Uneven plug colours

[MADMAX]

My plug colours (sorry, colors) look like this



Should I be worried? It's defo not right..... and I'm finding it difficult to pinpoint the problem.

Last month I replaced some plugs, all leads, the throttle positions sensor, both front O2 sensors and had all the injectors cleaned/tested.
I then did a dyno day pulling 582bhp (at flywheel) but still, plugs look like above.
Compression test is good.

Dyno results look like this


The only codes I've got standing are P0140 and P0158 which are rear O2 sensor related and probably because I don't have cats.
Other mods are genIII heads, Belanger headers and SCT tune.

Any ideas anyone....

[Speedandstealth]

Don't know if this could happen but could 3&5 wires be wrong way round?!.....faulty coil pack or injector control signals....air leaks causing lean running....3&5 look new.....it's a weird one.

My dad used to use a colortune kit so you could see the colour of the flame when the cylinder fired.....it was weird but worked!

Will be something simple when u find it....

[Venomous1 Racing]

My plug colours (sorry, colors) look like this



Should I be worried? It's defo not right..... and I'm finding it difficult to pinpoint the problem.

Last month I replaced some plugs, all leads, the throttle positions sensor, both front O2 sensors and had all the injectors cleaned/tested.
I then did a dyno day pulling 582bhp (at flywheel) but still, plugs look like above.
Compression test is good.

Dyno results look like this


The only codes I've got standing are P0140 and P0158 which are rear O2 sensor related and probably because I don't have cats.
Other mods are genIII heads, Belanger headers and SCT tune.

Any ideas anyone....

Has one head been milled? Looks like lead fouling on the other plugs to me and 5,7,9,10 look like clean burning plugs. You're right Codes are referring to rear o2 sensors. Are they seeing clean air? (Strapped outside exhaust path? If not it'll throw codes. If you have bungs still for rears, use spark plug anti foulers in bungs then reinstall rear o2s.
What type gas do you use over there? What plug wires are you using?

[Venomous1 Racing]

My plug colours (sorry, colors) look like this



Should I be worried? It's defo not right..... and I'm finding it difficult to pinpoint the problem.

Last month I replaced some plugs, all leads, the throttle positions sensor, both front O2 sensors and had all the injectors cleaned/tested.
I then did a dyno day pulling 582bhp (at flywheel) but still, plugs look like above.
Compression test is good.

Dyno results look like this


The only codes I've got standing are P0140 and P0158 which are rear O2 sensor related and probably because I don't have cats.
Other mods are genIII heads, Belanger headers and SCT tune.

Any ideas anyone....

Has one head been milled? Looks like lead fouling on the other plugs to me and 5,7,9,10 look like clean burning plugs. You're right Codes are referring to rear o2 sensors. Are they seeing clean air? (Strapped outside exhaust path? If not it'll throw codes. If you have bungs still for rears, use spark plug anti foulers in bungs then reinstall rear o2s.
What type gas do you use over there?

[MADMAX]

Many thanks - do you mean clean burning on 3,5,7,10?
I'd only considered that the white plugs were wrong, especially 3 & 5 which are very white (I hadn't thought rich burns on the other plugs were my problem but of course now you say it, 9 & 4 also look damp). To support what you say, people following me and lets face it, most people are always behind a Viper (sorry, couldn't resist that one) say they can smell fuel!

Both heads have been skimmed about 30 thou during the genIII head upgrade to bring the compression ratio up to 10.3 ish.

As for what fuel do I use - I always use the same brand of UK 98 octane (what USA call 92/93) and it's unleaded so I'm not sure what lead fouling is - can you elaborate.....

The rear O2 sensors are fitted to the zorst and electrically connected to the circuit - I like the idea of fitting spark plug anti foulers to overcome the problem (like this writeup I guess http://forums.evolutionm.net/evo-how...cel-light.html) assuming there isn't any way of inhibiting the error codes by changing a part of the PCM code.

I'll do a compression test again today and check injector connectors.

Something I should also say is that my PCM was bricked during code changes last year - I managed to get it unbricked with MoparBoyy's help but I have a doubt in my mind that "maybe" something inside the PCM isn't quite doing what it aught to.

[MADMAX]

Don't know if this could happen but could 3&5 wires be wrong way round?!.....faulty coil pack or injector control signals....air leaks causing lean running....3&5 look new.....it's a weird one.

My dad used to use a colortune kit so you could see the colour of the flame when the cylinder fired.....it was weird but worked!

Will be something simple when u find it....

Hi James - many thanks for these ideas - sorry I didn't acknowledge you earlier, not sure why I didn't see your reply.
I'll take a look at the leads tonight.

I did a compression test last night and all cylinders are healthy so no mechanical problems.
Brand new plugs and my spare PCM also fitted - can you see I'm clutching at straws now.
Problem with this PCM is that it got bricked and unbricked last year too - troubleshooting continues.

[Speedandstealth]

No worries!

Sometimes the simple things get overlooked.....especially when your knee deep in muck and bullets!

Cheers

[LifeIsGood]

As info...this is what mine looked like back in 2010 when I did my last change...stock 2001 RT/10...no orange hue like on some of yours...

[Troublemaker]

I'm only asking this because it was something I have run into before, but is that color uniform all the way around the plug? We can probably rule out lead fouling if he hasn't been running race gas. Ash deposits are another, but this isn't an area I know real well. I know reading spark plugs isn't something always done on 4 stroke motors, but my background is in two strokes where reading plugs is a way of life.

Have you run any octane boosters?

[MADMAX]

As info...this is what mine looked like back in 2010 when I did my last change...stock 2001 RT/10...no orange hue like on some of yours...

Interesting colour differences.
3 and 5 are the lightest.
Thanks for the chip-in.

[MADMAX]

I'm only asking this because it was something I have run into before, but is that color uniform all the way around the plug? We can probably rule out lead fouling if he hasn't been running race gas. Ash deposits are another, but this isn't an area I know real well. I know reading spark plugs isn't something always done on 4 stroke motors, but my background is in two strokes where reading plugs is a way of life.

Have you run any octane boosters?

No, no actane boosters - manybe that's what I need
thanks for input.

[Troublemaker]

No, no actane boosters - manybe that's what I need
thanks for input.

OBs can definitely be noticed on a plug, but dont jump to that yet. There are other things to look at, that's why I asked if the color was uniform around the plugs. It could be the head causing it or even sealing at the piston rings. Like I said this isn't my area of expertise, but have seen a lot of the symptoms in other types of motors. I may be way off, but there are smaller things that can lead you in the right direction. Learning the in and outs of this power plant is something I am still learning.