Another wont' start x300 XJR

I think mine is one of the first ones. All the interior parts with quality controll stamps are late '94. It is absolutely an x300 just in case anyone things otherwise.

Here's the problem and what I've done in order:

Car ran fine, started on the button. Took it for a drive and turned it off. Wouln't start next time. Will crank on the key, engine turns and turns but doesn't fire. Not even slightly. Fuel pumps will not turn on with they key but sound fine when hotwired (two in tank pumps).


I'm in Europe so immobiliser is a consideration but not applicable as check engine light stays on as it should.

Which of the fuel lines is incoming and which is outgoing in the engine bay, before or after the FPR? Because if I clamp the fully flexible line which doesn't connect to the FPR it wil fire once or twice every few seconds on a cylinder at a time. Not anywhere near starting but still something.

So is this possibly my FPR? Or would a bad FPR not cause a no start? My fuel lines in the engine bay give off a loud hissing sound when the pump is running, which btw it doesn't do on the key, only hotwired. The hissing is loudest from the FPR.

Getting a bit desperate. As I need this thing running so I can start the manual conversion.

 

I'm assuming by immobilizer, you mean the inertia fuel cutoff switch?

If not, that would be worth checking up on.

 

Immobiliser as in security system.

inertia switch behind ecu passenger footwel (lhd) its pressed in just fine...

 

Beuller?

 

I don't think the immobiliser has anything to do with it. If the car is immobilised it doesn't crank, and you certainly wouldn't get the occasional firing which you say happens when you squeeze the hose.
If I remember correctly, the primary fuel pump doesn't run continuously until the engine is running, and the secondary pump only kicks in when there is high demand from wide throttle openings under load.

 

yup. All true. But my fuel pumps aren't coming on at all, do function fine when the relay is jumpered but still wont get the car started ehen they are forced ro run.

 

The fuel pumps are commanded by the ECU on for 3-5 seconds as you start the car to prime the fuel rail and then turn of . This can throw you off as you troubleshoot . As the ECU sees rotation of the engine they will command the pumps on again . This rotation signal comes from the crankshaft position sensor . The camshaft sensor can completely fail and will start with a longer cranking time with the crankshaft sensor and then turn the pumps on as it sees rotation . Before getting into the wiring of the command or control from the ECU the inertia switch forward of the ECU that kills the pumps from what I have read can fail and not reset by pressing the reset button . It can be jumperd with the 2 white wires to bypass this , did this with mine . The hissing sound from the fuel pressure regulator is normal up to a point . By saying that by forcing the the pumps to run and it still won't start ( with a longer crank if the camshaft sensor failed ) points to the crankshaft sensor you just changed . You can go ahead and change the fuel pressure regulator ( before you tap in and measure the pressure at the rail after the FPR ) for they don't last forever . This is assuming your issue is fuel starvation for it could be ignition as well . Have you checked the Papa Indy One ( PI 1 ) pin 4 White / Pink wire for corrosion ( below the windshield washer fill cap ) ? Other then the timing sequence the coils are powered at all time through this one wire and are ground seeking through the ECU though the 6 wires .

 

thanks.

do you mean the 4 wire plug on the fuel pump (s) no corrosion there.

ill try the inertia switch trick although it was never tripped.

also ckps is bew ajd i do see 200-300rpm while cranking indicating functioning ckps...

i think it is fuel starvation but i dont get why.

perhaps the fuel pumps amd injectors arwjt being triggered. What would cause that?

 

See the last lines of the edited post above for the PI 1 connector . The crankshaft sensor signal as it fails from what I have read can be OK on one thing and not on all things . After breakfast I'll cover the fuel pump control circuit for mine was not wired correctly to get around a faulty wiring issue . Pics are the RS3 and ECU connectors .

Edit didn't go through , PI 1 connector is below the wiper fluid cap .

 

It is likely a fuel pipe has fallen off inside the tank. The two pumps are conected together in the tank and as the hoses get old the jubilee clip loses its grip.
It happened to mine. Running fine then nothing after standing for 10 minutes after a long journey. I tried C/S sensor, bridging out the fuel pump but if a pipe is off they just circulate fuel within the tank. Proper method remove tank. Quick method and is only ok on an early car with a central lap belt you can cut the parcel shelf and access the tank through the top and get your hand in to check and reconnect the pipe. Check the others while you are in there! You can disconnect the fuel pipe at the rail and when you bridge out the pump relay you may get a little fuel coming through but no where near the pressure required.

