|
|
Post by efiste2 on Mar 13, 2022 23:50:36 GMT 1
Having posted the issue in the general Mechanical section, I wont describe the issue in detail, just say that the car starts idles for a couple of seconds then dies. My question is, If the crank sensor was faulty would it generate a DTC code, even though the engine only runs for a short period. Im just wanting to eliminate the Crnak sensor from the list of "possible" causes.
|
|
|
|
Post by chippie on Mar 14, 2022 11:33:38 GMT 1
As you havent had a reply, I'd give it my thoughts............
The DTC codes arent set ( if any exist? ) until after the engine has started AFAIK.... but I stand to be corrected by some one more versed in vehicle diagnostics
Ergo, I'd say the crank sensor if faulty wont set a code and may/will prevent starting...
Best way is to swap it out for a new one or scope the waveform if you can....
|
|
|
|
Post by studabear on Mar 14, 2022 18:10:24 GMT 1
Or if you can access live data see if you see an engine speed when cranking.
|
|
|
|
Post by efiste2 on Mar 14, 2022 20:57:25 GMT 1
Thanks for the responses, as per my post in the Mechanical section it does start but then dies after a second or two. I can see the RPMS on the tacho and on Forscan live data until it dies. Does that indicate the Crank Sensor is operating correctly or are the RPMS taken from another source. I have a basic grasp of Forscan, but by no means fully conversant. Am I correct in thinking that unless the ECU sees the engine running (via crank sensor), it will shut of fuel and igniton. We have a new sensor on the way, and a fresh fuel filter as want to eliminate fuel starvation.
|
|
|
|
Post by Joepublic on Mar 14, 2022 21:11:06 GMT 1
I've seen a few hot rod programs where fitting a modern engine into an older body they had this symptom because the ignition switch powered ecu when cranking but no supply was there when in the normal run position, check for ecu power / ground after stall?
Immobiliser issue would also give the same symptoms?
|
|
|
|
Post by valhalla on Mar 15, 2022 0:51:41 GMT 1
I can see the RPMS on the tacho and on Forscan live data until it dies. Does that indicate the Crank Sensor is operating correctly or are the RPMS taken from another source. I have a basic grasp of Forscan, but by no means fully conversant. Am I correct in thinking that unless the ECU sees the engine running (via crank sensor), it will shut of fuel and igniton. We have a new sensor on the way, and a fresh fuel filter as want to eliminate fuel starvation. Older F*** softwares were not clever enough to revert to the cam-sensor as a back-up for engine speed. So to answer your question, I believe your crank sensor is working, as you are seeing engine speed over the Forscan toolset.
More modern calibrations can interchangeably substitute cam and crank-sensors for each other, albeit with some tweaks for a few engine cycles until it is all working properly. The worst sensor to "lose" is the cam-sensor, because it determines which bank the enigne is firing on. There are some clever algorithms for getting around this; the best are written by Rover Engineers. These work by remembering what cycle the engine is on when it stopped (Bosch also do this on some calibrations), and it is only when the ECU is powered-down, off the car, that the problems start. The ECU, on powering-up, has to determine which cycle the engine is on, and it does this by a) knowing that it has been powered-up from scratch, and has lost the register-entry for engine-bank, and b) monitors the engine-speed whilst trying to fire first on one bank, then another, and then picks the best solution.
A gasoline engine with indirect injection and lost-spark ignition is easy to get started, but not so easy to work-out which bank it is currently running-on. The cam-sensor is the ultimate arbiter for that decision, but I think your cam-sensor must also be working for no DTC to be set on cam/crank plausibilty.
|
|
|
|
Post by trickydicky on Mar 31, 2022 2:05:11 GMT 1
Will the car start and run on easy start?
Do our have a test light or noid lamp of some description?
Disconnect an injector plug and with the motor cranking use your test light to see If the injector is being switched after the engine dies.
One wire supplies battery voltage to the injector the other wire is a ground switched by the PCM.
Also make sure to do an EOBD scan not just Ford system
|
|
