Honda jazz Dsi coil replacement advice

[ericmcn]

Hi all,

The wife has a Jazz and it was driving like a Ford Model T so I suggested a timing issue, I plugged in the obd reader and sure enough got P0304 miss fire, this eventful dragged into more cylinders as she took the car out again and now multiple cylinders are mis firing

So I have pulled the coil packs but never took note of the order, whoopsie. I notice they have these codes
5902-C and 5904-C.

The pins also mention different numbers, firing order? 1-5, 1-3 etc..

Can anyone tell the correct order to refit these please? I have ordered new plugs but not sure will it fix the issue.. they were changed at 62k miles says the log book (now 85k) - I did check the resistance between the pins of all the coils and was surprised to see roughly all the same readings

I don't want to go replacing all coils for no reason.

Any advice?

Cheers

Sent from my SM-N950F using Tapatalk

[sparky Paul]

I think the coils only fit one way.

IIRC, the front ones have the securing bolt hole opposite the connector, and the rear ones have the hole at 90° to the connector.

[ericmcn]

I figured the -109 go on the front and the -108 fit the rear. Unless I am wrong..

The ones in front are all interchangeable and vice versa for rear.

I'll try clean these out with a electrical contact cleaner tomorrow and let them dry out and refit. I'm pretty sure the plugs are fine as they were changed quite recently

Thanks

Sent from my SM-N950F using Tapatalk

[Jocko]

Welcome. You say the plugs were changed recently. Did you change them? Many garages don't realise there are eight plugs, and when asked to do a service, only replace the front ones. A misfire is classic rear plugs haven't been changed.

[ericmcn]

Awesome, if that's the case I'll go wait for the plugs to arrive before replacing the coils and re starting.. if the problem goes away the wife will be happy as Larry! I found the rear coils were a b@#£* to remove so it could well be the rear plugs are dead. I never removed the coil distributing leads as I wasn't sure how it was taken off but took off the throttle cable for some access



Sent from my SM-N950F using Tapatalk

[springswood]

Access  to the rear coils and plus can be improved slightly if you slide out the clip holding the wiring to the coils. I mean the the clip at the left end which just slides out to the right as you look at it.

When you take the rear plus out take a look at the gap. It should be 1mm, when I first changed mine it was more like 3, so they'd been missed. I suspected my rear coils were on the way out. Being a cheapskate I put a secondhand set off eBay in but they were just as bad (I posted photos of the plugs I took out this week here https://clubjazz.org/forum/index.php?topic=181.450.

Unfortunately the resistance of the coils isn't the whole story. When the plug gap gets too big it takes a higher voltage to spark and that tends to break down the insulation, weakening the spark.

I've just put in iridium plugs which has stopped it pinking (I wasn't getting an error code) but I might replace he coils. The best place I found so far for them is AutoDoc, £20 - 25 each for branded ones.

Good luck

[culzean]

I think the coils only fit one way.

IIRC, the front ones have the securing bolt hole opposite the connector, and the rear ones have the hole at 90° to the connector.

IIRC the rear coil pack is also shorter than the front ones

[sparky Paul]

I think the coils only fit one way.

IIRC, the front ones have the securing bolt hole opposite the connector, and the rear ones have the hole at 90° to the connector.

IIRC the rear coil pack is also shorter than the front ones

I think you're right.

He had a pile of coils, and I thought the bolt hole would be the easiest way to sort them.

[ericmcn]

Guy,

I've taken off 1 plug from the front, it looks ok - twisted off counter clockwise..

How on earth are the rears held, which direction to take off.. stupid question I know. I can't seem to budge them and there is hardly any room to move a ratchet. I am thinking the ones in the rear are at fault


Sent from my SM-N950F using Tapatalk

[ericmcn]

Looks like the entire front wiper assembly needs to go, great!

Sent from my SM-N950F using Tapatalk

[ericmcn]

Gonna drop this off to the garage Monday! New plugs should arrive then.

Sent from my SM-N950F using Tapatalk

[culzean]

Guy,

I've taken off 1 plug from the front, it looks ok - twisted off counter clockwise..

How on earth are the rears held, which direction to take off.. stupid question I know. I can't seem to budge them and there is hardly any room to move a ratchet. I am thinking the ones in the rear are at fault

All the spark plugs are normal RH thread,  so undo counter-clockwise.  The coil packs just pull straight out after retaining screw is removed,  getting rear coil packs out is easier if you pull the loom off its clips.  If you do get plugs to start unscrewing and they are still tight on the thread try some penetrating oil down plug recess and for every bit you screw them out screw them back in a little until they loosen up ( like 2 steps forward and 1 step back ).

Get the engine hot before trying to take rear plugs out,  the aluminium of the cylinder head expands more than the steel of the plug and will allow thread to move more easily,  the steel wall of the plug is very thin where the hexagon joints the thread and they will snap off if too much torque is used ( then your problems are only just beginning ).  If the plugs have been in a long time the normal passivated zinc coating will try to stick to aluminium, long life Iridium plugs have a special coating ( NGK call it tri-valent ) to prevent sticking because the plugs are gonna be in place for 70,000 miles.

[culzean]

Looks like the entire front wiper assembly needs to go, great!

Sent from my SM-N950F using Tapatalk

Only on MK2 ( 2008 --> 2015 ) with VTEC do you need to get a scuttle plate out of the way,  the VTEC engine only has 4 plugs but they are at the rear of the engine - good job you only need to do it every 70K miles ( iridium are fitted as OEM on MK2--> ).  I just undid the 3 bolts holding wiper motor and slid scuttle plate out when I did our MK2 plugs.

[MicktheMonster]

I got the rear ones out using a breaker bar rather than a ratchet as it has a flexible knuckle joint on the end, this allows you to get in at different angles. It was still a bit tricky but not impossible

[culzean]

I got the rear ones out using a breaker bar rather than a ratchet as it has a flexible knuckle joint on the end, this allows you to get in at different angles. It was still a bit tricky but not impossible

I would be very wary of using a breaker bar on a delicate spark plug,  it is too easy to apply way too much force.

Normal socket set wrenches are made a certain length ( as the drive size increases from 1/4" to 3/8" to 1/2" the wrench gets longer ) to stop you easily applying too much force, spark plugs are fairly easy to shear off as the metal between hex and the thread is really very thin  https://www.championparts.ca/Technical/Tech-Tips/Removing-Broken-Spark-Plug.html

They don't say what happens to any bits of steel that may be chipped or cut off spark plug body by removal process and fall into cylinder ( wonder if they make magnetic easy outs ) maybe some grease on the easy out may hold onto the chippings, I have used grease to trap the chippings when using a tap to make or remake a thread in the past.

If you ever shear a plug off,  especially a rear one - massive PITA and £££££'s