Blistered Spark Plugs
I went to change my plug wires today and decided that I would check my spark plugs to see how they were holding up. When I pulled the first one I received quite a shock, the insulator was blistered and the electrodes were BONE WHITE! There was cosiderable erosion and the gaps had grown by several thousandths. The conditions were the same on all of the spark plugs. These plugs were put in a little over one year ago. This really suprised me since the ignition coil and cables are OEM from 1993, so I figured if anything I wouldn't be getting enough spark. I decided to go ahead and change to the high performance wires I had purchased, but I am going to wait to change the plugs until I hear some of the "experts" experiences. I did clean the plugs real good and regapped them, but I don't want to leave them in there more than a couple of months longer. I know there are a few conditions that I can think of immediately that will cause this, but those of you who have fought this problem before please tell me what solutions you found. Thank you in advance for your quick responses!
It runs and idles smooth, and I have yet to notice any pre-detonation. The O2 sensor is new and so is the fuel filter (okay, within the last year). I am leaning toward a cooling problem, but I am holding out for some other opinions.
Well.... I could live with the white color, it's just the blistered growths on the electrodes/insulators that I really don't feel easy about. These are not cheap plugs and they really have not lasted very long at all, and now that I have changed the plug wires I am afraid they could fail dramatically and cause damage within my cylinders. All advice/experience is welcome.
What brand plug were you using??? Bosch will run too hot in a
Ford engine......
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you should try running a cooler plug... did you check to make sure they're the right 'heat' plug?
agreed with the horribly lean looking plugs. On my engine, i get the same, it runs (ran) fine...
I wouldn't go blowing a lot of money on spark plugs for a tractor motor though
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Check the throttle body gasket. Very common on the FI 4.9. The gasket literally gets sucked into the manifold causing a leak which would probably cause a lean condition . I believe there is a TSB calling for a revised gasket.
I changed the plugs a few years ago and also noticed the bright white blistered appearance of the plugs. Motor still ran good except for a slight off idle stumble and ping when I really stomp on the gas ( 87 octane , no ping using hi test). I haven't checked the plug condition since the recent throttle body gasket change but it fixed the stunble and ping.
Last edited by bigbadjs; Aug 30, 2003 at 03:01 AM.


