[Adam Webb]

The joys of daily driving continue after Wraith and spot on shout with a dirty oil pressure light connection another few hundreds miles an a new issue!

Yesterday evening I experienced what felt like fuel starvation, despite the gauge saying other wise, but I know not to trust any of the guages. I topped up with fuel. Heard the pump prime and click to a stop, car started fine drove absolutely fine the last few miles of my journey.

This morning it was running very rough, I turned it off checked all the leads where connected, that the Rotor arm and cap were cleaning and carbon free, all good.

Restart same issue. Drove to work, about 5 miles, the misfire didn't clear, very down on power to point where it would barely move.

All ignition components are connected and clean, it had a new coil maybe 600 miles ago.

Could this be a fuel issue? Has potentially running the carbs dry caused something to stick? Where should I start to look?

Thank you

Adam

 

[Wraithman]

If you have the original Opus ignition module in the distributor, it is time for it to be replaced. Most suspect fuel issues with the symptoms you experienced, but it's usually electrical in many cases when things "suddenly happen". The best replacement is the Pertronix 9LU-281 for Lucas V8 distributors.

 

[shadow 11]

Sounds like you virtually ran out of fuel and crud from the bottom of the fuel tank got sucked into the system. I would blow out the fuel lines, change the filters and clean the carb float bowls & float needle valves.

 

[Adam Webb]

Wraithman - I like your thinking, it would certainly remove that as an on going issue. I'll see who stocks them in the UK.

Shadow 11 - float bowls was my thought too, from memory they have internal gauze filters?

 

[Wraithman]

The filter is located at the inlet pipe at the bowl. There is an O ring at the fitting that should be replaced for a good seal.

 

[Adam Webb]

Filters are clean and flowing, bowls fill up and are clean and free from debris.

I've taken all the HTs off and put them back, cleaned the rotor and dizzy cap. Checked all the vacuum lines for leaks.

It is the same 😵

I did note that the drivers side (RHD) exhaust was cooler than the passenger side, by dropping water onto it. Puzzling. Which would suggest that sides carb was under fueling?

 

[Wraithman]

Not quite accurate due to variations with the smog pump and the plumbing, however an infrared gun would be more fun. Don't chance cracking the manifolds. It's one of the most thermal stressed part on the car.

 

[Adam Webb]

I was thinking that as a squirted them 😂

What model is the distributor? Lucas 35D?

 

[Wraithman]

35 series V-8

 

[guyslp]

Repairing and Modifying the Lucas Opus Ignition 35DE8 Module

 

[guyslp]

If the ignition is bad you also have the option of replacing it with a Pertronix module. That has been discussed, repeatedly, both here and on the RROC-Australia Discussion Forums.

 

[guyslp]

See my long saga with a failing Lucas Opus ignition on the Australian Forums: A Christmas FTP!! . . ..

 

[shadow 11]

Each carb supplies fuel to 2 cylinders on each bank of the engine. It's not a case of e.g., A bank carb only supplying A bank cylinders.

 

[Adam Webb]

My plan tomorrow is to remove all the HTs leads, check resistance of each and make sure they've not been cut by the metal shielding.

Pull all the plugs and see what they look like.

Then pull the carbs off and open them up have a good blow throw with some carb cleaner.

Then when none of that works just by a pertronix kit 👌😂

 

[Jeff R 1]

If they're the old wires, or even if they've been in there for 5 or 10 years, as soon as you disturb them, you will need to replace them.
This assumes that they're resistor type wires.

 

[Quido]

Hello
I’m sure you have done this but it doesn’t hurt to mention.
Always pull HT leads off by the boots and not the wires.
Run the car in the dark and observe any sparking anywhere along the wires.
I’ve seen lots of burned hot leads shorting out #1 driver side and #3&#4 pass side RHD cars
Good luck
George

 

[Wraithman]

The plug boots can be a dog to get off. I fashioned a "pull tool" out of a metal rod, maybe 1/8" or so, 12" long with a 3/16 nub on the end to hook the front edge of the boot and breaks the "lock". Never a hassle since.

 

[shadow 11]

Looking at the spark plugs is a good idea, if there's a problem with one carb 4 of the plugs (2 on each side) should show evidence of lean or rich mixture. If they're oily you may need to do a compression test but hopefully that won't be the problem.

 

[Adam Webb]

And the winner is....

One dead HT lead, all but one showed a resistance between 18k and 15k, higher with length of course. The front left near alternator showed an intermittent reading, plugs where better than expected, light brown and some carboning around the base. All replaced with new ones.

I took a brand new HT lead off my RX7 Elford Turbo, and put it in the place of the dead one, started her up. Smooth as, no more misfire!

New HT leads on order and a cap and a rotor arm just to be safe!

Thank you for your advice and guidance all.

No doubt something else will explode, fall off or fail next week. Although I am running out of things to replace.

 

[Jeff R 1]

You know what they say, 99% of carburetor problems are ignition problems.

It's odd too, when the car starts acting up, everyone wants to start with the carburetors, no one suspects the 40 year old coil, ignition wires, and Opus ignition.
Or the ignition timing mysteriously falls out of time _ like how does that even happen, distributors just don't come lose ?

The forum is filled with posts such as this.

Glad you got it sorted.

One other thing, it's an old car, things are going to need restoration (depending on how it was looked after).
Most things are beyond a 2 hour trip to the garage.