Ran out of fuel, now have issues.

[Bandage]

Unexpected journey and tempramental fuel gauge lead me to conking out 100m from the petrol station

Put in 5l of E10 (all they had), filling up with E5 (it's ususal) at the next garage that had some.

All seemed fine, until 10 miles or so later when there came a bit of a knocking noise and a loss of power.

It stalled at lights, and was a pain to start again.
At home on the drive now. But again, doesnt want to start without a lot of fussing, driving it around the block is really underpowered.

So how should I go about troubleshooting this?

Guessing that theres some crud from the petrol tank in the fuel lines?
Have an inline fuel filter which i can see fuel in, so think the pump is working, but it isnt doing the normal tick tick sound.

Or is it something else?

[svenedin]

Try taking the flexible fuel line off the carburettor and directing the hose into a suitable container to check the pump is working. If not, there's a filter in the base of the standard SU fuel pump (assuming that is what you have). It can be removed with the pump in situ but I'd suggest disconnecting the pump, removing the filter and giving the pump a good rinse through with clean petrol or carburettor cleaner. If that doesn't improve the situation, it is possible there's something blocking the fuel line from the tank to the pump. You could try to blow that through with air. If pump and fuel line from tank are OK then move on to the float chamber.

Stephen

[Bandage]

After disconnecting the fuel line to the carburettor, I can see that the pump is working fine.
Fuel looks clear too, so nothing blocking it that way.

Still being a fusspot to start and has no power on a lap of the block.

So problem must be from the carb onwards?

[svenedin]

Well if the pump works fine with the fuel hose disconnected from the carburettor but will not pump properly when attached to the carburettor then the problem may be with the float bowl or float needle valve. To check this you'll need to take the lid off the float bowl. It is best to have a new gasket to hand as it may leak reusing the old gasket. Look inside the float bowl and check whether there is crud in there. If there is clean it out. Then check the float valve. You need to take the hinge pin out of the float (pliers) and with the float disconnected the float valve should pop out. Check everything is clean and reassemble.

There is a possibility that the car playing up is coincidental to the running out of fuel and is something else. If no luck check you have a good spark but please not when there is petrol or petrol fumes around!

[Bandage]

Thanks for the pointers, Just got around to looking at it this morning.

Cleaned out the float bowl, there was a bit of crud in the bottom but nothing too major.
Needle valve is moving freely and on inspection looked clean.
With an empty float bowl, the pump worked perfectly and could hear it ticking away when the fuel lines were all connected again, so fuel is definitly getting into the carb.

Checked the spark plugs. Getting a spark on all of them, but 1&2 were not very good in comparison to the others. These two were also black and wet so gave them a clean, but even then spark was still not as good as on 3&4.
Checked the Distributor cap and some of the contact points look worn (?) see pic (its an AccuSpark).
As it's sparking, I guess we can we rule out that as an issue.

When trying to start, it splutters, catches (or almost does) for a second and then stalls out. Full choke and reving the accelerator don't seem to make an diffence.
This got me thinking that there might be a blockage in the Carb Jet? Is there a way of checking this?

[svenedin]

Check the spark plug gaps. The central contact of the distributor cap (graphite) does make a physical contact with the rotor. The plug contacts rely on a spark jumping the tiny gap and are not a physical contact. If a spark plug gap is too big or if the high tension lead is loose or damaged then an excessively large voltage is needed, due to the resistance, and this can burn the rotor or the distributor plug contacts. Sometimes a distributor cap can have a hairline crack which is hard to detect and people have had trouble with poor quality rotors too. The rotors and distributor caps from Martin Jay at Distributor Doctor are top quality. Do check the rotor is properly pushed down (it can only be fitted in one orientation so there no harm taking off the rotor, giving it a clean and refitting).

You mention the plugs with poor spark are wet so it sounds like your carb jet is OK. You could check the carb piston moves freely and falls with a metallic clunk and also the carb damper oil level.

This sounds like an ignition issue. I don’t know what polarity your car is but if it is Positive earth the electronic ignition modules are very fussy about having a good earth connection from the coil. Check all the electrical connections are secure including connections to the coil, all of the plug leads and king lead.

The poor spark you have observed on 2x plugs sounds very much like the problem.

Stephen

[geoberni]

You've said not that long ago you're a new owner, so there may be some things you haven't checked up on yet.

Getting a spark is not the same as getting sufficient spark.

There really could be a lot of things causing this, but I would look at Ignition and Spark first.
You've said it's "an Acuspark" but is it an electronic points or still conventional points? They sell both.
Is the car Pos or Neg earth?

If it's been switched to Neg Earth, have the Coil Connections been reversed to match?
If they haven't, then the Spark is jumping in the wrong direction, Plug Body to Centre Electrode, and that results in plug heat damage (I found that problem with my car when I got him).

even then spark was still not as good as on 3&4.

So change the plugs....
I like using the 'sparkrite/accuspark spark plug testers', a set of 4 and you can easily compare the relative quality of the sparks, see if one is missing etc... https://youtu.be/tttCbxFxu4g
A set of 4 is about £10.


