TBI not firing injectors.

[urbex]

I would *think* even with a couple psi of fuel pressure you'd see something out of the injectors, but have you used a test light on one of the injector connectors just to make sure they aren't being pulsed and it's a no fuel issue?

FWIW..I've had a TBI truck running on 3psi of pressure before. Ran like absolute crap, and wasn't at all driveable, but it did run. I was shocked, as I didn't think the injectors would even open at that pressure. Picked that truck up for a song because the owner thought the engine was toast, and I was going to use it for parts anyways. Long story short, found the oh-so-common rotted pickup in the tank. Replaced that, was back to a solid 12psi, and motor ran great.

 

[black dawg]

get anywhere with this? Had one yesterday with a bad tps (ecm thought throttle was wide open...clear flood mode). Don't see that very often, but it does happen.

 

[Andrew Hare]

I’m having a similar issue when it’s cool out he truck runs just fine but when it gets hot out I intermittently lose my drivers side fuel injector. I put a summit distributor in the truck a few years back when my original distributor failed and the truck ran like a top and just earlier this year I started having issues with the driver side, fuel, injector, cutting out, and the truck, losing power and running like garbage. I’m curious as to where to start looking. I have just serviced the entire fuel system and rebuilt the throttlebody with two brand new fuel injectors, and the issue is still coming intermittently. I recently replaced the pigtails to the fuel injectors, hoping that it was a bad connector, causing a connection issue and causing the injector to malfunction. Any insight as to what’s going on with my reliable awesome truck would be greatly appreciated.

 

[Wes Harden]

I’m having a similar issue when it’s cool out he truck runs just fine but when it gets hot out I intermittently lose my drivers side fuel injector. I put a summit distributor in the truck a few years back when my original distributor failed and the truck ran like a top and just earlier this year I started having issues with the driver side, fuel, injector, cutting out, and the truck, losing power and running like garbage. I’m curious as to where to start looking. I have just serviced the entire fuel system and rebuilt the throttlebody with two brand new fuel injectors, and the issue is still coming intermittently. I recently replaced the pigtails to the fuel injectors, hoping that it was a bad connector, causing a connection issue and causing the injector to malfunction. Any insight as to what’s going on with my reliable awesome truck would be greatly appreciated.

If only one injector is acting up, possibly wiring issue. esp where wires pass through the air horn on the tbi. Or maybe the the injector itself.

 

[Andrew Hare]

If only one injector is acting up, possibly wiring issue. esp where wires pass through the air horn on the tbi. Or maybe the the injector itself.

I replaced the injector connectors and repaired a kinked wire that I found. When the drivers side injector cuts out code 13 pops up which is an 02 sensor code. The only reason that that code pops up is cause the 02 sensor is in the base of the drivers side manifold and that happens cause the drivers side cylinders don’t get fuel. I’m curious as to what brought this on all of a sudden I’ve been playing with this issue for about a month now.

 

[dyeager535]

I’m having a similar issue when it’s cool out he truck runs just fine but when it gets hot out I intermittently lose my drivers side fuel injector. I put a summit distributor in the truck a few years back when my original distributor failed and the truck ran like a top and just earlier this year I started having issues with the driver side, fuel, injector, cutting out, and the truck, losing power and running like garbage. I’m curious as to where to start looking. I have just serviced the entire fuel system and rebuilt the throttlebody with two brand new fuel injectors, and the issue is still coming intermittently. I recently replaced the pigtails to the fuel injectors, hoping that it was a bad connector, causing a connection issue and causing the injector to malfunction. Any insight as to what’s going on with my reliable awesome truck would be greatly appreciated.

Have you tested the signal on that injector when you are having problems? Ensure there is a pulse (need a test light or analog voltmeter). One injector wire on each plug is 12v(constant) the other is a ground (switched via the ECM).

I don't know the specs for TBI injectors, but you can test for resistance across the terminals. I had a few injectors that ran fine initially, but once the engine heated up, if I turned the truck off, it wouldn't restart. It was the injectors. When hot, I could see the difference via resistance.