Okay, my 1.4 is only running on three cylinders. The spark plugs are new, HT leads new, distibutor, rotor etc. all new. It sparks when the HT lead touches ground.


So I'm guessing I have a problem inside the engine? Could it be something causing the valves not to open/close like they should (pushrods??) The car doesn't smell like gasoline. If i open the valve cover, is it easy to see if something's wrong? Or do i have to take the whole cylinder head off

Oh and as an interesting side note there is a slight deposit of soot / smudge near the spark plug on the cylinder that doesn't work properly, while the others are clean.

I take it that when you say the HT lead for that cylinder sparks when grounded you have tested it grounding the spark plug too not just the lead on its own?

Not being patronising just ruling out basics first

Don't always take that just because they're new plugs that they are working, test them to ground but it still is not a guarentee that they work when in the car as they may be breaking down under compression. Try a different plug on that lead and try the suspect plug on a different cylinder to see if you get the same results on a different cylinder.

morgan105

If spark plug thread has failed it has no compression and if it has no compression it can do that. Well, often plug flies out in such situation too

I have had a lot of new spark plugs that do not work. Quality control is now done by the fitter and not the manufactures!!!!!!!

Well i don't know.. Anyway i screwed around with the distributor cap and i think the contacts look corroded, one of them is nice and copper shiny, while the three others are gray, and one of them has green corrosion on it (cylinder 3). Cleaned the thing with contact cleaner and scraped the contacts with a knife, and it seemed to help to a small degree, but sometimes it runs very good, and sometimes worse than before i did the "surgery". Sometimes the RPM is constant at idling and sometimes it's chasing (carb problems too most likely). The knocking sounds when giving gas are pretty much gone though (is this called ignition knocking in english?)

Strange as the dizzy cap and rotor are almost brand new (receipts in glove compartment indicates they were changed 3 months ago or so). So i guess he's been having problems too! But i found no receipts on HT leads, so maybe I'll change those too, that might be the issue

I bought a new dizzy cap and rotor today, and I'm gonna swap them over. I guess one of the problems was that the plastic "gasket" has a cutout in it to allow for moisture to drain out, this hole was mis-aligned so i guess that's why it's been corroding.



Only worry is that the previous owner might have screwed up the ignition timing when he changed it? Or would i know that very fast? I'm worried about screwing this up. I also wonder if the ignition sequence is correct, the haynes says 1-3-4-2 right (1 is closest to radiator), and the problem cylinder would in my case be #2.
When i pull the lead from cylinder #2 at idle it doesn't react much. It does run a little worse though, but not as bad compared to pulling one of the other plugs. It appears the cylinder is working intermittently maybe?

Or is it generally less noticable if the last cylinder in the firing sequence doesn't run too good?

And also, which holes on the dizzy cap does the spark plug leads plug into, tried to find a drawing in the haynes but couldn't.

I think mine's like this, is this correct:



Yes, i am a gifted artist..

BTW, i hear there's some sort of sensor for the Renix on the flywheel? Could this be broken?

I'm new to these 300's, but in general running on 3 cylinders would probably mean the timing is out no?

For the couple of quid its going to cost I suggest a new cap and rotor arm.

classicswede wrote:For the couple of quid its going to cost I suggest a new cap and rotor arm.

Cap and arm replaced. Is the firing sequence correct? Will try replacing HT lead.

i'll get back to you on that in 2 ticks my b14 is up on the drive:)

firing order is correct just checked mine:)

Damnit this is annoying.. I'll go over all the ignition things once again, dizzy cap, rotor arm and HT leads, and new plugs.

If it doesn't help, what could it be?

Can anyone else try to yank the lead from plug #3 and see what happens? Is it just a small, subtle change, or pretty big?

Well. New rotor, cap, wires once again. No change.

I did a stupid test. Hold wire in one hand and chassis in the other. Plug #3 doesn't hurt nearly as much as the others.

I think I have too weak spark on it to ignite properly (or even ignite at all).


But what can it be if it's only got a weak spark on plug #3? Is my distibutor failing? Can i use a dizzy from a renault or other car with the B14 engine?

Or could it be the renix? Or anything else?



I'm leaning towards unbalance in the dizzy axle or something else leading to partial short citcuiting towards the base of the distributor when it's firing at #3. It's actually the only plausible explanation i can think of.



However there's a plastic cover thingie between the dizzy and the dizzy cap probably acting as a gasket and as insulation for the rotor arm against the dizzy. This thing is cracked quite a lot on my car possibly leading to short circuits.




I'm going to try the cheapest solution possible at this time - insulating the metal parts of the dizzy around the #3 plug with electical tape just to see if it does makes a difference. I could be lucky.



Else i guess the ignition timing could be off..

It could be that one lead arcing out into the head through perished/faulty plastic in the lead. Have they been sitting some where for a while? try an old lead.

Could be the plug shorting out into the head if theres alot of gunk around it and the lead.

Just some thoughts

Cloud wrote:It could be that one lead arcing out into the head through perished/faulty plastic in the lead. Have they been sitting some where for a while? try an old lead.

Could be the plug shorting out into the head if theres alot of gunk around it and the lead.

Just some thoughts

It's not the wire.. i can change wires between cylinders 1 and 3 for example and 1 will run just fine with the lead from #3, while #3 will still be bad.

I'll try to clean out some junk.. also test the renix according to green book.

Well.. tried the insulation thing..

No good..

I dunno what to do anymore. The spark is just really weak. Faulty capacitor or some other renix crap? Plug is covered in soot.. indicating incomplete combustion (again probably due to weak spark)? The other plugs look top notch, so there's no problem with the mixture..

Also i get a lot of backfire down the down pipe..