X300 engine not starting
Just last week my 96 VDP arrived from across canada and was working pretty great up until yesterday, I drove down to a friends cottage for the weekend but then sunday morning it wouldn't start.
Engine turns over fine and battery voltage goes from around 12.5 to 11.5 while cranking.
Took out fuel pump fuse and dry cranked in case engine was flooded, still did nothing.
Came to the decision that it was either spark plugs or fuel related, but after pouring a little fuel into the throttle body and the car starting for a couple seconds I've narrowed it down to the fuel filter or possibly pump.
Before this I was noticing sometimes engine starts would sound almost weak and close to stalling, slightly fluttering in a way and then getting up to normal idle speeds and running fine.
Would anyone have any more advice on how to go forward?
One thing is I can't hear the fuel pump running ever, evening after taking out the fuse and dry cranking then putting it back in and I'm not sure if that means it's not working or just not audible.
Engine turns over fine and battery voltage goes from around 12.5 to 11.5 while cranking.
Took out fuel pump fuse and dry cranked in case engine was flooded, still did nothing.
Came to the decision that it was either spark plugs or fuel related, but after pouring a little fuel into the throttle body and the car starting for a couple seconds I've narrowed it down to the fuel filter or possibly pump.
Before this I was noticing sometimes engine starts would sound almost weak and close to stalling, slightly fluttering in a way and then getting up to normal idle speeds and running fine.
Would anyone have any more advice on how to go forward?
One thing is I can't hear the fuel pump running ever, evening after taking out the fuse and dry cranking then putting it back in and I'm not sure if that means it's not working or just not audible.
Last edited by GGG; Aug 10, 2022 at 02:59 AM.
Even fuel alone has many possibilities: the fuel pump relay, overdue fuel filter, contaminated fuel, water in fuel, faulty fuel pressure regulator, rust in fuel rail and clogged fuel injectors. The prime suspect would be the fuel pump relay.
43 PSI controlled by the fuel pressure regulator at the fuel rail
you can jumper the relay sockets with a heavy wire with blade type connector between the forward most socket to the aft most socket
someone was able to pinch the return line to the tank at the FPR to regain the fuel pressure for proper idle
if the fuel pump itself begins to fail it will damage the contacts inside the relay and burn the sockets at the pump motor connector
the fuel pump will only run for 3 seconds then off when you first rotate the key
the pump relay will close for the duration of your drive by seeing the engine rotation by the crankshaft position sensor
This is a crash / safety design
The CKPS can fail on this car in how it uses this single CKPS signal without giving a CEL code
There are 2 important and used at all times relays to power the ECU
You can swap the right engine bay fuse box king relay ( ignition positive relay ) with the left engine bay fuse box ( left in reality only honks the car horn )
You can swap the large ECU Controlled Relay for the same part # like the A/C clutch relay or headlight
this relay is controlled by the ECU and brings power back into the ECU , this relay also powers the fuel injectors
you can jumper the relay sockets with a heavy wire with blade type connector between the forward most socket to the aft most socket
someone was able to pinch the return line to the tank at the FPR to regain the fuel pressure for proper idle
if the fuel pump itself begins to fail it will damage the contacts inside the relay and burn the sockets at the pump motor connector
the fuel pump will only run for 3 seconds then off when you first rotate the key
the pump relay will close for the duration of your drive by seeing the engine rotation by the crankshaft position sensor
This is a crash / safety design
The CKPS can fail on this car in how it uses this single CKPS signal without giving a CEL code
There are 2 important and used at all times relays to power the ECU
You can swap the right engine bay fuse box king relay ( ignition positive relay ) with the left engine bay fuse box ( left in reality only honks the car horn )
You can swap the large ECU Controlled Relay for the same part # like the A/C clutch relay or headlight
this relay is controlled by the ECU and brings power back into the ECU , this relay also powers the fuel injectors
Last edited by Parker 7; Aug 13, 2022 at 01:46 AM.
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XJ XJ6 / XJR6 ( X300 )
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