Still Missfiring

Just wondering what is the best way of checking the coilpacks.

Car began missfiring this summer so I got the car serviced, the plugs were replaced and this sorted the missfire for 100 miles or so. I then replaced broken clips and I still have missfire on idle.

Its constantly on 5 cylinders from start up, clear white smoke out the back and very very rich.

In removing each coilpack clip one at a time and the car changing to 4 cylinders on all but one I feel I have found the culprit, the 3rd plug from the front (not sure which cylinder this is) can't be sparking as the tone of the engine didnt change when the clip was disconnected. This clip was replaced with a new one and checked several time so it shouldn't be that...

Should I test the coilpack for a certain voltage (if so what should it read) or is there something else I am overlooking?

Thank you all in advance for your help.

Adam

Have you swapped the coilpacks over?

As in try the suspected broken coilpack in another positon to see if it affects that cylinder?? I like your thinking!

Adam

Well I have changed the coilpacks round and it is still the same cylinder missfiring so not them. Im going to check the connectors again and also plugs (they are new but want to make sure not faulty)

Just wondering what is next if none of the obvious....injector, valves??

Thank you

I would get a compression check done as that's nice and simple. Check to see that there isn't anything wedged down the spark plug hole (I had this.) Also run it at night with the spark plug cover off to see if a spark is escaping and shorting out somewhere.

Just another thought. You might want to give the miss firing cylnders spark plug a clean as it could be badly fouled, which could still cause a miss fire.

Thank you mate I shall get cracking on that after the new year and see if there are any plug issues.

Am I going to cause any major problems running it on 5 cylinders to drive it to a garage...about 5 miles? Its running very rich but think I would benefit having a mechanic take over after Im out of options.

Cheers

check the ecu

Pop all the plugs out, it should be obvious which one is at fault because it's likely to look different to all the others. The state of the bad one will give you a clue as to what is wrong.

White smoke out the back is usually condensation or coolant - does it clear when warm? If not then head gasket could be a suspect (compression test will help diagnose this).

What makes you say it's running rich, have you got fuel monitoring equipment? Black smoke?

You can usually test the resistance of coil packs but the easiest route is to just swap in a known good unit

I wouldn't want to drive it until you know exactly what's going on but up to you

have you checked injectors could be an issue

Pop all the plugs out, it should be obvious which one is at fault because it's likely to look different to all the others. The state of the bad one will give you a clue as to what is wrong.

 

White smoke out the back is usually condensation or coolant - does it clear when warm? If not then head gasket could be a suspect (compression test will help diagnose this).

 

What makes you say it's running rich, have you got fuel monitoring equipment? Black smoke?

 

You can usually test the resistance of coil packs but the easiest route is to just swap in a known good unit

 

I wouldn't want to drive it until you know exactly what's going on but up to you

Thank you for the reply, some responses for your further thoughts;

Only one cylinder seems to be misfiring (3rd from front) the plug was soaked in fuel but dont expect this is the cause just a result of the problem. I dried it up and also swapped it with another plug and the same cylinder misfiring. Also swapped coilpacks and no change... Clips have been replaced and still it misfires.

Im not sure whether there should be a reading and if so what it should be but we have hooked up a ampmeter for reading and the wires leading to that coilpack/plug barely made 1volt but Im not sure if this is normal or if it wont actually read correct when not hooked up to the colipack (incomplete circuit etc)

Only say its running rich based on the incredibly rich smell of petrol out the exhaust..runs white but I don't give the engine long enough to warm up as I am worried about running it too long - perhaps I should get it to a garage and get diagnostics and compression test done.

Thanks again for your help so far!

Adam

have you checked injectors could be an issue

Not as yet wiggy but it did cross my mind..how is best?

Adam

check the water sensor on the water elbow, mine had come off and causing problems like you describe, i also checked all spark plugs and coil packs first

there will be 2, one for the ECU and one for the dash gauge

check the water sensor on the water elbow, mine had come off and causing problems like you describe, i also checked all spark plugs and coil packs first

 

there will be 2, one for the ECU and one for the dash gauge

Aaaah, I shall check this - would I be looking for breaks in the plastic and lose wires etc?

Have just gotten off the phone from a mobile mechanic who is coming out tomorrow and he seems to think that there is a possibility that it may be the crank sensor...his girlfriend has a Scooby import and had very similar problems, diagnostic showed faulty lambda sensor and this was changed but made no difference, he then noticed a hairline fracture in the crank sensor that was letting in water and causing issues - sound plausible?

Adam

Sorry Ric, noticed you had put come off - I shall check this!