Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Running rough

Hi all,

took the car out today (1997 +4 T6 rover engine) and it was running like a pig, hard to get it to above 50 and coughing nd spluttering all the way, as luck would have it I was passing BHM and called in to have a chat with Keith who diagnosed it as an ignition problem and told me to limp the car home clean all the ignition leads and distribution unit and run the car in semi darkness and observe the plug leads etc for signs of failure in the form of arching out leads etc. This I have done and sprayed the system with a mist of water to enhance any shorting out, nothing was evident but the car still appears to be running on only 3 cylinders or so. I believe that the leads are pprobarbly original but all seem well in that department.

Any ideas would be a help now before I renew the leads etc.

This has only just started to occur now, before this all was well.


Thanks in advance.

Can you pull off the plug leads one at a time to isolate it to one cylinder? (The one where removing the lead doesn't have any effect, at the risk of mansplaining 🙂) .... then try switching plug leads if length allows between the offender and a good'un and see if the misfire moves with it .... similarly with the plug if that doesn't furnish a result

K

With engine running, remove and replace plug leads one at a time. The one that makes no difference to sound will be the faulty one. (possibly ignition lead or sparking plug)
You may wish to do this with a rubber glove on in case you happen to touch a leaky bit.

To be honest if they are original I'd get a new set of leads, distributor cap and spark plugs it's a cheap option in the long run.
When I bought my 1999 Plus 8 seven years ago with 19,000 miles on it was the first thing I did £50 fit and forget, and I've got eight of most things .

I have to agree with +8 Rich, and if the distributor is an old style one with a contact breaker I'd think about electronic ignition and a solid state distributor. A bigger, hotter spark.

The ECU measure the manifold vacuum via a pipe that goes from the manifold on the drivers side to the ECU (the box on the scuttle above the steering shaft). They can & do rot. If they do the vacuum goes all over place. Take it off & bend it if it cracks or is hard replace it.

Guys I would caution pulling off plug leads. This can generate a back EMF and damage the ignition system. The correct procedure to do a power balance (that’s what your describing) is to SHORT out the HT not open circuit it. You can do this by pulling the HT lead spark plug end boot or by using a steel extension piece to the spark plug terminal (can be made with a slotted tube of thin metal) and shorting it to the cylinder head with a large screwdriver.

Crypton and Sun cabinets came with a box of such adapters. Google Gunson 77074 Spark Plug Extension Leads With Spark Tester

BR
Colin

Hi all,

Update, it is definitely number 2 cylinder. I think it is time to replace the leads and plugs my next question is what are the best plugs (size and make) and leads to buy?

At the moment the leads are Lucas RISTS suppression 1015.


All advice welcome and a help.


Cheers chaps.....

Oh, Lucas Rist's are old, probably the originals from when the car was built

If the car's been stood over winter old petrol won't help with running either

Rob (Buy British) will know what Plugs & HT leads fit

I went for some big Magnecor Silicon 8.5mm on my xflow. Bit pricey but have had no issues. Cheaper/similar options out there.