Injector Pulse Width At Idle

Daytona, FL 32119 TCFI Idle Tuning Tech Note (386) 304-0700 www. When in split pulse injector mode operation, the pulse width is about 50% more than a normal idle. Neither EV1 or EV6 is technically correct because those generations of Bosch injectors could come with either connector. When the ECM needs to know how much fuel to deliver it reads the MAP and RPM, then it refers to the corresponding row and column in its fuel table to obtain the correct injector pulse width, also known as the "base pulse width". The fuel injector control module energizes each fuel injector by grounding the command circuit between the fuel injector control module and the fuel injector. I now have a sct x4 that I love. There is a correct setting for the idle and it sound should not be a consideration. Did you ever wonder how a can of injector cleaner could clean the entire injectors in nine minutes?. 1msec total pulse width to dispense the right amount of fuel at idle, of which 0. Notice that the fuel-pressure regulator is located on the fuel return side of the system. GMan Bully is a Plug-n-Play Fuel Injection Controller with a very simple installation procedure. The time during which the injector is powered (or activated) is called the injector pulse width (IPW). 01 ms of each other, except again number 7 has a pulse width of. Changing injectors usually requires touching up the fuel table, idle area for sure. For low-impedance injectors (less than 3 Ohms), you need to limit the current to avoid overheating the injectors. This is called an injector pulse width. In 1989 the cold start injector was deleted. 8 ms of injector pulse width!. This cycling occurs because the engine computer senses the O2 voltage and then changes the pulse width of the signal driving the fuel injector on and off. Buy Automotive Fuel Injector Tester, 12V 4 Pulse Modes, Handheld Car Vehicle Fuel Pressure System Diagnostic Scan Testing Tool Gauge, Individual Test Stuck/Leaking/Burnt-out Problem: Fuel Pressure Testers - Amazon. The 'injector pulse width' shown on the scan tool is actually the injector response time. 8 Litre Pontiac Multiport Fuel Injection System (1985 - 1988) Injector base pulse width MSB: 25: 2 35 Idle Air Control 3 34 Mass air flow sensor low. I used to use one to watch ficm voltage, icp pressure, oil temp, and coolant temp. In Open Loop operation, this would mean the AFR will be lower than intended. Notice that it doesn't stall. All the balance rates are +/- 2. Harley-Davidson Electronic Fuel-Injection Tuning Aids D. Injector pulse width is an indication of fuel consumption per revolution. The injector_breakpoint doesn't determain which slope is used, it is a fuel adder that runs off of the dominate slope at idle. VE value is simply a number used to compute a pulse width. This bulletin is found in the Acadia, Enclave, Traverse (VIN R/V) Service Manual. SI engine control in the cold-fast-idle period for low HC emissions and fast catalyst light off Author, co-author (Do NOT enter this information. 1) It appears three of them have been sticking closed. Flowing in excess of 2000cc/min at 3 bar, the ID2000 will also provide a smooth stoichiometric idle on E85, and it will do all this while maintaining strict linearity up to 95% duty cycle at 9000rpm. 8 volt of ICP before the fuel injectors will be pulsed. Injector Pulse-Width It's important to use the proper size fuel injectors. If correct PW displays on cranking you can remove the valve cover and watch the oil spill discharge, every injector should discharge oil when pulsed by the IDM during cranking. The IAC or Idle Air Control Valve has a simple job, to let a measured amount of air pass the intake throttle to thereby adjust the idle speed. If you ship your injectors to. Pulse width is the width of the pulse driving the injectors as measured in time. However, if the air/fuel ratio is 16. Applications. In many cases, injectors purchased from Ford Racing will include all of this information. If you want it to idle, this table is important. At wide open throttle, computer lengthens injector pulse to richen mixture. Load sensor adjustment is frequently used to compensate for larger injectors. 7 parts of air for every one part fuel. idle speed when inspected with CONSULT-III. A digital high signal initiates the fuel injector to send fuel into the combustion chamber. Compared to our 4-stroke EFI kits, this kit can drive 2 injectors per cylinder (one big injector, one small injector). Injector Pulse Width Cylinder 4 ms Cyl #5 PW Injector Pulse Width Cylinder 5 ms Cyl #6 PW Injector Pulse Width Cylinder 6 ms Cyl #7 PW Injector Pulse Width Cylinder 7 ms Cyl #8 PW Injector Pulse Width Cylinder 8 ms Desired Idle RPM Desired Idle RPM rpm MAF Freq Mass Air Flow Sensor Frequency. William Denish posted Feb 24th, 2009 at 1:25am H-D's Electronic Control Module (ECM) is located either under the seat or behind the chassis side panel. 