How to troubleshoot the fuel pump on a Jaguar?

How to troubleshoot the fuel pump on a Jaguar?

Remove the relay plug-in socket and determine which terminal cavity corresponds to the white/green wire. This wire goes right to the fuel pump. Using your jumper wire apply 12 volts to this wire for just a moment (you are bypassing the somewhat tricky control portion of this circuit).

Where is the fuel supply hose on a Jaguar?

Disconnect fuel supply hose at the fuel rail (at the rear of later “straight rail” cars and at the bottom of the early “loop style” rails). Some fuel may spill, have rags and container handy. A properly operating pump will produce about 34 PSI so, again, be ready ! Position fuel hose so fuel will flow into the container.

What to do if your Jaguar XJ6 won’t start?

If your XJ6 or XJ12 won’t start, grab your voltmeter and follow this checklist. Covers checking spark plugs, coil, wires and distributor cap, ballast resistor, amplifier and distributor pick-up, fuel supply, fuel pump and relay, air flow meter, fuel injectors and ECU.

Is there an electrical system for a Jaguar XJ?

Available for most classic Jags, with XJ and XJ-S available soon. The diagrams are laminated in plastic and color coded to match the actual wiring. The supplier is:

What causes a fuel injector to stop working?

Over time the nozzle of the injector can become dirty and partially blocked. When you shut off your engine the injector will, soak up the heat of the engine. This causes any fuel left in the injector to evaporate, leaving behind hard deposits, inside the injector. Over time, these will eventually block the injector.

When do you assume there is enough pressure in the injectors?

If the engine runs, they assume the injectors are getting adequate fuel pressure. If the engine cranks but won’t start, and they depress the service valve on the fuel rail and some fuel squirts out, they assume the injectors have pressure. They do, but the question remains, “How much pressure?”

What happens if the fuel injector is not working?

Fuel injectors are a vital part of a complex fuel management system. Furthermore, New technology has made fuel injectors more precise than ever in dispensing fuel. If the fuel injectors are not operating properly, then other parts of the engine will be affected as well.

Remove the relay plug-in socket and determine which terminal cavity corresponds to the white/green wire. This wire goes right to the fuel pump. Using your jumper wire apply 12 volts to this wire for just a moment (you are bypassing the somewhat tricky control portion of this circuit).

If your XJ6 or XJ12 won’t start, grab your voltmeter and follow this checklist. Covers checking spark plugs, coil, wires and distributor cap, ballast resistor, amplifier and distributor pick-up, fuel supply, fuel pump and relay, air flow meter, fuel injectors and ECU.

What to do if your Jaguar has no spark?

If no spark, see step 3. If you DO have spark here then you have a faulty cap and/or rotor (spark is getting to the distributor cap but not getting to the sparkplugs). Remove the distributor cap and peek inside. Look for a burned center terminal, burned terminals to the plugs, cracks, or carbon tracks between the terminals.

What do you need to troubleshoot a Jaguar?

You will need basic hand tools, a 12-volt test light or voltmeter, and a jumper wire with alligator clips. I believe this info to be accurate for all 4.2 Series III cars, but the very earliest models have a combination relay instead of the separate pump relay, main relay, and diode pack.

What happens when you run out of gas?

And while that may seem like a relatively minor inconvenience, running out of gas has several long-term consequences for your vehicle, including increased fuel pump wear and fuel pump overheating. Running low on fuel can also cause the fuel pump to pick up sediments, which clog the fuel filter, fuel injectors, or high pressure fuel pump.

And while that may seem like a relatively minor inconvenience, running out of gas has several long-term consequences for your vehicle, including increased fuel pump wear and fuel pump overheating. Running low on fuel can also cause the fuel pump to pick up sediments, which clog the fuel filter, fuel injectors, or high pressure fuel pump.

Why does my Jaguar XJ6 engine not start?

For a period of approximately a month, the engine became harder and harder to start, until one day, it wouldnt start at all. The engine would crank and eventually start at time though.

Why is there no fuel going to the carburetor?

A hole in the fuel line on the tank side could also cause the fuel pump to suck air instead of fuel from the fuel tank. There may not even be signs of leaking, since a fuel line leak on the tank side would have to be above the fuel level for leakage to show. Remove and check all fuel filters located in the fuel line and in the carburetor.

What causes the fuel system to not start?

If problem persist after carburetor cleaned/rebuilt the new pump may be faulty, vacuum line to pump pinched or plugged. If all looks good and still no go, have the compression checked on the engine to see if rings/pistons worn or possibly valve sticking. Good luck.