Hi Guys,

I've got a problem with my gf's 2004 KA and was hoping someone might be able to suggest what to try before taking it to the garage.

The cars been feeling hesitant for a few weeks on and off, and a few days ago the engine management light finally came on and it began to run like a dog, misfiring and generally running rough.

Managed to get myself a ODB2 cable off ebay and pulled the fault codes - I'm getting a P0302 (Cyl 2 Misfire Detected). After a bit of googling, I'm lead to believe this is either plugs, leads, coil or a fuelling problem.

I've put some cheap spark plug test tool on each of the HT leads which shows some sort of power is getting to each plug. I've also pulled the lead on cyl 2 with it running - this made it run worse.

Since pulling the plug makes it run worse, would this mean its not an electrical fault or could the coil/other components be working but intermittently? Since its a single cyl would this rule out any sensor problem?

What should I check next? Should I move onto the fuel system yet?

Cheers,
Martin

 

It stil could be a sensor problem leading to a fueling problem.
There's allways 1 cylinder that misfires the first.
Check Long Term Fuel Trim in live data. Should be around 0%.

Air leak only for cylinder 2 is also possible. Check inlet manifold gasket.

 

Most favorite thing on these are coils and leads , checking if firing a plug that is out of cylinder does not load the system enough as it is easy to jump a plug gap at atmospheric pressure but not as easy when under compression pressure , see if a friend has another ford coil and try it , easy and quick , pity you that far away , but I am sure someone will help you

 

As said above, coil packs are prone to failing on these, along with plug leads.

 

Cheers for the help guys.

Today I removed cyl 2's plug and replaced to no avail, so I've got hold of a coil from a breakers.

After fitting, I've reset the engine management light and gone for a drive for about half an hour.

This seems to have cured the bulk of the problem, but I'm still getting occasional misfires at low speeds (around 2nd gear). The ECU hasnt detected these yet as no trouble codes have been reported.

Can the coil take other components out when it dies? I'm hoping nothing expensive !

Oxford - my sensor data is:
Long Term Fuel Trim = -3.1%
O2 Sensor 1 (Bank 1) = 0.120@0%
O2 Sensor 2 (Bank 1) = 0.435

This was taken after a 30 minute drive, does anything look amiss?

Thanks,
Martin

 

When you put the plug leads back on, did you pit a bit of contact grease up the leads, at the spark plug end? Ford recommend doing it because of misfires, might be worth a try?

 

Nope i didnt sapph, rekon it cant hurt to try for a few squid.

Would I be look at new leads otherwise?

 

There's a FREE and easy way to test the misfire where suspected from a coilpack, and that is to swap the 2 and 3 leads over at the coilpack, they still fire at the same time but the problem will move to no3 if it's that as no2 will now have the decent coilpack supply ht wise.
It's certainly possible for the coilpacks to pack up on ONLY one output from each pair, I had a real issues with ford coilpacks on my cossie, till I swapped to a Accel coilpack.
tabetha

 

Thanks Tabetha,

I've changed to coil now, and its slightly better. I'm thinking i've had a duff sensor for a while but not noticed it until the coil went. New coil seems to have resolved most of the issues.

I'm now trying to take the MAF out for a look... silly question - but where is the MAF? I've pulled the airbox out and expected it to be within the airbox?

What sort of values should I be seeing for sensor values on ODB2 to verify any problems? Is this sorta stuff published in a haynes?