yaris 2001 1.0 spark plug damaged

[VosperD]

Our Yaris that has been running fine now has 174000 on the clock.

Now missing on no1 cylinder. The spark plug has been damaged, the contact bent and the ceramic broken.

AA man says not seen anything like that before and that the broken plug may have damaged something in cylinder but I think something in the cylinder may have damaged the plug.

I've changed the plug and as I had a spare coil I changed that as well. It's still missing and the OBD unit says "missing on no 1 cylinder igniter problem" and the plug is wet when removed after a short run.

It's going in for a compression test tomorrow, i'm hoping it isn't anything terminal but I fear that it might be with that mileage, plus it's had a few knocks here and there.

I would be interested in anyone's comments while i'm waiting.

Don.

[Mooly]

If the contact is bent then the plug sustained physical damage... which may in turn have been caused by the insulator disintegrating... and that would likely cause damage internally to the valves/piston.

The fact you have replaced  the plug and coil and get a fault related to an ignition issue suggests maybe more than one thing is going on.

Have you tried the original coil pack with a new plug just for interest? on the improbable case the replacement coil pack is faulty. There would be no reason to even suspect the original coil pack based on the original symptoms.  

I suppose its possible the OBD registers a problem if the plug is trying to fire when there is no compression (suggesting mechanical damage) because the spark will jump more easily in that low compression condition and that might be recorded as a fault.

On balance I would say you may well have a compression problem. 

 

[flash22]

swap the coil packs and see if the fault moves if it does, its the coil, if not look at the pins on the connector

 

A borescope down the plug hole should see any damage at 174k it should have had 2-4 sets of plugs in its life, if they are original they are well past it and that's why the porcelain cracked

[VosperD]

Thanks for the replies.

So it  it looks like the plug did fail first then. Although I've never seen this before myself.

The car has been regularly serviced but recently it has been doing more mileage. The plugs were changed on the last service, about 10000 miles ago and the garage I take it to has been trustworthy as far as I am concerned but I never checked to see if he did in fact change the plugs.

Since posting I have reverted back to the original coilpack and it's still missing. The wiring looks ok. I only tried a new coil pack because I had one or two spare and nothing to lose by trying.

[flash22]

It looks like a NGK plug i wonder where the electrode has gone

swap the coil between cylinders - it could have bent a valve or knocked a hole in the piston - at this stage it may be quicker and cheaper to put an engine in, or send her to scrap

[Gerg]

I can't remember when I last saw one that looked like that!  

In the unlikely chance that it was original then it would've been a Japanese NGK, as a 2001 Yaris was a Japanese Yaris, wasn't it?

 

 

[VosperD]

Yes it was an NGK. but it says "Made in France"

The car was due for replacement as soon as we could find another at the right price and not too far away.

It's been a good family runabout with occasional long runs for a few years, both daughters had it as a first car but now it's doing more regular mileage.

My  youngest daughter has been getting insurance quotes for a replacement as it will go over to her name. Surprisingly  she gets a cheaper quote for a 1.3 than a 1.0.

I was hoping for a few more miles out of it and to part with it as a runner even if i had to give it away.

We'll see what the verdict is tomorrow..

Don

Edited January 21, 2020 by VosperD
added info

[donkeychomp]

Could it be as simple as an HT lead? I had this issue with my Suzuki. Swap one lead over and see if the problem migrates...

[VosperD]

Quick  check  by local  garage reveals hardly any compression on cylinder 1.

Sad to  say it's down to the local scrappie for £70.00 unless anyone wants to make a better offer!

Definitely going to  replaced by another Yaris when one comes along.

Don

[Mooly]

Sorry to hear that although it was pretty much what was expected unfortunately...

Good luck with whatever you replace it with.  

[VosperD]

Thanks for the reply.

I think we're looking at a 1.3 in Bristol tomorrow.

Don

[Mooly]

Well good luck whatever you decide and remember there are plenty out there so don't jump at the first you see.

[bathtub tom]

4 hours ago, VosperD said:

Quick  check  by local  garage reveals hardly any compression on cylinder 1.

It may be a piece of debris in a valve seat holding the valve partially open. Worth a look with a borescope down the plug hole?

[flash22]

Sadly any repair will out weigh the value of the car, if anything is wedged in the valve it will mean a bent valve, damage to the piston and or a damaged head -

[VosperD]

Another thing is that the MoT is due in a few weeks. With the high mileage there is always a risk the something else would crop up.

The Yaris has done good service for the last five years so  we can't complain.

Whipping the head off an engine,(by the kerbside in Fulham in days gone by) is no longer an option.

Don

 

[flash22]

1 hour ago, VosperD said:

Whipping the head off an engine,(by the kerbside in Fulham in days gone by) is no longer an option.

Don

 

I know that feeling, turn your back for 30 seconds and your tools will be walking down the road - In my teens i would think nothing about pulling an engine/gear box in a afternoon these days its someone else's job

[VosperD]

Well it's gone to our local scrapyard. So hope it might help to keep other Yaris's on the road.

At the last minute we found  replacement locally, a private sale. 2010 model  with low mileage and an affordable price.

A previous find from a dealer in Bristol, also low mileage but not such an attractive price being a dealer, fell  through. It looked good but they obviouisly hadn't checked it out.

Came up with a few  serious advisories on the MoT when they took it in. To  the dealers credit we were released from the deal and he quickly returned our deposit. We would have taken the car and got the work  done ourselves but he totally refused to  drop  the price. Who  would pay his price with the MoT on line showing the advisoried I don't know.

Don

[flash22]

Standard sort of thing from a dealer, they don't care - if it was a persistent issue you know the car was not looked after

 

Well enjoy your new toy - thanks for the update