Still won't start

Posted yesterday, still no progress, except to eliminate a couple of things.

4.6 - engine cranks, occasionally fires for a few seconds (it seems the slightest touch of the throttle to keep it alive, kills it instead), then dies and cranks until battery dies.

Checked fuel rail - good pressure, checked fuse 39, removed a couple of plugs, both sparking on cranking, in good condition and smelling of fuel (although I must say not wet with fuel).

I'm now at a complete loss as to what is causing this so any helpful suggestions would be really appreciated

Crank sensor fault? Or would this prevent sparking?

MAF?

If you've got enough fuel, a good spark, and compression, there should be nothing stopping the engine firing, unless spark timing is out or mixture is wrong. I'm assuming there's nothing physical wrong, like blockage in intake or exhaust...

RAC man just left - he tells me it is over fuelling. remove the fuel relay under the bonnet and it runs fine, replace it and it lumbers along and cuts out once the fuel in the rail has been used.

All readings ok except Air meter 0.00 until relay (above) is removed.

Sadly it's off on a flatbed to hospital

Why not post in the same thread so peeps dont have to go searching for other thread to know the problem.

Id av thort with the fuel relay there wudnt be any fuel delivered?

nathan5346 said:

Why not post in the same thread so peeps dont have to go searching for other thread to know the problem.

Click to expand...

Nobody responded and the post went down to page two

kieronf said:

Nobody responded and the post went down to page two

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All you had to do was reply to your thead and it woulda brought it back to the top.

Just write summit like BUMP.

As for youer issue it sounds like yer maf is knackered. Have you tried starting it and then pulling the plug on the MAF imediately after it's started?

ratty said:

All you had to do was reply to your thead and it woulda brought it back to the top.

Just write summit like BUMP.

As for youer issue it sounds like yer maf is knackered. Have you tried starting it and then pulling the plug on the MAF imediately after it's started?

Click to expand...

Im with Ratty, same thoughts. If you have the Ems read and look under the Maf settings i bet it will show default settings like -32c etc etc :blabla:

Apparrently it is the Air Intake Temperature Sensor, it thinks the temperature is -44c and is overfuelling, in effect providing too much choke and fouling the plugs. What I was beginning to think was fuel starvation was just the opposite and may in fact account for a recent rise in fuel consumption.

Its in hospital now, sensor and one or two other bits going on while they're at it.

Just a quick word for my RAC man, great guy, spent three hours with the car in the pouring rain.

Thanks to all.

You should be able to tell from the colour of the spark plugs whether the mixture is too rich - if they're light brown, then it's OK; if they're dark brown or have black deposits, then there's too much fuel. Wet plugs simply mean that there is fuel but ignition isn't happening (which could be due to a number of things).