TBI Popping under load

[1993blazerlt]

I working on a TBI engine and when I hit the gas it starts poping throught the Throttle body really bad. I have triple checked the timing, it has new plugs, wires and cap and rotor. This is confusing me what could this be?

[Sparky2263]

Plug wires crossed, weak/broken valve spring, tight valve......what am I missing?

...moisture in cap....

[biglouie_underpressure]

or lean condition.

[Sparky2263]

Thanks Louie ;).

[1993blazerlt]

Ok i am leaning towards it being a lean condition. It is only poping when the throttle is pressed down quick if i let back off i can then floor it and the blazer will go fine. I have checked for a vacum leak with carb cleaner with no avail. It starts up fine and will idle with no problem. Could my problem be that i am running a CPI engine with TBI on it with the TBI computer do you think that is not enough to handle the stock CPI cam?

[nomaboy]

that could very well be it. the stock cpi cams were a lot bigger than the stock tbi ones. if you could get a performance chip or somthin to put more fuel in that would work too.

[1993blazerlt]

I really don't want to spend the money on a chip because the TBI is only on there for a short time until the money and parts are gathered

[Sparky2263]

CPI triggers one large injector. TBI has to trigger 2 injectors. Thinking you're gonna be short on fuel. I'll try the math on it later.

[Matt 4.3 TBI]

He said he's using the TBI computer, tho. That should not be an issue. I ran my Edelbrock cam (Larger than the CPI) on a stock chip on a drive from Dallas to Houston with no major issues. I DID have popping on WOT at low speeds, though. Tuning mine required less fuel at low speeds/high vaccum, and more at high speeds/low vacuum. Most likely it's lean, you might want to think about a adjustable fuel pressure regulator if you don't want to get a chip. They might cost about the same, though.

[1993blazerlt]

Thanks for the help i am just going to get rid of the TBI i just bought a 94 with cpi now i am dealing with a CPI and 4l60E swap