33 seconds and the highest time was 59. Negative values indicate fuel is being removed. If you could figure out a way to remove the injectors from the engine but keep them hooked up to the fuel rail and electrical connectors, aim them at a container to catch the gas, and get them to go into inject mode while the fuel pump was running, then you'd know for certain. The most important function of the MAP sensor is to determine barometric pressure. Idle speed control vale (ISC) 184: Above spec manifold air flow sensor : 185: Below spec manifold air flow sensor : 186: Too long injection time pulse width : 187: Too short injection time pulse width : 188: Lambda sensor on left, mixture too lean (part throttle) 189: Lambda sensor on left, mixture too rich (part throttle) 191: Idle mixture too. of injector pulse width to correct the air/fuel. When propane is directed into the air intake, the O2S sensor voltage immediately increases, and the injector pulse width decreases. OPERATION - MODES OF OPERATION As input signals to the PCM change, the PCM adjusts its response to output devices. However, if the air/fuel ratio is 16. The calibrator provides a wider pulse width on startup to provide a richer mixture for a cold engine. 7 ms is a good minimum injector pulse), called pulse width. Testing or Repairing Bad Fuel Injection Relay. ” · Throttle Body Injection (TBI) This system delivers fuel in much the same way as a carburetor, generally above the throttle plate at the top of the intake manifold (usually right under the air. This is the control of Injection Pulse Time Open (ti) (also called Injection Pulse Width) over the entire range of engine operation. This is a percentage correction of the injector pulse width base. Another great benefit of the FIC 1100cc high impedance fuel injector is that it provides a great idle due to its low pulse width stability. I am trying to tell him if it was idling good before the injector swap then he needs to backtrack and see what he did wrong. 7 AFR) at wide open throttle (WOT), 6,000 RPM and standard atmospheric conditions. If the air flow meter is properly sized, the reduction in pulse width will cause the new, larger injectors to deliver the same amount of fuel as the stock injectors did at the original pulse width. One of the most common symptoms of a clogged fuel injector is a rough engine idle. (Throttle body blade is closed). If the idle speed rises to somewhere around 1000-2000 RPM's after the blipping, plugging the throttle switch back in should bring it down again (throttle closed). In this particular case, Steps 2 and 3 could be interchanged, but both are needed for a complete diagnosis. Fuel rail pressures stay about the same - injector duration is varied for operating conditions. injector pulse width. 000127 seconds). air-fuel ratio, ignition timing and idle speed, prior to the concept of ECU, these were set and controlled by information about injector pulse width and spark timing. Daytona Twin Tec LLC, 933 Beville Road, Suite 101-H, S. If deceleration is gradual, the PCM will adjust injector pulse width (flow), spark timing and the IAC to stabilize the slowdown to idle. Applications. I know we all miss things. 450 volts (1/2 division below the center shown here) when the air-fuel mixture is at the ideal ratio of 14. Here's the interesting part. 187 Injector pulse width shorter than expected or Mass Air Flow (MAF) higher than expected 188 (M) Fuel system was rich at part throttle - Left or Front HO2S 189 (M) Fuel system was lean at part throttle - Left or Front HO2S 191 (M) Fuel system was rich at idle - Left or Front HO2S 192 (M) Fuel system was lean at idle - Left or Front HO2S. The stock setting for #24 Lbs/hr injectors is 0. Symptom: After a Prostream intake service has been completed, the engine “May”. This is not a 'peak. it also would not. While this appears to be a somewhat better overall performance than our first example, it is NOT what happens. The Experimental Setup. 