Buick – 3100 SFI Engine Training (1994)

the Buick Division of General Motors is bolstering its competitive edge with an all-new powerplant for the Buick Regal and Skylark the 3100 SFI 60 degree V 6 l 82 engine with excellent horsepower torque and serviceability is available on 1994 regal and Skylark the 1994 Buick Century also features a 3100 SFI engine however the century engine features a different fuel management strategy one that’s similar to the well-known 3800 engine used on many popular Buick models the new 3100 SFI Regal and Skylark engine has been redesigned from the block up and features many improvements over the lho 3.1 liter v6 along with many mechanical changes to the engine a new fuel and emissions control system featuring a 66u PCM transforms this power plant to sequential fuel injection this new PCM is necessary to meet the upcoming emission standards of 1996 in 1996 engine management systems will be required by law to detect engine misfire as well as monitor catalytic converter efficiency canister purged flow rates exhaust gas recirculation flow rates and air injection reaction flow rates in this CPT presentation will examine the 3,100 sequential fuel injection v6 engine concentrating on is 66u PCM engine management system after an introduction to the engine and hardware will investigate the overall management strategy and system controls will also review system diagnosis as well as several related service procedures although the 3100 SFI VIN M engine replaces both the 3.1 liter VIN T and the 3.3 liter VIN n engines it has far more similarities with the 3.1 liter VIN t engine including bore stroke and displacement both are 60 degree v6 s the RPO code for the 3100 SFI is l 82 while LH o is the code for the 3.1 the 3100 SFI also features a higher compression ratio of 9.5 to 1 and sequential fuel injection compared to the 3.1 liter engines 8.5 to 1 compression ratio and multi-port fuel injection the 3100 SFI engine has several new features we will cover to start with the engine block itself has been designed with a priority lubrication system that delivers oil on a priority basis to critical bearing assemblies there is also a structural cast aluminum oil pan the oil pan is cross bolted into three of the main bearing caps to improve the rigidity of the entire engine assembly each oil pan crossbolt has an integral rubber gasket under the bolt head also notice that there is a new oil level sensor another feature is a new oil deflector or windage tray this deflector prevents oil from hitting the crankshaft during hard cornering maneuvers this improves in performance and helps prevent aeration of the engine oil the manufacturer of the camshaft is radically different from previous engines it features a hollow steel shaft with pressed on cam lobes the camshaft components are made of a variety of metals based upon their function the result is a highly versatile and durable camshaft along with this new roller lifters with a two-piece plastic retainer are used for peak performance the fuel injectors are precisely targeted at the back of the intake valve in addition to optimizing combustion

quality this configuration also helps control emissions the cylinder head design incorporates swirl induction intake ports and deport exhaust this translates into improved air flow through the combustion chamber and more horsepower on top of the cylinder heads our new conical valve springs which offer a variable rate tension on the valves this prevents valve float during high rpm and finally the rocker covers are of a composite plastic that helps reduce engine noise from the valve train along with improvements made to the engine you’ll see some new sensors that allow the 66u PCM to fire the injectors sequentially in addition to the familiar seven knotch crankshaft sensor and it’s 3x input to the PCM there is a high-resolution hall-effect 24x crankshaft sensor mounted at the front cover also new is a Hall effect type camshaft sensor which is mounted to the block and a four wire heated o two sensor is found in the exhaust manifold with the additional sensors and the 66u PCM more output control is possible using an advanced engine management strategy Skylark and Regal 3100 SFI engine management is controlled by the 66u PCM it is best to lay out the entire system before reviewing individual highlights major system information inputs on the Skylark include the manifold absolute pressure or map sensor the heated oxygen sensor the throttle position or TP sensor the engine coolant temperature or ECT sensor the intake air temperature or IAT sensor and the knock sensor also remember this engine has two crankshaft position sensors as well as a camshaft sensor furthermore there are sensors to allow PCM control of the 46 te transaxle shift feel and timing major outputs for the system also called controlled devices include each of the individually controlled fuel injectors as well as the fuel pump relay the idle air control or IAC valve the ignition module coil assembly the exhaust gas recirculation or EGR valve the evaporative emissions canister purge solenoid valve the AC clutch and the engine cooling fan the brain of the system is the 66u PCM it is really two controllers in the same box the esight GMP 6 controller and the t side also a GMP 6 2 controllers are used providing the processing power necessary to enable the engine management system to meet the upcoming 1996 governmental emission standards the e side basically handles the inputs and outputs that are event-based these include fuel spark EGR and canister purge time-based inputs and outputs are controlled on the T side transmission idle air control Diagnostics air can cooling fan and backup fuel functions are examples the 66u PCM has a programmable flash EEPROM memory which will be reviewed later in this presentation with the capabilities of the 66u PCM in mind let’s review the highlights of individual system control beginning with fuel the six sequentially fired injectors features saturated switch drivers and fuel can be delivered synchronous or asynchronous asynchronous delivery is for cold engine acceleration only at engine startup the PCM looks at engine coolant temperature and sets its run timer to end open-loop operation based on the ECT reading after the timeout period the PCM looks at the o2 sensor output voltage and determines if it is at operating temperature if it is the system enters closed loop operation this is similar to other engines you’ve experienced however there are several unique inputs and outputs for 3,100 SFI fuel control the cam sensor is the synchronizing trigger for sequential fuel control during cranking the PCM

