Misfiring while cruising

[AK260]

Not sure if you fixed this issue but I had exactly the same problem - turns out my magnecore kv85 leads were the culprit. I had assumed being advertised as high end items they wouldn't break down after just 9k miles but the coil end had disintegrated

 

 

and 2 out of 6 leads would change impedance dramatically - from around 5k ohms to over 300kohms - when you waggle them. The guy on the phone at magnecore was condescending when I raised it with him and refused to believe their leads could possibly fail. It's all the customer's fault !

 

Changed them for 8mm leads costing 1/6 the price and the car runs sweet as a nut again.

 

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F181999641503

 

Check / change your leads too and see what happens.

 

 

[AK260]

Not sure if you fixed this issue but I had exactly the same problem - turns out my magnecore kv85 leads were the culprit. I had assumed being advertised as high end items they wouldn't break down after just 9k miles but the coil end had disintegrated
 

 
and 2 out of 6 leads would change impedance dramatically - from around 5k ohms to over 300kohms - when you waggle them. The guy on the phone at magnecore was condescending when I raised it with him and refused to believe their leads could possibly fail. It's all the customer's fault !
 
Changed them for 8mm leads costing 1/6 the price and the car runs sweet as a nut again.

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F181999641503
 
Check / change your leads too and see what happens.
 

[jalexquijano]

On 9/29/2018 at 8:43 AM, Mark Maras said:

 Ok, If you've completed all the tests and found everything looking good put it back together with good (or new) plugs and take it for a run and then let it idle. I'm hoping that you've improved the connections while doing the tests. Let us 

38 minutes ago, AK260 said:

 

 

38 minutes ago, AK260 said:

 

Should i purchase that set of leads instead of another ngk blue wires?

[jalexquijano]

39 minutes ago, AK260 said:

 

 

42 minutes ago, AK260 said:

Not sure if you fixed this issue but I had exactly the same problem - turns out my magnecore kv85 leads were the culprit. I had assumed being advertised as high end items they wouldn't break down after just 9k miles but the coil end had disintegrated

 

 

and 2 out of 6 leads would change impedance dramatically - from around 5k ohms to over 300kohms - when you waggle them. The guy on the phone at magnecore was condescending when I raised it with him and refused to believe their leads could possibly fail. It's all the customer's fault !

 

Changed them for 8mm leads costing 1/6 the price and the car runs sweet as a nut again.

 

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F181999641503

 

Check / change your leads too and see what happens.

 

 

Should i dump my ngk blue wires?

[Mark Maras]

@jalexquijano Normally I would say no because we haven't proven them to be defective but I'm going to say yes, dump them. They're not that expensive and I still suspect the problem is in the wires or connections.

[AK260]

The way I looked at mine was v simple: eliminate every possible electric cause.

 

I changed:

 

the plugs in case one had a crack

The dizzy cap and rotor

The coil

The wires to the coil by running direct from battery (fused of course) temporarily.

Spark plug leads.

 

Also

Checked and cleaned up engine earth strap

Replaced a couple of connectors - see this one that was holding by a single strand you can see coming out of the connector.

 

 

 

Did each one at a time until I found the culprit - and I would say there were two issues in the HT leads and a potential other in the low tension connectors.

 

Bear in mind I had rough running and backfire at revs and when on power and missing visible on timing light. So given my experience I would say your problem is electrical in nature not advance related.

 

Good luck buddy.

 

 

 

[rcb280z]

4 hours ago, AK260 said:

missing visible on timing light

Now there's something I forgot about. You can do the same Alex.... with a timing light if you have. Check each wire that way. It'll show you a misfire if you have one.

Edited October 5, 2018 by rcb280z

[jalexquijano]

1 hour ago, AK260 said:

The way I looked at mine was v simple: eliminate every possible electric cause.

 

I changed:

 

the plugs in case one had a crack

The dizzy cap and rotor

The coil

The wires to the coil by running direct from battery (fused of course) temporarily.

Spark plug leads.

 

Also

Checked and cleaned up engine earth strap

Replaced a couple of connectors - see this one that was holding by a single strand you can see coming out of the connector.

 

 

 

Did each one at a time until I found the culprit - and I would say there were two issues in the HT leads and a potential other in the low tension connectors.

 

Bear in mind I had rough running and backfire at revs and when on power and missing visible on timing light. So given my experience I would say your problem is electrical in nature not advance related.

 

Good luck buddy.

 

 

 

Ill check those connectors. Which ones should i specifically check?

[jalexquijano]

1 hour ago, rcb280z said:

Now there's something I forgot about. You can do the same Alex.... with a timing light if you have. Check each wire that way. It'll show you a missfire if you have one.

How????

[jalexquijano]

2 hours ago, AK260 said:

The way I looked at mine was v simple: eliminate every possible electric cause.

 

I changed:

 

the plugs in case one had a crack

The dizzy cap and rotor

The coil

The wires to the coil by running direct from battery (fused of course) temporarily.

Spark plug leads.

 

Also

Checked and cleaned up engine earth strap

Replaced a couple of connectors - see this one that was holding by a single strand you can see coming out of the connector.

 

 

 

Did each one at a time until I found the culprit - and I would say there were two issues in the HT leads and a potential other in the low tension connectors.

 

Bear in mind I had rough running and backfire at revs and when on power and missing visible on timing light. So given my experience I would say your problem is electrical in nature not advance related.

 

Good luck buddy.

 

 

 

Which grounds????

[jalexquijano]

2 hours ago, AK260 said:

The way I looked at mine was v simple: eliminate every possible electric cause.

 

I changed:

 

the plugs in case one had a crack

The dizzy cap and rotor

The coil

The wires to the coil by running direct from battery (fused of course) temporarily.

Spark plug leads.

 

Also

Checked and cleaned up engine earth strap

Replaced a couple of connectors - see this one that was holding by a single strand you can see coming out of the connector.

 

 

 

Did each one at a time until I found the culprit - and I would say there were two issues in the HT leads and a potential other in the low tension connectors.

 

Bear in mind I had rough running and backfire at revs and when on power and missing visible on timing light. So given my experience I would say your problem is electrical in nature not advance related.

 

Good luck buddy.

 

 

 

Could i be missing a ground strap somewhere or any kind of ground causing the plugs to foul at idle?

[jalexquijano]

5 hours ago, Mark Maras said:

@jalexquijano Normally I would say no because we haven't proven them to be defective but I'm going to say yes, dump them. They're not that expensive and I still suspect the problem is in the wires or connections.

 

5 hours ago, Mark Maras said:

@jalexquijano Normally I would say no because we haven't proven them to be defective but I'm going to say yes, dump them. They're not that expensive and I still suspect the problem is in the wires or connections.

Went for a drive and once back left the car idling for 15 mins. This was the result. I did swapped plug leads 5 with 4 and 2 with 3. 

Order is 6 5 4 3 2 1