I have tested a number of similar daihatsu's and they all have high negative trims at idle. For low-impedance injectors (less than 3 Ohms), you need to limit the current to avoid overheating the injectors. At times, the voltage may test fine at the fuel injector, but when the pulse width is checked, it is found to be bad. The PCM reduces the injector pulse width in order to increase the air to fuel ratio. That's what the numbers you're seeing on a scan tool mean if it is displaying a percentage value. Decreasing fuel pressure results in less than optimum injector spray patterns. 608 volts above learned idle voltage) A/C WOT cutoff (certain automatic transmissions only). Use the labscope to look at the engine’s secondary ignition pattern. 3 volts on a scan tool, and the injector pulse width is high. The injector pulse-width should increase and decrease with rapid increases and decreases in throttle position and increases and decreases in engine load. Figure 78-1 Typical port fuel-injection system, indicating the location of various components. Turned off each injector from diagnostics. 006*IPW*RPM. I like to have it hooked up all the time so that if something starts messing up, I can see right then and there what is going on. AIR INDUCTION. It is impossible to physically run an injector HIGHER than 100%. {mospagebreak} Conclusion. 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. All other features are the same. idle speed” is. Then the ECM decreases the injector puilse width until the mixture goes lean. 5 cat back k-pro v3 up to date any other sugestions to my build would be great thanks in advance. Engine is a 427ci SBF with a ProCharger F1R. You hit the starter button, the motor begins to crank over. In both scenarios, I only adjusted the fuel injector pulse width for a stable idle. The later systems use a crankshaft position sensor on the flywheel to determine firing and injection firing position, and a camshaft position sensor to make sure that they occur on the correct stroke. Fitech Fuel Injection. Effectively the engine is doing more work per revolution during this period in order to accelerate up to idle speed. Dual pulse injector pulse width will be nearly double that of normal idle. If you run to large injector you will sacrifice your idle quality. It is this device that provides specific information for the ECM and allows for different timing characteristics,and injector pulse width for the 5. It has to alot to do with how well the injector can accurately operate in small pulse width situations like idle or decel. 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. Engine management unit. Base injector pulse width corresponds to the amount of fuel required to generate a stoichiometric mixture (14. Your injector has completely maxed out and only ran 100%, you just ran it past its operating range and the calculation shows that. - I have measured the pulse width at the injectors as you can see in the attachements, at idle with warm engine i have around 7-8 ms when turning the co adjuster know on the ecu full clokwise (rich) it goes to 12-13 ms (i can't do that long because that's really to much) but this works, if i could adjust in the other way the same amount it was. Mine are running about 4. Engine Coolant Temp sensor ECT. 000000 4 0 0 °C. How to check fuel injector pulse using a noid light This is a awesome test because it can be done very fast using a very inexpensive tool called a Noid light. Starting with the 1986 model year, the AMC straight-4 engines used a throttle body injection (TBI) or single-point, fuel injection system with a new fully computerized engine control. 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. Once this pulse width value is obtained there are adjustments made to it based upon other engine operating. Injector one off seemed to smooth out idle ( did this a few hours later and didn't notice the idle smoothing out) but ran much rougher when applying some gas. If you're not accurate with the injector sizing and fuel pressure values, then your basic tune will be out of whack. There is a good chance that it may be bottoming out on the minimum injector pulse width value, or possibly even the injector latency. can compensate at idle and at part throttle so use primary to adjust WOT. His particular car has an auto trans so I'm wondering if a manual trans would product different results. That equals about 40 degrees of crank revolution. Acceleration Mode The ECM monitors the changes in the throttle position and the MAF sensor signals in order to determine when the vehicle is being accelerated. Injectors: The injector waveform above shows, charging voltage, followed by the ECU earthing the injector, pulse width modulation. Pretty much what we expected. 