provides three prime pulses at all six injectors based on the low-resolution 3x signal for start-up it then looks for the falling edge of the cam signal to trigger injector number four after this the PCM primarily uses the 3x signal to time the sequential firing of the individual injectors however the high-resolution 24x crank sensor has a unique role in fuel control this is because the 24x contributes to filtering of the map signal at speeds below 3000 rpm the 66u PCM reads map output at each of the 24x reference input signals the PCM then averages map over every four counts of the 24x input signal to a more stable map reading for fuel control at low engine rpm the IAC valve position is no longer needed to calculate airflow at idle for fuel delivery this is also due to the filtering of the map sensor signal in essence speed density fueling is being used at idle in addition to higher engine speeds on Skylark and Regal as you’ve probably guessed this was all done to improve engine starting as well as cranking and idle quality furthermore this highly accurate 24x signal also provides other improvements including the elimination of an extensive idle relearn procedure and while the century 3100 SFI engine shares many of the sensors found in the Regal and Skylark version the century uses a mass airflow system rather than a speed density strategy the mass airflow sensor replaces the map sensor and allows the centuries PCM GMP for to see actual mass airflow entering the engine for combustion now to continue with the 66u PCM engine management system a heated oxygen sensor is used for improved control of the air fuel mixture like other heated oh two sensors the heater reduces warmup time and helps maintain operating temperature at idle control of ignition timing uses the 3x and 24x crank sensors similar to fuel control during closed-loop idle control with the throttle closed the PCM looks to the 24x crank sensor for idle speed minor deviations in idle speed are corrected by the PCM with spark control major deviations are handled by the IAC valve basically when engine speeds are below 1200 rpm the more exact 24x signal is used for engine speed above 1200 rpm the 3x signal is used in addition the 24x Bank sensor provides extra accuracy during crank and start for precise spark control the PCM continuously uses IC control for all ignition functions the bypass mode is only used for backup operation during a system failure the 3x crank sensor on the other hand is used off idle above speeds of 1200 rpm while the 46 te automatic transaxle has been around for a couple of years there are new inputs to take advantage of 66u PCM control the transaxle range switch helps maintain idle quality when shifting from park to drive as well as help maintain correct TCC engagement points by informing the PCM of the gear selector position the transaxle fluid temperature sensor or TFT is a two wire thermistor located inside the transaxle and operates much the same way as an IAT sensor major PCM transaxle outputs include the a and B solenoids that produce the four forward speeds the PCM also controls the TCC as found on previous models however the brake switch is not only hard wired into the TCC circuit but is also a discrete input to the PCM as well it’s important to note that the TCC solenoid and the canister purge solenoid are the only pulse width modulated outputs of the PCM on the 3100 SFI engine end part 1 you should now prepare to take the first part of the test for this course to take the test you must have a number 2 pencil and the official student attendance and test

