Bugger!

 

Just got the 300 out to make a start on cleaning the engine and get the tracking checked. As I started her up I noticed that she was running a little lumpy. Drove her down to the garage for the tracking and could smell she was running rich and there was an occasional back fire.

 

Got the car home and removed the coil conectors and there was a drop in revs on all but one connector (middle off side). Called Jim (at PowerZ) and he’s said check the injector connectors (look fine), remove spark plugs and check PTU2. Haven’t checked the last two items yet but is there anything else you clever fellows can recommend?

 

One the plus side the tracking was found to be out and now she drives like a dream.

 

Cheers,

Chris.

What have you checked so far on the ignition system which fires that cylinder?

 

The injectors resistance, the coil packs connector, swapped the coil pack and now removed the plug.

As it moved with the plug it would be the plug that's a problem. No ideas why it might have failed but a new spark plug is about £6 so no harm in changing the one.

 

If it didn't move with the plug I would have said ptu.

The injectors resistance, the coil packs connector, swapped the coil pack and now removed the plug.

 

Time to elimate the PTU from the equation. You can perfom a manual test on the PTU (it's in the FSM) but is rather involved and if there

is a problem with it that's vibration and/or heat related you may not see it.

 

See if you borrow a known good S1 PTU from member or from Jimmer.

Cheers Andrew. I’ll see what Jim can do. :cool3:

And just to double check what plugs we use it’s a HGK’s PFR6B-11C?

And just to double check what plugs we use it’s a HGK’s PFR6B-11C?

 

Yes - NGK PFR6B-11C.

https://www.opieoils.co.uk/pv-79729-ngk-pfr6b-11c-2684-laser-platinum-spark-plug-sparkplug.aspx

I forgot to update this so here it is.

 

After changing the offending plug I done a few short runs between 12-20 miles at a time. A week or so later I drove to see Jim about some other work I’m wanting done to the car. He pulled the plug and it was as good as new.

He also plugged the car in to see if there was a fault code and there was a PTU fault stored. This may have happened when I unplugged the PTU for cleaning after the plug had gummed up or it may have caused the problem.

Another thought was that it may have been a simple case of “cold fouling” from starting the car in the depths of winter to move it out the garage for cleaning/tinkering.

 

Either way the problem hasn’t returned. So thanks for everyone’s input, here’s hoping the problem doesn’t return.

 

Cheers,

Chris.

Sounds as though you had the same problem as me! I found mine to be a dodgy spark plug too, once swapped it's ran great since.

 

Mine was sat all winter too with the occasional start up to move it up the drive