0 m/s at idle in Drive and 3. They will never inject the exact same amount of fuel. Bosch injectors are commonly used in LT1s, and most of them have substantially longer offsets than the stock Rochester LT1 injectors. ” Obviously, two injectors add more dimension to the. The fuel injector ignition voltage circuit is Pulse Width Modulated (PWM) , between 20 volts at idle to approximately 93 volts in order to compensate for increased engine load and RPM. The power loss light should flash indicating that the computer is seeing changes in the neutral safety switch. 2 ms at idle for SC engine, 3. "A/F Sens 1 Curr. idling warmed up above 185F. Under light deceleration, the ECM reduces flow by shorten the injector on time (pulse width). Lets say the air flow meter and injectors are designed to support double stock engine power. Latency has the most effect on idle and the least effect at WOT. If any CUTOUT PULSE WIDTH values are within 0. When changing injectors, it is best to have a complete set of test data. Gen III - Speed Density VE Table and MAF Tuning Instructions with a Wideband O2 Sensor Create by 69lt1bird - Jeff Anderson 2 system is operating rich, long term fuel trim will compensate for the rich condition by decreasing the injector pulse width, and a negative long term fuel trim is indicated. I set the warm idle speed where I wanted it, and that was that. In 1989 the cold start injector was deleted. Also thought it might be negative because of vvt system was tuned to lower the injector pulse width at idle for econnomical reasons. injection spark ignition engine were studied under a typical cold-fast-idle condition (1200 rpm, 2 bar NIMEP). In practice, many modern common rail injection systems will use both a pressure control valve on the rail and one of the forms of high pressure pump metering to control rail pressure. Notice that it doesn't stall. 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. what would normal pulse width be?. how long the ECU sends the ground signal to the injector. The fuel-injection feedback loop controls the pulse-width algorithm for fuel injection events. This morning at 33C, my Fuel Injector #1 IPW (is the corresponding parameter to the IPW in the cranking tables), shows 11. Update: I pulled the valve cover to inspect #8 injector and replace dummy plug and stand pipe and I found the injector solenoid screw broke off gone and the injector in two pieces I got it out replaced it but it all back together and it's the same as before crank no start icp all good I might pull the other valve cover tommorow. During idle, and low part loads, ECU only opens the small injector for small fuel quantities; it will switch to the big injector for mid, or mid-high loads; and it will activate both injectors at WOT conditions. I tested the injectors down to 1. IP: Logged. 0:25 One of the setting in Fuel Injector data. These sensors feed information into the modulator unit to modify the default pulse width continually so that the injectors always feed the engine the correct amount of fuel. A digital. Fuel injector pulsewidth calculator. (injector flow rate varies with the square root of fuel pressure. Electronic Fuel Injection System The Electronic Control Unit is an integral. This is required by my CMR tuner. Idle valves function with a rapid pulse-width on the PWM signal. If the exhaust color change the other way around, faulty injectors. A fuel injection ECU system is an important part of a fuel injected engine because it serves several functions aside from regulating and maintaining the amount of fuel and air that the engine needs to increase horsepower. The Cummins HPI fuel injection system is an important fuel injection system used in heavy-duty and high horsepower engines since the mid-1990s. Pulse-width is the time in milliseconds the injector is on and can also be converted to duty cycle. If any CUTOUT PULSE WIDTH values are within 0. The duration that the injector is open (pulse width) is proportional to the amount of fuel delivered. With the x4 I watch eot, ect, ficm voltage, icp, ipr, trans temp, and injector pulse width. So at a 725rpm idle with a 3. The computer checks the RPM before and after each ignition event and it adjusts the injection amount of each cylinder to make the engines idle smooth. The earliest and simplest type of fuel injection, single-point simply replaces the carburetor with one or two fuel injector nozzles in the throttle body, which is the throat of the engine's air intake manifold. In both scenarios, I only adjusted the fuel injector pulse width for a stable idle. When the engine is cold, a longer injector pulse width is normal. Product Installation Manual & User’s Guide Electromotive, Inc 703-331-0100 9131 Centreville Road 703-331-0100 fax Manassas,VA 20110 [email protected] Find values that match your injectors. It uses 12V vehicle battery for power. As manifold pressure decreases, the vacuum increases, and the amount of fuel is decreased. The graph below shows the low pulse width portion of the flow vs pulse width curve for the Injector Dynamics ID1600 injector at 14volts, 3 bar differential fuel pressure. Pulse width is the width of the pulse driving the injectors as measured in time. The fuel injector drives will max out at 5 amps each, enough to drive one low-impedance (or 4 high-impedance) injector per bank. That is why. For some automakers, single-point injection was a stepping stone to the more complex multi-point system. Injector Pulse. 