10 replies to this topic

[coopersmate]

Model: City E 998
Year: 89 F reg
Description of problem (please be as in depth as possible):
My car is sick. The winter weather has taken its toll.
Car was cutting out then not starting then starting after a couple of hours and running on 3 cyclinders. So I looked at it today.
Took the plugs out to check and
Plug1: Fine
Plug2: Sooty
Plug3: Oil Fouling (light oil not sticky)
Plug4: Fine

So I checked they all had a spark and 3 wasn't sparking. I swapped the plugs around and we got sparks.
So problem was the plug. So I cleaned it all up and put it in and I had 4 cyclinders firing again for 5 min.
It then went back to 3 cyclinders. I took the HT lead off cyclinder 3 and no change in the engine. Still running of 3 cyclinders. So checked the plug again and it had oiled up again.

So can anyone suggest what is causing the oil fouling?

Any non-standard parts that might be involved with the problem?Stage 1 kit and stage 3 cyclinder head from Morspeed.
Car was on a rolling road and set up right at the start of the summer.

[Ethel]

soot 'n fuel can look like oil. If it is oil then inlet valve seal or piston rings

[coopersmate]

soot 'n fuel can look like oil. If it is oil then inlet valve seal or piston rings

Thank you Ethel
How can I tell if I have soot and fuel or oil?
If I had to choose then I would go for fuel as its too light to be engine oil. Think black wd40 consistancy

[Nightrain]

Do a compression test, sounding like the head gasket to me.

[coopersmate]

Do a compression test, sounding like the head gasket to me.

Thanks Nightrain
Compression test has shown nothing.

Cylinder 1: 14
Cylinder 2: 13
Cylinder 3: 13
Cylinder 4: 13

So I am still none the wiser as to why I am getting just one spark plug oiled up?
Help

[Ethel]

Petrol will evaporate if you leave the plug somewhere warm, oil won't. Just check all the usual suspects ignition components; swap the plugs leads between cylinders; air filter; airleaks....

Driving the car round the block would be better than letting it idle from cold.

[coopersmate]

Petrol will evaporate if you leave the plug somewhere warm, oil won't. Just check all the usual suspects ignition components; swap the plugs leads between cylinders; air filter; airleaks....

Driving the car round the block would be better than letting it idle from cold.

Thanks Ethel
I will go get that plug out now and leave it in the house over night. Do you want a pic?
Ignition I feel is alright as all parts have been renewed within 6months except for the the HT leads but they are about 12months old.
I am thinking an air leak at the manifold but wouldn't this affect cyclinders 3 and 4 ? How do I test this or should I just replace the manifold gasget?

The car ran rough today for a 10mile run as the battery had gone flat so I wanted to charge it up.

[Sprocket]

Check the dizzy cap.

If you swapped the plugs round but its still number 3 thats miss firing, its the HT lead or the cap.


Also try using a little less choke as it might be flooding the middle two cylinders. its that funny old A series thing, and is worse on a cold engine


Oh hang on this happens on a warm engine? Is your inlet manifold plumbed in to the cooling system? I recon its not and it should be

[coopersmate]

Check the dizzy cap.

If you swapped the plugs round but its still number 3 thats miss firing, its the HT lead or the cap.


Also try using a little less choke as it might be flooding the middle two cylinders. its that funny old A series thing, and is worse on a cold engine


Oh hang on this happens on a warm engine? Is your inlet manifold plumbed in to the cooling system? I recon its not and it should be

Thanks Sprocket
Sorry you misunderstand. It isn't the dizzy cap or lead as I can swap the plugs and it works until the plug gets oiled up again.

A little less choke ok

My manifold isn't plumbed in but never has been. What will this do for me? Oviously it will make it hotter but then I thought you wanted it cooler thus why you split the all in one unit that was standard on 998's

[Sprocket]

Check the dizzy cap.

If you swapped the plugs round but its still number 3 thats miss firing, its the HT lead or the cap.


Also try using a little less choke as it might be flooding the middle two cylinders. its that funny old A series thing, and is worse on a cold engine


Oh hang on this happens on a warm engine? Is your inlet manifold plumbed in to the cooling system? I recon its not and it should be

Thanks Sprocket
Sorry you misunderstand. It isn't the dizzy cap or lead as I can swap the plugs and it works until the plug gets oiled up again.

A little less choke ok

My manifold isn't plumbed in but never has been. What will this do for me? Oviously it will make it hotter but then I thought you wanted it cooler thus why you split the all in one unit that was standard on 998's

Is it the same plug that this happens to no matter where it is? if so then the plug is faulty. If you swap the plugs round but the problem is still on the same cylinder with a different plug, it is not the fault of the plug, more likely the lead or the cap.

I doubt its oil with compression readings you gave, its more likely fuel. The fuel is entering the cylinder but is not igniting. This could be due to one of two reasons. If the Air Fuel ratio is so high that combustion is difficult to maintain (too much fuel) indicated by black sooty and or wet plugs. The plugs can become fouled and no longer spark. the fuel then wets the plug and it will never spark from that point on untill the cylinders have been cleared of the excess fuel that caused the problem in the first place.

Why the outer two look ok and the center two look rich? Well thats down to the way the inlet ports are laid out on the A series engine. But, it should not be anywhere as bad as to cause fouling of the plugs. This brings me to the aluminium inlet manifolds. There normally have a pipe that passes through the manifold that should be connected up to the cooling circuit. This is to heat the manifold to ~80c. what this does os reduce the film of fuel that sits on the walls of the inlet tract, reducing hydrocarbon emissions and poor running. Consider a manifold that is not heated, as the fuel leaves the jet of the carb, it starts to evaporate. For a fluid to evaporate it needs heat, and in the inlet manifold that heat has to come from the walls of the inlet manifold. The local temperature of the manifold drops significantly to casue fuel in contact with the walls of the manifold to condense and pool. This liquid fuel is then carried down the walls of the manifold where it is then carried into the airflow and into the cylinder. It is a well known problem with the A series that the middle two cylinders are biased to get the best of the airflow and fuel, so if there is any liquid droplets in there the middle cylinders will get more than the outer two.. Lets for arguments sake say that liquid fuel is ten times more volume than vapour, you can see that it wont take much to cause a cylinder to run rich.

As for the argument that the whole point of keeping the inlet manifold as cold as possible is inacurate. removing the hot spots of the cast iron all in one manifold is a very good thing, but fitting an aluminium inlet manifold without heating it, is a bad thing. Please understand that because the iron inlet is attached to the exhaust, the hot spots will be hotter than the cooling system temps if the ally inlet manifold is plumbed in. Exhaust gas temps can reach 600c + so those hotspots will be much hotter than ~80 of the cooling system. That is the reason you ditch the cast iron manifolds. The heat from the cooling system on the inlet manifold will keep the fuel film on the walls of the manifold down to a minimum giving better drivability, lower emissions and more mileage.

Did I make that too complicated?

[coopersmate]

That wasn't too complicated at all Sprocket.
I have now changed all 4 plugs and the car runs a treat. I only changed the plugs at christmas so I am a little confused. But now I think there is a problem I will wait another month and see if problems occour again. I have swapped the HT leads around and know which cyclinder the suspect one is on. So if I get the same problem on another cyclinder or the sane one I can blame the HT lead or the dizzy cap.

As it goes I had a burst heater pipe due to cold weather and lack of anti freeze so I will take this oppertunity to plumb in my manifold as well.

Thanks for all the help

Lloyd