1650cc (180 lbs/hr at OE 58 PSI fuel pressure) FIC Fuel Injector Clinic Injector Set for LS3, LS7, L76, L92, and L99 engines (High-Z). This lets you start with a smaller pulse width and ramp in more pulse width, or start at full pulse width and reduce it. some things that change at idle. Use the labscope to look at the engine’s secondary ignition pattern. engine control unit will adapt to these long term changes by adjusting the base idle speed, base injector pulse width and ignition timing. The result is smoother idle and better efficiency. So these are a little different from what you first posted, but not terribly far off. These graphs depict the characteristics of various fuel injectors with effective pulse width in milliseconds (with 19 ms being equivalent to 100-percent injector duty cycle) and injector flow rate in cc/min. When I declutch, the injector pulse width comes back on. These two inputs, MAP and RPM, are the major determinants of the air/fuel mixture delivered by the fuel injection system. ” Since the pulse width indicates how long a fuel injector is open, it corresponds directly to how much fuel is actually delivered to each. The information the MAP sensor tells the ECU is applied to tables set to deliver the proper IPW (Injector Pulse Width) and Ignition Timing. Bosch injectors are commonly used in LT1s, and most of them have substantially longer offsets than the stock Rochester LT1 injectors. Canems Injection ECU www. This is the control of Injection Pulse Time Open (ti) (also called Injection Pulse Width) over the entire range of engine operation. one injector is turned on which allows for finer control over idle fuel delivery, while at higher RPM and. 0:25 One of the setting in Fuel Injector data. The fuel injector control module energizes each fuel injector by grounding the command circuit between the fuel injector control module and the fuel injector. I get around 2. Fuel Injectors What tests can I do Failure effects Different types What is it used for Duty cycle Pulse width Current Fuel pressure drop Actuator test (scanner) Non start Black smoke Misfire Poor performance Mechanical - Ve switch + Ve switch Injects the right amount of fuel Into the engine. The PCM also controls other actuators like the Idle Air Control (IAC) valve. With the x4 I watch eot, ect, ficm voltage, icp, ipr, trans temp, and injector pulse width. Jetronic is the older style connector, sometimes referred to by the Bosch generation EV1. The calibrator is a Programmable Read Only Memory (PROM) Chip which is installed in the ECM. This is why the Tuning Module is fuel efficient. Base pulse width is a function of engine speed (RPM) and load (which can be calculated from manifold absolute pressure). In addition, these units are high-impedance. An initial estimate of horsepower and injector size (flow rate) is used to calculate a base injector pulse width. Injector scaling/latency for various injectors: I figured on average the Evo fuel pressure is about 35psi base, hence the small scalings for large injectors (I. • Injector pulse width changed by allowing fuel trim (short term or long term) to add or sub-tract to the fuel injection pulse width. I tested the injectors down to 1. It includes the addition of the Small Pulse Adder. The frequency valve is a L-Jetronic pulse fuel injector. The minimum pulse width that the injector can stably run occurs in 1. it will keep the idle air control backed out. Below are some logs I took for the coolant temp vs Fuel Injector #1 IPW (ms) 33 11. IPW – Injector Pulse Width – The amount of time the computer commands the injector to stay open and allow fuel flow. 7 and the actual injection pump timing reads 8. injection spark ignition engine were studied under a typical cold-fast-idle condition (1200 rpm, 2 bar NIMEP). This can happen as the unit has a map of total injector duty so it can drive the injectors alone. 4 ms Technician A says that the cylinder head and piston design of a GDI engine is the same as in a port injected engine. (Pulse width - the length of time an injector is open and squirting fuel). "A/F Sens 1 Curr. Page 1 of 2: How to Test the Fuel Injectors (2. ECU monitors ECT signal to help determine injector pulse width, ignition timing, and idle control. Or im seeing that there is a Battery Voltage vs injector offset. To correctly size the injectors we need the following basic information about the engine and. The stock setting for #24 Lbs/hr injectors is 0. When the ECM needs to know how much fuel to deliver it reads the MAP and RPM, then it refers to the corresponding row and column in its fuel table to obtain the correct injector pulse width, also known as the “base pulse width”. The HEUI injection system needs a minimum pressure of 0. This technology is referred to as pulsewidth modulation. The DME makes adjustments from base fuel trim using a 3D map. Also group injection systems can be converted to sequential injection. 7L TBI intermittently stumbles/stalls at idle, and frequently falls flat on acceleration down the road. At Idle Injector Control Pressure should be above 500psi (on a fully warmed truck pressure will generally be between 480psi and 550psi. In the Re-act phase, the PCM commands the fuel. since injector pulse width would be the same as the 19's. just recently installed a frank swap in my rsx runs lil rough i was wondering if lengthing my injector wires would cause my injector pulse width to go all out of wack? k24a1/k20a2 k-tuned fuel rail k-tuned tps prb intake w/ short ram stock header w/ 2. How Electronic Fuel Injection Works. Now with GDI engines there is very little fuel injector pulse width change. Pressure-sensing loop (PL) - Creates the basic injection pulse using inputs from the TS1, MPS, IM, and SC. If this signal is not received, the normal pulse width may be too short to start a cold engine. This allows the voltage to be reduced when the fuel demand is low, such as at idle and light cruise. 