7 and the actual injection pump timing reads 8. Injectors are pretty simple devices: turn on the electricity, wait till the fuel starts flowing. Changing injectors usually requires touching up the fuel table, idle area for sure. IMPORTANT: Make sure the fuel system is not operating in the Fuel Cut-Off Mode. Bosch injectors are commonly used in LT1s, and most of them have substantially longer offsets than the stock Rochester LT1 injectors. The Cummins HPI fuel injection system is an important fuel injection system used in heavy-duty and high horsepower engines since the mid-1990s. Professional Fuel Injector Pulsewidth Calculator This calculator will generate pulsewidth values for specific rpms, from idle to peak speeds. I need some help in figuring why the negative fuel trim at idle. Lets say the air flow meter and injectors are designed to support double stock engine power. What is your idle afr and base pressure? 900 rpm is a fair bit higher than stock too. 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 ?. Symptoms of Bad Fuel Injector. Because on a modern electronic injection injection system there is one injector pulse per firing stroke increased fuel flow for higher RPM isn't a major factor in injector pulse length. 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. 5 milliseconds for EFI cars. At the same time, the ECU tells the IAC to open, allowing enough air into the motor for start and idle. Symptoms of Bad Fuel Injector. This is called injector timing. sends a 110 volt signal to the injectors. Besides, the injector puller makes it so easy, just slide it underneath the lip in the injector housing and pop the injector out. Pulse width is the width of the pulse driving the injectors as measured in time. 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. 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). We offer it at wholesale price and free technical service. Control Module (ECM) controls the fuel rail pressure using two pulse width modulated fuel rail pressure regulators. Note that the injector pulse width is much greater for the first second or so. Weakening fuel pump - the engine may idle with or without misfires, but will misfire at higher RPM, under acceleration, or under load. Not every change in fuel pressure triggers an increase of the injector pulse width and the addition of fuel. 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. 3 volts on a scan tool, and the injector pulse width is high. If the engine floods, clear the engine by pushing the accelerator pedal down to the floor and then crank the engine. The graph below shows the low pulse width portion of the flow vs pulse width curve for the Injector Dynamics ID1600 injector at 14volts, 3 bar differential fuel pressure. 06 2000 PCM (DAC3) INJECTOR PULSE WIDTH IDLE = 0. 000000 0 0 mSecs 9 1 1000. If this opening and closing time is the same or close to the same as the complete pulse-width, then the. 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. 55:1 gears in the 12-bolt. Fuel Injector Pulse Width (FIPW) 5. pulse width reaches 17ms at around 87% duty cycle. Therefore, the amount of fuel actually delivered by injectors is regulated only by the duration in which they spray fuel, called the “pulse width. They will never inject the exact same amount of fuel. Also at high DC the injector pulse width can become unstable, and with some injectors, less fuel will actually flow at high DCs. Transmission: VSS, TCC and Shift Solenoids 12. Basically they manufacture a bunch of injectors and then conduct testing with them to see exactly how much fuel each injector injects. – Simultaneous Direct and Port Injection strategy. Benefits include smoother idle, 1. The PCM fires the injectors in a specific sequence. The Cummins N-14 is a great engine; quite possibly the best Cummins engine ever produced. 1993 Chevy K1500 5. 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). System is going lean, and after 20-30 seconds of running lean, then goes into open loop forever. All of this is dependent upon the driver's throttle demands. These are very inexpensive, simple, and reliable. Oxygen Sensor and Closed Loop 6. 608 volts above learned idle voltage) Deceleration fuel lean out Fuel cutoff during cranking at WOT (2. Fuel injectors are “open” for periods of time that can be measured in millionths of a second. 3 so they will either idle the same, or be very slightly less ideal (in which case you can bump up idle rpm a bit so required pulse width goes up a bit and makes it idle perfect again). A 1G DSM MAF-Translator has switches so you can adjust the base settings for idle, mid, and high rpm. Practical Rail Pressure Control. William Denish, Photography by D. Destination page number Search scope Search Text Search scope Search Text. It is important that injectors are tested at normal operating temperature, from low idle pressures all the way up to full load pressures (as much as 29,000 psi). No DTCs (diagnostic trouble codes) are found. 