Going In Blind

Hootar · June 22, 2019

7 minutes ago, alpinecrick said:

Good grief, that's about as hokey as it gets. Lose the inline fuel pump, drop the tank and install a Delphi pump. I'm surprised the truck even runs that way. Proper fuel pressure and volume are important the the injectors.

Most fuel pumps on these trucks don't die from use, they die from not changing the fuel filter every 15k or LESS.

Gonna just go ahead and send this mechanic talking about carburetors on home.

alpinecrick · June 22, 2019

What year is it? The TBI motors ('95 and older) and the Vortec motors (96 and newer) had throttle bodies on them but entirely different fuel systems. The Vortec is fuel injected.

And I don't know how the truck can actually run if its dumping a couple gallons a minute into the engine. You sure it's not pumping gas out onto the ground somewhere?

Hootar · June 22, 2019

2 minutes ago, alpinecrick said:

What year is it? The TBI motors ('95 and older) and the Vortec motors (96 and newer) had throttle bodies on them but entirely different fuel systems. The Vortec is fuel injected.

And I don't know how the truck can actually run if its dumping a couple gallons a minute into the engine. You sure it's not pumping gas out onto the ground somewhere?

1989 5.7l k2500. It might be in the engine bay and not making it to the ground and I'll find a puddle in the morning.

Or explode.

Hootar · June 22, 2019

Can't buy a carb for it on Rock Auto but you can buy injectors and pumps and a throttle body.

alpinecrick · June 22, 2019

Yeah, I'd refrain from lighting a cigar around the truck for a while. It's a TBI motor then. At that age rebuilding the TBI is probably a good idea.

Hootar · June 22, 2019

Just now, alpinecrick said:

Yeah, I'd refrain from lighting a cigar around the truck for a while. It's a TBI motor then. At that age rebuilding the TBI is probably a good idea.

I will absolutely rebuild the TBI... Just gonna take a guess at the acronym. Throttle body injector?

alpinecrick · June 22, 2019

These days, keep the OEM stuff and rebuilding it is often the better idea. The "replacement" parts too often are made in China. I'm sure they have complete overhaul kits for that TBI, and shouldn't be too expensive.

alpinecrick · June 22, 2019

Yes Throttle Body Injection. The 88-95 TBI has two fuel injectors located in it. The Vortec TBI simply meters in the air to the plenum on the intake where the F.I. spider takes over.

Hootar · June 22, 2019

2 minutes ago, alpinecrick said:

Yes Throttle Body Injection. The 88-95 TBI has two fuel injectors located in it. The Vortec TBI simply meters in the air to the plenum on the intake where the F.I. spider takes over.

Oh alright, so it's like a caveman fuel injection system where instead of each cylinder having it's own injector there's two injectors that spray the fuel into the throttle body and it's distributed from there...

That must be why there are wires. Yeah that mechanic is all sorts of fired.

TW97C1500 · June 22, 2019

Yes, it's not "Multi-Point Fuel Injection", it's "Single Point Fuel Injection". Whereas a carburetor works by having the air flowing through it suck fuel out of tiny holes, the throttle body injection system has a fuel injector or two there that spray the fuel in.

You know, thinking about it, if you have a rigged up external fuel pump, it may have been converted to a carburetor. A lot of people do that to the TBI motors.

In fact, to convert one I'm pretty sure you have to change to a lower pressure fuel pump, then the carb bolts right on in place of the throttle body.

Hootar · July 1, 2019

On 6/22/2019 at 2:03 PM, TW97C1500 said:

Yes, it's not "Multi-Point Fuel Injection", it's "Single Point Fuel Injection". Whereas a carburetor works by having the air flowing through it suck fuel out of tiny holes, the throttle body injection system has a fuel injector or two there that spray the fuel in.

You know, thinking about it, if you have a rigged up external fuel pump, it may have been converted to a carburetor. A lot of people do that to the TBI motors.

In fact, to convert one I'm pretty sure you have to change to a lower pressure fuel pump, then the carb bolts right on in place of the throttle body.

Nah it's not a carb, the guy who looked at it was just an idiot. There's two clearly electronically controlled injectors above the throttle body.

Sorry for the late replies I'm an offshore fisherman so I'm gone forever. So here's the deal, I know it needs a whole new spark system, distributor rotor, cap, wires, plug and coil along with a new frame ground.

It definitely has a fuel pump outside the tank and I agree with the above about replacing it with a real and reliable in tank pump. In fact I'll probably just replace the tank, pump and lines considering how easy it looks.

The thing that's driving me nuts right now is the fuel consumption. There's definitely no leaks, I moved it to a virgin section of my driveway, put five gallons in on top of the 3 already in there and it burned it up at an idle in about 30 minutes. It needs an air filter and there's no connecting piece from the air filter disc cover to the actual airbox on the side.

Could that, combined with a shoddy spark system create that type of fuel consumption? I'm at a loss. The only thing under the truck is a drip from the oil pan gasket, nowhere along the fuel line run is there a leak and there's nothing in the engine bay...

It runs smoothly, then the revs kick up noticeably, then back to smooth, then runs out of gas.

Fuel lines? Injectors? I've told her that back lot wasn't her grave but I'm not sure she has the will to live.

riverbanks · July 1, 2019

It is possible that the external pump is overloaded,working too hard to pull thru another pump,you would have to top off the tank,run it,when it dies, top of again, measure fuel usage,go from there,I mean, your oil would stink of gas and your lifters would be chattering if that much fuel actually entered the engine,and plugs can't rebound that quick

Hootar · July 2, 2019

1 hour ago, riverbanks said:

It is possible that the external pump is overloaded,working too hard to pull thru another pump,you would have to top off the tank,run it,when it dies, top of again, measure fuel usage,go from there,I mean, your oil would stink of gas and your lifters would be chattering if that much fuel actually entered the engine,and plugs can't rebound that quick

What's chatter sound like? No fuel smell at all