2 Batteries 1. Includes key design features, engine specs, horsepower/torque ratings, & more. If you use very large injectors, your idle pulse widths get very short. Blip the throttle a couple of times. As the engine approaches desired idle speed, fuel delivery and idle speed control is maintained. To prevent the added drag from the torque converter and transmission from reducing the idling speed, the PCM will command the idle control valve to allow more air to enter the engine, while at the same time, adjusting the injector pulse width to inject more fuel to suit the increased amount of air. This technology is referred to as pulsewidth modulation. If the pulse width on the injectors drops by about 50% and the engine then smooths out, this is considered normal operation and no repairs should be attempted. idle speed” is. However, the easiest way to think of the PWM% is as a percentage of the supply voltage, so 50% PWM on a 14 volt supply becomes effectively 7 volts on average, 28% would be 4 volts, etc. “The magic of this 1100cc injector is in the latest fuel injector technology, which makes it a very linear injector,” said Jens von Holten, head guy at Fuel Injector Clinic. Pulse width is the width of the pulse driving the injectors as measured in time. ) Latency: the length of time after the injector is turned on before it achieves its linear flow rate. 5 volts at WOT. Example: 20 ms x. If fuel pressure is normal, monitor the injector patterns with a labscope. 42 crank degrees to make it 90 is calculated as the measured injection opening delay of about 1. The baseline data we collected earlier indicated a fuel injector pulse-width of a steady 2. Staged injection which is fully configurable including minimum pulsewidth lockout and activation engine speed. The signal controlling the injector is a 12-volt square wave. just recently installed a frank swap in my rsx runs lil rough i was wondering if lengthing my injector wires would cause my injector pulse width to go all out of wack? k24a1/k20a2 k-tuned fuel rail k-tuned tps prb intake w/ short ram stock header w/ 2. Yes it's real and with out it a newer car would not run right. Under light deceleration, the ECM reduces flow by shorten the injector on time (pulse width). Load is added to the engine to maintain small to medium throttle openings at lower RPMs. When the engine is cold, a longer injector pulse width is normal. 0 causes the AFR to start oscillating. The ECU uses this signal to switch to a wider pulse width for starting enrichment. 9 ms pulse and as the RPM increases I would have a 4 ms pulse, or even just a flat 4-5 ms pulse all the time is OK. That is correct. This is a stepper motor-operated valve that bypasses air around the throttle plate. Most hot rod engines are not like that. 2 at idle, except number 7 is at -3. To use these coils I needed to simulate a signal that the factory igniter box sends to the cars computer. of injector pulse width to correct the air/fuel. i have now changed b4003 and b4004 to. Ignition timing advance Fuel injection pulse-width Idle (learned value or minimum TPS) Off-idle (0. Before installation begins please disconnect the negative lead from the bikes battery. Hummmmm, that is the value listed for #60 Lbs/hr injectors, fuel_injector_minimum_pulse_width in SCT Basics of Tuning book. Cutlass Siera. You are correct that the min pulse width is a clip, basically it is saying that below this number cannot be compensated so don't go below it. Adding Larger Injectors. The specified injector duration must therefore take these factors into account. You hit the starter button, the motor begins to crank over. Which sensor has the greatest influence on injector pulse width besides the MAF sensor? TP Tech A says that the port fuel-injection injectors operate using 5 volts from the computer. Idle Air Control Motor Position; Idle Diagnostic Filtered RPM Error; Ignition 0 Input Voltage; Ignition 0 Voltage; Ignition 1 Voltage; Ignition Cycle Counter; Ignition Timing Advance; Ignition Voltage; Ingition 1 Voltage From PPSW; Injection Pump CAM Ref Missed; Injector Pulse Width #1; Injector Pulse Width #2; Injector Pulse Width #3; Injector. Pretty much what we expected. This process will cause the customer to see increased black smoke, soot, rough idle, or minimal