FMB

[djj_engineer]

I seem to have a problem.
The plugs on the left bank are white (lean) on 1 & 4 and Black (rich) on 2 & 3.
Those on the right bank are white on 2 & 3 and black on 1 & 4
The left is Nearside.
I am at the moment looking at the ignition system and will concentrate on the distributor.

I don't think it can be head-gasket or carbs as they don't seem to fit the outcome.

The latest start, and FMB seemed Ok until it suddenly wouldn't tickover.
I will investigate later this am to see if I can spot anything that may cause the symtoms
DJ

[cameronfurnival]

Re: FMB

Hi Derek, are you running the SU carb set up? A common cause of weird rich/lean running is often down to PCV/ crankcase ventilation systems believe it or not. I'm sure you will have addressed the infamous Rover V8 crossfire problem if leads 5 and 7 are parallel?

[philcoyle]

Re: FMB

Always worth clamping off the pipe to the servo just in case the servo has sprung a leak and allowing air in to weaken the mixture on one bank, but don't drive it anywhere!

[djj_engineer]

Re: FMB

Hi Guys
Ta for the thoughts.
It was the Lumination Ignition unit. I swapped it for the other one on the car and the normal tick-over returned.
All i have to do now is figure out how I fixed the old one so that I can replace it with the one that works,
cheers
DJ

[greyV8pete]

Re: FMB

Hi Derek. That kind of makes sense since if you plot your black/ white plug colours against the V8 firing order 1 8 4 3 6 5 7 2 it suggests that the ign module is only firing properly on every other cylinder. Glad you sorted it out. Peter.

[djj_engineer]

Re: FMB

Hi Peter
Yep that was my thought. I concentrated on the Ignition side. I couldn't couple the plug colour with any other cause.
If it been one bank I might have thought head-gasket, but it wasn't, thankfully!!
Derek