Blitz Access ecu

[JasonGlanza]

the Blitz access is mapped for nearly stock setups or nearly ones which may include stock injectors aswell so with the 295cc injectors one will work fine!

 

[MARK@CMBAUTOS]

my stock ones run 98% so im currently waiting for the snow to disapear then ill get to try my sard 330cc without anythin trimming the fuel ill keep u posted

 

[JasonGlanza]

gd gd Mark, what turbo and boost ur running?

 

[MARK@CMBAUTOS]

gd gd Mark, what turbo and boost ur running?

what i call a (ct green) same spec as the evo green .turbo dynamics finest ct9 hybrid's full boost @2500 rpm 1.3 bar :rockon: on std internals :drive:

 

[Texx]

You need to remember the stock ECU (or a modified stock ECU) is not mapped as such, it learns and populates its own lookup tables over time, based on the initial programmed parameters and from the adjustments it has to make from these initial parameters to maintain the programmed targets. However the adjustments the software is able to make has it's constraints so is not limitless.

The TCCS software can adjust basic injector duty from it's initial program parameters + or - 20%, but the final result will depend on what Blitz have set the initial program parameters to and what long fuel trim the ECU has learned from it's previous live short fuel trim adjustment.

It will most likely take 100-200 miles of driving with the ECU in closed loop with the O2 sensor for the software to update the long fuel trim parameters after any adjustments have been made i.e. injector size or fuel pressure.

 

[Ted]

but with 330 injectors would it be able to trim down far enough so its not really rich on idle and gentle driving? throwing fuel down the drain there.

im a fan of some of these ecus but as std injectors will do up to over 200bhp i think anyone looking big power would be better off with an emanage.

 

[JasonGlanza]

gd info Texx, yes obviously those ecus are limited to such extent too and for bigger boost, turbos, injectors etc it will not be capable to continue to supply them with the needed fuel etc.

Regards upgrading the software of this ecu to the setup one will need to have (i.e. the 'self learning' process), what do you mean by in closed loop with the O2 sensors? how this is achieved?
its very interesting to know more and more how these work!

 

[JasonGlanza]

but with 330 injectors would it be able to trim down far enough so its not really rich on idle and gentle driving? throwing fuel down the drain there.

im a fan of some of these ecus but as std injectors will do up to over 200bhp i think anyone looking big power would be better off with an emanage.

yes im with you, for bigger power over lets say well 230bhp better managment will be needed and so as i said before those ecus will be to their limit to cope for more power!

 

[Texx]

Toyota will probably give you a better understanding than I could, so here's a copy and paste from part of the fuel system training manual. It's a basic overview, but gives a general idea of how the system works.

What you need to take into account is that the TCCS software is designed to provide efficiency in fuel economy and emissions, it's not designed to provide maximum performance which is where the modified ECU's come into play but obviously not documented below.

Closed Loop Systems

A system that controls its output by monitoring its output is said to be a closed loop system. An example of a closed loop system is the vehicle's charging system. The voltage regulator adjusts the voltage output of the alternator by monitoring alternator voltage output. If voltage is too low, the voltage regulator will increase alternator output. Without the voltage regulator, alternator output could not be adjusted to match the electrical loads. Many systems are closed loop systems. Some other examples are: cruise control, ignition system knock control, idle speed control, and closed loop air/fuel ratio correction control. When the ECM corrects the air/fuel ratio based on the oxygen or air/fuel ratio sensor, the system is said to be inclosed loop.


Open Loop Systems

An open loop system does not monitor its output and make adjustments based on its output. The temperature control in a vehicle not equipped with automatic air conditioning serves as an example.


