MK4 Fiesta Zetec cold start probs

[davros89]

I have a Fiesta '98 1.4 Zetec. On cold frosty mornings the car struggles to start. When it does start it rumbles(like its misfiring) then after a few seconds will run fine. However, it then stalls when pulling upto junctions until its warmed up. Then it is a pain to start and requires a good 10-15 second cranking time before it will fire up again.

I have replaced the idle speed valve,engine coolant temp sensor, coil, leads, plugs and it has had a full service but to no avail. Car has done less than 80k.

Can anyone suggest any other solutions before i go mad and push the car off a cliff!!

[jackosimbo]

i have the same problem with my mk4 1.6 golf. i had a new C02 sensor fitted which cost about �60. that has stopped it cutting out when pulling up to junctions but the revs still fluctuate slightly.
when u have trouble starting it when it does cut out, giving it a small amount of gas when turning the key works best. if u give it 2 much gas u could flood the engine, then it'll take longer to start.

i hope this is of some help

[davros89]

Cheers for your reply. I have tried feathering the throttle when trying to re-start the engine but has no effect. i am sure its an electrical gremlin somewhere but i do not want to keep buying new parts in the hope of finding the problem. Think will have to take to a garage for a diagnostic check.

[Matth354]

From past experience I would look at the crank shaft position sensor something tells me its that I don�t think its sending a strong enough signal to the ECU see if its adjustable and put it closer to the crank pick up.

Hope this helps

Matt

[jackosimbo]

i've completely fixed the problem! ! ! !
and its so simple it takes 2 minutes and u can do it yourself.
the problem of my car cutting out and the revs fluctuating came back again but my cousin showed me how to fix it.
all u need to do is clean out the throttle body so the air can flow better.
1. switch off the engine.
2. unclip the air filter/air mass meter from the throttle body.
3. push down on the throttle body to open the valve.
4, clean inside the valve (we used an old toothbrush for about 1 minute.)
5. put the clip back on.
and its sorted
i hope this can help u. if u do this could u let me know how it goes please, thanks
jack

[davros89]

i have completely cleaned the throttle body and associated hoses and it made no difference. I have got the car running much better now.

The first thing i done was adjust the output from the throttle position sensor to 0.7V. This was done by elongating the holes and twisting the tps anticlockwise.

I also replaced a couple of electrical connectors, one on the alternator and one on the coil.

I fitted a new vehicle sensor and that has also helped keep the revs down.

The idle is still high and the revs tend to hang a little long. I am fairly sure i have got a small vacuum leak somewhere which is causing many of the problems. Its just trying to find the leak!

i wish i had paid to get my old fiesta welded up for its MOT rather than buying a newer one