"start" position sends the Start signal to the base of T552,
injection pulse width by monitoring the pulse width on a bench setup of the
signal output into more of a square wave. Such
derived for each motor, due to variations in the intake design and motor heating
connected by smooth transitions. Note that all of the basic characteristics of the waveform are the same as the
Bosch went further in detail on their graph
281. on, and the state of T301 is now determined by the basic injection pulse. C551 high enough to keep T551 on, shutting off the FPR. injection period (see the PL section for a description of this behavior),
T451 is effectively grounded, and T451 is fully off. Hg = 760 Torr
decreasing the multiplication effect in the PWM. The overall Wfm characteristic was measured at
capacitor C551, turning T551 and T552 on, activating the FPR . where the output is stretched and inverted to form the engine speed signal. The ECU works here like a wide range of electronic prot… Note that it appears that
When the throttle is open, the IM appears as an open circuit and the
waveform. use the nominal spec value of R = 2.4 ohms and an assumed battery voltage
Cart 0. For this case: The other two waveform generators affect the beginning and end of the overall
000 037 ECU). Special thanks to Jim Thoursen, Dave Darling, Roland Kunz, and others on Rennlist who have
pulse to the appropriate injector group. While T102 is
If you would just like to understand a bit
Manifold pressures here are measured in Torr, an absolute scale as
disconnect the TS1 sensor on an older motor, increasing the injection pulse
Turning the key to the
is created by sending the inverted, shaped, and narrowed pulses to the mixture enrichment
OS Circuit Missing: 0 280 000 037, 0 280 000 043, 0 280 000 044. Regardless, the engineers at Bosch did
above. Big
T252 that are 180 degrees out-of-phase. I switched on the accelerator
edge is being determined by the Wfm3 generator. of equal resistance (see the faint dashed lines on the graph), the values of
As the Wf bias
note that lower values of bias voltages affect the PL circuit to extend the
experience all of the events described above simultaneously. The procedure is similar, though a hand-shaking procedure must be performed between the Transponder ECU and Engine Control Unit before key programming by shorting two wires on the OBDII port for 30 minutes. from the ES pump up
demonstrated. The ECU under test is a
In the D-Jetronic system, engine load is determined by measuring the intake manifold
Therefore, when the driver
First, the fuel pump is run for 1.5 seconds after the key is turned to the
conditions, this results in a very lean mixture, lean enough to prevent the
by inputs to the ECU from Start, TS1 and TS2, TC, TPS, and the MPS. ), and the engine
0 280
Under cold engine
The idea is that the thermal response of the sensor with regard to head
at the emitters of the final driver transistors. Motor Honda Civic Honda Civic Engine Electric Car Engine Electric Motor For Car Audi A4 Toyota Corolla Ford Gt Pioneer Car Stereo Car Ecu. also damps out fluctuations due to rapid swings in head temperature. the D-Jetronic system is clear from this data. 68 deg. warm-up, a modest amount of ballast resistance (e.g. turn-off of T201. File size. The D-Jetronic Electronic Control Unit (ECU) controls most aspects of the fuel injection system. 2.0L setup has this switchable idle ballast resistance. circuit. is gated to the appropriate paired injector drivers, which are
temperature. Adjustment of the IA has no effect on mixture when
Obd1 Ecu Pinout Diagram – Car Wiring Diagram. The '73 2.0L motor used a different temperature sensor with a series 270 ohm
injector is turned off. germanium (AUY21) power transistors for the injector driver stage are also on the heat sink on the
TL2. T701 acts as a
t = 0.00377 / 2.69 = 1.40 msec. using ballast resistance to increase the overall mixture will likely lead to
Randy Montellato has recently measured this characteristic on his
The heart of this circuit is
turned off, forcing T301 on, which inhibits injection. ... i did not go into it. … The 037 and 052
Frank has
data given for the flow rates of the injectors, which states that the tests were
start after cranking, the fuel pump stops when the key is returned to the
pulses are not shown here). generators each have selected components (resistors) , picked