 

Oops looks like you already checked this. Apologies

 

Any updates

 

haven't had time yet.

Will double check spark and have a look at the p1 connector as wel as check for 12v.

To be clear: my fuel pump(s) aren't switching on at all. I've cut open the parcel shelf for acces and also had a helper turn the ignition on and start while I listened and then later measured for voltage at the pump plug.

Pumps aren't being driven.

I don't think spark is the issue as when I use a hose clamp (pincer type to cut off fuel supply) if I get don't squeeze it all the way it will hickup a few times on a cylinder here and there.

Would a bad FPR cause COMPLETE no start and/or non running? Surely it would run off pump pressure just not perfectly, unless it's blown wide open and the pressure is too low to open the injectors when they pulse...

Seems to me the first thing to get working is the fuel pump. It works fine hot wired, both do, so it's in the either the wiring or the command sequence. All fuses are good as are the relays... i'm a bit baffled.

Ran fine, then nothing.

I'll check the connector and pin that feeds spark. I've cleaned both ECU plugs already.

FPR seems unlikely to me but you never know...

 

What did you do recently to the car which may have disrupted the wiring/harnesses that supply power or channel sensor signals to the fuel pumps? Another possible suspect is the Body Processing Module (BPM). It sometimes partially fails and may cause such problem.

 

nothing untill it wouldnt start due to aformentioned symptoms

 

I suggest a test of the control circuit for the fuel pumps . Important not to touch any of the other sockets during this test . You can simulate the ground that the pulling coil of relays are seeking by removing the ECU connector and taking a specific socket to ground . This is a low current circuit so no arcing .

Remove the battery terminal before removing the ECU connector

Look for socket Black 19 ( Pink / Brown ) then double check

Remove PI61 ( next to PI1 ) connector and locate pin 7 ( Pink / Brown )

read through ECU connector socket Black 19

This verifies you are on the correct ECU socket

Reconnect PI61 connector only

Reconnect battery and turn key to on not start

************************************************** ********
******* Important not to touch any of the other sockets **********
************************************************** ********

provide ground on the ECU connector socket ( not the ECU side ) and observe pump operation

First pump = Black 19 ( Pink / Brown )

Second pump = I'm still looking

Disconnect battery and then reinstall ECU connectors

Reconnect battery

This test looks through the RS3 pin 22 and PI61 pin 7 connector next to the other PI1 of interest .

Don't ask why they went forward with the wire run but it does ring out on mine .

 

Rediting done

 

where is PI61 located? Couldn't find any lugs under the washer filler cap or near. This is on the passenger side up front behind the headlights. So I'm assuming it has something to do with the wiring related to the ecu relay?

If I can find the right plug I get measuring for continuity in wiring to confirm no breaks and I also get the purpose of grounding as the ECU would do the same. I just don't get where PI61 is or RS3.

I myself was the one who said: best to get the fuel pumps running, but even when I hotwire the relay(s) for them and they pump, engine still won't start... or is the thinking that a non functioning fuel pump circuit = non firing injectors? Shall I pull the rail and see? I don't have a noid light to check for pulses...

 

The PI1 (white ) and PI61 ( black ) connectors are behind the right headlight on the car frame rail . There is a Jaguar bullion to move the location higher to get out of the way of water stream though the headlight opening causing corrosion . The RS3 connector is forward of the ECU as it is a bulkhead connector from the cabin to the right wheel well . I would try another crankshaft sensor ( not a camshaft ) that effects both fuel pump , ignition timing and injector pulse . You could have had a camshaft sensor fail some time ago then the takeover crankshaft failed . Tug on on the crankshaft connector wires and check for exposed / shorted wires . You could have received a bad part out of stock . You can probably feel by touch if the injectors are firing . Do you get the initial fuel pump charge of 3-5 seconds before it shuts back off to be commanded back on with rotation ? This will also confirm the pump control wiring . You can check for pulse signal with a common needle meter on the injectors without pulling the rail . All the injectors are powered at all times though pin 4 of PI1 and are ground seeking in the ECU by the 6 ( other then the spark coils ) wires , 12 volts

 

no 3-5 second initial charge. Fuel pump does nothing at any time. CKPS could be bad, pretty simple sensor though and rev counter is showing the 200-300rpm when trying to start. And as mentioned, when pinching fuel supply line with fuel pump hotwired it wil fire randomly here and there indicating spark...