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. Once this pulse width value is obtained there are adjustments made to it based upon other engine operating. 25 COASTING IN GEAR ABOVE 1150 RPMS = 0. I used to run an 850 Holley. The PCM will reduce the amount of fuel (negative - fuel trim) by decreasing injector pulse width. The second two letters in the alpha code refer to the end of the injector’s response time. Nissan Cefiro A32 engine idle shake fault. IP: Logged. 09 Jetta SpWag CR won't start - No injector pulse VW MKV-A5 Golf Vag-com shows about 80bar during cranking and i know that it is supposed to be 175-300bar at idle. Your VE values with the OE injectors are at least valid. Injectors are shut off during deceleration. If you want it to idle, this table is important. 4 EFI Connectionscontinued from page 1. Re: Need Fuel Injection recommendations for boosted 1200-1300 HP SBC Thanks a lot for the good info Scott. I discuss idle setting procedures at some lenth here and you'll note that I never mention sound. I had a similar no-restart problem on my '89 780, and the problem was, in fact, the fuel injection relay. Then the ECM decreases the injector puilse width until the mixture goes lean. The ECU then corrects the whole table and stores this values to LTFTs table. sends a 110 volt signal to the injectors. 8 ms of injector pulse width!. 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. Is the pulse width at idle too low? I believe once you start going under 2ms you can have problems. So at idle I would have a 4. RB Racing-RSR produces 200mph Land Speed Record holding exhaust systems, turbocharger kits,turbocharger components, and fuel injection systems for motorcycles. This is why you have to make sure it is total injected fuel rate. For full throttle and boost I would like the piggyback to apply its map only. Today everybody, including the OEMs, inject just after TDC on the intake stroke cylinder, at idle, assuming fully sequential operation. 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. A pulse width of 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. One of the members on our Genesis Coupe forum claims that injector pulse width reads very low (0. With drive by wire, we no longer need the IAC system. Injector pulse width will be longer than expected (significantly longer than 2. Some of those numbers are getting awfully high. and consequently the amount of fuel sent into the cylinder- depends on the pulse width (i. If the pulse width on the injectors drops by about 50% and the engine then. (Throttle body blade is closed). i think the o2 sensor tells the ecm to change the pulse width of the injector to adjust the amount of fuel as necessary for a given demand and exhaust content. Figure 78-1 Typical port fuel-injection system, indicating the location of various components. If fuel pressure is normal, monitor the injector patterns with a labscope. What is your idle afr and base pressure? 900 rpm is a fair bit higher than stock too. You can estimate your idle pulse width beforehand. it will keep the fuel injector pulse width up above 0. engine control unit will adapt to these long term changes by adjusting the base idle speed, base injector pulse width and ignition timing. So if you put a larger primary in you could click the idle setting leaner, which fools the ecu to adjust the injector pulse width. 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. Pulse width is a term to describe how much average voltage is applied to an injector coil over a given time span - typically about 2. Subtracting from total pulse width, I get 1. It can work with any fuel pressure tester. The TL supplies the injection timing signal for injection pulse initiation and synchronization Idle mixture adjustment (IM) - Adjusts the mixture at idle using inputs from the IS and IA. The frequency valve is connected to the lower chambers of the fuel distributor and is fitted with a connection leading to the return line. The ECM receives input signals from various sensors in the EFI system which in turn transmits controlling outputs (open/close) to the injectors. This is not a 'peak. The pulse width of fuel injector is increased as engine RPM’s also increase. The calibrator provides a wider pulse width on startup to provide a richer mixture for a cold engine. See the scope photo above for an example of the output of the PWM. Uses fuel injectors controlled by the computer …no carburetor The computer uses sensors to gather information from the engine, then calculates the required fuel needed. The engine is a 468ci big-block with a mild hydraulic roller cam, a TH400, a warmed-over converter, and 3. Neither EV1 or EV6 is technically correct because those generations of Bosch injectors could come with either connector. pulse width reaches 17ms at around 87% duty cycle. Vehicles running very large injectors will need to have the Minimum Allowed Fuel Pulse Width Value lowered to allow the injectors to open for a very small period of time, this is either a 2D map against ECT or a 1D value. Professional Fuel Injector Pulsewidth Calculator This calculator will generate pulsewidth values for specific rpms, from idle to peak speeds. 