Hi All,

Been experimenting with my cold weather "no start" issue....
It's been a gradual issue based on ambient temperature. The colder it is the longer the engine needs to crank to fire off. Not a battery issue, it appears to be fuel delivery.

This morning 10 degrees. turn key to acc. count to 5, turn key off, turn key to acc. count to 5, turn key off, turn key to acc. count to five, turn to start and she fires right off.

This leads me to the residual fuel pressure. Where is the check valve that holds fuel pressure in the lines, I assume it is built into the fuel pump. So now I am thinking I need to change out the fuel pump. AARGH....

Tom
2004 XJ8 daily driver, 205K miles

PS
Found it.... Skip to 13:30 - I bet that's my issue!

 

Don't be a pessimist like me.

Diagrams I have seen indicate it is associated with the fuel pump (which you can get to from the top of the fuel tank BTW).

However when I finally changed my fuel filter I came across a small device

right next to the filter.I have photos but they will not upload.

2w93-9s446-0311 and 135400-0311 Denso

Now if you google this code all the results describe it as a vacuum

solenoid valve because it is also used in the evap system

according to the German description.

The device shown is identical and the code matches the code in a photo.

Just one thing.....there is no electrical connection to this device on my fuel

line.

Go figure.

 

Access to fuel pump is under rear seat.


http://www.mediafire.com/download/9b...Powertrain.pdf


Link is for powertrain workshop manual. Fuel pump removal instructions start on page 3392. Manual also includes other possible causes of hard to start cold condition.



Isnt this great? I'm just north of you. I hope it isn't another long winter.

 

BTW First thing is to scan for a code.

 

Nope, no codes....
Its related to the amount of time the car sits and how cold it gets. Needs to "cold soak" as opposed to the usual "heat soak" issues.

Once started in the morning the car is fine starting the rest of the day as long as it's not too cold or it doesn't sit (cold soak) for say 6 to 8 hours... no issues above 30 degrees.

lets hope we have a mild winter!

This is Sweet though, the manual. I assumed I had to go through the package shelf.. this will be MUCH easier! I should have looked. the video is on and XK, must be different than the XJ

>>>>>
2w93-9s446-0311 and 135400-0311 Denso
<<<<<
I will have to do more research on this - interesting. that just might be my issue. worth trying $30 on in any case.... THANKS

Tom
2004 XJ8

 

No codes?

You could measure fuel pressure when it is v cold using the schrader valve

on the fuel rail.

Just a guess but should be about 50 psi.

 

I would definitely start with fuel pressure readings. Target is 55psi. Measure at Schrader valve (under engine cover, drivers side, has blue cap I believe) or a code reader that can read live data would work also.

 

This morning... crank for 5 seconds - no start.
turned key to ignition and counted to 5 turn key off - did this three times. (build up fuel rail pressure) start car as normal on fourth turn. This tells me the fuel rail pressure is bleeding out overnight.
I do have a live data code reader - I will try that in the morning.

So... back to my original question. Does anybody know definitively where this check valve is? Is it part of the pump mechanism or a separate part in the fuel line somewhere.

Tom

 

Live data reads between 54 and 57 psi. while running. so, that's good.
drops to 47 psi on engine stop?

first reading in the morning before the car is started read 52 psi this morning.

still turned the key 4-5 times to cycle the fuel pump before starting. never moved off the 52 until it started. then right to 55psi.

Tom
2004 xj8

 

Looks like fuel pressure is not that simple:

Jaguar Workshop Manuals > XJ (X350) V8-4.2L (2005) > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Fuel Pressure Sensor/Switch > Component Information > Description and

Need a code

 

If it were mine and the fuel pressure was over 50 psi after sitting all night, I would replace the fuel pressure sensor. The check valve is fine. By the way, it is a part of the pump unit. These cars do not have a return type fuel system, the sensor regulates the pump pressure.

 

Was there a resolution to this thread? This describes my symptoms to the tee on my '04. Trying to come up with a plan of attack...

 

Lagonia,

Have you scanned your car for any stored codes with a system capable of reading all the proprietary Jaguar Diagnostic Trouble Codes (DTCs)?

Don

 

Don,

My updates to this problem are kept here:

https://www.jaguarforums.com/forum/x...5/#post1348395