Now here's a challenge! I have a '97 4.0 X100 that I've been working on through lockdown. The car started instantly last week-end and I ran it until the temperature gauge rose, to avoid the dreaded cylinder wash problem. I tried to start the car again an hour or so later, but it would crank and not fire. I'm getting "failsafe mode" and check engine on the dash, but no fault codes on a generic reader. I've searched the forums and a worn brake switch is a common cause of this, but it only seems to be associated with cars that have cruise control. This car doesn't have CC fitted.

I've made sure the battery is fully charged. The battery was new when the car went into my garage a couple of years ago and it's been left disconnected and topped up periodically. I have also left the battery negative terminal off for a few days, but the issue is still there today. Any ideas please?

 

Have you tried starting it in neutral ?

My car, an ‘02 XKR, would intermittently display the failsafe and no codes when trying to start.with the shifter in park. And then not start, the starter motor would turn the engine over but that’s all.

But if I first turn the key all the way towards start position, but stop before the starter can be engaged, ie, stop turning the key when the dash lights come on, then step on brake to release the shifter and “row” the gears all the way to drive then back to neutral. Leave shifter in neutral and turn key to engage starter. My car starts fine every time with that procedure. Never a failsafe.

worth a try.

Z

 

Hi Zray,
I read that on the forum somewhere, but the set-up must be different for UK cars. I can drop the box into neutral, but in any position other than Park, I just get a "click" and the engine won't turn.

 

The underlying cause could be a bad contact inside the shifter mechanism. I’ve never had one apart so I’m just supposing here..... if rowing the gears and returning the shifter to park before trying to start doesn’t help you then perhaps a look at the manual where the shifter is concerned might be of some use to you.

Z

 

Good shout. I had the gearbox replaced just before I laid the car up and it has been tricky getting it out of park. I'll get the centre console out and check the cable alignment.

 

In these cars there are LAYERS of codes that regular obd devices can't and don't read/display.

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I've just been down to the garage to check for fuel pressure at the schrader valve. After turning the key to position 2 I can hear the pump run briefly, but all I get is a dribble from the valve. I'll do some diagnostics on the fuel system and start another thread on that if I need to. Thanks for the input.

 

Problem solved. I took the old fuel filter off before Christmas and the fuel that came out of it was foul - very cloudy and full of bits. Using a bit of general purpose hose on the fuel line and a suitable container to collect some petrol from the tank, I could see that the fuel left in the tank was clean.

New fuel filter and fuel pressure at the schrader valve went from "dribble" to "OMG it's everywhere" when I tried to connect my shiny new pressure gauge. The car started with a first turn of the key and is purring again. I'm so relieved that it wasn't the fuel pump.

Thanks to everyone for their help with this.

 

Well done. Installing a new fuel filter every 50,000 to 60,000 miles seems to keep our fuel pumps much happier since they do not have to work nearly as hard....