form in front of you make sure the first seven digits of the course number printed in block 9 of the student attendance and test form match the first seven digits of the course number printed on the course book and the videotape label if you do not have the correct materials stop the video and get them begin by placing the student attendance and test form in front of you so that the clipped corner is in the lower right in the upper left-hand corner of the form you will see a series of circles below the letters A through e at this time you’ll be filling in the test answers only at the end of this video instructions for completing the remainder of the form will be provided this is the only answer sheet you will need for this course in a moment you will see the first test question and several possible answers when you have decided on your answer completely fill in the circle below the letter corresponding to the correct answer since this test will be corrected by computer it is important that you avoid making stray marks on the paper if you change your mind about an answer be sure to erase your first choice completely before marking the correct answer it is also important to avoid getting dirt or grease on the answer sheet or folding it as this may cause the computer to incorrectly score your test as you take this test remember that there is no time limit you may take as much time as you wish to complete the test you may also review the course book or rewind the videotape to find the correct answer begin test part 1 at line one of the test form test part 1 question number 1 event-based 66u PCM inputs and outputs are handled by the a ignition module B T side C east side or D EEPROM question number 2 during cranking the PCM provides three prime pulses at a injectors number one and two B injectors number three and four C injectors number five and six or D all six injectors question number three the 66u PCM averages map every four counts of the a3x crank signal B 24x crank signal C half x cam signal or D 64 X output signal question number four the 3100 SFI v6 features to a crankshaft position sensors B camshaft position sensors C input shaft position sensors or D output shaft position sensor when you must diagnose the 3100 SFI you’ll find that the more elaborate engine management strategy offers you advanced data parameters and capabilities to fix it right the first time as with any vehicle diagnosis must begin with a clear understanding of the customers concern a thorough visual inspection is also essential a loose wire or disconnected vacuum hose must not be overlooked also remember that despite the advanced electronics this is still an internal combustion engine and basic mechanical operation must be sound for good performance diagnosis must begin with the onboard diagnostic system check using the tech one the tech one starts by trying to establish data communication with the PCM if data is not available follow instructions to diagnose a lack of serial data next the tech one will ask you to perform the malfunction indicator lamp or M il system check if the mi L is not functioning properly use chart a1 to determine the cause then start the engine if the engine won’t start crank but won’t run diagnosis is necessary the final step of the check is to request diagnostic trouble codes or DTC’s special note flash DTC’s are no longer available by grounding the data link connector you must use a scan tool to read codes if there are no DTC’s compare scan data values with the service manual data list if values are normal use section be symptom diagnosis if there’s a value that isn’t normal use the appropriate component system check in Section C there are several new

DTC’s associated with the 3100 SFI that are related to the transaxle none of the transaxle DTC’s will illuminate the mi l each of the sensors that contribute to idle quality have codes as with the transaxle DTC’s circuit errors for the cam and both crank sensors do not turn on the mi l and finally these codes relate to system power and the 66u PCM note that a double EEPROM error does not turn on the mi l also keep in mind that several dtcs have been renumber a complete list is found in the reference book that accompanies this CPT video release while much of the available scan data is familiar there are some new values to aid your diagnosis of the 3100 SFI for ignition control you can view both the 3x and 24x crank sensors in addition to cam sensor output it is important to realize that the actual rpm figures of these readings will vary slightly due to the updating rates of the sensors this is normal also remember these sensors influence both idle fuel and idle spark control if the 24x sensor fails the mi L will not light but the system will set a code 36 the PCM will calculate engine timing using the 3x low resolution sensor in this case the customer may experience rough idling if the 3x sensor fails the car won’t start code 82 will set and again the mi L will not light regarding emissions control the requested percent of evaporative purge can be seen you can also view the number of key cycles since a dtc was set or clear after 50 cycles any history DTC’s are erased also the prom ID has been relocated it is now called the calibration ID and is found under miscellaneous tests there is another Tech one capability worth noting the cylinder balance test is programmed into the tech one mass storage cartridge be sure to follow Tech 1 instructions and thoroughly refer to the service manual discussion of this test the injector coil test is one of the available tests to verify operation and should be done only after performing the other tests it requires fuel injector tester je 39 0 to 1 and digital voltmeter je 39 200 or equivalent begin by relieving fuel system pressure according to the service manual procedure be sure to follow the instructions supplied with the tester basically the tester connects to the vehicle battery and an individual injector the meter connects to the tester set the tester amperage supply to the 0.5 amp position engine coolant temperature should be between 50 and 95 degrees Fahrenheit basically room temperature if not you’ll need to compensate the readings using a subtracted value method according to the service manual chart merely push the test start button and record the lowest voltage ignore the voltage during the first second where a current surge occurs each injector coil should show between 5.7 and 6.6 volts also readings may increase during the test as the injector windings warm a low reading shows high resistance within an injector also an erratic voltage reading during the test indicates an internal intermittent within the injector also related to injector testing is the tech ones ability to reset an injector driver during an English cycle regarding the new sensors diagnosis is efficient and accurate using the proper tools and procedures let’s quickly review a DTC 36 which is a 24x signal circuit error in this example our vehicle runs so we begin by installing the tech one to see if the 24x signal shows an RPM reading since we didn’t have a signal we turned the ignition off and go to the PCM after disconnecting PCM harness connector see turned the ignition on then connect the DVM to harness pin 21 and look for system voltage if no

