wa9zug

We have a 1990 G2500 van with a 5.7. It dies suddenly. Happens randomly at various speeds. More so when lower RPM's. If I crank it a while it will start back up. I pulled a plug wire while it was turning over to restart it I saw spark( verified three times). I had no gas spraying in the TBFI. If I spray a little carb cleaner in the TBFI it will fire up and stay running. I drove around with the doghouse and air cleaner off and when it would die I saw No gas spraying, but as soon as I sprayed a little cleaner it would fire up (did this many times). What am I missing? It seems like both TBFI's are turning off at the same time and then they turn back on when I spray the cleaner. I don't get it. Haaaalp!

GBousley

If fuel delivery fails could your fuel pump be going out? I think you can put a gauge on the return line to monitor pressure (someone keep me honest here). Also, if you haven used a TBI rebuild kit in a while they work wonders (if it's not pump related). I removed both injectors in my 305 TBI and cleaned them and noticed a huge difference in how they sprayed afterwards (along with the rebuild kit).

wa9zug

Thanks for the reply. It stops spraying like a switch is turned off. It starts spraying as soon as I spray some carb cleaner (or starting fluid) in the TB, It will run and then die quickly without a stutter. BTW never heard of a TBI rebuild kit.

wa9zug

Do these TBI's have fuel pressure regulated to them? How? Is it vacuum?

GBousley

See: https://www.autozone.com/fuel-delive...-tbi/gmc/g2500
Replaces all gaskets, and fuel regulator. As for TBI, I know it needs a specific pressure / volume from the pump, and I'm sure there's a return line to the tank. Not sure on the specific numbers.

William Kisselstein

Throttle Body Injection runs about 13-15 PSI from a pump in the tank, which you should be able to hear running.

Did we replace the filter? Is the tank dirty?

These are OBD-1 systems and can be checked for trouble codes by connecting a wire (bent paper clip works) between A and B terminals on diagnostic link, turn ignition on and count flashes of check engine light. It shows two digit codes by flashing each one three times. 12 is normal. They will not give as much information as an OBD-II system does but it can be a help.

wa9zug

Does that rebuild kit give you the stuff to rebuild the pressure regulator, or is that a separate item?

GBousley

Yes, it's the small orange piece (gasket) with a spring. Just make sure you enter your vehicle details and ensure the kit matches your application.

wa9zug

Popped in a TBFI rebuild kit and VIOLA, no more issues! Talk about nailin' it! Thank you O wise sages.

GBousley

Awesome! Glad that worked out!