modern coils

[elfman]

This is just to help any body who has a more modern car with coil per plug..

I have a 05 Mazda 3 and its been very reliable and a good value car,  last year it started going a bit lumpy underload , pulling out of tight corners etc ..but ran fine once on the open road.

Changed the plugs and air filter and all back to normal.... Few weeks ago started doing the same thing again,  Filter is still new so changes plugs, no joy, cleaned MAF no joy..

Checked all connections nothing, got a OBD reader ! no faults.....head scratching.

Friend who runs a Garage said its probably a coil but god knows which one,,,,so got one ( pricey) and started swapping it around going for a run etc and the third try it was coil number 3...

I would have thought it would have broken down full stop but it was only playing up under load at low revs.....learn something every day. 

[Rich]

Aug 10, 2019 9:14:45 GMT elfman said:

I would have thought it would have broken down full stop but it was only playing up under load at low revs.....learn something every day. 

Fairly normal failure condition, windings break down and cannot deliver a decent spark, it's enough for idle and high speed-low demand running but under high load-lower speed running the spark is 'blown out' and won't properly ignite the fuel mixture. You've changed the plugs which is often the root cause, a bad plug putting a higher demand on the ignition system causing accelerated failure.

Lets have some cool old cars as this thread is somewhat lacking.

[elfman]

The old plugs were changed over a year ago, the two sets I was using to test were fairly new and brand new...
In the past we used to put coils in a reasonably cool place in the engine compartment,,,but these days they put them in the hottest place you can find on top of the engine and in the head, that's not good. But that's progress for you they also charge more for one coil than the old ones who used to supply many more plugs..but saying that i have seen on old coil pack in on a run on the motor way no warning just stop..but then you could get a coil easy to get you going. Mine was on a camper on the M4 and i was towing my race car, took the one of the race car put it on the camper and drove away...simples.

Love the cars, well 2 out of 3 not bad... just because its old does not make it cool or good you cant polish a turd if it was curse word in the day its still curse word..my neighbour had one in a lovely baby poo colour looked horrible, painting it Gas Monkey green does not help still looks horrible.