This started out as what seemed to be running on three when accelerating or generally under load, despite idling nicely. It would clear when desired speed was reached and throttle was let off.

I figured it was water getting in or around the distributor or leads and causing a short. Due to the heavy rain and water on the roads.

Dismantled it all, cleaned and inspected the leads, dizzy cap and rotor. Checked the coil for any signs of shorting and checked and cleaned the plugs. Even though they're new.

After putting it all back together and feeling quite confident, I was surprised to find it was still doing it. But it's been starting well and the above symptoms have been intermittent.

 

This morning, it fired and died, which is unusual, but I put it down to the frosty night.

Then it took ages to get going, with continual cranking and foot to the floor to try and prevent flooding. It was trying and would fire a bit more and a bit more and a bit more, until it eventually fired and then revved right up, all fine. Until I went to pull away. Then it was doing the, what sounded like, firing on three under load.

Three miles later, at a junction, it cut out and didnt want to restart. It eventually did, after an extended version of what happened earlier. Then dying again and taking ages to start. But trying and gradually getting nearer and nearer and nearer, until it finally fired. Once fired up, it would rev right up, smoothly with no missing. But when trying to pull away, it would die. But eventually, with a wing and a prayer, I got going and I limped home. Although low revs would cause it to die.

 

Now I'm wondering if it's not ignition at all, but a fuel problem ? But what ? It's got a new fuel filter and new Bosch fuel pressure regulator.

I was wondering if the fuel pump has a filter/sock that might be clogged up ? As the old filter was full of crap.

 

I checked the coil to dizzy lead checked the cap and cleaned the edge of the rotor. She fired up fine, but then did a bit of the missing when under load. But this time, got me to the supermarket and back. But really didnt want to start in the car park. Eventually fired and was fine being gently driven home.

 

But it's the intermittent nature of the problem that is making it difficult to ascertain. If it packed up completely, then you'd know when you found the problem.

 

Any suggestions as to what to test and how ? would be very gratefully received.

 

PS. There are no error codes.

I've been driving it around this evening and apart from a bit of spluttering that felt more ignition than fuel, whilst accelerating, it ran fine.

As I got close to home, I floored it from low speed, up a slope and it was fine.

 

But I know this isnt the end of it.

I wouldnt be surprised if I have a repeat performance of the intermittent fault tomorrow morning. In some degree or other.

 

I think the first thing to do will be to put some better HT leads on there and see how we go ?

Anyone got any ideas ?   Is there anything peculiar to this model that fits the symptoms ?

sounds a bit like Hall sender failing inside the distributor, but it's 6N so I doubt it has that... which engine?

 

oh has a dizzy cap. Is there a 3way plug on the dizzy?

 

Also, you say 6N1, but profile pic is a red "Breadvan" so mk2 or mk2f. What year is the car with intermittent poor running?

 

Edited 7 March, 20242 yr by dvderlm

On 06/03/2024 at 21:56, dvderlm said:

sounds a bit like Hall sender failing inside the distributor, but it's 6N so I doubt it has that... which engine?

 

oh has a dizzy cap. Is there a 3way plug on the dizzy?

 

Also, you say 6N1, but profile pic is a red "Breadvan" so mk2 or mk2f. What year is the car with intermittent poor running?

 

 

Thanks for reposnding. The profile pic is my old Polo that unfortunately got destroyed in a fire, midway through some restoration work.

 

The car in question is a 98 , 1.4 - 8 valve and does have a 3 way plug on the dizzy.

 

The intermittent poor running eventually became permanent one day and she was obviously running on three. So having a look under the bonnet when it got dark, I could clearly so a spark where it shouldnt be.  There was some deterioration in an HT lead next to the metal sleeve that does over the plug. It was shorting to the metal sleeve.

Prior to this becoming a permanent fault, I think there was a small amount of seepage, causing a weak spark. In varying degrees, depending on moisture present.

Some silicon and insulation tape had it all insulated again. This was supposed to be a quick, get you running repair. But it has been fine ever since.  I will splash out on some new leads at some point.

 

I do think this was a separate issue to the original, conking out at a junction scenario. That did seem like fuel was not getting through for some reason ?

But all good for now, so fingers crossed.

Edited 18 March, 20242 yr by Polo3

Well found!

 

Wonder if someone had pulled on the lead not the spark plug boot at some point?