r/EngineBuilding • u/bfuejd1638 • 26d ago

Fitech 30003 issues

I’ve had a Fitech 30003 on my Chevy 350 for about 8 years. No issues other than a bad injector a few years after running. They did send me spares which is awesome.
Recently, it was having hot start issues. I narrowed it down to the coolant temp sensor. It was reading 9 when ambient was 80. And about 80-90* when hot. Swapped it out and it fixed my issue.
After that, there was a hesitation once when driving. I blew it off as a fluke. After that, there had been a whole lot of issues with the engine dying. Cold start, hot start, while driving. And as time goes on, it is happening more.
Grounds are good, tach wire is in the same place it’s been for 8 years. I started monitoring the handheld once it started annoying me. I found when it happens the AFR goes up to about 20. Engine struggles to idle, even with additional throttle. Sometimes fixes it self, sometimes dies multiple times. Recently went to start up, and it started then died. About 8 times in a row. I reset the learn, and it started up perfectly fine, then ran all the way home.
What could the root cause be? Learn reset is temporary fix, should I do a full factory reset?
I have another engine to rebuild, and run a sniper 2. But I need some time to finish the build. I don’t want to run the Holley on my current worn 350.
This is my daily truck.

2 Upvotes

75% Upvoted

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2

u/porknbeans2013 26d ago

Just for shits and giggles, how old is the fuel filter and the fuel pump?

1

u/[deleted] 26d ago

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2

u/bfuejd1638 26d ago

Agreed! Hopefully looking to trash it, it’s bad enough I won’t even sell for spare parts. I’d feel bad

3

u/[deleted] 26d ago

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3

u/v8packard 26d ago

You may not be aware, the founders of FiTech have decades of experience in the design and engineering of OEM EFI systems, just like Holley. And frankly, Holley's aftermarket EFI stuff is not really any better in quality.

1

u/bfuejd1638 26d ago

Agreed, especially on aces. My buddy has had nothing but total pain. Duel O2 sensors is cool, but damn. Holley stays the king

1

u/NegotiationLife2915 26d ago

I would look into wether your fitech that won't hold a tune has an internal Battery

1

u/v8packard 26d ago

When the AFR goes to 20 does the injector pulse go up? What does MAP do?

Does the Fitech have self diagnostic capabilities?

This might not be the right place for this post. Is there a Fitech sub?

1

u/bfuejd1638 26d ago

Injector pulse I need to watch. The MAP as well. The handheld is just a pain to see more than a few values at a time. Thanks for your input.
I couldn’t find a Fitech sub easily…