Pro.. With the abillity to not only monitor what the spark advance is, but to modify it.
(I have not yet got this to work however.. but I have it wired up this way...)
So, back on topic.. how to raise fuel cut, and not buy a standalone ECU..
My theory is that the larger 780cc injectors will allow much more headroom before the 1500hz rate is reached. And the ability to monitor, and then adjust the spark advance will allow me to keep the engine from detonation in the lower Hz rates while it's building boost.
The fuel cut problem seems to be worse with a fast responding turbo. (I had a bolt on T4 60-1 dual ball bearing CHRA that spooled up VERY fast, and it was so fast on the stroker engine, that lag really is not an issue.. tire traction is in short supply. BUT it would spool so fast, and then hit fuel cut, it was no fun to drive, as you really could not open it up, and enjoy the power most of the time.)
So, new larger turbo, new exhaust manifold and larger injectors with the Translator Pro (Maft Pro) was the plan a few years ago.. and it's still not running.. LOL (My life has become very busy, and I have little time for project cars at this point.)
Short answer might be that with your fast spooling turbo, and only 550cc injectors, you will have fuel cut at times when you do not want it.. IE: Anytime you boost more than 1500Hz signal to the ECU.. (You can limit the signal on the Maft Pro/Translator Pro to say 1499Hz, and that is the max signal it will send to the TCCS, but if my Eman Blue experience was any indicator, it will not solve the problem 100% of the time..) Have not tried, but does the Translator Pro let you plug in 1499 or does it cut at 5Hz or 10Hz values? (The Eman Blue was adjusted at 50Hz values.. thus the 1450Hz max signal sent to the TCCS.)
Good luck.
I've run the Eman Blue, and the Lexus meter... air screw backed all the way out, and flowing as much "leaked" air as possible, and was able on WOT could see 25psi with no fuel cut, but if I tried to floor it in a lower gear, and loaded up the engine, it would instantly hit boost cut. (Not that on bad fuel, I melted a piston with a spike to 28psi.. but on good fuel, it would boost at 21 to 25 psi and was a hoot to drive.. At that time, I was running 30% Toulene most of the time.. and for some reason, the 3psi spike change was the point of no return for the stock pistons... Coated forged ones might hold up better, but there are no absolutes in this world, especially with engines and parts, so tune/push at your own risk.)
Now, I had the Hz signal going to the TCCS clamped at 1450Hz. (The TCCS calls for fuel cut at Hz levels of 1500 or more.) I've read many posts by guys like Jet Jock and others who have much more knowlege on the stock TCCS than I do, but there are more parameters than just the Hz rate that causes fuel cut.
So, here is what I've come to think.
The larger you go fuel injector size wise, the more Hz rate you pull from the signal being "fed" to the TCCS by the piggyback computer.
This can cause problems at high boost, as the lower Hz rate is interpeted as less airflow, and the TCCS assumes the engine is stock.. so it keeps the same spark advance as a stock engine running 440's at a given RPM rate and TPS signal. (Please correct me if I'm wrong, I'm not sure the TPS signal has a role to play here? Thanks in advance.)
So, in theory, if you put 880cc injectors, the engine would only need to see half the "stock" Hz rate to run at the same air fuel ratio. BUT the spark advance table/setting might be way off. Example would be an engine running 4000rpm with 440's would "see" the same air flow Hz rate as one running 2000rpm on 880cc injectors.
Now, I'm only guessing here, but I'd bet that the spark advance for 2000 rpm is much more agressive than the one for 4000rpm when the turbo can be building boost at that point. (So, if due to your larger injectors, you are building boost at 4k, but your TCCS is being fed the airflow Hz rate for 2000rpm, that would be bad for the motor, as too much advance can cause detonation..)
So along comes the Translator Pro.. With the abillity to not only monitor what the spark advance is, but to modify it.
(I have not yet got this to work however.. but I have it wired up this way...)So, back on topic.. how to raise fuel cut, and not buy a standalone ECU..
My theory is that the larger 780cc injectors will allow much more headroom before the 1500hz rate is reached. And the ability to monitor, and then adjust the spark advance will allow me to keep the engine from detonation in the lower Hz rates while it's building boost.
The fuel cut problem seems to be worse with a fast responding turbo. (I had a bolt on T4 60-1 dual ball bearing CHRA that spooled up VERY fast, and it was so fast on the stroker engine, that lag really is not an issue.. tire traction is in short supply. BUT it would spool so fast, and then hit fuel cut, it was no fun to drive, as you really could not open it up, and enjoy the power most of the time.)
So, new larger turbo, new exhaust manifold and larger injectors with the Translator Pro (Maft Pro) was the plan a few years ago.. and it's still not running.. LOL (My life has become very busy, and I have little time for project cars at this point.)
Short answer might be that with your fast spooling turbo, and only 550cc injectors, you will have fuel cut at times when you do not want it.. IE: Anytime you boost more than 1500Hz signal to the ECU.. (You can limit the signal on the Maft Pro/Translator Pro to say 1499Hz, and that is the max signal it will send to the TCCS, but if my Eman Blue experience was any indicator, it will not solve the problem 100% of the time..) Have not tried, but does the Translator Pro let you plug in 1499 or does it cut at 5Hz or 10Hz values? (The Eman Blue was adjusted at 50Hz values.. thus the 1450Hz max signal sent to the TCCS.)
Good luck.
Good post! I'm pondering ways to raise my fuel cut safely as well. I need a new turbo and a standalone is not in the budget yet. A bigger turbo will have me in fuel cut all the time with 550's.
Hks FCD worked like a charm now boosting happy no issues good a/f and running mean hoping to dyno in the next couple weeks.
