More fiesta problems - VERY odd issue!

[lunchbox]

I've posted my problem on a few forums with little or no response, help!

I said:

My 1.1 hcs has decided to start cutting the fueling at random times while driving. It seems to do it when under load, such as going up a hill. It is definitely not stalling, even if the engine is at a healthy amount of revs (above 2krpm) it just suddenly cuts out. It doesn't splutter or cough. It runs perfectly and doesn't hesitate when running. The only thing I could say is it seems to run a little rich.

It does not restart at the roadside despite a healthy battery and turning over easily. The fuel is definitely getting to the CFi/carb unit, as if I remove the hose and turn it over it spits petrol out. Frustratingly, once being towed home, it will restart and drive flawlessly after several hours of being switched off. Obviously I cannot wait for hours by the roadside for the car to "do its thing" and sort itself out!

If I took it to a garage they would just start it up and say no problem, or just say it needs this and that which will cost £££. Surely there is a reasonable explanation for this problem?? ECU?

And then an update

I said:

Ok update, after doing some odd tests...

Slamming the bonnet seems to temporarily rectify the problem, and it won't start until the bonnet has been slammed several times. VERY odd. I took it round the block once I started it and it did cut out after about 5 mins. Didn't restart straight away, did the bonnet thing, it started. :-? :-?

Seems (not sure on this) to cut out at a certain number of revs, 3500-4000 rpm or there abouts. Doesn't always do it there though.

Any ideas?

[andy_quantum]

Wiring!

Do you suffer from the odd flat battery or slow starting?

[lunchbox]

I agree it seems electrical, but never had any problems in the past. Any idea which part of the loom will cause the fuel or injectors to cut off? I just feel like such a numpty going into a garage saying "It's a wiring problem" and feel they will fleece me for something that can be fixed with 25p worth of wire and spade terminals.

[D2x]

going to be a loose connection /bad wiring somewhere if it fixes itself when slamming the bonnet!

Get someone to turn it over while you waggle all the wires..... and when running do teh same til it cuts out

[Brink]

Sounds like a corroded ground link.

[andy_quantum]

An auto electrician would probably give you a quicker service than a garage if you know the problem is electrical.

Nothing stopping you having a crack with a multimeter, start at the battery and work your way around

[lunchbox]

Yea I spent several hours trying to multimeter out the problem and wiggle stuff to try and find the problem. Nothing found as of yet, but I was reading it could possibly be the fuel relay or equivalent. Apparently that can go funny and require a little knock to get it to make contact, which sounds plausible. Will take a look tommorow, and thanks for the help chaps.

[lunchbox]

Ok.. nothing found and eventually gave up and took it to a garage.

They've driven it round a bit and let it idle for 2 hours and it didn't cut out. (Sod's ing law)

Suggestions they made were crank position sensor or fuel pump. I very much doubt it's fuel pump as fuel is actually getting to the CFi unit, just not being injected (when it's cut out).

Fortunately they're not charging to have a look at it.

Thanks for reading, any more advice...feel free.

Edited by lunchbox on Saturday 12th January 19:17

[lunchbox]

Fixed!

It was the Crankshaft position sensor. New one fitted for 35 quid.

Hope this helps any future Fiesta owners with a similar problem

[AGAR]

Glad you got it sorted - your symptoms sounded very similar to my 1.1 HCS engined Fiesta when it suffered from carb/throttle body freeze.