Ford Focus Engine Cut Out Problem

[james_tigerwoods]

I'm posting this on behalf of a friend as she doesn't have a PH account.... This is the problem in her words:

The problem started about 4 months ago, I had slowed to negotiate a roundabout but I lost all acceleration as I tried to pull away. Engine turning over OK, Revs OK, no warning lights, petrol at about ¼ tank…just no umph!

After about 20 mins the problem righted itself and off I went. Didn’t occur again until 2 weeks later…again left it 20 mins and off I went this time dropped it off at the garage ( I did call the RAC but they told me 4hr wait, I said don’t bother). The only thing they could find wrong was a split on one of the engine pipes so they replaced that, they advised it could be the fuel pump but they could only test that at the time of the incident, so he told me which fuses to swap over it if it happened again.

Anyway…no further issues until Monday (although I did have my throttle position sensor replaced as it was sticky on natural deceleration between these two incidents). This time I when I pulled over I tried to swap the fuses over but I couldn’t get the damn things out! Called the RAC again, waited about 45 mins. He could find no problems, computer error said something along the lines of ‘Cat below threshold’ he said that wouldn’t cause the problem, my garage concurred when I relayed that info back.

Anyway after some tinkering the message did clear and didn’t reoccur. After giving the RAC dude the history he managed to swap the fuses over, and car went. Dropped car off at the garage, garage replaced fuse based on what I had said but I believed It only ran as the car sat for a while like it had done on previous occasions.

I was right as problem arose again on Thursday night. This time I just waited 20 mins and drove off. Problem doesn’t occur when driving at high speed, just when starting off and between 20-30 miles, can get a steadyish speed with a careful balancing of accelerator pedal but it’s not quick and if I ease up or put my foot down it loses all power.

Garage seems to think it is the fuel pump, but as they can find nothing specifically wrong it’s just going to be a case of replacing bits until the problem doesn’t come back. Other suggestions have been blocked fuel pipe. Plan to get some Redex and will treat car when I fill up again juts as a precautionary measure.

It's a 1.4 X reg model....

Thank you

JTW

[sunbeam alpine]

I could be completely wrong (I usually am) but it might be the vents for the fuel tank blocked/partialy blocked.

I had this on my Land Rover and it baffled me for a while - I had similar symptoms - could drive for a while - then no oomph. Stopping the car allow the tank to vent a bit and then I could drive again etc.

I drove for a couple of days with the filler cap open to confirm. Maybe your friend could try this (costs nothing! )

[scarble]

james_tigerwoods said:

just no umph!
[..]
It's a 1.4

I think I've found the issue

I'm not aware of this fuel tank vent thing being an issue before but it sounds entirely plausible, one thing your friend could do is if it happens again, get down on the floor and have a look at the fuel tank, if there's a vacuum in the tank (against which the pump is trying to pull) then the tank may be visibly bowed in. Makes sense that after 20 minutes it's slowly recovered to atmospheric pressure.
Some cars have a pressure relief valve built into the filler cap (it's really hard to tell if they do) but mostly they just rely on the vent-to-atmosphere from the purge canister, little plastic can near the back of the car, really easy to pop it off if you've got the tools and the car in the air, garage should be able to take it out and blow through it to check it's clear, should take them half hour to check, with a tea break.
Could be blocked by spiders

[james_tigerwoods]

Thanks - 2 things for her to try - She's read them and will try them out

Any other suggestions welcome

[Krikkit]

Next time, further to the above, get her to open the fuel cap and replace. If it's immediately better then you've found the trouble.

[iain014]

I had a very similar sounding problem with my ST, in the end changing the dash clocks over seemed to fix it, no idea why though.

[james_tigerwoods]

iain014 said:

I had a very similar sounding problem with my ST, in the end changing the dash clocks over seemed to fix it, no idea why though.

That's pretty random!

[scarble]

Krikkit said:

Next time, further to the above, get her to open the fuel cap and replace. If it's immediately better then you've found the trouble.

This is much better than my suggestion of crawling around on the floor

On my old Escort (which ran perfectly) if I ran the tank near empty there was an audible schwwp as the vacuum was relieved when I opened the filler, I think most cars do it to some extent.

Edited by scarble on Friday 18th July 15:26