voltage is present turned the ignition off and disconnect the 24x crankshaft position sensor pigtail harness connector the DVM should display battery voltage when it is connected between terminal a and ground a lack of voltage indicates an open in circuit 6:39 which is the ignition feed end part to you should now prepare to take the next part of the test for this course if you are unsure of the answer you may stop the tape to think about the question review the course book or rewind the tape and review it before answering test part to begin this portion of the test at line 5 question number 5 history DTC’s are erased after a 25 key cycles B 30 key cycles C 40 key cycles or D 50 key cycles question number 6 the centuries 30 100 s fi engine uses a management strategy based on a mass airflow B speed density C air density or D engine speed only question number 7 when viewing 3x and 24x sensor output on the tech 1-hour p.m. figures will a be the same be very slightly C be shown as ranges or D not be available simultaneously servicing the features related to the 3100 SFI system on Skylark and Regal is basically what you would expect however here are a few special highlights including using the service programming system or SPS which we’ll cover later the 24x crankshaft sensor takes a little effort to get at after removing the serpentine drive belt remove the torsional damper bolt and washer the torsional damper requires tool J 24 420 dash B or equivalent for removal notice the back of the torsional damper there is a twenty-four window disk which triggers the Hall effects switch after removing the harness retainer the 24x crankshaft position sensor and its two bolts can be removed the camshaft position sensor is held into the front of the upper block by one bolt the 3x crankshaft position sensor is also retained by one bolt and is found on the rear of the block also related to 3100 service are the state-of-the-art micro PAC 100 PCM connectors you may recognize them from the ABS 6 controller special crimp tool Jai 38 125 – 25 is required for terminal replacement the secondary push lock retainers must be used to secure the connectors to the PCM the 66u PCM allows you to take advantage of the service programming system or SPS the tech line terminals such as the T 100 T 60 T 50 and T 20 connect directly to the vehicle with the tech one programming is remote using any cd-rom terminal approved by tech line please realize that a service replacement PCM require is programming if unprogrammed the engine will fail to start after exchanging plug-in knock sensor or KS modules verify that all data line and power connections are secure any interruptions of data transmission or power during an SPS procedure can damage the 66u PCM before beginning an SPS procedure check for the latest service bulletins information then turn the ignition to on the engine must not be cranked during the ki cycle verify battery voltage is between 11 and 14 volts and all accessories are off be sure to exactly follow the procedure for the type of tech line equipment you are using you must wait for the programming successful message it is important to turn the ignition off for five seconds to power down the PCM before disconnecting the equipment for further information refer to the SPS certified plus training course number 56 o 10.00 end part 3 before answering the last video test questions please complete the

portion of the student attendance and test form that identifies you and your dealership if this portion of the answer sheet is not completed correctly you and your dealership will not receive credit or certification for this course begin by placing the student attendance and test form in front of you so that the clipped corner is now in the upper right print your last name in block 1 located in the upper left hand corner putting only one letter in each box print your first and middle initials in block to print the name of your dealership in block 3 your dealership city in block 4 and state in block 5 be sure to use the official US Postal Service abbreviation for your dealership state print your social security number in block six enter your dealer code in the space provided print today’s date in block eight return to block one in the upper left hand corner of the form below each letter of your name is an alphabet fill in the circle with a letter that corresponds to the letter of your name at the top of the column follow the same procedure for the numbers of your social security number in block six today’s date in block eight and your dealer code in the space provided you should now prepare to take the final part of the video test for this course test part three begin this portion of the test at line eight question number eight after receiving a programming successful message when performing an SPS procedure a road test the vehicle be let the engine run at idle for five minutes C turn the ignition off for five seconds to power down the PCM or D check the M il for dtc 71 question number nine 24 x crankshaft sensor removal requires removal of the a serpentine drive belt B torsional damper C harness retainer or D all of the above question number 10 during an SPS procedure verify that a data line and power connections are secure B battery voltage is between 11 and 14 volts C all accessories are off or D all of the above you have now completed the video portion of the test the course book accompanying this videotape contains the final part of the test once you have completed the test you may wish to make a photocopy of it for your records after photocopying place the student attendance and test form in the pre-addressed envelope no postage is needed remember to complete the questions in the back of the course book before mailing the test form to cpt headquarters good luck the next step in engine management the 66u PCM and its network of inputs and outputs will have a major role in all GM products meeting the increased government standards of 1996 use this train the available service information and your years of experience to make each one of your customers totally satisfied