Fuel System

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FSUTony

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Hi. Little help im stumped. Fuel pump is working, fuel filter is fine, but throttlebody is not injecting fuel. If i add a little fuel manualy it runs for a few seconds so its not ignition. Any ideas?

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FSUTony

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Hi. Little help im stumped. Fuel pump is working, fuel filter is fine, but throttlebody is not injecting fuel. If i add a little fuel manualy it runs for a few seconds so its not ignition. Any ideas?

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Its a 4.3 litter v6 1992 by the way.

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GL1500

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Sounds like the Passlock or VATS system is causing the fuel pump to shut off but I'm not sure if 92's were so equipped.
 

FSUTony

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Must be power to the injectors, relay/fuse or connection maybe?
Just purchased the relay will try it. Dont see a fuse for the injectors though

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FSUTony

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Just purchased the relay will try it. Dont see a fuse for the injectors though

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Weird. Now it starts gets gas for about 2 seconds and shuts off. Truck had half a tank of new fuel. Preasure regulator?

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df2x4

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Sounds like the Passlock or VATS system is causing the fuel pump to shut off but I'm not sure if 92's were so equipped.

That was my first instinct too, but Passlock didn't start until '98.
 

GL1500

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Couple questions.

First, did this problem first appear when you tried to start it, or did it shut off while running?

Second, can you hear the pump running to prime the system for a few seconds when you turn the key on?
 

GL1500

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...and a third; what part of US you located (hot or cold climate)?

...OK, one more for the masses. Is the fuel supply on a '92 dependent on seeing oil pressure?
 

someotherguy

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Hey Tony, a few thoughts:

1. You posted in the "Garage" section which is meant mostly for tools/work methods/etc. I see you're new so just as an FYI because your post may get a little less attention in this section than in the "Engine Performance and Maintenance" section.

2. To determine whether fuel pump is working correctly you need to do a pressure test.

3. Manually throwing some fuel in there and it runs momentarily is helpful info, but does not prove ignition module is 100%. The module has a few different failure modes. It can fail with no spark, it can fail with no signal to the ECM to fire the injectors, or it can fail totally. At this point the ignition module is my #2 suspect; #1 is adequate fuel pressure (9-13psi is spec for your engine, really any less than 10psi is not good)

4. Passlock/VATS antitheft systems as mentioned earlier not a factor at all because it didn't come in until 1998.

5. Don't depend on being able to hear the pump as the TBI pumps are usually too quiet to hear unless you're in a super quiet area.

Some helpful info on troubleshooting a no-start: http://www.chevytalk.org/fusionbb/showtopic.php?tid/253427

Richard
 
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