Closed Loop Fuel Control

The ECM needs to monitor the exhaust stream and adjust the air/fuel ratio so that the catalytic converter will operate at peak efficiency, reducing regulated emission gases. Measuring the amount of oxygen remaining after combustion is a means to indicate the air/fuel ratio. A richer mixture will consume more oxygen during combustion than a leaner mixture. The oxygen sensor or air/fuel ratio sensor measures the amount of oxygen remaining after combustion in the exhaust stream. From this information, the ECM will control the injection duration to achieve the desired, ideal air/fuel ratio of 14.7: 1. This is necessary so the catalytic converter will operate at peak efficiency.

Note: The engine operation often requires different air/fuel ratios for starting, maximum power, and maximum fuel economy. The 14.7:1 ratio is for catalytic converter efficiency.


Stoichiometry and Catalyst Efficiency

For the catalytic converter to operate at peak efficiency, the air/fuel ratio must be at the ideal stoichiometric ratio of 14.7 parts air to one part fuel as measured by weight. This why the ECM tries to maintain a 14.7 to I ratio whenever possible.


Open Loop Mode

The ECM will be in open loop mode when:

• starting the engine.
• the engine is cold.
• hard acceleration.
• during fuel cut-off.
• wide open throttle.

If the engine will not go into closed loop mode, the problem may be insufficient engine temperature, no response from the oxygen sensor or air/fuel sensor, or the heater circuit is inoperative.

If there is a driveability problem only in closed loop, anything that disrupts air/fuel ratio, the oxygen or A/F sensor circuit may be the cause.


Closed Loop Operation/Oxygen Sensor

When in closed loop, the ECM uses the oxygen sensor voltage signal to make minor corrections to the injection duration. This is done to help the catalytic converter operate at peak efficiency.

When the voltage is higher than 450 mV, the air/fuel ratio is judged to be richer than the ideal air/fuel ratio and the amount of fuel injected is reduced at a constant rate. The reduction in the duration continues until the oxygen sensor signal switches to a low voltage (lean air/fuel ratio).

When the voltage signal is lower than 450 mV, the air/fuel ratio is judged to leaner than the ideal air/fuel ratio so the amount of fuel injected is increased at a constant rate. The increase in duration continues until the oxygen sensor switches to high voltage (rich air/fuel ratio). At this point, the ECM will slowly decrease the amount of fuel, therefore the air/fuel ratio oscillates slightly richer or leaner from the ideal air/fuel ratio. The result is an average of approximately 14.7: 1. This produces the proper mixture of exhaust gases so that the catalytic converter operates at its most efficient level.

The frequency of this rich/lean cycle depends on exhaust flow volume (engine RPM and load), the oxygen sensor response time, and the fuel control programming. At idle, exhaust flow volume is low, and the switching frequency of the oxygen sensor is low. As engine speed increases, the switching frequency of the oxygen sensor increases, generally eight or more times at 2,500 RPM in ten seconds.


Closed Loop Operation Air/Fuel Sensor

With an A/F sensor, air/fuel mixture correction is faster and more precise. An oxygen sensor signal voltage abruptly changes at the ideal A/F ratio and changes very little as the air/fuel ratio extends beyond the ideal ratio. This makes fuel control less precise, for the ECM must gradually and in steps change the injection duration until the oxygen sensor signal abruptly switches.

By contrast, the A/F sensor outputs a voltage signal that is relatively proportional to the A/F ratio. The ECM now knows how much the A/F ratio has deviated from the ideal, and thus, the fuel control program can immediately adjust the fuel injection duration. This rapid correction reduces emission levels because the ECM can more accurately maintain the ideal air/fuel ratio for the best catalytic converter efficiency.

Therefore, when observing A/F sensor voltage output, the output is relatively constant because there is no cycling between rich and lean.


Fuel Trim

As the engine and sensors change over time, the ECM needs a method to adjust the injection duration for improved driveability and emission performance. Fuel trim is a program in the ECM designed to compensate for these changes.

When in closed loop, the ECM modifies the final injection duration based on the oxygen sensor. These minor corrections are needed to maintain the correct air/fuel ratio. However, if more correction than normal (as determined by the ECM) is needed, the ECM will use the fuel trim strategy to compensate. Fuel trim allows the ECM to learn and adjust the injection duration quickly by reducing the correction time back to normal. This means that driveability and performance will not suffer.