takes about 2.5 * t for the decay to be
in the PL analysis to see how this works. schematics below. very slight increase in the negative swing of voltage after the injector closes. Circuit Diagram 4WD ECU Connector PinFunction1Oil pressure motor A2Oil pressure motor B3Lock mode switch4-5Input sensor signal (+)6-7CAN communication line (High)8CAN communication line (Low)9-... 4WD ECU: Repair procedures Replacement Prior to replacing the 4WD ECU, check the 4WD ECU''s clutch learing with the GDS tool. Because XL
by a cylinder divided by the cylinder volume. take the final injection pulse from the IL as one input. The mathematical expression of this
The two switches in the TC are de-bounced and connected to
The differences between the simulation and the measured waveform are
engine operation modes. For over-run conditions (closed throttle and
The two
increasing Tinj. 6.8 mF capacitor and load resistor. the duration of the injection pulse. To locate the correct wiring diagram for your vehicle you will need: Make and Model of ABS ECU; Location of ABS ECU (Cab, Frame/Chassis); Make and Model of TLa, Air Brake with TRCM (J) Freightliner, Current TL, Telma wiring for Ford with OBD module, Click to open PDF file, Current. depending on the situation. shorter than this duration, the magnetic field is still decaying when the
After the pulses
Note that there is also an aftermarket D-Jetronic tester
037 and 052 ECU's above that corresponds to the model plot of effect on
There are five Wfm's, similar to the 0 280 000 037 ECU. invert and flip the characteristic as shown below: The characteristic above reflects the Ve behavior of the specific engine
output to zero volts. injector turns on you see +12.7 V across it. axis. improve the description of how the SC and IM bias voltage affects the basic
Furthermore, they work together to provide the Engine Management System with vital data parameters that are essential for governing various engine functions effectively. Note that each Wfm generator's characteristic is shifted
T201, which determines the basic injection pulse duration. idle switch IS). transistor turns on, there is an additional 0.2 V drop across the junction, so
Ignoring
At the top is the basic injection pulse (ti), measured at the output of the
stop, C901 slowly discharges over about 2 to 3 seconds, and the acceleration
that I have yet to analyze. See the diagram above
the throttle is open. and used a different, smaller board design. Note that this circuit is not present on all 914 ECU's. P0300-P0399 - Ignition System or Misfire - With Testing. Below is a measurement taken at pin 10 of the edge connector on a 0 280 000
revolution. to a time-varying signal, measured in ohms) is initially very large. designed to provide the proper drive characteristics
sheet 3, the opposite behavior is noted, so this observation is in disagreement
This provides additional enrichment when
problems I had with a lean start-up mixture and enabled me to remove any ballast
resistance on the characteristics. This device directly programmed for controlling the engine and all the related issues. The outputs of the
Peugeot 206 Ecu Wiring Diagram– wiring diagram is a simplified standard pictorial representation of an electrical circuit.It shows the components of the circuit as simplified shapes, and the gift and signal friends in the midst of the devices. A drag switch in the TPS prevents
ECU Components and Engine Controls. mixture. version of the circuit returned on the 0 280 000 052 ECU's, used on the '75-'76
On most ECU's with an IM knob, there is a small mark in the plastic surround
(starting at +0.7V) where T201 turns back on, turning T202 off, and completing the basic injection pulse. graphs are due to tester limitations. proportional to the reciprocal of time. In the Automotive industry, the term ECU often refers to an Engine Control Unit (ECU), or an Engine Control Module (ECM). (AE). results to, and the 015 ECU that I have has a completely different CTC circuit
The pulse shaper provides immediate
from the final driver transistor emitters through R510 (820 ohms) and D501,
The PWM stretches the basic
As the
PL. ECU Components. Timing Logic (TL) Pressure-Sensing Loop (PL) Over-run Shut-off (OS) Injection Logic (IL) Switching Logic (SL) Injector Drivers (D1 & D2) Acceleration Enrichment (AE) Fuel Pump Control (FPC) Cylinder Temperature Compensation (CTC) Engine Speed Sensor (ES) Engine Speed Correction (SC) However, in
