2001 1.8 cuts out when warm, not hot??

Evening all,

Well, my 2001 1.8 has developed a problem! It will start fine, run lovely at idle and whilst driving, but as soon as it warms up it'll stall and then refuse to start until cooled right down (usually a couple of hours).

When i say warm, i mean dash gauge up to halfway, but before cooling fans cut in. I've changed the coolant temp sender as i thought maybe it was faulty and giving an incorrect reading, thus causing the fans to stay off. But this has made no difference.

With it running so well to start with and then cutting out could a coil pack or maybe fuel pump be at fault (over heating)???

On Saturday we went for a run over the moors, lots of on/off throttle, and it was fine all day. Monday however, I drove up the motorway to Exeter, about 15 miles (70-75mph), with constant throttle and it cut out about half a mile from my destination, then wouldn't start even after an hour. I then managed to get a lift home, organised a friend to help me get it home and returned to the car. This was probably about 3 hours after breakdown. I jumped in it and it started!!! So proceeded to drive home carefully only for it to cut out about a mile from home!!

If anyone can shed any light on this i'd be extremely grateful.

cokes said:

When i say warm, i mean dash gauge up to halfway, but before cooling fans cut in. I've changed the coolant temp sender as i thought maybe it was faulty and giving an incorrect reading, thus causing the fans to stay off. But this has made no difference.

Click to expand...

the sender is on the inlet to the engine so i don't trust what it says.
mine cooked itself and the guage said it was fine

lift the bonnet and you'll probably discover it is very much warmer than the guage is telling you!

oh and after 4 years i'dve thought you would have at least introduced yourself in the section of the same name

Yeah it does seem warmer, just not cooking. As i say the fans don't even kick in?? I'm assuming there's no problem with them, I've removed the plug to the cts when the engine's running and both fans cut it.

Freelaner said:

oh and after 4 years i'dve thought you would have at least introduced yourself in the section of the same name

Click to expand...

Sorry.

mine don't come on til i've thrashed it in summer so you'd be hard pressed to get them come on at this time of year.

So it can't be the engine over heating??? There's no sign of hg failure, all oil and water seem fine and it does run really well, except when you're on constant throttle for a longer period.

Coils/coil packs have a habit of failing/overheating when at the end of their useful life. If the car won't start, I would be looking more towards the fuel pump as yours should have 2 seperate coil packs so theoretically the car should still try to start on 2 cylinders if one of the coils is broken.

Best get the codes read. I suspect the crank angle sensor is failing when hot.
Do you still hear the fuel pump prime when it's not starting?
The fans a very unlikely to come on in winter. The radiator fitted to the 1.8 is also used for the V6. The V6 dumps twice as much heat into the rad!!

I can't hear the pump priming even when it does start, I'll have to lift the rear seat and listen out for it. I did remove the crank position sensor when it cut out, gave it a clean as there were a few swarfs on the end of it, but still nothing?? I think my 1st port of call will be to run it till it stalls again and check the fuel pump and maybe fuel pressure.

cokes said:

I can't hear the pump priming even when it does start, I'll have to lift the rear seat and listen out for it. I did remove the crank position sensor when it cut out, gave it a clean as there were a few swarfs on the end of it, but still nothing?? I think my 1st port of call will be to run it till it stalls again and check the fuel pump and maybe fuel pressure.

Click to expand...

If you can get it to stall at home - take out the cps and stick it in the freezer for a few minutes ...put it back in when its cool and see if she fires up

I'll give it a go on sat, it has cut out once before after a bit of a run and then sat in stationary traffic for a while. I'm sure if I hold it at 2k for a while it'll warm up and stall.

Ok, so after an hour or so I finally managed to get the car to stall outside the house. It seemed to take for ever, but have now seen the fans cut in at a low speed and can confirm its not the fuel pump as it still primes . I didn't get chance to cool the cps as it took longer than expected to stall. That said once it had stalled it managed to start again after a few minutes. It ran really lumpy for the first minute or so, then seemed to clear up again and run fine. I left it running for another 20 mins before it stalled again. But once again after a few minutes started again, first with the lumpy running and then cleared up??

I'm confused??!!

Ok, a quick update. CPS replaced, coil packs checked and both fine, coil leads to other 2 cylinders replaced, plugs changed.
And still no joy!!
My next thing to check and possibly change, the ecu.

But can I simply 'plug and play' a new ecu or will I need to sync it with the immobiliser???

Thanks!!