Fuel trim can be observed on the Diagnostic Tester as a percentage. A positive percentage means that the ECM has increased the duration and a negative percentage means the ECM has decreased the duration.

There are two different fuel trim values that affect final injection duration and can be observed by the technician; short term fuel trim (SHORT FT) and long term fuel trim (LONG FT). SHORT FT is a temporary addition or subtraction to the basic injection duration. LONG FT is part of the basic injection duration calculation and it is stored in the ECM's memory.


SHORT FT

SHORT FT is based on the oxygen sensor, and therefore, it only functions in closed loop. SHORT FT responds rapidly to changes in the oxygen sensor. If SHORT FT is varying close to 0%, little or no correction is needed. When SHORT FT percentage is positive, the ECM has added fuel by increasing the duration. A negative percentage means the ECM has subtracted fuel by decreasing the duration. The SHORT FT value is temporary and not stored when the ignition key is turned off.

SHORT FT is used to modify the long term fuel trim. When the SHORT FT remains higher or lower longer than expected, the ECM will add or subtract this value to the LONG FT.


LONG FT

LONG FT is stored in memory because it is part of the basic injection duration calculation. The ECM uses the SHORT FT to modify the LONG FT. The LONG FT does not react rapidly to sudden changes, it only changes when the ECM decides to use the SHORT FT value to modify the LONG FT. LONG FT is stored in the ECM's memory and it is not erased when the ignition key is turned off. Because LONG FT is part of the basic injection duration, it affects injection duration in closed and open loop. Like the SHORT FT, when LONG FT is at 0% there has been no modification to the basic injection duration. A positive percentage means the ECM is adding fuel; a negative percentage, subtracting fuel.

________________________________________________________________

Fuel Trim

To better understand how oxygen feedback and learned corrections are determined, a brief review of injection theory is in order.


Review of Injection Duration Theory

Final fuel injection duration is a function of three steps:

· Basic injection duration
· Duration corrections for operating conditions
· Battery voltage correction

Basic injection duration is based on engine load, speed, and a correction factor called fuel trim. Duration corrections for operating conditions are based on the sensors listed below. These are adjustments to the basic injection duration based on changing operating conditions.

· Engine Coolant Temperature (ECT)
· Throttle Position (TP)
· Intake Air Temperature (IAT)
· Exhaust Oxygen (02S)

Battery voltage correction is an adjustment to the final injection duration to account for variations in injector opening time caused by changing operating voltage.


Calculation of Basic Injection Duration

The first step in determining how much fuel to deliver to the engine is calculation of basic injection duration. Basic injection duration is a function of:

· Engine load (VAF, MAF, or MAP)
· Engine speed (Ne)
· Long fuel trim (LFT) correction factor

This basic injection duration value is the ECM's best guess at the actual injection time necessary to achieve an ideal air/fuel ratio. Generally, this basic injection calculation is very accurate, typically within ± 20% of what actual injection needs to be. Once within this range, the ECM can trim the air/fuel ratio to stoichiometry based on oxygen sensor information.


Oxygen Feedback Correction

Depending on many different factors, the amount of correction required for 02S feedback will vary. If the amount of necessary correction remains relatively small, for example less than 10%, the ECM can easily adjust the mixture. As 02S feedback correction approaches the ± 20% limit, the ECM fuel correction range becomes limited. When the amount of necessary correction becomes excessive, the ECM has a "learned memory" to adjust or "trim" the basic injection calculation. By increasing or decreasing basic injection duration, 02S corrections can be held within an acceptable range, maintaining the ECM ability to correct over a wide air/fuel ratio range.


Fuel Trim Impact on Injection Duration

Fuel trim is a term used to describe the percentage of correction to injection duration based on oxygen feedback. There are two different fuel trim values which affect final injection duration; long fuel trim (Long FT) and short fuel trim (Short FT).

