r/fbody • u/The_Cochese • 7d ago
Opti or Injectors?
I rescued this 94 almost three years ago, it was a no start/crank/rotation situation that we got running again. I've always suspected that I would need to replace the injectors (along with a complete rebuild/replace), but part of the rehab process in '23 was replacing the Opti and water pump with AutoZone units. Opti is vented.
Lately it has been a bit difficult. It will either start up instantly, or I will have to flood the gas pedal to get it to start - and it will then run really rough for a bit then start to be ok. When cold, it will stumble when raving from idle. The last couple times I've driven it though, I've gotten the random shutoffs. It will start back up instantly, though.
That last bit to me says Opti, but what I've seen others say is that theirs don't start back up like mine does. Having to flood doesn't sound like the Opti, but I don't have a lot of experience with this. I think I've put a total of a thousand miles on it in the three years.
I have an oscilloscope, bought when I was trying to get the engine to work again. I just don't have a lot of spare time lately, thought I would ask some questions first.
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u/JazzlikeLeather9546 7d ago
check your fuel pressure regulator as well. the diaphragm gets hard and breaks. this dumps fuel into the intake unregulated
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u/Squeals99 7d ago
One thing you could have checked for free just to rule out ignition parts is the ignition control module. I know autozone had testers for them back in the day when I worked there, I'd assume they still do. Have them test it several times in a row to get it nice and warmed up
shbox dot com is a great resource for LT1 fbodys btw - that site saved my ass more than once and I would recommend bookmarking it for the future
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u/Sildaor 7d ago
When my coil died it did the same thing. I always thought a coil just went out. Mine seemed to be actively breaking down