In particular, the observation about tapping on the injectors does not sound right. There are two of them, and failure of one would be rare. To have both stop working at the same time is not very likely. A better suspect is spread terminals in the connector, but that usually causes intermittent operation of just one of the injectors. Tapping on that connector could overcome the bad connection and start that injector working, for a while.
You need to check for spark first, before you go looking for the hard stuff. The "clear flood" mode had better not prevent spark from occurring, as that would just make the problem worse. There was some confusion there to. The throttle position sensor on almost every engine has a 5.0-volt feed wire and a ground wire that will actually have 0.2 volts on it. The TPS has mechanical stops inside it that, for the sake of explaining theory, limits its range of travel on the signal wire from 0.5 volts to 4.5 volts. It is physically impossible for the signal voltage to go outside that range unless there is a break in a wire or a broken connection inside the sensor. Those wiring defects will send the signal voltage to 0.0 volts or 5.0 volts, and that is what the engine computer needs to see to set a diagnostic fault code. In actual practice, you may find the range to go from, oh, 0.38 volts to perhaps 4.2 volts. No two sensors are ever exactly the same. The point is you must never see 0.0 or 5.0 volts on the signal wire.
Also, understand that disconnecting the TPS may not prove anything. The open circuit on the signal wire will force an intentional 5.0 volts which is intended to set a fault code, and that code tells the computer to stop basing any fuel metering or other decisions on those readings. The TPS actually has the least say in fuel metering than any of the sensors. Also, nothing related to the TPS will cause loss of spark.
It is important to check for spark when you have no injector pulses. Too many people get hung up on the first thing they find missing, and neglect to see all the other related symptoms. About ninety five percent of crank/no-starts are the result of no spark and no injector pulses. The other five percent are caused by loss of spark, or loss of injector pulses, or a non-running fuel pump.
The coolant temperature sensor has absolutely nothing to do with the TPS or with modifying the TPS's signal voltage, except that multiple sensors share a common ground wire.
The place to start the diagnosis is always to first read and record the diagnostic fault codes. You can only do that yourself on Chrysler products, or on GM products older than 1996 models. It is possible to read them on 1995 and older Fords too, but it is a miserable procedure and takes a long time. For 1996 and newer GM's, you need a scanner or a simple code reader. Those fault codes may tell you the circuit or system that needs to be diagnosed, and for this problem, that is most often the crankshaft position sensor circuit or the camshaft position sensor circuit.
Friday, February 12th, 2021 AT 11:38 AM
(Merged)
