2003 Ford KA Duratec - Strange only-when-warm-low-rpm hesitation! - jon-

Hello All,

Sorry my first post is a tech question but I'm starting to lose the will to live with my girlfriends Ford KA.

It has a strange missfire that only occours when:

- The engine is up to temperature

- Low RPM (I'd say under 3000rpm but there's no guage)

- Medium Throttle

It usually misses / lurches 2 or 3 times and feels like just on one cylinder. I know what you're thinking... "this is easy, plugs or leads" but no! Here is what I've changed so far:

- Plugs
- Leads

- Coilpack

- Front Lambda
- Rear Lambda
- Fuel filter
- Cleaned all engine earths
- Cleaned TPS
- Cleaned throttle body

Help! Nothing seems to fix the problem. I've of course done oil / filter / coolant changes.

Bit of back history - before I met my girlfriend she thought the MOT was servicing, so the car did around 3 years and 30k on the same oil etc. I'm not sure if this could be part of the issue...

Thanks

2003 Ford KA Duratec - Strange only-when-warm-low-rpm hesitation! - jon-

Help anyone! :(

2003 Ford KA Duratec - Strange only-when-warm-low-rpm hesitation! - Gregory II

Have you looked at this:

If a Ka you own or are considering buying runs roughly, the following possibilities could be the reason:-
Pushrod wear, where unhardened push rods have been installed. Poor cylinder bock cleaning while machining (leaving burrs). And unexpected wear of correctly hardened push rod cups traced to problems with the adjustment screws. (Ford has now eradicated these problems for new production.)

http://www.honestjohn.co.uk/carbycar/ford/ka-1996/?section=bad

Have you tried obtaining any problem codes?

2003 Ford KA Duratec - Strange only-when-warm-low-rpm hesitation! - jon-

Hi Gregory,

Thanks for the suggestions. There are no fault codes and the 1.3 duratec is a DOHC engine. It was the 1998-2002 KA's that used the Endura pushrod engine so sadly that's not the cause.

2003 Ford KA Duratec - Strange only-when-warm-low-rpm hesitation! - elekie&a/c doctor

Did you use genuine Ford coil pack , leads and plugs.?These engines are very sensitive to inferior ignition components.hth

2003 Ford KA Duratec - Strange only-when-warm-low-rpm hesitation! - jon-

Ah no, they were pattern parts :(

They were genuine parts before I replaced them, and it was showing exactly the same symptoms though...

2003 Ford KA Duratec - Strange only-when-warm-low-rpm hesitation! - jc2

No help but the Ka Duratec is SOHC. along with chaincam,hydraulic tappets and roller cam followers.

2003 Ford KA Duratec - Strange only-when-warm-low-rpm hesitation! - jon-

A little bump for the thread as she's starting to do it when cold too. Compression testing this weekend.

2003 Ford KA Duratec - Strange only-when-warm-low-rpm hesitation! - Collos25

I will go for injector problems a wild guess .

2003 Ford KA Duratec - Strange only-when-warm-low-rpm hesitation! - rhyswilliams3

I'm having the same problem, also with my girlfriends car! (typical ey!)

Its intermittent, starts off happening when warm and causes the car to vibrate at low revs with a missfire?

I have a reliable friend with a garage and his computer come up with an Injector fault (No.3) NOW, when we left the engine off for a short while it healed the problem temporarily, which caused much confusion... so back we go to the garagey friend to ask what his profesional opinion was on the whole situation:

APPARENTLY

The injector is the root cause of the problem..

The engine runs on choke when its cold , i.e. more fuel through the injectors, but as soon as the fuel becomes less so (i.e. engine warm), the injector then starts to become sticky and causes an electrical resistance in the circuit which backs itself through the circuit to the Managment, now at a certain point this electrical resistance will reach a level (very little in terms of measurability) where the managment system recognises it and switches the injector off before it causes more damage

this is why when the engines stood for long enough the resistance will have gone and the engine will run ok. Except for the fact that the managment has now logged a problem and the dash light will come on.

So on that note, anyone got any spare injectors they dont want? haha!

Hope this helps

2003 Ford KA Duratec - Strange only-when-warm-low-rpm hesitation! - injection doc

when a car car flags an injector fault, you have to look a little deeper due to the fact that if the engine detects a misfire it will shut an injector off to prevent damage to the cat but often flag an injector fault !

Excesive carbon on the back of inlet valves can cause a hesitation and misfire at low rpm. I actually used to have a sand blasting unit with a hoover line on it that used to fire wlanut husk and olive stone mix into the inlet port with the valve shut and manifold removed and that used to make huge difference.

Is the car fitted with Ford plugs ? Fords do not like pattern ignition parts ! and if not ford plugs, the ceramic insulator is a different size to the lead causing a spark to jump down the side of the plug under load at low rpm.

I never use pattern leads, or coil packs on cars and always use manufactures plugs, can make huge difference otherwise you end up chasing your tail and costing you more. Find someone who has a scope and knows how to use it and they will find the fault without fitting any parts as guess work ! I lived with my scope and so many garages dont even know how to use one ! keep away from them as they are burning your money ! buy their guess work

2003 Ford KA Duratec - Strange only-when-warm-low-rpm hesitation! - madf

I would try injector cleaner and Shell V power.

 

Ask Honest John

Value my car