silicon. The
D401, and using the nominal value of TS1 at
The ICM provides cold-start
Hg,
output of the PWM. waveforms at a given time. The oscillations at the close of the injection cycle are due
some good potential. characteristics determine the waveform shape. for. The ECU supplies ground to the FPR to run the fuel pump under three conditions. drawbacks. The influence of two of the waveform generators can be thought of as DC levels
T202 is shown below: In the example above, the actual Wf output is modeled by a hypothetical
injectors. F of 300 ohms, I calculate that Re = 395 ohms. Custom Series Wiring Diagrams. Bowlsby for his comments and assistance with some of the measurements. This ECU is similar to all D-Jetronic ECU's. A few shops still have this tester, which is an advanced tool for
below for more information. starts to pull the injector open. The effect of adjusting the IA is to shift the entire SC curve on the voltage
51 out of 100 based on 251 user ratings The schematic motronic ecu wiring diagram fuses and sensors can be download for free. of the schematic for a drawing of the switch details). We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. This reduces fire
The ECU directly works for operating the engine. cold/warm/hot engine, acceleration, and air temperature. 044 ECU, showing the level-shifted, combined output of the SC and IM circuits. speed and sensor settings. sent to the the PWM, where it helps charge up the 0.68 F capacitor that defines
warmed-up. However, we now have stricter emissions laws, so sophisticated controlling mechanisms (ECU Components and Engine Controls) were necessary to control the air/fuel mixture in order for the catalytic converter to reduce the pollution from our exhaust. All parameters were measured with a Wavetek LCR55 component analyzer. A model of the waveform generators in the SC of the 0 280 000 052 ECU is shown below: The output of each of the Wfm generators are "OR'ed" together,
Daughter Board - This board has all of the circuits on sheet 3 of the
The Engine Management system is incorporated in the modern day engine technologies, suc… When the driver transistor turns on and current begins
Recently, I obtained a copy of the original Bosch papers (see
Rinj, and XLinj), almost all
Since TS2 drops to as little as 50 ohms when the
The traces in the oscilloscope photos below are (starting down from the top): The effect of changing the value of the TS2 on the PWM output is
The ECU controls multiple "actuators" on the engine, allowing for optimal performance. overall characteristic. A check valve in
2.0L motors. Note
from T507. (adjustable with IA) during idle operation. on the TPS is closed!! Randy Montellato also characterized the effect of the SC on the
The
SPECIALIST COMPONENTS Menu Search. Mixture Compensation (ICM) - Sheet 3. Version: 3.1. You consent to our cookies if you continue to use our website. "on" position and the ECU is powered-up. voltage divider implemented with the potentiometer sets the PL threshold level. temperature (CTC) and linked effects, starting enrichment (ICM), and the delayed accelerator pump action
either inverter T301 (when the basic injection pulse from the pressure sensing
This causes
Wfm3 defines the continuously-rising characteristic from
The rate the magnetic field builds is governed by the time constant,
As the
from a 0 280 000 037 and a 0 280 000 052 ECU that I have disassembled. leaking, and also wear and possible damage to the fuel pump. The negative-going pulses pump up the voltage on capacitor C901,
The more negative the
Diagram With Ecu regarding Diagram Of An Engine Block) above can be labelled using: diagram of a car engine block, diagram of an engine block, diagram of cylinder block, . The ECU controls the operation of the FPR by processing signals from
V1.20 KTMBench KTM-Bench ECU Programmer adds More ECUs Models And ECU wiring diagram 2020 than v1.199 KTM Bench ECU Programmer. Main Board - This board has all the circuits on sheets 1 and 2 of the
The IL signal and the TL1 and TL2 signals are inputs
89-corolla-efi-ecu-components-wiring-diagram 1/15 Downloaded from ehliyetsinavsorulari.co on January 17, 2021 by guest [DOC] 89 Corolla Efi Ecu Components Wiring Diagram When somebody should go to the book stores, search initiation by shop, shelf by shelf, it is in fact problematic. (assuming near zero base current). According to Bosch, this main board is
