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Hello. I already put a post on here about TBI SBC to Carb and got a lot of good answers of things to look for. Still having a issue with it not running right. No power! It’s a 88 Chevy Pickup. We built the motor, installed it. Runs, just not right. We went back with a Quadra Jet and simply put an inline electric pump in place of the fuel filter. The original pump is still in the tank. So the new pump is pulling through the old pump. Have we Inadvertently created a vaccine? Someone asked on my last post how I had it vented.
 

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I asked about the vent since TBI controls that by the computer, so you need to replumb the tank vent from the purge canister to the atmosphere.

Usually you can put an external fuel pump that pull through the intake without an issue, but it is common when pulling the intake pump out to find its pre filter mostly plugged with gooey stuff. This doesn’t seem to have a huge effect on the factory pump but then the TBI engine isn’t much of a fueling challenge; but a remote low pressure pump and if I recall an L31 engine to feed may not be as tolerant.

My preferred method on these TBI to carb conversions is to use the in tank pump with an external bypassing regulator. You can find these on Ebay at reasonable prices.

Something to consider is that in my street experience the stock L31 isn’t much of an acceleration event over an LO5.

Bogie
 

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Is the Electric pump over powering the carb's needle and seat With to much fuel pressure, over filling the fuel bowl. and the engine running pig rich?
As for the vent issue, to test, drive it with the fuel cap off. if the problem goes away it is a venting issue,
Also check that the throttle when pressed is opening the carb blades fully.
You said you went back to a Q-JET is this on a different intake or sometype of adapter plate to mount the q-jet on the tbi intake?
Is the tbi computer still controlling the spark?
And now not getting any TBS input to know go much timing to advance or take out?
 
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