Stump
Active Member
I did spend copious amounts of time searching existing posts here and via google, just trying to get my arms around this. o-360a1a, GRT4000 eis.
i recently changed all 8 spark plugs (now using Tempest fine wire) and haven't flown since. work and life interfering. first test run last week was fine. today, during test run on the ground, while idling along, my #3 cht went to zero, stayed at zero to 3-5 degrees for a short while then slowly steadily rose back to match up with the other 3 cht's. did a couple mag checks, nothing abnormal there, egt's were same'sh for all four cylinders.
couple hours later do another run, this time #3 cut was really lagging the other 3. they got to high 200's, #3 was about 100 degrees cooler, all 4 EGT's relatively match. mag check seemed fine.
shutdown, cowl was already off. put a thermometer in the probe hole on #3 cylinder and it quickly rose way above temp the eis was showing. all four cylinders seemed to be about the same temp this way, and all four above what the eis was showing. i have not yet taken a torch to the cht probe, that is next.
my thought is cht probe is going/gone. am i off base with that idea? any other thoughts? perhaps a plug issue?
thanks.
i recently changed all 8 spark plugs (now using Tempest fine wire) and haven't flown since. work and life interfering. first test run last week was fine. today, during test run on the ground, while idling along, my #3 cht went to zero, stayed at zero to 3-5 degrees for a short while then slowly steadily rose back to match up with the other 3 cht's. did a couple mag checks, nothing abnormal there, egt's were same'sh for all four cylinders.
couple hours later do another run, this time #3 cut was really lagging the other 3. they got to high 200's, #3 was about 100 degrees cooler, all 4 EGT's relatively match. mag check seemed fine.
shutdown, cowl was already off. put a thermometer in the probe hole on #3 cylinder and it quickly rose way above temp the eis was showing. all four cylinders seemed to be about the same temp this way, and all four above what the eis was showing. i have not yet taken a torch to the cht probe, that is next.
my thought is cht probe is going/gone. am i off base with that idea? any other thoughts? perhaps a plug issue?
thanks.
Last edited:
