what exactly does the computer do in a TBI situation

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markmitchinnh
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what exactly does the computer do in a TBI situation

Post by markmitchinnh »

Referring to pre 92- I am just curious as to what the computer controls, Do the computer know stuff like cubic inches, compression ratios, or injector size. Can a 4.3 computer run a 305 or a 305 computer run a 350?
Recently bought a 1989 Astro RS from Florida. Replaced stock engine witha 1997 5.7 vortec with TBI and replaced transmission with rebuilt 700R4 with mild shift kit.
Bought on Monday the 16th of April 2012
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Smiliesafari
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Re: what exactly does the computer do in a TBI situation

Post by Smiliesafari »

The main function of the ECU is to adjust the air/fuel ratio to keep the engine running efficiently. It does so by monitoring airflow, intake air temperature, engine temperature, ignition timing, and oxygen content in the exhaust stream. With this information it regulates fuel flow from the injectors. No, The ECU does not know the compression, number of cylinders or cu.in. I've been lead to believe that the 4.3 ECU, with some mods, will operate a V8. I'm going to find out when I complete my V8 conversion.
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Topic author
markmitchinnh
I sleep in my van
Posts: 589
Joined: Wed Oct 13, 2010 2:07 pm
Location: Barrington NH

Re: what exactly does the computer do in a TBI situation

Post by markmitchinnh »

cool I had a custom chip burned for a 305 with EGR delete and the crank went bad before it was even broke in and now I am building a 350 with TBI.
Recently bought a 1989 Astro RS from Florida. Replaced stock engine witha 1997 5.7 vortec with TBI and replaced transmission with rebuilt 700R4 with mild shift kit.
Bought on Monday the 16th of April 2012

NotDadsW41
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Re: what exactly does the computer do in a TBI situation

Post by NotDadsW41 »

TBI ECUs are pretty basic. I do not think you will be able to run a V8 with a V6 PROM. It's pre-set values or assumptions for injector size will not allow it so compensate for the V8.
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