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Sensor school
Please someone (anyone) learn me about some of these sensors I keep hearing about. Please tell me the FUNCTION, and SYMPTOMS of MALFUNCTION, so I can understand how my engine works [and also how these might be involved in my present problems - intermittent rough idling and car shuddering (shaking) that are undiagnosable to date]:
1. Crank sensor 2. Cam sensor 3. Knock sensors 4. Throttle position sensor THANKS Jim |
#2
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The crank sensor is a magnetic pick-up, there are two mounted to the oil pump frame right at the top of the engine. There are two revolving plates with points attached to the crank, the points pass by the crank sensors. When the point passes by the sensor it generates a voltage pulse that tells the ECU where the crank position is located. This is used to adjust the timing of the engine so that the ECU know where top dead ceneter is for each pistion. If these fail the engine will not know when to fire.
The CAM sensor is also a magnetic pick-up the reads the position of the driver side cam shaft. I am not sure why it's there. I'll check the SM. Knock sensor are accelerometers used to measure the engine vibration and to find firing detonation and adjust the timing thru the ECU. If these fail the engine should still run but may detonate. TPS tells the ECU where the throttle position is. This is a variable resistor that changes value in proportion to the gas position. The ECU and the TCU use this device. If it's got dead spots the ECU would know what's happening. Search on TPS test. Maybe someone could you loan you working sensors to see if the problems go away. |
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re: knock sensors
so how do you tell if your knock sensors are out?
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Quote:
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ASE Certified Master Automotive Technician w/L1. ASE Certified Master Medium/Heavy Truck Technician. Certified EVT (Emergency Vehicle Technician) |
#5
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Knock and TPS sensors?
OK! I appreciate the info on the sensors, but what about the Knock and Throttle Position Sensors:
Would either (on intermittent failure) produce a rough idle or poor performance as I've described earlier (under transmission post by James Scott). THANKS, Jim Last edited by James Scott; 01-20-2003 at 01:05 AM. |
#6
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The knock sensor will not affect the idle and it would be very odd that the TPS would either. The TPS can cause many assorted maladies as the computer tries to figure out how an engine would produce a rpm figure with the throttle only open a certain amount (if the TPS was reporting incorrectly.) The TPS can also affect shift quality and shift timing, as the transmission relies upon it also. I'm not saying that this is or isn't your problem, but it is worth checking into. It's not, in my opinion, worth buying one just to find out though. There are ways to check the TPS with meters, etc. The knock sensor(s) will cause the computer to light the check engine light if bad.
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ASE Certified Master Automotive Technician w/L1. ASE Certified Master Medium/Heavy Truck Technician. Certified EVT (Emergency Vehicle Technician) |
#7
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one more sensor?
Thanks Beav! That helps my understanding alot!
I forgot to mention one more sensor in my post > > > > > What about the Mass Airflow Sensor? Please give me some schooling and your opinion on its possible involvement. THANKS AGAIN for all your time and expert advice, Jim |
#8
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Troubleshooting guide
Jim,
You might be interested in the following; The Workshop Manual has a troubleshooting chart for the fuel system. It lists probable causes in order of priority, #1 being first call. This priority system indicates which part to check first,but I am not sure this means it indicates this part is most likely culprit, or is the easiest and most sensible to eliminate from the list first. Here's the list for "Rough Idling" : #1 ECU power supply* #2 By-pass air control solenoid valve #3 Air flow sensor #4 Ignitor #5 Ignition coil #6 Spark plug #7 Fuel pump #8 Pressure regulator #9 Fuel Injector #10 Throttle Sensor #11 Water temperature sensor #12 Crank angle sensor 1 #13 Crank angle sensor 2 #14 Cam angle sensor #15 02 sensor 1 & 2 * Instructions to "Include ECU grounding circuit" Joe
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Black Betty [Bam a Lam!] '93 UK spec, still languishing Betty Jersey Girl Silver '92 UK [Channel Isles] 40K Jersey Girl @ Mersea Candy Purple Honda Blackbird Plum Dangerous White X2 RVR Mitsubishi 1800GDI. Vantastic 40,000 miles Jersey Girl |
#9
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Priority list . . . . .
Yes Joe, Thanks for the nice diagnostic priority list. [I just typed a long response to bring this up to date and deleted it by mistake. YIKES!] I'll have to update my story later >>>
THANKS AGAIN, Jim
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Jim 1995 Laguna Blue SVX AWD L - 240K (daily driver) - "ReBuILT" used engine at 236K miles (6/13) 2013 Veloster Red - Driver Now??Dropsprings [1/2" rear, 1" front] with Koni Strut Inserts> Magnaflow Exhaust System> ECUTune Stage 1av1 Upgrade (from 1v4)> ECUTune TCU MOD> Aluminum Crankshaft Pulley> Stainless Brake Lines> Phenolic Spacers> Perforated Brake Rotors (dint like, OEM now)> SmallCar Shift Kit (resting since TCU MOD)> 7-Position Ground System> High-Pressure Fuel Pressure Regulator (resting)> ATF Cooler & Campaign Filter> Yellow Polish Polyurethane Bushings> Pioneer Double-DIN Stereo with JL AUDIO Speakers> Driveshaft Rebuilt with C-Clip U-Joints> 15 Min MOD> 20 Min MOD .. . (2011) Valentine One Radar Detector with Remote Display - ucan'tseeme! Last edited by James Scott; 01-24-2003 at 01:23 AM. |
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