hi. ive got a 2003 Mondeo 1.8 petrol. it has been misfiring, coughing, spluttering and just generally running poorly. so ive put new plugs in new air filter, ran carb cleaner through it. checked the fuel injectors but still no change. checked leads to plugs (in the dark ) and no arcing. then 1 by 1 took leads of spark plugs. so leads 1 and 4 engine ran the same
lead 2 engine ran worse
lead 3 engine ran better
and lead 4 gave me electric shock

 

please help

thanks

31 minutes ago, dickydonk said:

hi. ive got a 2003 Mondeo 1.8 petrol. it has been misfiring, coughing, spluttering and just generally running poorly. so ive put new plugs in new air filter, ran carb cleaner through it. checked the fuel injectors but still no change. checked leads to plugs (in the dark ) and no arcing. then 1 by 1 took leads of spark plugs. so leads 1 and 4 engine ran the same
lead 2 engine ran worse
lead 3 engine ran better
and lead 4 gave me electric shock

 

please help

thanks

Sounds like your leads are kaput! time for new ones.

thanks russ

I was unsure if coil pack or leads.

On 30/06/2016 at 4:53 PM, dickydonk said:

1 by 1 took leads of spark plugs. so leads 1 and 4 engine ran the same
lead 2 engine ran worse
lead 3 engine ran better
and lead 4 gave me electric shock

Interesting, but inconclusive!

I am not very surprised about the shock, if you took the plug leads off the running engine! Though if you were definitely holding the insulated part, it might indicate a damaged lead, but it might just be a bit dirty. 25kV can find all sorts of ways to get you.

For the future, and anyone else, it is not advised to leave plug leads open circuit on modern ignition systems. Best to connect the lead to a spare plug, body wired to the engine. That reduces over-voltage at the ignition circuit, and you can see & hear the spark. (Open the spare plug gap up to say double normal, to simulate the compressed gas in the cylinder.)

You can try replacing the leads, if they are not too expensive. Whether that works, or not, please post here, then others can learn / help.

Peter.

5 hours ago, dickydonk said:

thanks russ

I was unsure if coil pack or leads.

You can double check its definetely the leads by using a meter https://www.ngk.de/en/technology-in-detail/ignition-cables/diagnosis/testing-of-ignition-cables/

 

no joy with the new leads

38 minutes ago, dickydonk said:

no joy with the new leads

Is there anyone you know who you could swap their coil with to check it before you buy a new one?

On 30/06/2016 at 4:53 PM, dickydonk said:

it has been misfiring, coughing, spluttering and just generally running poorly.

Unfortunately there are a lot of things could cause that. Next cheapest possible item is the crankshaft sensor, probably.

I assume no warning lights are on?

Even so, there could be some error codes in there. It should be OBD2 compliant (Petrol engines had to be by about 2001), worth getting hold of a scanner to check. A basic self contained OBD2 unit (like U480) can be bought for about £10 to £15.

The old trick of disconnecting plug leads to check compression & plug condition does not really work now. With an older carb. engine, disconnecting a plug on a good cylinder made the rpm drop. On these, the PCM just boosts the fuel to try to compensate.

You could try the test I suggested above with a widened gap plug, to hear/see if one coil pack was underperforming. But stop the engine on each change to avoid more nasty shocks!

A proper compression test might be worth while to check rings & valves.

Then it is into the realm of MAF/MAP sensors, O2 sensors, and even the PCM.

 

thanks. getting a compression test done tomorrow. I will see what the out come is then go from there.

update compression test came back fine. while out I put petrol in and some diptane. after a short while engine ran a little smoother. next day started fine and drove like a dream.  today its back to  coughing and misfiring. so removed fuel filter all clean and working. how do I check all sensors re working properly

 

thanks

another question will the wrong grade of engine oil cause this problem

3 hours ago, dickydonk said:

next day started fine and drove like a dream.  today its back to  coughing and misfiring

It does not really sound like an oil problem, unless the plugs are oiling up, but I guess you have looked at them, and checked they are clean, and the typical light brown colour? Not black & oily, or ash white. Also compression ok suggests the rings are not stuck, a likely thing for wrong oil to cause.

Does this fault happen only at tick-over, at low power (cruising), high power, or all over the range?

Have you checked the battery: High battery voltage (overcharge or poor battery) or big voltage dips at starting can cause bad running, by upsetting the pcm.

If the ignition system is ok, the next suspect areas are fuel, mixture & timing. But you have checked or changed air filter, fuel filter & injectors. But there remain quite a few items: Fuel pump, injector solenoid(s), MAF (air flow sensor) or MAP (Pressure sensor), O2 sensors, crank sensor, maybe even knock sensors or camshaft sensor. Plus more mechanical things like air leaks (into the inlet manifold, for example).

These electronic items can be hard to diagnose. A good garage, or maybe one of those call-out tune-up/car mechanics might be the best bet.

There are software systems that plug into the car, and can not only display error codes, but also display live & stored data about the performance of individual items. Current ignition timing settings, and readings from most of the sensors.

I, or others here can help with setting up such a system. It can cost as little as £15. But it may require some interpretation. I have not used it on a petrol engine myself, but others have. If you want to go down this route, ask here.

Otherwise, it looks like you may have to call in the assistance of someone who has the diganostic equipment.

All I can think of at present, I am afraid.

Peter.