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Car only runs when fed gas through the tbi

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Old Mar 25, 2025 | 05:23 PM
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1989305RS's Avatar
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Car only runs when fed gas through the tbi

Car is a 1989 305 rs. I rebuilt my tbi with new injectors but the car still won’t run. Fuel pump primes and when I crack the fuel lines going to the tbi gas will come out but it’s not a forceful stream. The car will run when gas is poured into the tbi. I’m going to change the fuel filter. I have no history on the car other then it’s been off the road 5+ years. Any ideas would be awesome I’m hoping I don’t need to drop the tank!
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Old Mar 25, 2025 | 06:21 PM
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bk2life's Avatar
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From: az
Car: 91 WS6 GTA
Engine: 5.3
Transmission: 4l60e
Re: Car only runs when fed gas through the tbi

Originally Posted by 1989305RS
when I crack the fuel lines going to the tbi gas will come out but it’s not a forceful stream.
no you need to test fuel pressure before doing anything else.
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Old Mar 25, 2025 | 06:31 PM
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8t2 z-chev's Avatar
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From: belle fourche,s.d.
Car: '82 z28
Engine: L83 5.7
Transmission: 700r4-1985
Axle/Gears: 3.42 posi
Re: Car only runs when fed gas through the tbi

Inside the fuel tank is a little foam rubber coupler hose between the fuel pump and the steel line that comes out the top of tank-this hose often turns to black goo after a period of disuse and falls off...drop tank to fix...Use a "noid" light to check for power/injector pulse at the injector plugs.Is "check engine "light operation normal?Also remove and reinstall all the fuses in the fuse panel one by one-to restore good connections.
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Old Mar 31, 2025 | 07:57 PM
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Re: Car only runs when fed gas through the tbi

Do those "new" injectors actually spray?
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Old Apr 2, 2025 | 06:49 PM
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1989305RS's Avatar
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Re: Car only runs when fed gas through the tbi

Originally Posted by Schurkey
Do those "new" injectors actually spray?
yea they do.
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Old Apr 2, 2025 | 08:06 PM
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From: Cincinnati, OH
Car: '90 RS
Engine: 377 LSX
Transmission: Magnum T56
Re: Car only runs when fed gas through the tbi

As mentioned, you need to check fuel pressure. A dying pump can still give the illusion that the injectors are spraying normal.
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Old Apr 27, 2025 | 10:42 AM
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Car: 1988 IROC-Z
Engine: L03 to L05: 350 TBI
Transmission: MD8: 700R4
Axle/Gears: GU2: 10 bolt/2.73
Re: Car only runs when fed gas through the tbi

Curious if this was ever resolved.

Being that the car sat for 5 years with likely ethanol in the fuel I would bet that it started to gum up. If it hasn't gummed up the sock on the fuel pump, surely the fuel filter needs to be replaced as you suggest, and I would highly recommend.

But before doing anything I would check fuel pressure. It should be 9 -13 psi. TBI's do have a bleed off so don't be surprised to watch the pressure drop once the fuel pump prime (2 seconds) stops.

Sadly though, it sounds like a fuel tank out, clean/flush and while I was there, I would suggest replacing the fuel sending unit, possibly the tank and fuel pump. I would flush the lines with some cleaner and compressed air.
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