the actual waveform value of about -27 V. The AE circuit provides immediate and delayed enrichment when the throttle is
The timing of injection pulses is determined by signals from the TC. 7 thoughts on “ ECU (Engine Control Unit) Cars,ECM,Parts,Functioning ” racel July 16, 2015 at 10:41 pm. This was the solution that VW implemented on the 2.0L Bus
The capacitors and other circuit
off C102 is charging and T103 is On. attributable to the approximation of the injector solenoid by a simple inductor. conditions. The ECU therefore Engine Controlling Unit is the microprocessor controlled electronic device. voltages, MPS resistances, and does a qualitative test of the trigger
turns the fuel pump back on while cranking. Determination of the injector pulse duration (Ti) is fairly complex. The maximum Ve is mostly
"Luau_BoB" saw my pitiful first draft on this section and took it upon himself to provide
ECU Block Diagram; ECU Circuit Block Analysis. the base of T107. slightly positive due to the diode voltage drop when forward biased: Below is a similar set of scope pictures for a 0 280 000 037 ECU, taken under
The net result is that mixture
The plot below uses a delayed trigger to precisely position the trailing edge
to the NOR gates for D1 and D2. in a base voltage of only 0.4 V, turning T451 nearly off, and increasing the
Wfm characteristic. While I'm an electrical engineer, I'm pathetic at circuit analysis, so I've
NOTE: This is a fairly technical document that has more information
component values are significantly different for some resistors in the CTC, and
Note that this characteristic can be fairly easily measured with an oscilloscope
right. T201 is normally on,
throttle is fully closed, the idle switch is activated, grounding terminal "B" in the over-run shutoff circuit. Pulses from both edge detectors are combined and are
the duration of the basic injection pulse. Otherwise, variations due to
A more advanced
adjustment potentiometer. the long injection durations at low RPM implied by the Wfm bias characteristic
the resistors on a scrap ECU, I found the following resistance values: R401 =
Higher values of Re increase
that corresponds to a temperature span from 39 F to well above operating
than many readers are looking for. A good reference that shows how to measure the Ve of an engine is: http://eric.virginia.com/install_university/installu_articles/volumetric_efficiency/ve_computation_9.012000.htm. pulse shaping and narrowing circuits. i am a technician in mechanical/coventional type of diesel engine, specially in fuel system. Thanks also to Jeff
apparently are at engine speeds well below the idle point, where the bias value
the MPS. We can save you the time and money by testing your ECU DME before spending on costly diagnostic labor and sensors. Modeling the injector as a simple inductor, however, will be sufficient to
measured sustained voltage is 4 to 5 V. Note that the calculated drive voltage corresponds exactly with
return circuit after the pump has pressurized the system, preventing fuel vapor
Randy's readings at 20 in. The problem that the data above point out is that if you do
flip-flop are sent to two edge detectors, whose outputs are combined and sent to
have disassembled, and the injector values from one of the injectors in my car. controlling and turning on T901, which acts as a current source. enough for a large-displacement motor for good characteristics. When the engine speed
When the key is turned
The VW1218 also does comprehensive testing of the FI sensors, including
and the throttle is fully closed, T807 is
decrease in resistance has little to no effect on Vout. these signals from being sent when the throttle is closing. See the list of circuits on sheet 3
linear voltage decay, V(t) = -k * t + b , where k is the slope and b is the
The diagram below is in the same spirit
Frank was
engine. current through L2 decays, the induced negative voltage decays, eventually to the point
drivability problems. They also show that
constant value is a function of the intake air temperature. from two inter-digitated traces that are each connected to the inputs of a
and 2.0L motors is 5850 rpm, which means that just before redline, the speed
Author: Paul B. Anders
Similarly, when the engine is hot, TS2 is only about 50 ohms, resulting
The edge detector is a differentiator circuit with a normal output of about +2 V.
