OT? Ford Fiesta fuel problem?

[ChrisJ]

I'm not sure if this is classed as off topic but as I'm going to fix it myself (all being well) I thought I'd at least try...

I've got an N reg 1.25 Fiesta Zetec with 80k on the clock. It starts first time every time and runs fine and smoothly. However I have the following two problems.

Problem 1. After starting, although the engine sounds fine its absolutely gutless and has a real job pulling away up a slight gradient (yes I AM in first gear and the brake is off). Once its warm its OK. No problems at all. My only thoughts are that it might be something to do with the auto choke which is the only thing I can think of that would be so different with a warm engine to a cold one. This has been going on for about 2 months.

Problem 2. This started after the service and it didn't happen before the service. We live in a hilly area and so regularly use engine revs between

4k-6k. Before the service the engine would rev freely into this range. Now however the engine revs freely (as before) until it hits approx 4100 rpm then its like someone has put the handbrake on and the engine only accelerates slowly to 6k. Its a real change in acceleration. Change gear and the engine pulls strongly up to 4k again. The garage has changed the fuel filter to try to fix this problem. Their computer said the car was reporting a low fule pressure but they couldn't work out where.

I'm not sure if either of these is related but any suggestions appreciated.

(inlcuding a more appropriate list/forum of necessary.

ChrisJ

[andrewpreece]

appreciated.

I've no idea, and cars don't generally feature on this newsgroup. However, have you had a look at the spark plugs, to see if they're gapped correctly, and are the right colour, i.e. not contaminated. Look at the oil filler cap to to see if you have a water leak in the block ( cap will look milky inside - a longshot ). Also, is there a decent spark getting to them? Take one out and connect its body to the block so it will still spark. Are the leads OK? Run the engine up in the dark and see if you can spot electricity arcing to earth from the leads. A long shot, but it's good to eliminate the obvious stuff, weak sparks can make an engine perform poorly, though it generally doesn't improve. Is your thermostat working? If it were stuck open the car might perform poorly from cold. Has this car got an electronic engine controller? That could also be a prob. I think you'd be better off on a more knowledgeable newgroup. Is there a Fiesta Owners Club? Otherwise it could be down to you changing over components like the fuel pump etc until you get lucky.

PS: Try uk.rec.cars.maintenance as a more appropriate newgroup.

Andy.

[Mathew J. Newton]

A group in the uk.rec.cars.* hierarchy would be worthwhile.

Best of luck,

Mathew

[dmc]

Could this be a misfire? We had this problem and apparantly it's quite common.

[snip]

Did you happen to have new spark plugs fitted at this service? If so then I suspect you have a bad misfire (probably plug lead one from what I remember). I think this problem got so bad on the mondeos that there was actually a technical bulletin sent around about it - I *think* the fiesta Zetec suffers the same way.

Darren

[Dave Plowman (News)]

That's my bet too. It's fuel injection?

Change the regulator.

Other possibility is a fuel pump on the way out, but a decent garage should be able to check both pressure and flow.

[ChrisJ]

Yes we did have new sparks. Apparently the HT leads are carbon fibre rather than metal although I can't remember the reason, something to do with durability, but they tend to snap!

It runs really smoothly so I don't think its a misfire. It really doesn't feel or sound any different below 4000rpm.

Chris

[ChrisJ]

It is fuel injection.

The garage said it could be one of many things and they'd be happy to change them all for us. I was trying to find which was most likely to minimise costs as I don't want the parts to cost more than the car!

Chris

[Clint Sharp]

In message , ChrisJ writes

OK, was going to ask......

It won't have an auto choke, it's not got a carburettor. It has warm up enrichment which is controlled by the temperature sensor and the ECU. Get someone with a multimeter to check the temperature sensor if you don't have one yourself. In the region of 5k cold but there are lots of different types with different values, you basically need to check that it changes value smoothly as it warms up and doesn't jump. For more info, you'll have to wait as I don't have the tech data here.

Get it fixed, if you have a fuelling problem you could be damaging the catalytic converter which will hurt if you want it to pass another MOT.

**DO NOT TOUCH THE HT LEADS WHILST THE ENGINE IS RUNNING** This is not a car that uses points and condensor, a shock from a modern car's ignition system can kill or cause serious injury, at the very least it will hurt a LOT. After the nasty warning, make sure there are no dangling cables (I.E. Unplugged or dislodged) and do a waggle test on the sensor cabling with the engine running (make sure you stay clear of hot parts, rotating parts and especially hot rotating parts) and see if the engine note changes or the engine stumbles.

