My 96 XJS won’t start. It was running fine when I park it a few weeks ago. It cranks but it does not seem to fire. I checked all fuse and relays, I have fuel pressure at the fuel rail & when I crank it, the tachometer does move. I think it may be the crankshaft sensor or the camshaft sensor but I don’t know how to test them. Any help??? Please???

 

Welcome to the forum tedmier96xjs,

I've moved your post from General Tech Help section to the XJS section. It will be seen here by members with the same model as you have who are best placed to offer advice.

When you get a minute, please follow this link New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum to the New Member Area - Intro a MUST section and post some info about yourself and your vehicle for all members to see. In return you'll get a proper welcome and some useful advice about posting to the forum.

Graham

 

If the tacho registers about 200rpm when you crank the engine, the CPS is probably fine.

If the engine is turning over and you have fuel pressure at the rail, check to see if you have spark and that your injectors are working (ticking sound).

Also it's quite common that these cars can flood, especially when trying to start after some lengthy idle period. Try starting but keep the accelerator to the floor and hold it there, it may take 5-10 secs but if it is flooded this normally sorts it out.

Cheers,

Allan

 

Thank you all.
The outcome:
Check all fuses & relays – Good
Check fuel tanks with stethoscope and hear fuel pump - Good
I checked the fuel pressure at rail and it was - Good
Tach shows about 200rpm so CPU should be – Good
Checked spark - NO spark
Finally checked crank sensor – BAD
To check the crank sensor I removed it an checked the resistance with a simple meter. It should be 150 to 300 ohms.

 

Hope this information will help someone in the future

 

I had the same thing happened and found out that the Tach will read 200 RPM's or so when trying to start a 95' or 96' with a bad CPS. This is important to know as many thought the Tach will not read if the CPS has stopped sending the correct signal. The CPS on the AJ16 will go bad from age as best I can tell the magnets will get weak with age. I would replace every 10 years and from my research it is a common enough failure with age ( not just mileage) that I now carry a spare in my trunk just in case. Fairly easy to replace CPS and common for car to run fine and then next start up will crank but not start-no spark-tach shows 200Rpms on cranking and fuel pressure to the rails-very common failure on AJ16 engine. Hope this helps to clarify.

 

I just posted a new tread but looking to give this one life again as I have a similar issues. Mine started after I cleaned, with water, out the engine bay. When I crank it the tac goes up on first rev and then stop. Will this be the CPS? Looking for a replacement guild for this CPS as I’m having an issue locating it.

 

Hi MattVo

Here is my Complete Guide to removing and replacing the Crank Position Sensor on an AJ16 Engine together with lots of Photos

Just to add to what you will find in this guide

(1) Always get to it from underneath the Bonnet/Hood (not from under the Car)

(2) Get yourself a Mirror on a Stick and/or a Smartphone Inspection Camera (Not essential but it does make things a little bit easier)

(3) Undoing its (Clip Together Plug) is a bit of a PIA and so it may be easier to remove the Bracket that Holds the Plug held by two small bolts (its in the guide) and this is why you need the Mirror as those Bolts can be hard to locate and then you have to remember where they are, as there is only room for one hand which will then obscure your Vision

(4) No need to remove any hoses or anything else providing that you do have fairly small hands

(5) The Crank Sensor itself is held in by just one bolt (see guide)

(6) Tricky to do the first time but once you see how it all hangs together you can Change it by the Side of the Road in only a Couple of Minutes

(7) Do an Ohms Continuity Test with your DV Meter on the Two Terminals of the CPS reading should be 150-300 Ohms if so then all good, where the problem could be that the Magnet is dirty and needs a Clean or you need to adjust the gap Max 0.042

(8) As has been already said Carry a Spare in the Glove Box as the CPS on an AJ16 can go a bit flaky from time to time

Here is the Guide: How to remove/replace the CPS Crank Position Sensor on an AJ16 Engine