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Discussion Starter · #1 ·
I have a 1993 caprice (TBI) and i just tested the fuel pressure and when primed i get pressure but it doesnt hold. It goes up to 13 psi and then drops to zero. I was wondering what is the cause of this and the first thing to check?

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I have a 1993 caprice (TBI) and i just tested the fuel pressure and when primed i get pressure but it doesnt hold. It goes up to 13 psi and then drops to zero. I was wondering what is the cause of this and the first thing to check?

Thanks
Suicide
Check the fuel pressure regulator (mushroom -shaped canister on the fuel rail) for any presence of fuel in the attached vacuum hose or on the nipple when ignition is ON. There should be none.

The other suspect is the fuel pump itself.
 

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Check the for leaky injectors, faulty regulator, a faulty fuel pump check valve, or a leak in the fuel line somewhere. I dont think TBIs have a fuel rail..I think the regulator is between the injectors on the throttle body. iirc
 

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Discussion Starter · #4 ·
Check the for leaky injectors, faulty regulator, a faulty fuel pump check valve, or a leak in the fuel line somewhere. I dont think TBIs have a fuel rail..I think the regulator is between the injectors on the throttle body. iirc
well my injectors are ok but idk about the regulator and i know there are no leaks in the fuel line so i guess it might be the fpr ill chech tomarow to see it the gasket is old or has cracks in it thanks bowtie
 

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TBI cars bleed down pressure as soon as the pump is turned off by design. As long as it holds pressure while the pump is running it's fine.
 

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What are your symptoms?
 

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Discussion Starter · #8 ·
TBI cars bleed down pressure as soon as the pump is turned off by design. As long as it holds pressure while the pump is running it's fine.
well it does just that how come the system doesnt hold the pressure in the lines like a normal fuel system? That just doesnt seem right. And Forbes I know its like that timing chain on your ford explorer. lol
 

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Is your fuel system lack of pressure causing you any issues?
 

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well it does just that how come the system doesnt hold the pressure in the lines like a normal fuel system? That just doesnt seem right. And Forbes I know its like that timing chain on your ford explorer. lol
I looked it up in the FSM, it really is supposed to be like that. Think it said something about preventing vapor buildup.
 
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