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1991 Chevy s-10, won't start on its own


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bdeusen
Novice

Aug 24, 2015, 8:46 PM

Post #1 of 11 (1860 views)
1991 Chevy s-10, won't start on its own Sign In

I have a 1991 chevy s-10, 4.3 motor that we can't get gas to spray out of the throttle body, we have replaces the fuel pump, fuel filter and throttle body, any other suggestions will be greatly appreciated. thanks


(This post was edited by bdeusen on Aug 25, 2015, 6:19 AM)


Tom Greenleaf
Ultimate Carjunky / Moderator
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Aug 24, 2015, 10:02 PM

Post #2 of 11 (1854 views)
Re: 1991 Chevy s-10, won't start on its own Sign In

Let's begin with what engine and fuel system is in this thing. No carbs used that I know of in these but a throttle body injected one looks a bit like one.


What do you have?


T



bdeusen
Novice

Aug 25, 2015, 6:16 AM

Post #3 of 11 (1838 views)
Re: 1991 Chevy s-10, won't start on its own Sign In

Throttle body, can't get fuel to spray out. 4.3engine, thanks for the reply


Tom Greenleaf
Ultimate Carjunky / Moderator
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Aug 25, 2015, 6:35 AM

Post #4 of 11 (1835 views)
Re: 1991 Chevy s-10, won't start on its own Sign In

OK - Try priming it with starting fluid. It should at least react or run for a few seconds is info.


That and do you even hear fuel pump prime up at tank? Just does that a couple seconds till pressured up. If nothing then check if power get to it at its plug - and ground.


Seems silly but if you changed that out how much fuel did you put back in? It won't pick up one gallon by all odds.


What lead you to think it was a fuel pump to begin with? What was fuel pressure and what is it now if any?


Seiously - don't just toss parts at it, rather zoom in on the real problem. If this will react and fire with priming at least we could rule out lack of spark or not concentrate on that.
Other: Make sure oil pressure switch is plugged in! Some (dunno which) wouldn't run without it working. Should be down back by distributor,


T



bdeusen
Novice

Aug 25, 2015, 7:00 AM

Post #5 of 11 (1830 views)
Re: 1991 Chevy s-10, won't start on its own Sign In

Have primed it and it will run for a few seconds, and do hear fuel pump. please explain better about fuel back in and won't pick up one gallon by all odds. Truck has about a half a tank in it. All started in the beginning because the truck wouldn't start. No gauge for fuel pressure. Oil pressure switch is plugged in. Thanks again for taking the time.


Tom Greenleaf
Ultimate Carjunky / Moderator
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Aug 25, 2015, 7:28 AM

Post #6 of 11 (1827 views)
Re: 1991 Chevy s-10, won't start on its own Sign In

The ONE gallon thing: Many vehicles that run OUT of fuel somehow use up a bit more and even adding one gallon only on a road call (did and will do many still) won't run till more. Fuel with vehicle at an angle - who knows - just I'm sure of it plus the screens aren't on the exact bottom on about any.
You said you changed the pump so guessing you emptied the tank?


Just to rule out silly stuff like that you need to know.


OK: Now that you know ignition can run engine it's down to lack of fuel DELIVERY. That is possible for a few reasons. Lack of enough pressure for one so rent a gauge if need be. Major parts outlets do that - ask locally for free with full deposits. It has to hold and be at spec with just key on run and engine off - that much at least. If it leaks right down or not up to snuff (you or I will look it up but think 35PSI not sure yet) it won't run. It also has to trigger the fuel injectors. I think a noid light will work on a 91 TBI is your system and watch it flash. If not more to test out.
Gotta begin somewhere with what is known and what isn't till the probably ONE thing at fault is narrowed down to.


Hey - many complaints with new fuel pumps so don't be so sure new is good - suks but happens,


T



Hammer Time
Ultimate Carjunky / Moderator
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Aug 25, 2015, 8:22 AM

Post #7 of 11 (1820 views)
Re: 1991 Chevy s-10, won't start on its own Sign In

TBI fuel ressure is 9-13 PSI



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



bdeusen
Novice

Aug 25, 2015, 8:30 AM

Post #8 of 11 (1817 views)
Re: 1991 Chevy s-10, won't start on its own Sign In

Didn't remove tank. but I will check this stuff out.


Tom Greenleaf
Ultimate Carjunky / Moderator
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Aug 25, 2015, 8:45 AM

Post #9 of 11 (1814 views)
Re: 1991 Chevy s-10, won't start on its own Sign In

Thanks HT for the pressure spec. OP - I can't know how you replaced pump or if it was full when you thought failed or what. As much as a pest as they can be it's nice to see how dirty they might be inside some too.


At the moment only thing known is it lacks fuel delivery. Pretty sure there's a cap on the fuel rail to hook up pressure gauge to on this too. Forget size in NPT but should be able rent with assorted sizes. Good stuff is costly,


T



Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Aug 25, 2015, 9:57 AM

Post #10 of 11 (1810 views)
Re: 1991 Chevy s-10, won't start on its own Sign In

If I remember correctly, these things had a pulse damper in between the pump and the housing that should be removed and replaced with a section of rubber line.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



bdeusen
Novice

Aug 29, 2015, 9:13 PM

Post #11 of 11 (1757 views)
Re: 1991 Chevy s-10, won't start on its own Sign In

I haven't been ableto work on it any more,have had a lot on my plate, hopefully this afternoon with any luck, thanks again for trying to help me figure this out, I feel like its something small that I am overlooking, but just not sure ya know.






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