Hello, first post here! I recently bought an X300 4.0, drove it two hours home, drove it over the weekend, had no issues. I haven't driven it in three days, and went to start it today and ran into an issue. On it's own, it turned over and spluttered on a few cylinders when the starter motor was engaged, but wouldn't get going. Hooked up to another car's battery, the car cranks and splutters into life with stabs at the throttle, but it won't hold idle and stalls unless I balance it on the throttle. Occam's Razor tells me that this is simply an aged battery that's lost its juice over the last few relatively cold days, but is this symptomatic of something else? Any tips would be greatly appreciated, I have a few days to get this car running again before I have to move my current car on, so there is a whiff of urgency about it at the moment. Thank you all.

 

Codes ?

A " full " crankshaft position sensor failure code P0335 rarely shows

Underperforming fuel pump ?

You can jumper the fuel pump relay in case the power contacts are compromised limiting the current to properly power the pump

In the starting sequence the fuel pump is commanded on for 3 seconds only , this trapped fuel pressure should carry you through to when the CKPS sees engine rotation to turn the fuel pump back on for the duration of your drive , safety / crash design

There are a couple of relays that can be swapped if they are compromised and not powering the ECU , sensors and fuel injectors

Water get into the fuel tank , the fuel cap filler well can get clogged allowing water to go past the fuel cap seal

 

No codes on display, I doubt it's the fuel pump as it has performed faultlessly over the last few days. Hot and cold starts, long and short drives, two full tanks of fuel no issue etc.

When hooked up to another car via the battery it was runnning with my foot on the throttle, holding it between 1000 and 2000 rpm, surely if the fuel pump was bad it either wouldn't start at all or wouldn't be able to maintain a constant running, even if assisted with throttle inputs?

 

When the engine is running at idle the volt meter on the gauge is very accurate and should be above 13.5 volts

this will be slightly above a fully charged battery of 12.75 volts

With the alternator putting out ( and being used ) it has no bearing with the battery state and the battery condition has no effect on things

 

Thanks, when I could keep it running with my foot on the throttle it was reading around 13-14, so that looks normal. So you think it isn't battery related?

I just went out and tried again, without the car hooked to a jumper. I primed the fuel pump a few times, then managed to get it running with my foot on the throttle. When cranking the tachometer needle moved from below zero up to zero, and sometimes jumped up towards 200 approx. It still stalled out after 10-30 seconds of rough idling.

 

There is no priming of the fuel with this model

There is the term charging as this relates to the first 3 seconds of pump operation and trapped fuel pressure between the injectors , fuel pressure regulator and a check valve in the fuel pump

If you hold the pedal to the floor in the starting sequence the ECU knows to cut of fuel for a purpose

This can be seen on page 74 for the AJ16 engine , wide open cranking

jagrepair.com/images/Training Guides/801S - 2000.pdf

The cranking RPM is 300

If the alternator is putting out 13 -14 volts ,,,,,,,,,,,,,,,,,,,,,

There is some of the alternators current being used to recharge the battery after a starter cycle

 

Your tach jumping would point to the CKPS that has both fuel pump enable and spark / injector timing

If the tach ( in that use of the single CKPS signal ) is jumping around on you at idle and above it will drive you crazy anyway

Some keep a spare in the trunk

It can be sourced from any auto parts store as it is a generic part and not a special Jaguar part

The X300 got away from that in it's design fortunately

You can still do some ECU power relays swapping

right engine bay fuse box relay # 9 with the left engine bay fuse box relay , the left only runs your car horn

Large right # 5 ECU controlled relay , this relay is controlled by the ECU and brings power back into the ECU and 1 / 2 of your engine sensors and power sitting on your injectors

You can swap with a headlight , fog , A/ C clutch as long as they have the same 6707 part #









Pics coming

Clean the face of the CKPS of debris , this is different than connector clean

 

When turning the key to the ignition position, I can hear the fuel pump coming on and pressure going to the engine, sort of a whooshing or hissing noise around the fuel pressure regulator for a second or two.

I managed to start the car now without much cranking, like normal, but it sat idling at 500 rpm, and was shaking a lot. This time however, whilst it was idling the battery needle was reading below 12v, as low as 10 sometimes. The exhaust sounded like it was running at least a cylinder down, maybe two. Despite this rough idle, it managed to keep itself alive unassisted for about 2 minutes, before finally stalling out. At higher RPM it sounded smoother, around 1800-2500 it sounds like all 6 cylinders are running.

Confusion abounds. It seemingly has electricity, it has fuel, and it can 'start' itself, but it wont run smoothly and won't have a normal idle. No error codes or warning lights. Any common failures which might have caused this?

My next attempt, tomorrow so as not to disturb the neighbours, will be fitting a new battery and trying to keep it running long enough to warm up and adjust to the slower idle.

 

So is this functioning correctly?

 

No , but no definitive test without an electrical scope graph , just clues

The CKPS will read as a basic meter test as 1300 ohms resistance , this is not a functional test with spinning reductors ( teeth )

There was someone that had more than one missing tooth as an extra was broken off confusing the CKPS

 

I think I'll start with that then, as it seems to be a common failure point. Thanks for the pictures and information so far Parker, I have much to research.

