1997 XJ6 No Start -- Rare I know...
 

Hello,
Longtime reader, first time writer. I have seemingly viewed all no-start stories, and cant seem to find similar symptoms that plague my fathers '97 XJ6. After running great for years, one morning a non-start. The engine cranks and cranks, but will not turn over.
No "check engine" light on, the battery is charged, strong fuel flow to the rail (and strong smell of fuel while cranking), strong spark from the plugs and tach dances while attempting to fire (which I believe eliminates crank sensor)? We replaced the cam posi sensor (used part albeit) and still same result. Checked fuses etc and cant seem to find source of the problem. Only fault code vehicle has ever shown was oxy sensor.
Before my father donates his favorite car, is there anyone out there who can steer us in a clearer direction? Thank you in advance, and I appreciate your time and assistance.


Take care,
Scott

Flooded perhaps? I had a similar thing happen, got it towed to the mechanic and all it took was removing the plugs, drying them off and it fired right up.

The "strong smell of fuel" thing makes me think it is flooded. Battery fully charged and voltage not dropping while cranking? Maybe jump it with another known good battery just to make sure? If the voltage drops too far under cranking all sorts of weirdness can happen.

After drying the plugs, perhaps try starting it normally, and if no luck then floor it. That puts the ECU into "clear flood" mode and won't fire the injectors while cranking.

Did you replace the cam or crank position sensor? You said cam, and that's the round thing on the side of the engine. It's not strictly necessary for running, as if the ECU doesn't detect starting it will flip the spark to the other stroke and see if the engine starts. Crank position sensor is essential though.

Jagboi64-


Thank you for your advice.


The plugs were pulled, and were actually dry and relatively clean. I will try the starting procedure and peg it if it hesitates, after confirming the battery is fully charged. The cam sensor was changed, but after reading several threads, I was under the impression if the tach danced and there was spark during cranking, the crank sensor was not the issue? Either way, I will clean the crank sensor first, then follow your advice.


I certainly appreciate your time.


Take care,
Scott

Second thought, you said there was strong flow of fuel to the rail? How did you determine that? There isn't easy access to the fuel on an X300. I was going to suggest measuring the fuel pressure, but that's not easy to do on these cars.

There have been reports of water ingress to the ECU and that causing problems. It's located behind the passengers footwell trim panel, right side, just forward of the door opening. Worth checking the connectors for any corrosion.

Also, do you have an OBDII scan tool that can display a live datastream, rather than just codes? That might be useful to plug in and then crank to see if the ECU is really seeing a tach signal.

Maybe I overstated - the fuel line was removed under the hood and the engine was turned over to inspect the fuel flow.


I will also check the ECU, which I have read was a idea worth investigating.

What does that mean? When the key is turned to the run position, before the crank position, the pump should run for a few seconds and really spray some fuel out. Fuel pumps and a little hose in the fuel tank are known problems for these cars.

True. I have read that in previous posts. But the smell of fuel under the hood while attempting to crank would eliminate this wouldn't it? I believe getting fuel is not the issue. I checked the ECU and found no moisture/corrosion and the reset button was not in need of a reset (no resistance to pressing). Battery has full charge as well.

Smell of fuel is somewhat ambiguous. I would crack a line to see if I had pressure since you have eliminated many of the other possibilities.
Spark, Fuel, Air, Compression - in the right quantities and timing about covers it!

Have a look at:
https://www.jaguarforums.com/forum/g...d-first-30792/
Have a look at item 4. An unlit propane torch can also be used to introduce fuel. It can also pop back in your face :)

Thank you for your continued effort.
We have already attempted the starter fluid directly into the intake during our initial head scratching analysis. This is the frustrating issue, as it seems everything checks out, but it just doesn't want to turn over.
I am going out of town on business until the following Monday. I will assist my father in another sweep of the vehicle when I return.

A sincere thank you to those who chose to assist with their personal experiences and sound advice. Take care.

If the engine has spark and fuel, it's possible that you are experiencing bore wash, not common in the XJ6, but it could happen. A compression check would resolve that possibility.

This may be a moot point, but hear me out.

I'm thinking you should check the fuel pressure regulator. If it fails, it will route gas back to the tank. You mentioned that your plugs were quite dry. If the engine is sparking and receiving gas but not turning over, I would imagine they would show signs of flooding. Usually if the regulator fails it will result in a long crank time, but I bet it's possible for it to prevent the car from starting if it is bad enough. You mentioned the gas smell and this makes me think of a small leak in the return line and possibly the regulator itself. This fits most criteria for your symtpoms, assuming the unit can fail to this extent. I would try swapping the fuel pressure regulator (it's clearly labeled on the rail) with a borrowed unit, OR maybe someone else here knows of a way to plug the lines or otherwise make it possible to test the regulator.

Trevor:
That seems reasonable to me, too. There should have been a test port on an X-300 for fuel pressure, but "they" left that off! :) I bought a schrader valve and was going to drill and tap the metal block fitting on the fuel rail to install it, but never got around to it.

It does seem weird to exclude that, doesn't it, Ross? Do you think the OP would be able to block off the return line to rule out the regulator (or hopefully get the car started!), or...?

Yep! I suspect, but without good basis, given the reports, that there is not fuel pressure.