(T) Ht leads and coil pack

Hey guys,
Can someone please tell me how I can test if my car's HT leads and coil pack nead replacing?
I'm planning to test them both and replace them if necessary.
Thanks all.

No one?
Gonna go in the morning and buy me a new set of ht leads and replace them cos I don't think they were ever replaced!
Hopefully this will fix my cold start issue
How often should these be changed?
What about the coil pack? How do I know if it needs replacing?
Thanxall.

sorry been away on hols

you shouldnt test HT leads, just replace them. a coil can be tested using a multimeter. measure the resistance between the HT output pins on coiled pairs. so test resistance between outputs 1&4 then 2&3. both values should be very close, if there's more that a 15% difference you can be fairly sure the coil has enough internal wear to cause unever running. also a similar test can be done on the LT input pins. again measuring coiled pairs to check if they are close. cant remember the values i got on a new one i tested last year but it doesnt really matter, consistency between the 2 pairs is what you want to see.

Hey Jug hope you enjoyed your holiday!!
I went out and bought myself a set of Magneti Marelli HT leads but when the mechanic guy saw them and looked at the ones installed, he told me to return them saying that mine are like new and don't need replacing. They are branded FIAT not MM....
So I just changed the sparks...
About the coil, I'm afraid I have no experience in this, what's LT and HT?
Do I do the test when the car is totally off? And do I put the poles of the multimeter where the leeds plug in?
Sorry but this is my first time

Thanks Jug.

HT is where the plug leads jopin the coil. if you remove the plug leads you should see each HT output is numbered 1-4, representing each cylinder. the way the coilpack works is using 2 internal coils, each one discharges to 2 cylinders. when i say a "coiled pair" i mean 2 HT outputs (such as 1&4) that are common to one internal coil. if you test the resistance across these 2 HT outputs you get an idea of the conditon of the shared discharge circuitry. if you measure 1&4 then compare it to 2&3 and both are very similar then you know the discharge circuitry will provide an even output for all 4 outputs, important for even running.

there will be 3 pins on the LT side of the coil (iirc), LT is the side where the connector is plugged into the coilpack. its how the coilpack is powered. the 3 pins are for earth (1) and power to the coils (2). you need to determine which pin is earth (do a continuity test on connector pins to determine coilpack earth pin) then test resistance between each of the other 2 pins and earth. the 2 results you get will give an indication of the conditon of the coils. a coil with less resistance will hold less charge and cause low sparking on 2 cylinders (the most common coil problem).

i am new to this, and i want to put a question on, about my brava and i cant work it out..

I have a fial brava 51 plate, the ems came on, so i took it for a diagnostic report £30.00..!! it said that it was missing on cylinder 3, this is usually the coil!! so changed the coil, still the same, so going to get new ht leads they are £28.00, what else could it be??? please help!! anyone...

Cant be the coil pack if just 1 cylinder is misfiring, because both plugs and leads are required for the firing circuit. Only real possibility is a duff plug.
Tony.

What engine size is it snotta? 1.6?

1.2. i hope this gets thru, believe it or not, i am not blonde!!!

what i cant understand is the bloke at the garage obviously does this as a living, he was going to change the coil and charge me mega money, i will go and get a plug tomorrow, do you think i need to do the leads aswell?

As Tony says. There are not 4 individual coils therefore as your coil governs more than one plug lead and spark plug, if the coil was knackered then you would not just effect one individual cylinder.

Therefore you need to be looking at items that will effect the loss of just one cylinder. These items include Plug lead, Spark plug, Injector,or worst case scenario, compression loss.

i'd have a look at the plug lead 1st then the spark plug on number 3 cylinder. Look for oil contamination on the plug. Oil can sometimes find its way down a plug hole especially if the rocker cover gaskett is damaged or not torqued down correctly

compare the plug to that of one from a correctly firing cylinder and inspect the condition of the firing end in particular.
Is wise to change the plugs particularly if they look old.

cheers, it was the ht lead, and thankyou to all of the replies i had,

I had this prob on my 1.6. pot 1 wasn't firing and blew my ignition pack. after going through a (so-called) automotive electrical engineer who told me that my leads where fine I ended up replacing the coil pack, ECU (I know), plugs and eventually found out that the leads connector, where it attaches to the top of the plug had failed and the lead was shorting on the block, boiling the ignition pack! needless to say the electrician gave me my money back and paid for half the new ECU. At least I know I've got a new electrical system in the car now. so Warning to all, check the leads and the plugs electrically and physically first before taking it to a garage.

My number 3 coil has stopped, I have got a new one coming, are they easy to replace ? Is it just a case of unbolting the old one and undoing connectors and putting my new one in and reconnecting and bolting back in?


That it, any re-collaboration needed ?

Very easy to replace, just a couple of alley\torx bolts to remove and unclip the lead to the coil pack no recalibration needed at all.