[Sarah326]

Hi all.

I wondered whether anyone else has coem across the same problem...?

My S reg 1.7 keeps being tempermental. (I like to think it is the cars personality but guess it must be more than that)

Occationally, my puma decides to miss a couple of cylinders, the engine feels unbalanced and the power output drops dramatically. This can happen when first started up or after a period of driving...but usually just as I get close to a rbig roundabout in Harlow (essex)where you need all the power you can get to escape into the right lane!

I noticed the problem a couple of months ago and took the car to a local garage where after running a computer diagnostic they replaced the "electronic distributer unit" (which they charged extra to program!) and put new HT leads and sparky's in.

Things were fine until yesterday when the problem/fault re-occurred.

Any ideas? (there is no change in fuel consumption, and the problem seems to come and go depending on bumps in the road so I'm thinking sensors are ok)

Cheers for the thoughts

[Mountain Lion]

Well, it's either electrical or fuel-related I think.

If the cause is electrical, I'd normally investigate the plugs, leads, coil pack, alternator and earthing. You say you've had new plugs and leads, so it shouldn't be those, although I'd check all of the lead connectors to make sure they're firmly seated. I'm interested in what the garage meant when they said "electronic distributor unit". Did they mean a coil pack? If they did, then as far as I know, it shouldn't have needed to be programmed. It's also worth checking the earthing strap that runs from the back of the engine to the bulkhead - they can become badly corroded. The problem coming and going when you go over bumps does seem to suggest a loose connection somewhere. There are certain visual checks that you can perform on the alternator (see this gallery picture). I know of one car that would consistently cut out on a particular bend; the problem turned out to be a worn alternator, the core of which would only move enough out of line on that particular bend.

On the fuel side, you've got the fuel pump, fuel filter, fuel lines and injectors (off the top of my head).

Good luck with it.

[Sw33t]

Hmm "electronic distributor unit" sounds quite close to "electronic control unit" or ECU which can be reprogrammed AFAIK

I have no further suggestions than what Ian has suggested though.

[Sarah326]

That'll be the one! - I shall have agood look at the earthing strap and the alternater connections providing the rain stops this eve (thanks for the photo Ian).

Bought myself a Ford workshop CD-ROM that is supposed to contain any info needed to repain/maintain these lovely beasties so hopefully that will arrive through the post soon.

Cheers guys for your help!

This post has been edited by Sex Kitten: 26 June 2007 - 12:15 PM
Reason for edit: No need to quote post above

[BOK]

With the work already done I'd get a cylinder compression test done.

I'm not sure that the problem being intermittent means it might not be a physical engine problem but it's worth doing to make sure you don't end up replacing all the ignition and fuelling parts for no reason.

How many miles has your engine done? Burning oil (check dipstick frequently)?

If compression is the problem you might be sufferring NIKASIL bore lining breakdown- but best get it tested.

This post has been edited by BOK: 26 June 2007 - 12:13 PM

[Sarah326]

With the work already done I'd get a cylinder compression test done.

I'm not sure that the problem being intermittent means it might not be a physical engine problem but it's worth doing to make sure you don't end up replacing all the ignition and fuelling parts for no reason.

How many miles has your engine done? Burning oil (check dipstick frequently)?

If compression is the problem you might be sufferring NIKASIL bore lining breakdown- but best get it tested.

Thanks Bok - thats a scary one to read. Ronald (the Puma S**4 RLD, couldnt think of any other name) has just last week passed his MOT (isn't it always the case) and the emissions showed to be very clean. He has just rolled over the Ton mark for mileage tho.. (100,000). keep kidding myself the car is new as the "1" of "100,000" doesnt appear on the odometer!

I check the oil levels (and smell) regularly, and there has been no change in consumption so there are no pointers from this... *sniff*. Good thinking though.

[happy-kat]

please say you had the cam belt changed during 2004? (it is 5 years or 80k miles for the 1.7 which ever comes first, the interval was changed during 2004)

you sure they didn't fit you a new coil pack?
A new ECU is like £600 pounds.

Check your earth straps to just as an idea. There is one at the back of the engine that can get damaged/wear and cause funny problems.