misfires during cold start and should be considered normal. For example, at idle the petrol injectors might need a pulse width (opening time) of 2. Is this indicating an injector going bad?. This is called injector timing. The pulse width at idle will be about half of what it. The fuel injector drives will max out at 5 amps each, enough to drive one low-impedance (or 4 high-impedance) injector per bank. A positive number is the PCM adding extra pulse-width (add fuel/richen) and a negative number is removing pulse-width (remove fuel/lean out). I had to baby sit the gas pedal on cold start for a couple minutes till the engine warmed up to the point it would maintain its own idle, small compromise for race car. What actually controls fuel injectors on a car, the COMPUTER (ECM) or Sensors on the Throttle body like? the Mass Air Flow (MAF) Sensor or the Idle Air Control Sensor (IAC) or the Throttle Positon Sensor? Which 1 actually supplies the power wire to the Injector? Car is a 1991 Olds. pulse width, or pending 20 Data drifted high 188 Engine Speed At Idle, Point 1 (Engine. 000400543 for #60 Lbs/hr. Forces the idle air control to reset at part throttle (approximately 2000 rpm). EVAP System 14. • TP = Theoretical Pulse width (MAF Load) • MAF input and RPM are used to calculate final injector pulse width • Load (TP) is a result of adjusting Load Multiplier (K constant) • Load Multiplier is increased when MAF load has changed (upgradedMAF) or reduced when adjusting injection pulse width for different injectors. As the engine approaches desired idle speed, fuel delivery and idle speed control is maintained. Effective pulse width is the IPW value before any battery or ignition voltage offset values are added to compensate for delays in injector. Injector Lag Time Multiplier and Offset. Changing injectors usually requires touching up the fuel table, idle area for sure. It adds or subtracts a given pulse width from the map fuel number across the whole map, therefore having a much greater percentage effect at small pulse widths. ECT is a 2-wire thermistor. This duration or period is referred to as the injector pulse width. This can affect how well the injectors respond. 7 grams of air to 1 gram of fuel. In general, if an injector has a high resistance specification (12-16 ohms) the ECU uses a 12 volt saturated circuit driver to control it. Starting in '85 the 5/6/7 Series no longer have an ICM - the ICV is controlled by the Engine Management Computer - which is a digital "computer" circuit that needs only accurate sensors to calculate the correct ICV pulse width to maintain the idle speed. The use of the dual runner takes away another problem that a long pulse width injector can cause and that's front to rear fuel reversion on single throat TB's. If the engine is too hot, let it cool down for about an hour. Injector dead-time table and short pulse width adder table configurable for staged injectors; Auxiliary injection that can be used as a third. 000000 0 0. 6 indicates the duration of the injector pulse. I have also noticed that my injector pulse width at idle is 0 but as soon as I accelerate it'll jump up to ~2 ms and the farther I open the throttle, the higher the number climbs. This is called injector timing. orifice of the injector is maintained constant by the fuel pressure regulator. I set the warm idle speed where I wanted it, and that was that. 1:1 (lean) during the Sense phase, the PCM makes the decision to increase the injector pulse width to correct the lean air/fuel ratio condition. The engine control unit uses a formula and a large number of lookup tables to determine the pulse width for given operating. When pulse width times get very low, the injector doesn't fully open and the flow rate won't be accurate. The pulse width of each injector was tested and the lowest time on idle was 58. Example: 20 ms x. Less injector, same idle quality. Now the injector pulse width can be shortened by the e-manage Ultimate intercepting the Injector pulse signal. HP Tuners GM Gen III part 5 walks you through how the GM ecu converts its airmass calculations into an injector pulse-width and spark timing to the engine. Injectors that are too large for your application, won't idle well due to low pulse-width operation. Note the reading on the tester. 