Missing, spluttering, popping then....dying. Thoughts?

[MilesA]

So, in advance of the IWE, took the 3A on a run today about 30 miles up the A1M from North London to visit a friend. Journey north fine. Happily cruising at 60 - 70mph. Journey back the same until about 6 miles from the lock up.

First, the car seemed to be a little less smooth(!), then fine (my imagination?). Then definitely missing occasionally, so declutched a revved it a bit. Fine. After a while coughing and spluttering and popping / banging, but cleared itself after more vigorous revving and fine for a mile or two. Finally, 100 yards from the lock up on the A1000 in rush hour, by now travelling at a modest speed, it did all three and just died. Pretty stressful location so was not actually concentrating on 'how' it died I am afraid, other than no matter how hard I revved it was just not firing properly, going slower and then ceased completely.  Pressed the starter button after a few seconds and it fired up and I drove gently to the lock up. Phew.

The set up is Facet fuel pump with filter just after the tank, another filter in the engine bay before the pressure regulator and two Weber 45s. Lucas Sports coil and Petronix / Aldon LU 142A electronic ignition.

So wise ones, what's your diagnosis? My first thought was fuel supply, but the problem was definitely getting worse until it became terminal. It wasn't the same problem appearing randomly. So wondered if it was an electrical problem -fuel pump failing or dodgy electrical connection to the pump or  coil / ignition(?).

There is a lot of rubber hose from the Facet pump to the engine bay filter which was installed 20 years ago when the car was restored. Been meaning to get it replaced with kunifer for several years. The filter in the engine bay looked clear, but of course that is no guarantee there isn't some **** somewhere else in the line. The pump was pulsing as normal when tested back in the garage, but could be different when under pressure / on the move.

Thanks chaps - could be attending in something less glamorous at the weekend - b****r!

Miles

 

[ntc]

Look inside the fuel line, remember most of the time it is electrical 

[iain]

Umh. Not sure but I think I’d 

Pull the plugs….rich or weak?

Check the fuel filters

Has a fuel regulator gone wrong….popping and banging is usually from being rich?

Check when cold , does run ok? Then I’m with Neil it’s electrical breakdown somewhere.

Iain

 

 

 

[DavidBee]

Miles, I am, regrettably, not a"wise one", but I had two separate behaviours with my Weber DCOE 45s, set up in exactly the way you have outlined (right down to flexible hose fuel lines instead of Kunifer, which latter I also plan to fit one of these days).

The first was due to accumulated gunge in an inline fuel filter, by the Facet pump. It caused intermittent starvation, so the engine would stop firing. I would try to start it up, rev it, and then it would stop again. This was due to old loose grit from the tank which had piled up in the filter. Only a small amount of fuel could get through.

The second was due to fitting a new fuel pressure regulator. The engine would backfire, splutter, stall, stop. Flooding meant I had to wait to fire up again. Plugs very black, exhaust pipe too, very sooty.

The pressure was set too high. I bypassed it with the old one which I set at 2psi. I cleaned the plugs. Then took for a long drive and checked plugs. Grey instead of black. Running rich, but not as bad. So, the first problem was due to a lack of fuel, the second, due to an excess of it.

At least that particular problem was solved.

David

Edited August 9, 2021 by DavidBee

[Lebro]

My thoughts are:

partial blockage in the fuel line

or ignition coil dying

Bob

[Z320]

In my case it was the petrol filter

[Ben Freer]

I had something similar recently with Geoffrey. Running a bit rough and then what I think was fuel starvation, stuttering, lack of power and gradually losing cylinders 4-3-2-dead.
Like you it never happened when I was in a position to do a calm and methodical diagnosis. I have a Facet pump - with its associated filter, which you can’t disassemble to inspect. Plus two additional in-line filters that can be disassembled. After several embarrassing episodes I noticed that just stopping for a few minutes and then restarting seemed to “solve” the problem. On previous occasions the stop time was spent disassembling filters (only to find then clear).