 

There is a slipping harmonic balancer on the crankshaft to be marked and checked for slippage

This would drive the CKPS nuts

The alternator may not be at speed at 500 indicating ( ? ) to not be activated ( alternator field windings need excitation feed voltage regulation ) and not be on line

This is a pic with a performance enhancing CKPS mounting bracket ( Andy Bracket )

The painted on marks should be lined back up after a engine run , load with A / C compressor and high electrical load

You don't need to remove belts

 

Can't remember if the timing tooth ring is effected by a slipping harmonic balancer

Genuine Crankshaft And Main Bearings-3.2/4.0 Litre (less 6.0 Litre) For Jaguar Xj 1995 - 1997 (from 720125 To 812255) Classic | Jaguar Land Rover Classic Parts

Held in place with a very torqued 33 or 34 MM bolt on front and D key

never mind the circled 3 and 5



There are 4 bolts ( irem # 9 ) that come in from the back side into the balancer

I never took a balancer off

Don't worry about removing the balancer until tested

I don't think new battery is needed

 

To add a layer , the CAMSHAFT position sensor ( CEL code P0340 ) is used in the very beginning of the starting sequence for more accurate ignition and fuel injection

After a point the crankshaft position sensor takes over those duties

You can remove the CMPS connector , and the engine will still start , but takes more revolutions

There is an adjustment to the CMPS , but would be low on my list

This may explain your somewhat getting through the start sequence and then ............................

 

I think I'll start with the CKPS, as that's a common problem for all sorts of non-start issues according to my research. What confuses me is that the car will run, even if only on a few cylinders and very reluctantly. I'd prefer if it showed no signs of life, that would make more sense in diagnosing the issue.

So, plan of action: CKPS, Coolant Temp Sensor, new battery, new plugs, Cam Angle Sensor, throttle position sensor, MAF.

Looks like I won't be driving this car next week after all. When I bought the car last week, it had a high idle issue. Idling around 1600-2000 RPM, and pulling itself along in drive. This I 'resolved' by slackening off the throttle cable. Does a dodgy high idle, in combination with my current lumpy idle issue point towards any specific component?

Any further ideas to resolve my lumpy idle and inability to hold a normal idle would be welcomed.

 

Do not adjust the throttle position sensor just yet as there is a specific reading at the butterfly idle stop

Do not adjust the idle stop screw inside the throttle body

More to come alter on dialysis chair after getting there

 

The TPS on the middle Green / Yellow color wire should read 0.60 + or - 0.02 volts DC at the idle stop . you can check this with engine not running but key in the run position . the connector most stay installed , ensure the connector lock metal lock bar is intact , you can stab the wire as it comes up over the fuel rail bundle , if the connector lock bar is missing it it can be sourced from a trunk dome light

The MAF should read 1.2 volts DC on the middle Green / Pink color wire at the proper idle speed , you can stab the connector wire exit with a needle to read

The CTS should read 1700 oms resistance at room temp ( 86 F )

You can check it against boiling water to be 170 ohms

Close loop mode is at 88 Celsius and will read about 250 ohms

The CMPS is a 3 wire hall effect sensor that will read 600 ohms as a basic meter reading

The CKPS is an inductor and will read 1300 ohms as a basic meter reading

The plugs are a specific heat range but cheap Champion cooper with a change in gap , no exotics , the plugs are generic and at any auto parts store , not Jaguar part

Check the coils for swelling and cracks . oil in the wells . and corrosion on the coil well walls

The rear 2 coil wires can be crossed

The rear most wire # 6 is Light Green / Purple color

The next # 5 is Light Green / Orange color

They will all be feed 12 V on the White / Pink wire

05.1-07 Amended (jagrepair.com)

The Champion # is on another broke computer

 

Latest update: got home from work, had a crack at the Jag. Took the CKPS out and gave it a clean, also adjusted the throttle cable, managed to get the car idling with my foot on the throttle. Eventually, when warmed up a bit, it held an idle of 1500-2000 on its own. It held this for 5-10 minutes, then died suddenly, with the transmission warning light coming on. Restarted it, managed to drive it around on my driveway a bit, but it stalled in reverse at one point. Restarted again, drove it another 10 metres, left it in park, and it idled fine for 20 minutes before I shut it down.

Had a break, then had another go. Managed to start the car again on the second try, it had a very low idle of around 500, quite rough, then adjusted itself to 1000, then 1500, then back to 1000. Up and down. Eventually it settled on 1500, but after 5-10 minutes it died suddenly and wouldn't restart, wouldn't even splutter as it had done before. Not a sign of life from any cylinder, just lots of cranking.

Had another break, came back. Now fully cold, the car did start, with the same low idle. After 5 mins or so it increased up to 1000 and then ran ok. The engine was quite shaky still, and the exhaust sounded a bit poppy, so I suspect it is misfiring on at least one cylinder.

Apologies for the rambling, just recounting my memories of how it ran. Awaiting a new CKPS in the post, tomorrow's job will be checking for spark and adequate coil performance. Hopefully new plugs will help, and not new coils.

 

The CKPS sensor does feed the transmission ECU as the transmission and engine regulate ( dance ) together

There is a somewhat common thing of the on the transmission body connector getting dirty

The fault accurse as you are shifting throttle range , driveway

This is a special connector removal , but can be cleaned without jacking the car

This is for the 4.0 liter model



The connector must first be pulled aft about 1 / 8 inch and only then rotated counterclock wise , notice the use of tie wraps to grip the connector barrel from someone's excellent pic

 

Thanks Parker for more wonderfully detailed information. I'm putting together a very extensive shopping list of things to try out before I start ordering loads of parts. How do you access that transmission connector without jacking the car? That picture looks like the underside of the car to me, but I'm not yet an X300 anatomy expert.