350 TBI, only one injector squirting.

[midnitewarya]

Hey all, got a problem, looking for some advice.

I just dropped in a new crate 350 in my 1991 K5. I kept everything original, no modifications to cam/valves/intake/exhaust/fuel.

I did rebuild the TBI. I added new seals and injectors, stock flow.

Went to crank it up for the first time today. Timing was almost spot on. When it cranks, only one injector is firing, and it isn't the steady constant flow I'm used to seeing. It's bursts of fuel, kind of sputtering out. The other injector isn't squirting at all. The motor will run if I give it a little bit of throttle, but otherwise it stalls out right after it fires up. I quickly checked to make sure the wiring harness was connected to the injectors, but that's all the troubleshooting I did.

I made this discovery after a long day in the garage, and just walked away from the problem before I got angry. Do any of y'all have any advice on where I can start troubleshooting this one?

Thanks!

 

[dyeager535]

I can't recall if the injectors are fused individually. I'd check that first though.

Keep your eyes open for problems that might be related, but it COULD be that the one injector pattern seems odd only because the ECM is using it to try and compensate for the problem via the O2 sensor. Of course, if it's happening when the engine is cold, that won't be the problem, but nonetheless, need to fix the non-working injector first.

Pop the injector connector off, make sure it's got 12V with key on. Then, assuming 12V, using a noid light, ensure that it blinks while the engine is cranking/running.

Since you dropped in a new engine, I'd be looking at pinch points where wires would get caught (such as between the bellhousing and block) and where they might have been over-extended.

Edit: 4x4HIGH's process is easier. Just swap connectors and see if the problem goes with the connector or stays with the injector.

 

[midnitewarya]

Awesome, thanks. The battery was bad, just waiting to gather the funds to get a new one. Hopefully I'll have a follow up here shortly.

 

[dyeager535]

Awesome, thanks. The battery was bad, just waiting to gather the funds to get a new one. Hopefully I'll have a follow up here shortly.

bad battery caused a one-injector working issue? That's an odd one!

 

[midnitewarya]

Not a 100% it was the battery, but we shall see.

 

[WyoSquareMan]

I had a 94 with only one injector firing but would fire a noid light turned out the wires just off of the injector conector layed over each other and wore and stuck to each other causing the issue taped up the wire and good to go

 

[midnitewarya]

Got it! It was a combination of a low battery and an injector that sat for quite awhile. Once the new battery was in, gave the injector a smack with a screwdriver and it fired right up. Timed it to zero, plugged the ecu wire thingy in, ran the breakin, and this Blazer is back on the street. Thanks guys!