All,

I have run out of ideas, and things to check/test. I have a non-starting Jaguar XJ6 S3. I followed the Cranks but No Start checklist, and all checks out EXCEPT one thing. With key on, when I move the airflap inside the AFM the fuel pump doesn't turn on. I have spark, and fuel gets to the injector, but the injectors don't squirt gas into the cylinders. i have checked as much wiring in the engine bay that effects (as far as I know) anything running related, and nothing stood out. I installed a new starter some months ago as preventive maintenance, cleaned the positive and ground mounting points on the firewall, and checked continuity of every wire from connector to wiring harness. It didn't start after I did all this work, and for the life of me can't figure out what the f**k is going on here. And yes the coolant rail ground, and the big ground strap underneath the car is clean. If I connector my meter to the + on the battery I'll get 12.9 V when i touch those grounding points.

Please any insight into next things to do are much much appreciated.

-Alan

 

Well, you either have a dead switch inside the AFM or a problem elsewhere in the fuel pump circuit. Or the pump is dead.

Have you seen the Fuel Pump Circuit checklist?

Also, you can bypass the pump control circuit just to see if the car runs. Do you want directions on that?



Are the injectors clicking when you crank the engine? Do you have a noid light to check the injector circuits? Or, even a 12v test light will at least tell you if the injectors are getting supply voltage.

Of course if there's is no fuel pressure in the fuel rail (due to an inoperative fuel pump, for example) the injectors won't squirt even of they're operating electrically.

Well, IMO, the first step is repair all obvious faults. In this case, an inoperative fuel pump

Cheers
DD

 

I tried two AFM, the one I had installed in the car, and a spare one. Could be both are bad. When it turns over fuel sprays out if I slightly loosen a hose clamp on the fuel rail. I get spark as indicated by an inline spark tester. I followed the fuel pump circuit checklist, but step 7 where fuel pump should turn on nothing happens. I can check the wiring from the AFM back to the diode pack, and see what I get. If I remove a couple spark plugs and spray in a little starting fluid it starts up until its all burned away then engine stops running. I haven't checked the injectors themselves for current with key on or when turning over.
I'm using the two checklists in the Sticky HOW TO section at the top of the forum's page. Those two are Engine cranks no start, and Fuel Pump Circuit Checklist. If you think I may have overlooked something I definitely go back through the lists again.

 

This was my issue the first time my 85 XJ6 S3 arrived and it took me 3 years till I hired a Jaguar expert auto mechanic and reset/repositioned the timing on the distribution cap and on the ignition plugs and immediately the car started and had never experience that again till now is undergoing a major maintenance.

Please check the timing settings