Find a better garage, if it's got a fuel pressure problem you need a fuel pressure guage and the know how to use one safely, petrol pressurised to 60PSI squirting over a hot engine is guaranteed to make your bum twitch. Seriously, if their computer told them this they should have been able to find it. I'd be amazed if they actually measured it.

It's possible.

[Dave Plowman (News)]

Plug leads haven't been copper for many, many years. They use a fibre soaked carbon to provide the resistance needed to suppress interference to both your radio and things like other's TVs, etc.

[Dave Plowman (News)]

Fuel regulators ain't expensive. Usually. But if they haven't got the diagnostics to find out which bits are faulty, take it to another one.

[The Natural Philosopher]

Thats standard with garages and fuel injection.

You need someone who actually knows how to fault find it.

There are garages that have the test equipment.

Thibgs I have had problems with have been temperature sensors and air flow meters

Tem sensoirs will give problems when hot or cold, but not both usually - my GF's Pug had a water temp sesnor go high - started and ran, but would flood and stall when hot.

Airflow meters are often nothing more than a flap that turns a potentiometer and a light spring to close against air pressure. If its sticking then full RPM may well not get you full fuel - leading to weak running at high RPM.

The garage may have adjusted the mixture weak anyway to get CO emissions down.

See if you can ID te fuel flow meter - generally in the inlet pipework. A leak in that pipework that by-passes teh meter may alos have bad results.

Check it turns freely, and if you have a resistance meter, check that the potentiometer is not wormnn out - resistance is erratic etc.

Replacements from scrappies should work.

[:::Jerry::::]

I would just point out that on modern HT systems the above is likely to damage the ECU / ignition system and lf human fingers etc. get in the wrong place, possibly kill the said human...

Gone are the days when the test described was advisable without the correct knowledge and test equipment.

[:::Jerry::::]

ECU's also need an induction / ambiant air temp sensor, this can go out of calibration.

[Ian Stirling]

What some may find useful is the FAQs at

most are probably not up to installing said system, the FAQs on "how to set it up, and why it works" are excellent.

[Clint Sharp]

In message , The Natural Philosopher writes

The Zetec S engine uses a hot wire MAF, no flap, no potentiometer. Do not prod about in it, you could irreparably damage it.

Not valid, see above.

Not adjustable without using brute force to crush the fuel pressure regulator so unless they are a real bunch of thugs who enjoy stretching fuel pressure regulators it's not been 'adjusted'.

What fuel flow meter?

Providing they've not been rained on with the loom unplugged.

[The Natural Philosopher]

Oh mi gwad. Piss off Jerry.. You are talking out of your arse again.

Yawn.

[daddyfreddy]

If it happened after the service I'd check every single connection and wire loom. I had a car in the past where some halfwit mechanic had severed a cable and created an intermittent fault. As for the garage and their diagnostics, I know some here won't like it but many garages and their diagnostics are out of their arse. They'll tell you all sorts of crap about what they checked when they haven't even made any attempt to look at the problem. They would rather do straight forward jobs and let you work out the fault by deduction. I'm not familiar with that engine so beyond that can't help. Regards the spark plug test that others have discussed, forget modern engines, I handled a HT lead on an '83 1.2 Astra OHV engine many years ago and got a shock. Not enough to cause me damage but it still hurt - never tried that test again!

[:::Jerry::::]

I've also seen the same fault after a not so good 'service' by a halfwit, trouble was it was the owner who was the halfwit and had to come pleading to a garage to sort out his f*ck-up.

I have also seen halfwit owners make a perfectly safe braking systems into a lethal death traps - and cleaned the mess up afterwards when their car didn't stop...

They'll

engines,

Yes, and that system is low powered by modern standards.

[Parish]

SWMBO has the same model and it developed _exactly_ the same problem. The cause was a blocked or contaminated MAF (Mass Air Flow) sensor. Total cost, at a Ford main dealer (including the initial diagnostic check) £200.02 inc VAT.

A Ford dealer will hook the car up to the diagnostic kit and can confirm this from the error codes - although I'd be surprised if something else produced _exactly_ the same symptoms.

If you want to take a chance and DIY, the sensor was £51.13+VAT (12 months ago).

The MAF sensor is the cast aluminium bit with wires attached in the inlet tract between the air filter and the engine. If you want, I'll take a piccy tomorrow (too dark now).

HTH

Regards,

Parish

[Parish]

Here's the pic