Wardhill68,

I am really feeling for you!!!

BUT

I would like to rehash some old information that was discussed earlier in your effort to resolve the no start.

You mentioned that you had NO SPARK. Can you please explain exactly how you checked for no spark?

You mentioned in one of your responses that you had no help…….That is why I am curious.

There is a $5 tool that you can purchase at harbor freight or probably Amazon called an in line spark tester. This will allow you to check from inside the car while turning over the engine and just looking for a light to go on. You can check whether it is just one cylinder or more.

please don’t get discouraged…….I have been through this many times and with perseverance and support from this site…….you will get it repaired.


Thanks


Softball60/Paul

 

Yes I am flying solo on this. What I did to check for spark. Pulled plug and coil grounded plug by attaching a wired alligator clamp to threaded section of plug and grounding wire to block. Cranked engine over and could see no spark from plug. Today I stuck the end of a test light in the ecu relay base at #30 location and saw no indication of power there even with ignition turned on so I’m thinking my no spark is due to no power getting thru to my ecu relay, yet… my tach does jump when cranking so I’m confused I’ve checked both internal switches and resistance to ecu,ecm, load ,and aux load relays all checked out fine

 

Just noticed that Grant is on the site. I’m not wanting to put you on the spot but wondering if you had an opportunity to review Wardhill68’s current problem?

Grant a couple of years back you helped me with a very similar issue on my 96 xjs. In my case it ended up being the cam position sensor.

Any ideas?

thanks

Softball60/Paul

 

Yes, I think we get your message. One bad neighbor's experience means they are all bad.

 

Wardhill68,

I just went through some of my old notes. A non functioning cam position sensor can create a no spark condition. The cam position sensor communicates with the ecu which in turn sends signal to the engine. Ecu basically simulates the distributor for this function……..electronically instead of mechanically.


Softball60/Paul

 

I’m about to have this car towed to a mechanic that claims to work on jaguars. I’ve asked around for a referral but have gotten nothing. Is there a way to test the cam position sensor?

 

No, the cam position sensor will not create a no spark condition. It's only purpose is to tell the ECU when Cylinder #1 is TDC. A failed sensor, which is very rare, only causes prolonged startup as the car does a trial and error process without it.

The crankshaft position sensor, which I believe has already been replaced can cause a no spark.

 

Wardhill68,

It seems as though I am having difficulty explaining why I think it could be the cam position sensor.

Sorry about that.

Please refer to original posting by me back on 9-23-20 …”Takes a while to start”.

This posting sounds very sillier to what you are going through.

Go to threads section located on the upper right side and type Softball60. Go to page two (2) and look for “Takes a while to start” and read on.

There are some posts from Grant Francis explaining the cam sensor and some info you can download load

Softball60/Paul

I am not very computer literate and don’t know how to simply forward this posting.

 

sB60 i truely appreciate your help on this but i feel my situation is somehow different as i cant get the car to fire at all even after long cranking. I am 99% sure there is no spark at the sparkplugs or power at the base of the ecu relay #30 in the passenger side knee bolster. I have read that the multifunction control unit located near there can also be a culprit. But I have yet to figured out how to remove it to inspect for corrosion. I strongly believe that moisture inside the car over the winter has created this situation. But as a starting point to clean grounds i cant seem to find any other than the one for the ecu and those located in the trunk.

 

The attached is from the AJ16 Service Manual, and it looks like there is one item you haven't considered yet -- the Throttle Position Sensor. Might be worth a look.

 

Ill have the mechanic look into that. Do those tend to fail suddenly as the car was running great until parked?thank you btw

 

wardhill68,

If you're not seeing a feed on the EMS Power relay, or the ECM Controlled relay at terminal 30, then I would go back to Fuses 7 & 14 in the Right front fuse panel and check for output voltage there. It is possible that the problem is further back in the power circuit. Don't worry about CPS. CKPS. or TPS at this point. If you haven't got input power to the ECU, it's not going to start.

You've got access to the wiring diagram. Start by looking for ignition controlled feeds to the relevant fuses above. If there's no input voltage there, go back to the ignition switch. If there is input voltage at the 2 fuses. then check for output voltage of those fuses. When you get voltage there, go to Terminal 30 on the relays. Just follow this through logically.

You WILL get this sorted!

Good luck

PAul

 

thank you paul i will pass this onto the mechanic tomorrow and will report back. Grateful for your response, jeff

 

Just run a temporary 12-volt supply to the relay and see if the car starts then.

 

Attached is the lastest assessment fron the mechanic, i feel like im back at the beginning here please see attached

 

You need a good mechanic that does more than throw parts at the problem.

 

Jeff, this is certainly a long shot, but you have nothing to lose at this time. In your original post you thought it could be related to the security system. I don't know if the security system will prevent the car from starting or not, but maybe the car thinks it is in alarm. The emergency reset procedure is to unlock and open the driver's side door and then, within 15 seconds, turn the ignition key from off position to position "II" THREE times. This will reset the alarm condition. Worth a try.

 

That sounds familiar, you should give it a try and nothing to loose.

 

Thanks . I will try that procedure and report back. Although I never lock the car.

 

Could you give me some direction on how to do that? Sounds interesting