need help with dsmlink global and deadtime

[95dsmgsx95]

Hi everybody, ive been searching everywhere and i cant seem to figure out how to set the global and deadtime for my injectors im logging LTFT Lo and LTFT Hi and there both saying 12.5% and they wont changed no matter if i change the global or deadtime setting. Im following dsmlink guide to the best of my understanding but cant seem to figure it out,so if someone can point me into the right direction that would be cool, thanks in advance.

 

[blackhawkgsx]

baseinjectordata [ECMTuning - wiki]

Fuel Injector Clinic (FIC) 650 Global -31% Deadtime 210µsec This is just a base estimate you will need to make some adjustments based on your set up. Hope this helps

 

[gyd23]

Hi everybody, ive been searching everywhere and i cant seem to figure out how to set the global and deadtime for my injectors im logging LTFT Lo and LTFT Hi and there both saying 12.5% and they wont changed no matter if i change the global or deadtime setting. Im following dsmlink guide to the best of my understanding but cant seem to figure it out,so if someone can point me into the right direction that would be cool, thanks in advance.

+1 for figuring out/understanding the deadtime and global.. even though i do know that the global is dependant on your fuel pressure and what sized injectors..
im pretty sure if you go to calculate put in your injector size and what fuel pressure your running it'll show you. can someone confirm this for me? I am just as lost as you though on deadtime.

 

[Dert]

http://www.dsmtuners.com/forums/showthread.php?t=262460


Sent from my iPhone using Tapatalk

 

[blackhawkgsx]

you can use link to calculate the global based on injector size by going to "ecu config log" Fuel tab "calculate"

 

[95dsmgsx95]

i know the base global and deadtime of where to start at but im supposed to fine tune global and deadtime for my injectors by having LTFT Lo and LTFT Hi around 0% and im at 12.5% and they are supposed to changed if i adjust the global or deadtime settings but there not they just stay at 12.5%. Has anyone else had this problem?

 

[blackhawkgsx]

I had that problem until I reset my fuel trims and I also followed this >>http://www.dsmtuners.com/forums/articles-tuning-ecu/262460-basic-dsmlink-tuning-guide.html

I'm still going through hell trying to get my 1650s perfect , hope this helps!

 

[95dsmgsx95]

All my fuel, timing and airflow are all at zero i havent adjusted anything yet can that be my problem?

 

[blackhawkgsx]

It would help for you to post a log.

 

[asap1320]

what injectors and size do you have

 

[95dsmgsx95]

fuel injector clinic 650cc

 

[Jaydog]

Go with the 31.6 global and 220 deadtime to start with. Also make sure your Fuel pressure is set to 43.5 with the vacuum line blocked off.

 

[Colt4G63 also]

What is your STFT doing, and what's your front O2 reading? It would help to log that, and make sure your engine is at full operating temp, or the ECU won't change LTFT no matter how rich or lean it is.

 

[95dsmgsx95]

What is your STFT doing, and what's your front O2 reading? It would help to log that, and make sure your engine is at full operating temp, or the ECU won't change LTFT no matter how rich or lean it is.

ok ill log it tomorrow and post it up.But im supposed to log LTFT Lo and LTFT Hi to determine where to adjust the global and dead time right?

 

[Calan]

i know the base global and deadtime of where to start at but im supposed to fine tune global and deadtime for my injectors by having LTFT Lo and LTFT Hi around 0% and im at 12.5% and they are supposed to changed if i adjust the global or deadtime settings but there not they just stay at 12.5%. Has anyone else had this problem?

No, you set your global and deadtime based on your injectors, base fuel pressure, and type of fuel you are running. Once that's done, don't touch those properties again unless you have a really good reason to.

You dial in your fuel trims (and every other thing related to airflow) by adjusting the MAFComp sliders if running a MAF, or with the VE table if running speed density.

The goal here is to get accurate data into the ECU for both fuel and airflow, which is really a process of calibration. Only after that is done can you start to truly "tune" the motor by changing the desired AFR or timing advance.

 

[Colt4G63 also]

No, you set your global and deadtime based on your injectors, base fuel pressure, and type of fuel you are running. Once that's done, don't touch those properties again unless you have a really good reason to.

You dial in your fuel trims (and every other thing related to airflow) by adjusting the MAFComp sliders if running a MAF, or with the VE table if running speed density.

The goal here is to get accurate data into the ECU for both fuel and airflow, which is really a process of calibration. Only after that is done can you start to truly "tune" the motor by changing the desired AFR or timing advance.

Don't you normally fine tune the criuse and idle trims by setting global and dead time, then move on to MAF compensation and fuel sliders for WOT tuning?

I was under the impression the base injector settings they provide were just a starting point.

 

[Calan]

Ideally, you have actual flow data from your injector manufacturer that you can plug in, along with a known base pressure and fuel properties. The reason the global and deadtime values are "starting points" is because people rarely have this information.

The only reason that calibration (notice I didn't say tuning) is such a PITA is because of all the unknown values. Some people do actually "tune" with the fuel properties, but I choose not too simply because that is the only thing about my motor that I DO know...mostly.