 I had noticed that the Facet pump was quite warm. Was it cutting out intermittently? It was only installed in 2017! Anyway I swapped out the pump and the Facet filter and it hasn’t happened since.
I don’t know if that helps! I thought Facet pumps were pretty reliable and TBH I’m still not completely sure if it was the culprit.

[BlueTR3A-5EKT]

Mine has done that twice. 

It was a fuel line blockage in both cases.

I now carry a length of pipe to fit into the disconnected flex line from the tap to pump and blow through it back to the tank with the fuel cap open.

Hopefully the replacement tank will resolve that crud in the fuel line  issue, but it has introduced others like the tank sender continually bashing the tank wall and the incorrectly constructed vent line, that causes a petrol  stink when cornering with more than a 1/2 tank full.

 

[John McCormack]

4 hours ago, Lebro said:

My thoughts are:

partial blockage in the fuel line

or ignition coil dying

Bob

I'd go condensor 1st, easy to replace, coil 2nd. If not fixed check fuel filters and fuel lines.

95% of fuel problems are ignition. 

[John Morrison]

I'm with John, 

did/does it start normally the next day?

John

[ntc]

Check the voltage at the pump 

[MilesA]

Thanks everyone. The speed and quality of response on this forum is fantastic. 
 

Good to know that my initial diagnosis is reflected by your experiences. Going to start by swapping out the coil with the spare I carry on board. Is there a way to bench test if a coil is failing / on its way out?

 

After that, will work through the other options. Must remember to be methodical and try one solution at a time. If it’s not the coil it ain’t going to be fixed before the IWE. Shame because the car is otherwise set up / running better than it has been for years. 
 

Oddly, living in London, the biggest challenge is not having access to roads where you can gun the car and break down safely. 
 

Thanks again chaps. 
 

Miles

[Z320]

Please, see my petrol filter problem

[MilesA]

29 minutes ago, Z320 said:

Please, see my petrol filter problem

Thanks Marco. I will have a VERY close look at my filter when I get over to the garage!

Miles

[MilesA]

So, spent the afternoon in the lock up.

First. I changed the fuel filter in the engine bay just before the regulator. A few flecks of stuff on the gauze - so its doing its job. Once washed and dried I blew through one of the 4 panels of both the old and the spare I had. Certainly a bit more resistance on the old one. but not completely blocked like Marco's. I would be surprised if that caused complete fuel starvation and the engine stopping completely.

Also, swapped out the old Lucas SP12 coil and replaced it with a spare Lucas DLB 105. Car started and everything seemed fine (so at least I wired it correctly) but not driven for any distance or put under strain, so not confident enough for the 200 mile journey I was to do in the TR at the weekend. Living in London I need an early Sunday morning when I can get on the roads and breakdown in relative safety!

In the meantime, I have a length of new ethanol resistant fuel hose being delivered so I can replace the fuel line from the engine bay filter back to the Facet pump near the offside wheel too. Not sure how to deal with half a tank of fuel though in order to replace the hose from the tank to the pump. Need to find a large container to drain it into I suppose. Already have a spare Facet cube and filter if they need to be changed out too.

Although I do not think (yet) that it is the culprit, I have discovered that the Sytec adjustable (1-5psi) fuel regulator I use is now 'unobtanium'!

Any thoughts on a suitable alternative if the regulator does come under suspicion?

Thanks for all suggestions and ideas which have been very helpful.

Miles

 

[stuart]

Sytec one here, I know its got 6mm tails but IIRC you can swap them out with 8mm ones. https://www.ebay.co.uk/itm/353613767127?hash=item525505e1d7:g:SJkAAOSwBB5hD87O

I would have changed the front to rear pipe with a solid 5/16" copper line for safety. If you have a solid line out of the tank to a flexible to the pump then split it there to drain the tank.

Stuart.

[MilesA]

Brilliant Stuart - snapped it up.

The new hose is a temporary fix to get the car running and until I can get the hard line installed as I don't have the necessary kit to do it. At present, classic car engineers are as busy as conveyancing solicitors in Cornwall, but I guess you know that! 

Thanks for the tip about the drain down.

Miles