5 volts at WOT. Typical injector pulse width for an idling engine at normal operating temperature is between 2. 1 Oil Pumps and Lubrication 2. Injector dead-time table and short pulse width adder table configurable for staged injectors. If you ship your injectors to. At the same time, the ECU tells the IAC to open, allowing enough air into the motor for start and idle. A BAD fuel injector can cause your 3. Weakening fuel pump - the engine may idle with or without misfires, but will misfire at higher RPM, under acceleration, or under load. If this opening and closing time is the same or close to the same as the complete pulse-width, then the. 42 ms fuel pulse width will not allow injectors to be enabled, but does keep the IDM and PCM synchronized until sufficient injection control pressure is. Load sensor adjustment is frequently used to compensate for larger injectors. There is a good chance that it may be bottoming out on the minimum injector pulse width value, or possibly even the injector latency. Injectors bad; Injectors with high miles (200,000 miles or more) can fail to operate cold. The tester is located where it is clearly visible. The engine conditions were; fully warm, unloaded, & Lambda = 1. The graph below shows the low pulse width portion of the flow vs pulse width curve for the Injector Dynamics ID1600 injector at 14volts, 3 bar differential fuel pressure. implements an idle air fuel ratio map. They pulse faster as you accelerate based on the air flow into the engine. The TPS(Throttle opening) sends signal to ECM ,then ECM sends a pulse signal to fire the injectors for exact amount of fuel to be injected. As manifold pressure decreases, the vacuum increases, and the amount of fuel is decreased. one injector is turned on which allows for finer control over idle fuel delivery, while at higher RPM and. The fuel injector duty cycle (IDC) is the percentage of time the injector is supplied with power. When I declutch, the injector pulse width comes back on. 0L Ford Explorer (or 4. Injector Sizing. 8 ms of injector pulse width!. When the engine is at idle, the manifold pressure is low. Control Module (ECM) controls the fuel rail pressure using two pulse width modulated fuel rail pressure regulators. The chip is a Programmable Read Only Memory (PROM) Chip which is installed in the ECM. Choose top quality brands AC Delco. Or rather, you have to narrow the pulse width too much to properly cycle. Pontiac Grand Am Rough Idle Due To Fuel Injector Short Circuit. Injector dead-time table and short pulse width adder table configurable for staged injectors. Fuel injectors operate though the brief charging of a solenoid and subsequent opening of a valve. This is called multi-port fuel injection. The length of time the injectors stay open is considered pulse width. The FICM automatically adjusts injector pulse width to account for variances between injection event strength. known as the Injector Pulse Width. Typically the voltage of the "on" pulse is zero, because the injector driver provide a ground to the injector to energize them. A lab scope is used to measure an injector signal voltage on an idling engine at operating temperature. The 80's get REAL close to the typical pulse width to idle a 2. Fuel Injector Pulse Width (FIPW) 5. Once the RPM’s begin to drop again, the injector pulse width is decreased a few percent. These are very inexpensive, simple, and reliable. 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. The experimental setup used in this case is shown in figure 1. Electronic Fuel Injection System The Electronic Control Unit is an integral. 0 bar boost, and better low-end driveability. (Throttle body blade is closed). The pulse width of each injector was tested and the lowest time on idle was 58. Changing to a different Fuel Injector Size. 3L Power Stroke "hiccupping" while running (vehicle, idle, spark plug) You can also have an injector going bad but that acts more like a fouled spark. The ECU sees the low RPM, and quickly goes to the Cranking fuel Table, increasing the Injector pulse width, allowing more fuel to get the motor started. If this opening and closing time is the same or close to the same as the complete pulse-width, then the. The result is smoother idle and better efficiency. 