Thread: yellow spark 89 classic

Hi all .
My 89 3.5 efi has misfire and ive today checked spark to all cylinders by jumping the spark from each high tension lead to earth with engine running . Ive identified the 2 cylinders at fault by pulling the leads 1 at a time while engine running and cyls 4&6 made hardy hardly any difference to running characteristis but I am alarmed at the yellow spark Ive witnessed at all leads . I think its the fault , not strong enough to jump the plug gap under pressure . I guess I should have a cracking blue spark . Even my lawnmower spark is way stronger . My guess is it can only be the high tension side . Coil , rotor , cap or either coil and plug leads . These items are all new and lucas items so im baffled ! Bit frustrating but I believe Ill need to doubt the performance of one of these items . I replaced them all at once as part of a service .
Thanks for your input .
Mark

Originally Posted by theg

Hi all .
My 89 3.5 efi has misfire and ive today checked spark to all cylinders by jumping the spark from each high tension lead to earth with engine running . Ive identified the 2 cylinders at fault by pulling the leads 1 at a time while engine running and cyls 4&6 made hardy hardly any difference to running characteristis but I am alarmed at the yellow spark Ive witnessed at all leads . I think its the fault , not strong enough to jump the plug gap under pressure . I guess I should have a cracking blue spark . Even my lawnmower spark is way stronger . My guess is it can only be the high tension side . Coil , rotor , cap or either coil and plug leads . These items are all new and lucas items so im baffled ! Bit frustrating but I believe Ill need to doubt the performance of one of these items . I replaced them all at once as part of a service .
Thanks for your input .
Mark

I can highly recommend the ignition upgrade, sure makes a difference.

As for your miss fire problem I would suggest you do a compression test, I think you probably have a blown head gasket between 4&6,

Something to keep you occupied for a few hours, good luck.

Cheers