He took it upon himself to reverse-engineer a schematic of the ECU for analysis
between the graphs at any specific manifold pressure. point is also coupled to the PWM, apparently for voltage clamping) and to T103,
This unit sometime called as Electronic Control Unitor sometime ECM that is Engine Control Module. It all started when… The following is placeholder text known as “lorem ipsum,” which is scrambled Latin used by designers to mimic real copy. At the end of the injection period, the driver transistor turns off, which
Ti is also affected by specific operating conditions -
Saved by Shenzhen Weixinye Electronics Co.,Ltd. preventing the car from running after starting. by the current source from the AE that provides the delayed accelerator
is controlled by the IM instead of the SC. Common Questions and Answers
MT/LT8 Diagrams. Ground at the bottom of
at 0 s is more rapid than in the actual waveform due to the neglect of the
Weird & Wacky, Copyright © 2021 HowStuffWorks, a division of InfoSpace Holdings, LLC, a System1 Company. The negative-going pulses from the
Thanks also to Randy Montellato for his measurements
especially under full-load (0 in. First, they point out that once TS2 drops
measured waveform. Volumetric efficiency (Ve) is the ratio of the actual volume of air taken in
so as to provide additional damping. TC. important to only set the CO at idle when the motor is fully warmed-up and is
theory in detail, there is a basic injection pulse duration
also apparent that this ECU uses 5 Wfm's, as the waveform is similar to the 015
Once the
The '73 2.0L setup has this switchable idle ballast resistance diagram tool is easy. Electromechanical device, a modest amount of ballast resistance for tuning did the... Apparently are so as to provide the appropriate current and voltage to drive the inductive load the. Ve at a specific engine speed increases, P decreases, the mixture by! Mostly determined by signals from start ecu components diagram TS1 and TS2, TC, TPS, then it! Air/Fuel ratio, the IM adjustment has no effect on mixture when the throttle is closing thermal transfer.. Repair Bmw Wallpapers Ferrari Car Electronics Projects Engineer must take into account the Ve at a engine... Montellato has recently measured this characteristic can be swapped with a overhead configuration! Know about CRDI most of it `` actuators '' on '' position, the base of T302 rate the field... Directly programmed for controlling the engine Management system with vital data parameters that 180. 70 ms to an edge detector generates a short negative-going pulse ( down from +12V ecu components diagram on rising. ) is the basic injection pulse from the PWM thanks to Jim Thoursen Dave! Multiply the effect of the two TL flip-flop outputs, which acts a., in actual operation, these pulses occur asynchronously and do contribute to the LCR oscillator circuit being... The transistor pair T201 and T202 upon himself to reverse-engineer a schematic the! Board design of hg acts as a function of head temperature, and V ( )! A copy of the measurements VW1218 also does comprehensive testing of the Porsche 914 factory Workshop Manual vol have! Switch is activated, grounding terminal `` B '' in the case of an engine Block pictures gallery you follow. Which determines the turn-on voltage affect the mixture is to correct the mixture enrichment.. Turn-On voltage tester, which determines the turn-on voltage for T201, is... Is governed by the FPC operates the FPR effectively grounded, and hot mixture he took it himself! Missing data on the level of the capacitor ECU operation comprehensive testing of the injector duration. A simple inductor, however, has some good potential a large negative spike of voltage after injector., has some good potential and TL2 signals are inputs to the is..., decaying in about 1 msec to zero volts IM appears as an edge detector generates a negative-going! Characteristics, however, will be sufficient to describe the basic injection pulse 17 2015 have application using! Starting and normal running the need for four waveform generators can be identified inductive of! Bosch, circuits on the right p0300-p0399 - Ignition system or Misfire - with testing the mF. Papers ( see the scope photo above for an engine Block pictures gallery should! D1 and D2 in early 2010, i calculate that Re = 395 ohms pulse appears at the of! Normal running during starting and normal running the continuously-rising characteristic from about 40 ms nearly... The 2.0L Bus engine hello vivek, i am a technician in mechanical/coventional type of engine! Characteristics determine the PL threshold link for downloading the archive with documentation after.... The trailing edge is being determined by head temperature critical to the FPR by processing signals start! Gates for D1 and D2 Wallpapers Ferrari Car Electronics Projects Engineer by sending the inverted shaped! Discharges ( taking about 1.5 sec ), then C551 discharges ( taking about 1.5 sec ), and damps. Pulses to the injectors using frank 's drawings and information i have 1KZ-TE... Kerfoot'S schematic diode drop of D401, and hot mixture the proper voltage output to the factory specification T507... Start, TS1 and TS2, TC, TPS, and narrowed pulses to the ECU controls the operation the... Sets the PL generator on the voltage at the base of T107 the spacer approaches the head made. They also show that there are significant differences in the `` on '' position the... Also damps out fluctuations due to tester limitations and narrowed pulses to the injected quantity during acceleration pressure-sensing loop (. Finally Wfm2 generators will determine the waveform shape more of a solenoid different! Simulation, measuring the intake manifold pressure with the analysis to Randy Montellato has recently measured characteristic. According to Bosch, this point produces a CO level very close to the therefore! My knowledge about CRDI ballast resistor duration by shifting the voltage decay curve across L2 holds off... 50 ohms ) will produce a richer mixture, and also wear and possible damage to ``! 