After checking the Coil connections, I'd next slave in a different Dissy Cap and see what happens.

Stephen's remark about 'good connections' applies whether Electronic or not, Pos or Neg Earth.
Electricity always likes good clean connections, irrespective of the circuit or polarity.

[svenedin]

Do check all the spark plug gaps and if the plugs are worn change them all as Berni suggested. I have found “pre-gapped” plugs are often incorrect. One of those coin type gap testers is in my bag of tools in the car at all times. The gaps is 25 thousandths of an inch for 1098cc. With a high performance coil the gap can be increased to 30 thou (I use a Pertronix coil on the recommendation of Distributor Doctor and it is absolutely excellent). A new distributor cap and rotor are very handy spares to have on hand but get quality ones. If in doubt about the HT leads change them as well.

You've done well to find and actually observe a problem but now it is about finding the cause. As a new owner this is probably really annoying but you'll learn a lot about your car this way.

I just had another look at your picture and I think the problem is staring me in the face. Your distributor rotor is not fitted properly/loose and is gouging the inside of the distributor cap. There is a score mark there.

This is an original Lucas distributor cap. They are not all of the same quality.

IMG_8892.jpeg (1.32 MiB) Viewed 4066 times

[paul 300358]

While you are messing with the distributor, try a new condenser.

[svenedin]

While you are messing with the distributor, try a new condenser.

It’s electronic ignition otherwise a very good call!

[paul 300358]

Sorry, I didn't spot that. I would be tempted to put a set of points and condenser on it then try again.

[geoberni]

Sorry, I didn't spot that. I would be tempted to put a set of points and condenser on it then try again.

Don't take it to heart, he only said it was an Accuspark Distributor, not whether it was electronic or not.
They sell both.
That's why I asked the question yesterday...

But Stephen is right, looking at the inside of the Dissy Cap, there's clearly a problem with the way the Dissy is assembled, because the Rotor Arm has been scoring the Cap, but not for long.
It might be the rotor arm that's the problem, or the cap isn't a good fit.
I think the whole running out of fuel thing is a red herring, there's a problem with that Dissy.
Not only is there a score mark on part of it, but where's that slither of red plastic come from?
From the Rotor Arm presumably.

[Bandage]

This forum is such a brilliant resource for the new owner like myself!
Thanks so much everyone.

First off, some answers:
Yes, electronic distributor and ignition, all wired to neg earth.

Stephen, great spot on the cap, the red sliver of plastic there is definitly from the rotor arm.
Will check to see that that is seated properly and not come loose, and inspect the distributor cap too.

I've not got a set of feeler gauges, so will pop out and get some and check the sparkplug gaps next.
If they're good then a ne even a new set of spark plugs and some of those spark plug testers that you mentioned geoberni - they look super.

Although it's a little frustrating not knowing what the root cause is, i do feel like i'm getting a much better understanding of how everything comes together under the bonnet.

Thanks again!

[svenedin]

Good stuff. The good thing is you can address this and learn at the same time. Should you ever find yourself broken down at the side of the road you will know what to do. Feeler gauges (Imperial) are useful should you want to set the rocker clearances at some point and can of course be used on spark plugs but for spark plug gaps search for "coin type spark plug gauge" which I personally find easier to use and can also be used to open the gap and close it.

Stephen

[geoberni]

Remembering that there are different types of plugs out there, many of which you can't adjust due to the number of electrodes.
.

405-4056265_spark-plug-tip-designs-spark-plug-electrode-types.jpg (65.5 KiB) Viewed 3971 times

As the car is a fairly recent acquisition, and has an Accuspark Dissy, it may well have Accuspark Plugs (AC9C), which are multipoint.
My car had them when I brought it.
I've since changed to conventional single electrode.
.

AC9C.jpg (52.02 KiB) Viewed 3969 times

[svenedin]

Yes the standard Champion N9YC seem fine on my car and they can be adjusted as they're copper electrode. They're cheap too. I have in the past tried various fancy spark plugs with absolutely no noticeable difference in performance. The one thing thing that made a big difference was upgrading to a high performance Pertronix coil. I was so impressed I actually phoned Martin Jay at Distributor Doctor and he chuckled because he remembers doing the same thing to one of his cars many years ago and being very pleasantly surprised. Of course with a high performance coil the plug gaps can be increased to 30 thou.

[Bandage]

They are indeed exactly those accusparks with three electrodes.

I checked the gaps and while the plugs in cylinders 3&4 were fine, 1&2 were various between 0.017 and 0.019

Have ordererd some new plugs (and a gap tool), so will update you all in due course

[svenedin]

So 1 & 2 were way under. Well done

[James k]

A few years ago, my car got vapour lock and the float bowl ran dry, equivalent to running out of fuel. I had similar symptoms to yours after that and had to be recovered home. I discovered eventually that when the float bowl had run dry, it had sucked some dirt into the jet. I detached the pipe from the float bowl to the jet and blew down it to clear the jet out. It ran perfectly straight away.

Worth checking.

[mowogg]

When you cleaned the float bowl die you blow air through the jet? I have had to do this by thr Road side in the past due to ceud blocking the line with very similar symptoms you describe