Long FT is part of the basic injection duration calculation. It is determined by how closely the fuel system achieves the design air/fuel ratio.

Long FT is a learned value which gradually changes in response to factors beyond the control of system design. For example, fuel oxygen content, engine wear, air leaks, variations in fuel pressure, and so forth.

Short FT is an addition to (or subtraction from) basic injection duration. Oxygen sensor information tells the ECM how close it comes to design air/ fuel ratio and the Short FT corrects for any deviation from this value.


How Short FT Works

Short FT is a temporary correction to fuel delivery which changes with every cycle of the oxygen sensor. Under normal conditions, it fluctuates rapidly around its ideal value of 0% correction and is only functional during closed loop operation.

Short FT is a parameter on the OBD data stream, that can be displayed on the Diagnostic Tester. Its normal range is ± 20%, but under normal operating conditions, rarely goes beyond ± 10%.

Short FT responds to changes in 02S output. If basic injection duration results in a lean air/fuel ratio, Short FT responds with positive corrections (+1% to +20%) to add fuel or enrich the mixture. If basic injection is too rich, Short FT responds with negative corrections (-I% to -20%) to subtract fuel or enlean the mixture.

When Short FT is varying close to ± 0%, this indicates a neutral condition where the basic injection duration calculation is very close to stoichiometry, without any significant correction for 02S.


How Long FT Works

Long FT is a data parameter on the OBD data stream. It is a more permanent correction to fuel delivery because it is part of the basic injection duration calculation. Long FT changes slowly, in response to Short FT. Its normal range is ± 20%, positive values indicating rich correction and negative values indicating lean correction.

If Short FT deviates significantly from ± 10% for too long, the Long FT shifts, changing the basic injection duration. This shift in basic injection duration should bring Short FT back to the ± 10% range.

Unlike Short FT which effects injection duration calculation in closed loop only, the Long FT correction factor effects the basic injection duration calculation in open and closed loop. Because Long FT is stored in a nonvolatile RAM (NVRAM) and is not erased when the ignition is switched off, the fuel system is able to correct for variances in engine and fuel conditions even during warm-up and wide open throttle conditions.

On OBD data streams, Long FT is displayed as Target A/F. On non data stream equipped engines, Long FT is referred to as Learned Voltage Feedback (LVF) and can be accessed from the check connector VF1 terminal.


Learned Voltage Feedback and Target Air Fuel Ratio

Although Long FT, Target A/F, and LVF (Learned Voltage Feedback) are essentially the same, there is a difference in how this data parameter is displayed on OBD engines. LVF and Target A/F are displayed as a voltage signal with a range of 0 to 5 volts. The signal, which varies in fixed 1.25 volt increments, has a nominal value of 2.50 volts.

When LVF is at 2.50 volts, it indicates that basic injection duration calculation is within ± 10% of required injection duration (to achieve 14.7 to 1 AFR). If basic injection duration deviates more than ± 10% of required injection, LVF will shift to correct the excessively lean or rich condition.

Lower voltage indicates decreased injection duration to correct for a rich condition. Higher voltage indicates increased injection duration to correct for a lean condition.

 

[JasonGlanza]

fast reply with info mate,thnks alot so quickly repped
basics taken!

 

[JasonGlanza]

another curiosity does these ecus manage to work with a forged engine with CT9 Hybrid turbo still fitted at 1 to 1.1bar max? (normal work done of forging will be done like 0.5mm oversize pistons (Wiseco 10cc dished) and Scat rods and the related stuff like bearings etc etc, no major headwork only skimming and fresh rebuilt, standard cams and crank).

as i might going that way with the engine later on and wish to keep the current setup going ahead, just in case i will need a rebuild!

 

[Texx]

but with 330 injectors would it be able to trim down far enough so its not really rich on idle and gentle driving? throwing fuel down the drain there.

