TBI not starting

[NicBop03]

I just bought a 1990 R1500 Suburban. Ran great for about an hour then nothing. I have checked everything between the throttle body and the tank. The pump is new and works great. I can jump the relay and it gets power and runs but its not receiving power outside of the jumper wire. I tested the relay on another truck that I knew ran and drove and its perfectly normal. I know the oil pressure sensor thing is tied into the system but how would I check that? Could it be a grounding issue? I know TBIs like their grounds. Is there something I'm missing? Remember everything works perfectly fine as long as you pour gas down the throttle body.

 

[yevgenievich]

Probe the fuel pump signal from ecm at the relay. Oil pressure switch is a backup source to power the relay. If it does not run with fuel pump relay jumped and there is fuel going to injectors, then ecm is not running injectors. Worth trying to check for codes

 

[Rusty Nail]

The distributor module is the only part that can kill both fuel AND spark together but I bet it's your issue.
Auto parts stores swear they can test them - at least they're cheap.

 

[Ricko1966]

If you jumped the relay and heard your pump run you should be getting fuel to the throttle body.Verify that. If you jump the relay and have fuel then you need to check for pulse at the injectors.I made a cool light for doing that.2 leds.leds only work in one direction so you. Twist the negative leg of on to the positive leg of the other and vice versa solder some 2 conducted cheap speaker wire to that and 2 t pins as probes back probe the injector throw the led end of thhe wire up on the windshield hold it down with the windshield wipers get in and crank 1 led should blink.

 

[Ricko1966]

The distributor module is the only part that can kill both fuel AND spark together but I bet it's your issue.
Auto parts stores swear they can test them - at least they're cheap.

He said it runs if he pours gas down the throttle body. I don't know the whole story so I told him how injector pulse. If he's got pulse I'm wondering if the injectors are plugged.

 

[Ricko1966]

Check injector pulse and check for fuel to the throttle body with the relay jumped.I made a cool tool for doing this.2 leds twist them together negative to positive and positive to negative.Solder on a few feet of thin 2 conducted speaker wire to your twisted ends solder 2 t pins to the other end of the speaker wires .Put your leds less on the windshield hold them down with the wiper.Backprobe an injector get in a crank 1 led should blink while cranking. If you can jump the relay and have fuel and pulse I'd be looking at injectors.

 

[Ricko1966]

Check injector pulse and check for fuel to the throttle body with the relay jumped.I made a cool tool for doing this.2 less twist them together negative to positive and positive to negative.Solder on a few feet of thin 2 conducted speaker wire to your twisted ends solder 2 t pins to the other end of the speaker wires .Put your less less on the windshield hold them down with the wiper.Backprobe an injector get in a crank 1 led should blink while cranking. If you can jump the relay and have fuel and pulse I'd be looking at injectors.

Well I know how to work on cars but I certainly lack skills with knowing how to post correctly. Sorry for doubling up. I also keep letting spell check kma all the times that said less it was supposed to say led.

 

[NicBop03]

Yes I have spark and compression. The fuel pressure is also within spec. Like Ricko said I'm leaning more towards something with the fuel injectors. I'm about to go start working on it. Will report back.

 

[Rusty Nail]

He said it runs if he pours gas down the throttle body. I don't know the whole story so I told him how injector pulse. If he's got pulse I'm wondering if the injectors are plugged.

Uh huh. I can read.

But this is the internet... all you gotta do is toss a module in it.

In this board, new guy, we like throwin parts at **** and wastin money. We are really into makin easy stuff hard.

 

[NicBop03]

Well it runs great now. Started probing around and figured out the computer wasn't getting power. I just did the head gaskets this passed weekend. Turns out I missed one wire on the back of the alternator and I guess it just wasn't sending power. I feel REALLY stupid now, but I learned more about the fuel system so it all worked out.

 

[Ricko1966]

Lol

 

[Rusty Nail]

What kind of module did you get though?

Dont say rock auto

 

[Ricko1966]

Lol

This was meant for rusty posts post at 7:20 and 9:57