First of all, it's been awhile since I've been around (which can be a good thing ... it means happy cars!). But the XJS has my shop flummoxed right now.

It went in for a front end alignment and as they were backing it off the rack, it died. Engine will spin, no start. I'm going through Grant Francis' stickied post right now and copying/emailing pages to the shop but I wanted to briefly describe the issue to see if we're on the right track.

Fuel pump seems to be working fine. Filter not clogged. We have air and fuel. We don't have spark/pulse.

The shop's first inclination was to throw another cap and rotor on it. We now have spark going to the plugs but we probably don't have an injector pulse. I'm having them look at the Ignition Amplifier issues (white coaxial wire, or the innards of the box itself) and the injector resistor pack. The only thing that bothers me is according to them, we had no spark at all until the cap/rotor were replaced. That would point to a distributor issue or some kind of crank position sensor issue, would it not? Regardless, we now have firm spark going to the plugs so this is going to point to IA/IRP issues, I think, unless you tell me differently.

The car has been running great for months. Starts fast, drives well, no other issues. This was a sudden failure that at least happened at the best possible place.

Jess

 

Jess,

Have you definitely got the pump running:

- for 2 seconds then cutting out every time you turn on the ignition

- continuously when cranking the engine

Paul

 

Hi Jess

If your shop has been working on the Front End, they may have disturbed the Gap on the Crank Position Sensor

The Rear Sensor Monitors the Engine RPM for the ECU

The Front Sensor (which is more likely to be the problem in this case) Triggers The Injectors and the Spark

Gap for either one of these is a Maximum of 0.042 any wider and then it will not Trigger the ECU (this Gap is pretty Crucial and if it moves out of Position it will cut your Engine Dead just as if you had turned off the Ignition (ask me how I know or rather don't)

How to Test the Fuel Pump Relay (All on your own with a Test Light and No Assistant required!) as after all Assistants are well known for getting in the way!

Just have a look at my Video! so easy to do, its just like a 'Walk in the Park' How to Test the Fuel Pump Relay using a Test Light 'Watch the Video'

Just in case you need to know The Fuel Pump Relay is behind the Black Plastic Cover near the Gas Strut in the Boot/Trunk RHS on a UK Car

The Red (Relay Holder) is the Main Relay and the (Black Relay Holder) is the Fuel Pump Relay These Relays are Not inter-changeable as The Main Relay in the Red Holder with the Red Stripe has a Diode

Also the Main Relay needs to be Working or the Fuel Pump Relay won't work!

Although if all else fails then there is always 'The Nuclear Option' as if you Ground the Orange Wire from the Fuel Pump Relay, the Pump should run Continuously (don't go driving around like that) as it could cause a Fire if something goes wrong and is only meant to be used as a Quick Relay Test

If none of that works then it could be that the Plug and Socket on the Resistor Pack needs Cleaning, this is 'The Silver Box' down by the Headlamp Nacelle

Cleaning the Plug and Socket of the Resistor Pack (It needs to be really Clean) Use a Toothbrush and Electrical Contact Cleaner

 

Update so far ...

Looks like it was the GM module inside the ignition amplifier. They replaced that part and it fired back up. If it turns out we have additional problems I'll report back. Thanks for the suggestions!

Jess