[pumapilot]

The engine will start up and run perfectly EVEN if the Earth strap is completley removed, if you doubt this then ask Richard at Tremona, as he told me this information.

[Jessie]

[matt posting- i.e. Tiggr]

It will, it gets earth through various sources, including the throttle cable. I had one weld itself wide open once - not nice

[happy-kat]

oh, thought people had had poor running adn they had dodgy earth strap... only and idea

[Jessie]

Kate, it will run, just not exectly well

[happy-kat]

which is the problem I thought reading the first post, it runs just not very well

[Sarah326]

which is the problem I thought reading the first post, it runs just not very well

Thanks everyone for your input

I have the problem that I kinda know how an engine works (I could build and replace parts in a trial and error fashion) but I have no idea what the different bits are called.

The unit that was replaced was like a small flat black box, from which signals are sent to the correct spark plugs for ignition to occur. The unit links onto the HT leads (I think directly). However he (the mechanic) did say it needed programming (overall cost £95) - whether he was taking the Mick I simply don't know. I had to trust that parts needed replacing depending on the vehical diagnostic.

I hate the reliance on thece vehical diagnostics. I prefer the thought of a knowledgable mechanic identifying the symptoms and looking for the root cause of the issue. I guess with everything becoming more computerised the world is changing.

Th car is missing on 2 cylinders - 1 and 3. It starts fine but as it fires on 2 cylinders the balance of the car.... well.. the poor thing feels horid.

The fault comes and goes hence I am thinking it more liklely to be electrical than mechanical. Sometimes the car runs smoothly for the entire journey and sometimes it feels like im being pulled behind an old diesel lawnmower.

When I lifted the bonnet on Monday to check out the (kindly suggested) earth strap that runs from the back of the cylinder head to the bulkhead, I could see it dangling free and easy - it had been burnt away (over time) at the cylinder head. I guess that bit gets kinda hot!!

Tonight on my way back from work I shall be popping to pick up a new earth strap (one ordeded from ford for ease of convenience - although Pumabuild charge a lot less) I shall fit it tonight and see what difference it makes tomorow morning.

Thanks everyone for your help so far - I shall keep you informed. If the problem doesnt rectify then I guess it's off to Ford themselves for another diagnostic. (better not book a holiday - they 'aint cheap!)

Am still smiling!

[Sarah326]

Oooh - I forgot to mention, Thanks "Happy Kat", I have to trust that the cam belt was changed. I only bought the car in 2004, and so to me it is 3rd hand. There was no stamp in the service book with "cam belt" or similar marked down but looking at it - it looks fairly damage free and does not have slackness issues (nor is it too tight).

I do intend to have it changed in the near future but I keep having other more immediate things to do to the poor thing (wheel bearing unit had cracked on front passenger side, and brake calipers on drivers side became sticky - cleaning didnt help so had replaced)

Thanks for the thought. Could the timing belt prevent the occational missing of cylinders 1 and 3? Good thinking. Anyone know?

Saz

[Clawz]

No, a timing belt problem affects the entire engine, not only 2 cylinders. A snapping timing belt will leave on camshaft opened and will sent your pistons crashing into the opened valves. Result is a lot of bent valves and a bill with 4 figures.

[happy-kat]

You can not see the cam belt, only the auxillory belt. The cam belt requires you taking a cover off to see it.
It is the tensioner unit as much as the belt that can fail.
All you need to know about what to change (as a minimun) and when it should have been done
http://www.pumapeople.com/forum/index.php?showtopic=13895

good luck

[phill751]

do a compression test.

tester available from halfords (scum) or you local independant motor factors

test procedure is in any haynes manual you can find about a ford zetec engine be it fiesta, focus, mondeo etc

finding the correct figures will be difficult - but you are looking for a difference in compression between the cylinders - they should all be similar values.

i had a mondeo which started running appalingly and eventually wouldnt start... hence why i ran out and bought a puma (as transport is vital for uni).

whipped the head off the mondy and re lapped the valves and shes perfect now - my dad uses it

btw that block that fires the spark is the coil pack, and it does not need programing its just a coil of wire (or 2 coils of wire in actual fact)

good luck

phill