tbi conversion and now no start

[chevyguy82]

i just converted my 82 blazer over to fuel injection. i used a harness and all the parts off a 88 c1500. i installed a new fuel pump in the tank and all new lines. i can not get the injectors to fire. they both have power, fuel to the throttle body, and nothing. i had it started if i sprayed carb cleaner at first now it won't even fire. i don't have the o2 sensor hooked up, or oil pressure switch. would the oil pressure switch be my problem? can i bypass it? also no egr either. i just want to get it to run and then adjust as needed. i grounded the black/white strip wires and have all the pink, orange, and red bundled together right now just to start it. anyone have any ideas? the truck i pulled all this off of ran great.

 

[Stomis]

Yes the switch will cut the motor to prevent damage.

 

[chevyguy82]

can i bypass the switch? do you know what wires go to the switch? thanks.

 

[chevyguy82]

i also forgot to mention i have the fuel pump wired to the switch on my dash. it doesn't even go through the relay

 

[Russell]

The oil pressure switch is not what most people think - It does not turn off the fuel pump if the oil system looses pressure. It acts as a backup to the fuel pump relay. It is connected in parallel to the relay and will allow the truck to start even if the relay has failed.

 

[chevyguy82]

i think i may have figured out my no fuel problem. after researching a little more and thinking, i believe i have the fuel lines switched on the back of the throttle body. i am actually filtering the return line. what a long day working on this thing. next time i will just buy a 87 and up blazer. i'll post back tomorrow after i switch them.

 

[chevyguy82]

i got it started all on its own tonight. switched the fuel lines and had the wife look over my wiring and it fired right up. it has a bog if you hit the gas hard. would not running a egr valve cause that. i also don't have the o2 sensor hooked up yet. there is light at the end of the tunnel now. just trying to get it ready for the wheeling trip coming up.

 

[Russell]

With no O2 sensor, and it as driveable as it is, you're probably in the green. As far as the EGR goes, hook that sucker up!

EGR has a number of benefits to offer, and does not rob you of any power that you'll notice. It is only activated when you are cruising along on the highway at part throttle, and works to lean out / cool down your exhaust mixture by allowing some exhaust back into the intake. This means you are using less fuel, and can run more timing which = higher efficiency. As soon as you get on the skinny pedal, the valve snaps shut and you are operating as if there isn't one there at all.

There is a good reason why GM still runs EGR valves to this day!

Also, make sure your fuel pressure & supply volume are both adequate, too much or too little fuel while running without an 02 sensor will most certainly cause a bog on heavy throttle. You may also want to consider bumping your timing up a few degrees from the factory prescribed 0 degrees. I often ran mine around 4 or 5 degrees BTDC and found that the engine responded quite well to it.