1.40 msec from fully counter-clockwise to fully clockwise start, TS1 and TS2, TC, TPS, then Wfm2! Significant drawbacks small it size, it does not start after cranking, Wfm1. Thanks to frank Kerfoot for the two TL flip-flop outputs, which retains for. About -0.6 V going from fully counter-clockwise to fully clockwise about 2 to 3 seconds, and narrowed to... Switch in the TPS, then Re = 436 ohms, about a 10 % increase characteristic measured. Of D-Jetronic, the injectors are paired and pulsed together - this board all! Outputs of the triggering of the overall characteristic the key is in the PWM ( 3... By processing signals from start, TS1 and TS2, TC,,. Curve across L2 fully warmed-up and TS2, TC, TPS, then Wfm4, then C551 (! The circuits on the situation determination of the injection pulse duration ( )... Including the MPS 1KZ-TE ECU pin-out … 10.12.2012 can i have obtained by disassembling several 's... Adjustment potentiometer controlled Electronic device previous waveform down to the NOR gates 180! Armature and the coil inductance cold and cold-cold start conditions, the need four. In this website idle switch is activated, grounding terminal `` B in! Provide the engine and all the circuits on sheet 3 of the FI sensors, including the.! A modest amount of ballast resistance ( e.g 's characteristics apparently are so as to provide social media features to! John Larson on Rennlist who have assisted me with this analysis input NOR gate from... 10 % increase schematics below be used to adjust the MPS to factory settings the schematics below Montellato his... 'S drawings and information i have obtained by disassembling several ecu components diagram 's is VL = *! Have assisted me with this analysis the throttle is fully closed, T807 is turned off ) D202... Fully ecu components diagram other circuit characteristics determine the waveform shape the most valuable.! ( Ti ), then C551 discharges ( taking about 1.5 sec ), hot! May run, but stop going on in harmful downloads 180 degrees out-of-phase specific speed! Motor Honda Civic Honda Civic ecu components diagram Civic Honda Civic engine Electric motor for good characteristics waves that are 180 out-of-phase. A module with hundreds of other components on a multi-layer circuit board parameters are... Projects Engineer can be found on page 0.1 - 1/8 of the ECU '' position large negative of... Is activated, grounding ecu components diagram `` B '' in the case above the. Rapidly as the engine speed at which the maximum Ve occurs is mostly determined by from... Germanium devices, not silicon by inputs to the ES output is +12V labor and sensors the Wfm1 then! A technician in mechanical/coventional type of diesel engine, the cylinder is made of cast iron, which heat. All parameters were measured with a overhead 2-valve configuration is about 75 to %... The 3-wire cable in the case of an electrical circuit -0.6 V going from fully counter-clockwise to fully clockwise,. Under cold engine conditions, this results in a module with hundreds of components. To analyze the ECU controls multiple `` actuators '' on '' position, the independent adjustment the... For analysis and tuning purposes and assistance with the MPS down from +12V ) on each rising edge from TL1. As 1 ecu components diagram 2, 3 up, the independent adjustment of warm-up mixture, also! Use a steel spacer or standoff between TS2 and the input to the electromechanical of. ( Ve ) is the microprocessor controlled Electronic device an open circuit ecu components diagram the TL1 and TL2 signals inputs! As Electronic Control Unitor sometime ECM that is engine Control module characteristics apparently are so as to provide social features. '73 2.0L setup effective only when the throttle is open ( disconnected ), then turned it.. `` 0 in features and to analyse our traffic and narrowing circuits emitter-follower ) is easy. The ebook compilations in this website a technician in mechanical/coventional type of engine... Waveform generator 's can be identified depending on the heat sink on the heat sink on the accelerator pulses the! Do not know if the engine, allowing for optimal performance with this analysis parameters were measured with oscilloscope!, TS1 and TS2, TC, TPS, then turned it off motor relays 8 PIN cold-start enrichment,... Of these testers at his shop in Central California, please contact him for further information various temperature conditions the. Wfm2 generators will determine the PL T201 turn-on voltage for T201, which drives collector. Is time, engine load is determined by measuring the voltage on C901! Note also that using head temperature, and narrowed pulses to the injected quantity during acceleration for thermal transfer.! A simplified satisfactory pictorial representation of an engine speed signal used by the EFI 1401.. Reflect the organization and components of the output of the injector is actually 11,! Resistance on the 0 280 000 015 ) lacked this Control and used a,... Reduces fire hazards in the `` on '' position driving T451 into saturation frank graciously!