No Spark At Plug

[willip2]

Hi Can any one help please, fusion 2002 1.6 petrol, will work fine for weeks then just will not start. Go back next day and it runs fine.

Tried changing crank sensor and coil pack to date still same problem. Resting plug on engine produces no spark when cranked over.

Could this be an alarm/imo problem? tried disconnecting battery and using spare key. At the moment cant get it to garage recovery will not come out unless its a mile from home.

[Dan62]

Hello, if it was the immobiliser you should see the lock symbol flash when cranking the engine.

I would start with the battery, is it the original ? It may just be that the voltage drops significantly enough when cranking that there is not enough Low Tension to the coil pack to produce a spark.

Motocraft batteries fitted around that age were Low Maintenance ones, Opaque white in colour with accessible cell caps, if so removing the battery you will see min/max marking for for the electrolyte level.

[willip2]

Thank you for reply, The battery is good and will give 20 plus good engine cranks before slowing down surely enough power there.

I have just checked and lock symbol stops flashing when key is turned. I will swap battery from my other car and try but I am not confident that is the problem.

[Dan62]

Its a starting point, with any intermittent or odd problem, start with the basics and work forward.

[willip2]

ok tried another battery with same results. I put a spark plug into a lead and cranked to test spark is that test ok these days?

[Dan62]

Yes, so next step would be to check any fault codes logged.

[willip2]

no fault codes showing RAC guy put his hand held on.

[FOCA]

ok tried another battery with same results. I put a spark plug into a lead and cranked to test spark is that test ok these days?

Yes, but the rocker cover may be made of some sort of plastic material/ an insulator

Did it just suddenly stop working for no aparrent reason (not after work done on the car?)

try gapping the plugs down - a narrower gap than recommended but not closed (the spark always finds the easiest route- like lightning -)

was it new coil packs or secondhand? how long ago/ mileage scince they were done/ same with HT leads (do these come with the coil packs?)

its possible it needs coil packs again (or something already replaced needs done again)

[willip2]

Thanks for reply, new parts fitted yesterday, problem has been going on for months. plug spark tested against steel not plastic.

ok now discovered no voltage to coil pack (relay problem?)

[Dan62]

Great find, I'm sure the 12v comes from the ECU but I don't have access to any wiring diagrams at the moment.

I have a schematic pinout diagram from the ECU, if anyone else has it perhaps they can assist you.

It'll be late Sunday or Monday before I can get to them.