| My grandad has been going on about the firing order of my car - which in the Rod Grainger manual - says 1,3,4,2. When looking into the bonnet from the front of the car, the order from left to right where they are plugged in is 3,2,1,4. Can anyone give me an explanation that I can give him as to why they don't appear to be in any cyclical order sequence? (7/01) |
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Plug lead order, reading (your) left to right (inlet side to exhaust side) across the coil pack: 3-2-1-4 on a 1.6 |
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Ahem! Just checked my 1.8 manual - shows 1-3-4-2?
(7/01)
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| I always thought a 4 cylinder engine fired 2+2, i.e. 1&4, then 2&3. This reduces the stress on the crank and ensures even wear in the bearing liners by ensuring the bending moments are equal on each end of the shaft. Am I wrong? (7/01) |
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For your Grandad - the order on the coil pack is not the firing order. In a normal distributor the rotor arm goes round in a circle from one lead to the next and a 4 cylinder firing order is normally something like 1 3 4 2. It has to be wired in that order. The MX5 coil pack has no moving parts so the layout is not really relevant. Also the MX5 pack produces 8 sparks per cycle (so called lost spark design) so I think the order of the terminals can be swapped in some ways and still work but 4 1 2 3 is normal and delivers the goods. (7/01) |
| The firing order on the 1.8 is 4-1-2-3 but on the 1.6 it is 3-2-1-4. (7/01) |
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Have just searched through the miata.net garage section: http://www.miata.net/garage/ignition.html#plugs Shows: 1.6: 3-2-1-4 It would appear that Rod Grainger's 1.8 Enthusiast's Book is incorrect. Also, mention is made on the miata.net forum that the Haynes manual is incorrect too!! (7/01) |
| http://www.ngksparkplugs.com/techinfo/spark_plugs/ for interest. (7/01) |