Crank speed sensors - go/no go?
Discussion
By scanner, do you mean an oscilliscope on a tuning machine? Forgive my ignorance on this. The car is not displaying the check engine light and there are no codes displaying on the on board trip computer LCD screen. I don't know if this model of Jaguar has a connector for a computer diagnosis.
I will see if there is someone in town who might know what they are doing on a Jaguar of this age. Like I say, I live in a relatively small town where 'Jagwires' are often mistreated by owners and garages.
I will see if there is someone in town who might know what they are doing on a Jaguar of this age. Like I say, I live in a relatively small town where 'Jagwires' are often mistreated by owners and garages.
geeman237 said:
By scanner, do you mean an oscilliscope on a tuning machine? Forgive my ignorance on this.
No, I mean a basic EOBD fault scanner, which also lets you see live data. Generic stuff is more limited than vehicle specific, but it should still give some info.That said, I dont believe you have stated the age of the vehicle, only a model.
But an oscilloscope to test the crank sensor output would be a better test if they component or it's wiring is believed to be suspect. And oscilloscopes are portable these days.
For a garage, maybe try asking over here. It is a more trade/diagnostics based forum, so may have better leads as to competent garages if you ask are there any reccommendations in your area.
http://www.bba-reman.com/forums/
The symptoms are on light throttle I can feel a light 'miss', its regular, the engine never cuts out or falls down on power. I can really notice it in 3rd gear near 30mph. New plugs, rotor, car, and coil just fitted and plug leads new about 3 years ago.
I have just had the fuel injectors cleaned and flow tested. I will fit them later this week.
I have just had the fuel injectors cleaned and flow tested. I will fit them later this week.
I realise I am a wee bit late to reply to the original message but just wanted to say that I too have a 1994 XJS 4.0L. I recently encountered running problems (irregular turnover) which progressed to starting problems. Eventually, the car would turnover with no hint of it being able to start. I don't do any maintenance so it was loaded on to a load loader and taken to the local garage I use. The garage replaced the crankshaft speed sensor and it was/is working again. So, my problem progressed over a matter of weeks but my use of the car is very infrequent so I suspect it would have been much sooner if I had been using it more but it does suggest that there is a middle area between it working and not working. I hope this helps. I had prior to, and still have, a slight irregular running at tickover and I have just ordered a new distributor cap and rotor arm to 'throw' at it to see if I can get a smoother tickover.
Crank sensors are subject to the heating and cooling of the engine.
The different materials that make up the sensor expand at different rates.
Eventually, they will fail whether open circuit, short vref to ground, losing sensor ground.....etc.
I've found hundreds that were intermittent.
The most common pattern is having a car that starts fine only to glitch about 5 minutes after a cold start.
The different materials that make up the sensor expand at different rates.
Eventually, they will fail whether open circuit, short vref to ground, losing sensor ground.....etc.
I've found hundreds that were intermittent.
The most common pattern is having a car that starts fine only to glitch about 5 minutes after a cold start.
Indeed, they can be flakey things. I had a Viper that stalled at idle when the clutch was depressed............ (turned out the car had a hookey "racing" flywheel fitted, which was allowing the crank target wheel to actually contact the sensor when the clutch thrust loads were applied)
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