I just bought an 88 Firebird 305 w/ TBI yesterday. There was fire damage from a backfire. I have looked under the hood for prob 3 min max. I dont think the Vac hoses are right.

My father had a TBI conversion van that gave him nothing but trouble.
I would much rather do a carb swap but if its a simple fix ill go for it.
The ole man has a Chevy restoration shop, so i already have a good 305 Quadrajet and HEI, need to find an intake but that will be cheap <$50

I have read about making the TBI Regulator adjustable, and checking A/F using the O2 and volt meter.

It runs like a pig, very strong fuel smell out the exhaust/ dark smoke, wont drive over 40mph (dont know what thats all about). Any way it has a bunch of add ons
Rebuilt 305 w/ cam
Rebuilt 700R4
headers
single 4 in flowmaster exhaust

the previous owner said he replaced the regulator, who knows if he did it right.
I understand FI , the newer version, but this TBI is just old tech i would rather throw away.


where should i start???

EDIT: forgot to add the Cat has been deleted.

 

So do you want help fixing it, or are you just going to toss it???

If it was in a fire, first thing I'd be looking at is anything plastic. Like all the vacuum lines! THey break from just age, let alone major heat.

Your MAP sensor could very well have been cooked, amongst others.

Hose plumbing on these is very simplistic.
There should be a sticker under the hood showing the routing.

 

Mallory carries adjustable fuel pressure regulators with the return bypass so you could carb that motor quite easily by ignition on wiring the stock fuel pump, adding an intake, carb, and routing a charcoal canister dump out of the engine compartment. You will prolly want a new cam and heads as the L03 motor was very weak due to these components, especially the heads.
--TBI being in a fire, check the TBI gaskets for damage, along with any other gaskets-heat=bad. Check your fuel lines and fuel filter for leaks, also make sure the charcoal canister is hooked up and all vaccuum routing is in very good shape.
my 2 cents

 

If its an easy fix of course i would want to keep the TBI.

But,
I have everything here for a free swap. Regulators, Carb, intake, HEI etd..
might cost $20 in gaskets.

Thanks for the start, ill check the Vac. hoses etc...
It sucks that i dont know everything the previous owner tried.
and Connect a Voltmeter to the O2 as i make changes.

 

Won't tell you much. Narrow Band O2's really only tell you when you're stoich, then either leaner, or richer (not by how much).

If you hook up a scan tool to it (or WinALDL) at least you can read the various sensor values and see if they're all within scope. This is really the only way to go.

But make sure all the basic hardware is 100% before you go chasing your tail in circles. I've wasted much time in the past looking for some seemingly complex problem, when it turned out to be a split hose or something!

 

Thanks,
In the process of removing the red (teenager) wire looms i sliced open my finger...bad kinda hard to type w/o an index finger.

I cleaned up the engine compartment and found one vacc port open.
Front far right. EDIT: Thermac, it has headers so i know thats gone... Just gonna plug it up.
And the Air temp sensor unplugged. Its plugged up now but im sure it toast.
I dont have the diagram but ive seen it here and will look.
When i started the car and plugged the port w/ my finger it revs fine.
but Idle sucks.
Im sure it needs plugs, and fresh oil
are the o2's toast from running rich?

Gonna try a few things and take it down the road. If it doesnt do better, its getting carbed.

 

Like they said, make sure all the sensors and wiring and such are in good shape. I've had firsthand experience with a coolant temperature sensor going bad, exhibited the same symptoms you're describing. So make sure the sensors and connectors are good, check all the vacuum lines for cracks and/or being disconnected, then try again.

 

After the fire damage there is no telling whats wrong w/ the FI. so i said F-It.

I will admit in the process of removing the Dist. Cap, one of the hold down screws was stripped completely, leaving it very loose. There was even a ring of pollen inside the cap.

I scored an alum. intake from a friend, correct bolt holes. place for the egr, etc..
I have a quadrajet, Fuel Regulators that we use on our racecars, 1 input 2 outputs for feed and return, I have an HEI distributor w/ a new cap in the box dad.

Im going to the parts store tomorrow for oil, plugs, cooler thermostat, etc... tune up stuff.

 

the bird


the garbage


whats left

 

sounds like to vaccum at the map sensor or a broken wire at your map or a shorted o2 sensor

 

I converted to carb.

I think it was an overzelous fuel pump.

 

In that case a stiffer FP spring and making the FPR adjustable would have done the trick.