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Need help with miss.

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Old Apr 12, 2021 | 02:21 PM
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scurcio's Avatar
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Default Need help with miss.
Hello,
I have carbed LR4 in a 75 280z. 700r4.stock holley 4160, Sanderson headers. Msd6014.
new coils, plugs,wires.
MSD is set to truck ho.
it runs and starts well but I it seems like there’s a miss and stumble.
good compression and new valve seals.
Any tips to get it smooth???
Thanks
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Old Apr 12, 2021 | 03:57 PM
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Plug gap? How rich/lean?? With a carb that IS a crapshoot...
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Old Apr 12, 2021 | 05:15 PM
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Dialing in a carb really needs an AFR gauge. A miss and stumble can have many causes.
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Old Apr 12, 2021 | 08:18 PM
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Best thing I did... AFR meter.

Instant answers on your tune.

I would check all plugs and plug wires, maybe do a temp check on the primary tubes to narrow it down IF a miss.

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Old Apr 13, 2021 | 08:08 PM
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Plugs are gapped at .40 . Changed all plug wires.
Thanks
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Old Apr 13, 2021 | 08:17 PM
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Originally Posted by scurcio
Plugs are gapped at .40 . Changed all plug wires.
Thanks
Problem solved?
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Old Apr 13, 2021 | 09:10 PM
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Miss and stumble under what condition? All?
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Old Apr 14, 2021 | 06:51 PM
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Default May have found the culprit.
Originally Posted by Woodylyf767
Miss and stumble under what condition? All?
l pulled each coil connector and found #4 cylinder coil not firing. Changed out coil and no change.
i replaced the aftermarket harness with the old
original one and that seemed to do the trick.
still need to get the carb dialed in but it’s running much smoother. I’ll know more tomorrow after some test runs.
thanks
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Old Apr 14, 2021 | 07:49 PM
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Default May have found the culprit.
Originally Posted by Woodylyf767
Miss and stumble under what condition? All?
l pulled each coil connector and found #4 cylinder coil not firing. Changed out coil and no change.
i replaced the aftermarket harness with the old
original one and that seemed to do the trick.
still need to get the carb dialed in but it’s running much smoother. I’ll know more tomorrow after some test runs.
thanks
Reply
0
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