5mm3 at idle, and other models I believe can go as high as 3 for pilot. However, bank 1 reported zero for pulse width and zero for duty cycle. With drive by wire, we no longer need the IAC system. ) set theAFR at this idle to somethng like 14. Therefore, the amount of fuel actually delivered by injectors is regulated only by the duration in which they spray fuel, called the “pulse width. sends this pressure information to the ECM, and the ECM increases the amount of fuel injected, by increasing the injector pulse width. since injector pulse width would be the same as the 19's. This can affect how well the injectors respond. The injectors are mounted in the intake manifold so that they spray fuel directly at the intake valves. ” · Throttle Body Injection (TBI) This system delivers fuel in much the same way as a carburetor, generally above the throttle plate at the top of the intake manifold (usually right under the air. Positive values indicate fuel is being added as a result of the correction. Jump to Latest Follow 1 - 11 of 11 Posts. The injector pulse-width should increase and decrease with rapid increases and decreases in throttle position and increases and decreases in engine load. But why not just pick the biggest ones you can find? The answer has to do with idle and cruise pulse widths. 4 Power management 1. The stock setting for #24 Lbs/hr injectors is 0. The frequency makes the unit have a humming noise. For example, a 2150cc injector may need a 1. That's bad!! Can you look at it with an SDS. Jetronic is the older style connector, sometimes referred to by the Bosch generation EV1. The ECU controls the fuel flow by pulse width modulation. So the power steering, brakes, and alternator are all still working. Since the sensor cannot read how rich or lean the mixture is, the computer continually increases and decreases injector pulse width (the amount of time the injector(s) is on, and so, how much fuel it injects) in an effort to achieve and average of 0. We often think about ignition timing as being critical, but so is injector timing. The values in the tables control how the ECM interprets the fuel requirements of the engine through sensor inputs. Pressurized fuel enters the injector from the fuel rail where a small electronic solenoid opens and closes for a specified time to deliver fuel to the engine, where it is mixed with air being drawn into the intake port. I had to baby sit the gas pedal on cold start for a couple minutes till the engine warmed up to the point it would maintain its own idle, small compromise for race car. 2% of the total time available or a 59. Billet Atomizer Injectors are purpose built pieces that are blueprinted internally to minimize friction, along with the atomization technology (consistent pulse to pulse dosage, smaller droplet size) allows for excellent low pulse width control, which allows the engine to idle at low rpm very smoothly. This is a stepper motor-operated valve that bypasses air around the throttle plate. A 1G DSM MAF-Translator has switches so you can adjust the base settings for idle, mid, and high rpm. This is a percentage correction of the injector pulse width base. implements an idle air fuel ratio map. An initial estimate of horsepower and injector size (flow rate) is used to calculate a base injector pulse width. it never knows when you really have your foot off the throttle. Transmission Shift Times, Fluid Temperature, Torque Blue Tooth or WiFi Real Time Data Web View. If the engine is too hot, let it cool down for about an hour. The “minimum idle speed” must be less than the “target idle speed”, otherwise, during normal operation, the IAC pintle could bottom out on the air passage seat of the TBI, and damage will occur to the stepper motor of the IAC control. {mospagebreak} Conclusion. The Injector Dynamics ID2000 has set the standard for linearity and control in a large injector. Grams Performance 550cc Injectors - K Series + AP2 S2K. To answer your question about VE + dead time. Remember this and do not get confused. Professional Fuel Injector Pulsewidth Calculator This calculator will generate pulsewidth values for specific rpms, from idle to peak speeds. IAT and FIPW 10. This adjustment is called fuel trim and can be read using a scan tool. Bosch injectors are commonly used in LT1s, and most of them have substantially longer offsets than the stock Rochester LT1 injectors. My injectors are Precision 1000cc and according to Precision specs, the minimum injection pulse time is 1. Go EFI Pulse Width Modulation Instructions With Pictures Did you know that you can control the pulse width modulation (speed) of your fuel pump with your hand held controller? Your system comes shipped with the fuel pump control pwm set for frame mounted pumps. Device control includes CASE crank learn, idle speed, cylinder cut drops. This tells the technician if the fuel injector pulse is correct from the ECM. Pulse Width (also called Injector Pulse Width or IPW): Length of time between the 'on',or 'actuation' of the injector and the 'off', or 'deactivation' of the injector for one pulse or fueling event. It includes the addition of the Small Pulse Adder. If you are too rich, you need to decrease it. Now we can see how much actual time this represents by multiplying