4L injectors, I highly suggest copying from the FBody. The examples you give are correct. With EFI and a fast enough microcontroller, I could theoretically put in a "correction factor" in the firmware adjusting the pulse width on each injector to compensate for mechanical variations (orifice size, wear, etc) Theoretically (THEORETICALLY), you could do this "analog old-school" style by adjusting the fuel distributor and modifying the. 30 Lb Injector Fuel Pressure Question. Less injector, same idle quality. The injector started lifting at 1 ms and exhibited full opening at 1. " An injector that is stuck closed will give you a reading of. I need to decrease latency by about that much to get the same total pulse width if my idle trim is zero (it's slightly positive, so I need to take out slightly more than that). I used to use one to watch ficm voltage, icp pressure, oil temp, and coolant temp. There are two types of engine control operation:. The first is pre-injection, a short duration pulse which reduces combustion noise and Oxides of Nitrogen (NOx) emissions. engine control unit will adapt to these long term changes by adjusting the base idle speed, base injector pulse width and ignition timing. The six injectors are mounted in two common fuel supply rails. Yes, injectors can be too big. The duration of time that the injector is open (called pulse width) is proportional to the amount of fuel delivered. The ratio of the "on" time to the "off" time determines the current through the injectors. Typical fuel pressure for a stock 22RTE engine is 43 psi. Indian Fuel Injection System Overview Idle, Intermediate, and Main. Preliminary Information Bulletin - Unknown - For 2014 Buick Enclave - AWD. Turned off each injector from diagnostics. Idle and large injectors. As temperature increases, resistance and signal voltage decrease. Once completed, the engine will smooth out. Here's the interesting part. I can see how it can change pulse width, and the timing of the fuel entering into the injector body itself from the solonids controlled by the ECM. conditions, above idle and less than full throttle, the MEFI module uses TPS MEFI Injector Pulse Width Table. how much port injection pulse width you need at any RPM and at any load (Boost or Vacuum). The ini-tial injector pulse width is rather long, but the goal is to inject a lot of fuel into the cylinder to get it started. Transmission Shift Times, Fluid Temperature, Torque Blue Tooth or WiFi Real Time Data Web View. This is why you have to make sure it is total injected fuel rate. 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. This can affect how well the injectors respond. You hit the starter button, the motor begins to crank over. Also group injection systems can be converted to sequential injection. In 1989 the cold start injector was deleted. This can cause false indications by the scan tool. it never knows when you really have your foot off the throttle. Highlights The flow linearly varies with longer pulse width and nonlinearly varies when the pulse width is less than 2 ms. With EFI and a fast enough microcontroller, I could theoretically put in a "correction factor" in the firmware adjusting the pulse width on each injector to compensate for mechanical variations (orifice size, wear, etc) Theoretically (THEORETICALLY), you could do this "analog old-school" style by adjusting the fuel distributor and modifying the. So the power steering, brakes, and alternator are all still working. sends a 110 volt signal to the injectors. For proper tuning, you will need an idle pulse width of at least 1. 2% of the total time available or a 59. Injectors that are too large for your application, won't idle well due to low pulse-width operation. Therefore, when the PCM detects that it is unable to add a sufficient quantity of fuel (by altering the injector pulse width) to maintain the air/fuel mixture to within acceptable limits when the engine is running above idling speed, it will set code P2177, and may also illuminate a warning light as a result. If an injector stays on all the time, it is said to be static (wide open, or 100% duty cycle). You can keep your original and have this one as a spare. Notice that the fuel-pressure regulator is located on the fuel return side of the system. It actually accomplishes this by generating a time delay of 83. So a given VE value + dead time may equal the same pulse width as a different VE value and a different dead time. Acceleration Mode The ECM monitors the changes in the throttle position and the MAF sensor signals in order to determine when the vehicle is being accelerated. Injector Pulse Width. 5mm3 at idle, and other models I believe can go as high as 3 for pilot. The PCM fires the injectors in a specific sequence. On cold start enrichment It's 23 degrees at 68%. ECU then computes fuel injector pulse width ("on" time), spark advance, ignition module dwell, idle speed, canister purge cycles, EGR flow and feedback control from this information. The TBI injectors are getting a good signal and I can watch the pulse and inject fuel in the start mode and immediately peter out in the idle mode. ECT, Cooling Fan and IAC 11. If after 20 seconds the pulse width of the injectors reduces and the engine idle smooths out, this is considered normal operation and no repairs should be attempted. Also thought it might be negative because of vvt system was tuned to lower the injector pulse width at idle for econnomical reasons. Wide Open Throttle, Open Loop and the PCM. 85ms and now able to get just below 1.