-20% duration trim from a 330cc injector would theoretically provide the same volume of fuel as a 264cc injector at the original duration. When in closed loop an additional -10% trim is available, so theoretically during a warm idle condition the ECU is able to trim a 330cc injector to provide the same volume of fuel as a 237.6cc injector at the original duration. That would suggest the ECU could trim enough fuel to prevent an overly rich mixture during warm idle and light throttle conditions.

The concern then would be whether the AFR would become too lean during hard acceleration after the ECU has learned long fuel trim to -20%, as the ECU will not be making any ± short fuel trim adjustments using the feedback from the O2 sensor as it will have switched to open loop. So that has the potential to result in an open loop mode condition where 330cc injectors are fitted, but the engine is being delivered the volume of fuel equivalent to that of 264cc injectors.

However, saying that, I think it's extremely unlikely the ECU would ever see the need to learn long fuel trim at -20% just from a small increase in injector size and it's also possible the modified ECU's may ignore any negative fuel trim adjustments when in open loop mode to avoid a lean AFR.

 

[GP82]

The TCCS software can adjust basic injector duty from it's initial program parameters + or - 20%, but the final result will depend on what Blitz have set the initial program parameters to

I'm sure i've seen Blitz plug & play ecu mapped for a K1 or K24 - 26? The bigger turbos flow air that a 20% increase in injector size would not be enough to fuel it even @ 80% + injector duty. I think the parameters would be changed by the tuners to like + or - 40% and so can accept bigger injectors and trim accordingly?

 

[Sheldon]

another curiosity does these ecus manage to work with a forged engine with CT9 Hybrid turbo still fitted at 1 to 1.1bar max? (normal work done of forging will be done like 0.5mm oversize pistons (Wiseco 10cc dished) and Scat rods and the related stuff like bearings etc etc, no major headwork only skimming and fresh rebuilt, standard cams and crank).

as i might going that way with the engine later on and wish to keep the current setup going ahead, just in case i will need a rebuild!

why would you want to drop the cc for using a hybrid at 1.1bar? try to keep stock compresion.

 

[Texx]

my stock ones run 98% so im currently waiting for the snow to disapear then ill get to try my sard 330cc without anythin trimming the fuel ill keep u posted

what i call a (ct green) same spec as the evo green .turbo dynamics finest ct9 hybrid's full boost @2500 rpm 1.3 bar :rockon: on std internals :drive:

Mark, at what RPM and boost pressure do your injectors reach 98% duty?
Any idea of the AFR reading when they are running at 98%?

 

[MARK@CMBAUTOS]

Mark, at what RPM and boost pressure do your injectors reach 98% duty?
Any idea of the AFR reading when they are running at 98%?

not sure wat boost or rpm id need to look at my dyno sheet ill do that monday as its at the garage the afr is def 11's 12s

 

[JasonGlanza]

why would you want to drop the cc for using a hybrid at 1.1bar? try to keep stock compresion.

ur right Sheldon. Forge pistons can be bought flat, dished etc but a fe wkls ago on here there was a thread about that and a poit was done regards this that slightly dished are better than flat ones as using the latter may be more risky for a hg failure! compression will be quite nearly to stock as i will use stock hg with both head and block skimmed when i do it!

 

[JasonGlanza]

not sure wat boost or rpm id need to look at my dyno sheet ill do that monday as its at the garage the afr is def 11's 12s

hmm 11s-12s low or high?

 

[Texx]

not sure wat boost or rpm id need to look at my dyno sheet ill do that monday as its at the garage the afr is def 11's 12s

It'll certainly be interesting to see if your Blitz ECU will maintain the same or a similar full boost AFR with the 330cc injectors at a lower duty cycle.

 

[MARK@CMBAUTOS]

It'll certainly be interesting to see if your Blitz ECU will maintain the same or a similar full boost AFR with the 330cc injectors at a lower duty cycle.

thats what i say its worth a bash ill keep u posted