If you don't have fuel data, and since by definition the airflow isn't known, you're really shooting in the dark. The more known values you can start with, the further ahead you are. People seem to get themselves into trouble when they try to calibrate airflow by going back and forth adjusting everything, rather than starting with some fairly solid assumptions (fuel properties) and working off of that.

The one exception to that is that you can definitely tweak the deadtime a bit once you get airflow close, to help get low-RPM conditions in line. Injector deadtime (basically latency) has more of an effect at low RPM's.

Does that help or did I complicate it even more?

 

[Colt4G63 also]

No I just did my tune differently. Since I have a stock unhacked DSM MAF, and my injectors are aftermarket, and my fuel pressure gauge is of questionable quality, I figured the airflow was the one constant I could rely on.

 

[95dsmgsx95]

Don't you normally fine tune the criuse and idle trims by setting global and dead time, then move on to MAF compensation and fuel sliders for WOT tuning?

I was under the impression the base injector settings they provide were just a starting point.

That's what I thought. Dsmlink user manual says to get the global and deadtime adjusted first by LTFT idle and LTFT cruise (which im guessing is LTFT Lo and LTFT Mid) and then it says to adjust WOT after.

 

[Calan]

No I just did my tune differently. Since I have a stock unhacked DSM MAF, and my injectors are aftermarket, and my fuel pressure gauge is of questionable quality, I figured the airflow was the one thing I could rely on.

It is, unless you've done anything to affect the airflow path (intake filter, intake pipe, IC, turbo, TB, PCV system, etc.).

Unless the car is completely stock, it's usually safe to assume that the ECU isn't accurately reading the amount of air entering the engine under most operating conditions.

Here's a few good articles. (There are many more in this same area of the ECMLink wiki):

http://www.ecmtuning.com/wiki/quickieafsetup
http://www.ecmtuning.com/wiki/v3mafadjcombft
http://www.ecmtuning.com/wiki/maftcalibrationbywbo2
http://www.ecmtuning.com/wiki/maftcalibrationbyloggedboost

 

[95dsmgsx95]

Ideally, you have actual flow data from your injector manufacturer that you can plug in, along with a known base pressure and fuel properties. The reason the global and deadtime values are "starting points" is because people rarely have this information.

The only reason that calibration (notice I didn't say tuning) is such a PITA is because of all the unknown values. Some people do actually "tune" with the fuel properties, but I choose not too simply because that is the only thing about my motor that I DO know...mostly.

If you don't have fuel data, and since by definition the airflow isn't known, you're really shooting in the dark. The more known values you can start with, the further ahead you are. People seem to get themselves into trouble when they try to calibrate airflow by going back and forth adjusting everything, rather than starting with some fairly solid assumptions (fuel properties) and working off of that.

The one exception to that is that you can definitely tweak the deadtime a bit once you get airflow close, to help get low-RPM conditions in line. Injector deadtime (basically latency) has more of an effect at low RPM's.

Does that help or did I complicate it even more?

Isn't the LTFT Lo and mid supposed to change when I adjust the global or deadtime?

 

[Calan]

Isn't the LTFT Lo and mid supposed to change when I adjust the global or deadtime?

Of course it will.

The ECU needs to know exactly how much air is entering the engine at any given time in order to decide how much fuel to inject. If you change global, you are telling the ECU that your fuel system is either larger or smaller than it really is, so the end result is that the ECU injects the wrong amount of fuel, which throws the fuel trims off one way or the other.

Likewise, if the ECU thinks more or less airflow is entering the engine than there really is, the same thing happens. So you can get the trims in line by adjusting either the fuel or the airflow compensation. I prefer to adjust the airflow, since I'm pretty sure about what my fuel system can do thanks to published injector flow rates, known fuel properties, and knowing my base fuel pressure.

 

[Colt4G63 also]

It is, unless you've done anything to affect the airflow path (intake filter, intake pipe, IC, turbo, TB, PCV system, etc.).

Unless the car is completely stock, it's usually safe to assume that the ECU isn't accurately reading the amount of air entering the engine under most operating conditions.

Here's a few good articles. (There are many more in this same area of the ECMLink wiki):

quickieafsetup [ECMTuning - wiki]
v3mafadjcombft [ECMTuning - wiki]
maftcalibrationbywbo2 [ECMTuning - wiki]
maftcalibrationbyloggedboost [ECMTuning - wiki]

I've read some of those. Generally they say you can tune idle and cruise either way, but that if grams per rev are in the expected range then it would be perfectly acceptable, or even preferred to adjust deadtime and global to get trims in check.

 

[95dsmgsx95]

Of course it will.

The ECU needs to know exactly how much air is entering the engine at any given time in order to decide how much fuel to inject. If you change global, you are telling the ECU that your fuel system is either larger or smaller than it really is, so the end result is that the ECU injects the wrong amount of fuel, which throws the fuel trims off one way or the other.

Likewise, if the ECU thinks more or less airflow is entering the engine than there really is, the same thing happens. So you can get there by adjusting either the fuel or the airflow compensation. I prefer to adjust the airflow, since I'm pretty sure about what my fuel system can do.

OK that's my problem, mine doesn't change they both stay at 12.5% no matter what I change.

 

[Colt4G63 also]

You are running too lean, or your car is still too cold to compensate.

I would reduce the global a few percent. (lower number, or Minus less%)

Got any idea what STFT is reading?