Please Help!

Drove home parked and wouldn't restart next day.

New fuel pump and filters
New fuel pressure regulator
Good spark
new plugs
Starts with starter fluid
injectors have 12 volts power at connector.
Good grounds on fuel rail.
Both fuel relays engage.
Fuel to fuel rail.
No fuel spraying from injectors.

Where do I go from here?

Ed Scott

 

The injector pulse in the L-Jetronic system is actually a ground pulse, there is 12v at the injectors all the time, the ECU grounds them all twice per engine revolution. Grounding time is varied to vary the time of fuel injection. The 12v at the injectors is grounded via a resistor pack. So you need to track from injector to resistor pack and then to ECU.

This site explains how it all works: -

Fuel injection and the Jaguar XJ6 4.2 Series 3 / AJ6 Engineering

Whole system is a triumph of old-style analogue electronics !!

 

Check the white/black wire comeing from the "-" post of the coil.

Remove the connector from the coolant temp sensor and jump the contacts with a small wire or paper clip. Now try starting the engine.

Post back.

Cheers
DD

 

Ok guys thank you. Already checked coil wire connections and tried jumping coolant sensor. No luck.
Check ECU connector and did find condensation on connector. Cleaned connector and ECU terminals. Still no start. Dont know where "So you need to track from injector to resistor pack" is. check link you gave as well as Haynes manual. And what would i be checking for? Intermittant open?
Still no start.

Discouraged,

Ed

 

The injector ballasts/resistor pack is on the voltage side. Since you have voltage on the injectors I'm inclined to think you're OK on that end. The resistors drop the voltage to the injectors when they are grounded by the ECU.

I'm about out of ideas. I'm beginning to wonder if the ECU itself is faulty. Rare, but it happens. Moisture in the connection could be a clue that the ECU has been water damaged...perhaps from a rainwater leak? Is there dampness in that area of the car?

Cheers
DD