the actual amount of time in 100% of the cycle by the duty cycle to get an actual injector pulse width. Required Fuel - For some ECUs and EFI systems, the injector pulse width, in milliseconds, required to supply the fuel for a single injection event at stoichiometric combustion, 100% volumetric efficiency and standard temperature. This can affect how well the injectors respond. The injector manufacture should be able to provide you with the injector flow curves which define the linear operating area for the injector. Control Module (ECM) controls the fuel rail pressure using two pulse width modulated fuel rail pressure regulators. tells EEC to adjust injector pulse width for proper idle. Despite the high flow rate, they are linear and controllable at low pulse widths and have been used in ULEV applications! This allows you to use a larger injector than normally possible without hurting idle and low speed driveability. If you’re not accurate with the injector sizing and fuel pressure values, then your basic tune will be out of whack. The result is vastly superior cylinder to cylinder consistency, even at very low pulse widths. and idle rpm. Below is a list, by section, of the information and tests which are contained within the Diagnostic Assistance software. Engine Coolant Temp sensor ECT. So at idle I would have a 4. The engine conditions were; fully warm, unloaded, & Lambda = 1. So if MAF sees 4. This guide can help you get those injectors back in shape applying some simple tests you can apply to both TBI and EFI systems. Idle is in the 550 PSI range and this is more as a means of being able to stabilize the idle instead of having to reduce the injection pulsewidth to the point the point the the injectors are barely firing. If any CUTOUT PULSE WIDTH values are within 0. conditions, above idle and less than full throttle, the MEFI module uses TPS MEFI Injector Pulse Width Table. So the PCM is decreasing injector pulse width to compensate for a slightly rich condition. HP Tuners GM Gen III part 5 walks you through how the GM ecu converts its airmass calculations into an injector pulse-width and spark timing to the engine. 7 milliseconds. A vehicle fails an HC emission test at idle and 2,500 rpm, and the engine has an acceleration stumble. I now have a sct x4 that I love. When you turn the key, the injectors do not pulse. It can work with any fuel pressure tester. No pulse width modulation (PWM) to limit injector current. 0+ Installation and Operation Manual. These two inputs, MAP and RPM, are the major determinants of the air/fuel mixture delivered by the fuel injection system. So the goal here is for Higher flowing injectors to allow a lower pulse width ? From memory our Throttle Bodies are 50mm , anyone know of any 60mm that could be used ?. The engine control unit, or ECU, determines how much fuel to release into the cylinders. Lastly, we learned that the larger the injector the lower the pulse width at the same engine rpm, load, and AFR. Depends on which fuel rate and what engine. If it starts, the relay is probably flaky. 0 m/s at idle in Drive and 3. What is your idle afr and base pressure? 900 rpm is a fair bit higher than stock too. It includes the addition of the Small Pulse Adder. The PCM would have commanded an increase in injector pulse width the next time the injector supplied fuel to cylinder 4. When the ECM needs to know how much fuel to deliver it reads the MAP and RPM, then it refers to the corresponding row and column in its fuel table to obtain the correct injector pulse width, also known as the "base pulse width". Pulse-width is the time in milliseconds the injector is on and can also be converted to duty cycle. If fuel pressure is normal, monitor the injector patterns with a labscope. It uses 12V vehicle battery for power. This calculator is intended to help people generate a reasonably close idle pulsewidth value for DIY fuel injection systems. For larger injectors reduce the pulsewidth by the ratio of the low injector slope change. Injector dead-time table and short pulse width adder table configurable for staged injectors. Most hot rod engines are not like that. EGR System 13. This is a stepper motor-operated valve that bypasses air around the throttle plate. If you want it to idle, this table is important. Negative values indicate fuel is being removed. 608 volts above learned idle voltage) Deceleration fuel lean out Fuel cutoff during cranking at WOT (2. • Deceleration enleanment or fuel cut-off mode - is reached during periods of deceleration. 85ms and now able to get just below 1. There can be unintended consequences when doing piggyback tuning. The ECU uses this signal to switch to a wider pulse width for starting enrichment. This is required by my CMR tuner. from the rear oxygen sensor.