I was checking some fuses this morning and then went to move the car but it won't stay running. It cranks well, fires and runs normally for about 3 seconds and then instantly dies just like someone turned the key off. Can't find any bad fuses and it ran great all day yesterday. Had codes P1367 and P1368. Cleared them and it is not rethrowing those codes but still dies a few seconds after it starts. What could be causing this?
Also getting a code U0151 lost communications with passive restraints module. Not thinking it related but cant be sure.

 

Have you put in gas recently? Has Michigan switched over to winter blend gas yet? Did you have warm weather that day?
I say that because if I have winter gas in the car, it won’t want to idle during warm weather after starting when the car is still warm.

 

No recent gas, drove all day yesterday. Moved it this morning to clean her up and it was fine. looked for a blown fuse as my passenger seat is not working. Went to mover her to the garage and she starts and dies in about 3 seconds. Runs and then shuts off like the key was turned off. Almost like it is seeina a fault and shuting itself down. No engine light while it runs and no new codes? I am frustrated and lost.

 

When you moved it, you started it from cold? And then shut it down almost immediately?

I used to have this problem on my X308 4.0 and my X350 4.2. The cold start fuel volume washed all the oil out of the bores and there was no compression. But in that case it usually wouldn't (re)start at all, or would fire and die. When it happened I would put a few moments aside for swearing at myself for forgetting again, then pull the plugs and put a few teaspoons of engine oil into each cylinder. After which it would eventually start. The solution was to always let the engine run at least until it came off cold idle before shutting it down.

But if your car does start and run, I guess this isn't the same problem.

 

According to the manual, U0151 could refer to inertia switch, which in turn will cut the fuel pump. I'd dig deeper. Maybe there's a blown fuse you missed.

 

Went out this morning and have the same situation. Car starts and runs about 3 seconds and seemely purposfully shuts itself off. I was checking fuses before this started happening. Not sure it is related but its a curiosity. Can't believe I am the only on who has had this issue.

 

An inirtia switch problem would make sense possibly. I do not know anything about one. Don't know fure or location. Hopefully you will find something. Thanks for your help.

 

It would be interesting to know what's happening with your fuel pressure...

 

But if the fuel pump wasn't running there'd be no fuel pressure and the car wouldn't fire at all. There must be some fuel pressure at first, if the car will repeatedly start?

 

I went to check fuel pressure yesterday but the XK does not have a port on the fuel rail. I assume you need a special tool or adapter to put the guage inline? I wish I knew the fuel pressure as it would give a direction to work toward.

 

Hi J.J. Do you know where the inertia switch is located? I notice there is an orange triangle on the dash that is not normally lit up. Seems like I read somewhere that it possibly indicates an inertia switch issue...

 

No clue, mate. I think I saw a reset procedure in the repair manual, but unable to check at the moment.

 

Finally was able to look at fuel pressure. None! Except once in a while it will spike and the car will fire.
Now I have to figure out why the pump is only pumping occasionally???

Any thoughts would be appreciared!

Thanks, Eric

 

no idea where the inertia switch is but from the manual: The electrical supply to this fuel pump is controlled by the ECM via a relay and an Inertia Switch which will turn the fuel off upon a vehicle impact. The fuel system is pressurized as soon as the ECM is powered up, the pump is then switched off until engine start has been achieved.

You Amber light - INERTIA SWITCH TRIPPED Amber warning triangle illuminated in LCD.

Vehicle may have been involved in an impact which has caused the Restraints Control Module to activate the inertia switch. Check for fuel system leaks. Perform the inertia switch reset procedure. For additional information, refer to Electronic Engine Controls (303-14B Electronic Engine Controls - Vehicles Without: Supercharger) I can't find anything else. Make sure your front and rear seat belts are working correctly and fully retracted.

And this is where my help ends - in earlier models, the inertia switch is controlled within the REM module but that doesn't;t exist on the X150 - again per manual - The X150 uses the AJB, mounted on the passenger com- partment rear bulkhead, behind the rear seat center sec- tion. Battery power is supplied from the battery junction box (BJB) via a 175A megafuse.

The X250 uses the RJB, located behind an access panel on the RH side of the trunk. Battery power is supplied from the BJB via a 250A megafuse.

The AJB/RJB replaces the REM technology used on previous vehicles and is combined with a power junction box, which is why it is also known as the rear smart junction box (RSJB). This combination reduces vehicle wiring and allows systems to operate faster and more efficiently.

The AJB/RJB is also known as the ‘Master’ module because it contains and broadcasts the Car Configuration File (CCF) with all of the current personalization settings. So your problem likely lies in the rear junction box or the fuel pump and I'd start with pressure at the filter.

 

Still having same issue. With the fuel pressure guage I can see it does not pressurize the fuel system until the starter has been cranking about 10 seconds. Then the fuel pressure spikes and the car fires. After about 3 seconds the fuel pressure drops to zero and the engine dies. It does not produce fuel pressure every time I crank it, maybe 1 out of 4 times. No dealer near me for help either. This is turning into a nightmare...
Any thoughts are appreciated.

 

Might want to check grounds and wiring:

 

This is beyond my technical knowledge. All I know is that the fuel pump should fire up when the ignition is switched on, to pressurise the fuel system, and then will turn off until the engine is cranked. So, I assume you're saying that if you turn on the ignition - i.e. you press the start button without pressing the brake - then fuel pressure doesn't come up at that point. Can you rig something to show when the pump runs, such as a multimeter?

 

According to the manwell:

 

Seems a coincidence that the problem started after you were checking fuses.
was there a problem beforehand that made you check the fuses.
might be worth reseating all of the fuses where you were checking them originally in case one isn’t seated properly.

not sure where the fuel pump is but maybe see if you are getting power it.

with all of the diagnosing is the battery still fully charged . Might be worth disconnecting it and doing a hard reset

 

You are correct. If I dont press the brake and make the starter crank there no fuel pressure. I can see my fuel pressure guage wheli cranking.