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96 Gmc Savana 5.7L 96K mi intermitent no start


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ghross
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Oct 11, 2015, 6:20 PM

Post #1 of 16 (909 views)
96 Gmc Savana 5.7L 96K mi intermitent no start Sign In

   I have a 96 GMC Savanah that has me stumped. Van sat for a while (3 yrs) but was occasionally started. It ran great when parked. .--------last time I tried, it would not start---no pressure at fuel rail----------disconnected line from tank to fuel filter, no fuel when key is turned on---------replaced fuel pump. Also rerplaced Cap and wires and plugs -----------double and triple checked all connections.
Van now starts with a jump , and will sit and run for a half hour with no trouble---(sometimes have to check to make sure it is still running). Shut it off and try to restart, will not start---has fuel at rail.--------------quick shot of ether and it fires right up and will run smooth until shut off again.------Also find that I now have Trans fluid in the cooling system, HAVE ANY IDEAS---this thing driving me nuts


Hammer Time
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Oct 11, 2015, 6:48 PM

Post #2 of 16 (895 views)
Re: 96 Gmc Savana 5.7L 96K mi intermitent no start Sign In

What is the fuel pressure?



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ghross
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Oct 11, 2015, 7:02 PM

Post #3 of 16 (892 views)
Re: 96 Gmc Savana 5.7L 96K mi intermitent no start Sign In

Not certain----don't have a way to check---if I push the valve in the shrader it releases fuel, but doesn't really spray at that point--------if pressure is low, what would be the issue? I replaced the tank a while back (Year ago)--hasn't been driven since, but started once in a while---pretty sure I changed the filter at that time as well, would have been the logical thing, but not sure-------possibility?


(This post was edited by ghross on Oct 11, 2015, 7:07 PM)


Tom Greenleaf
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Oct 11, 2015, 8:11 PM

Post #4 of 16 (885 views)
Re: 96 Gmc Savana 5.7L 96K mi intermitent no start Sign In

You need to check for actual pressure not just if it leaks a bit of fuel or not. It's not a fuel filter by all chances if it can run at all.


Battery if not tended to is probably junk after 3 years of sitting around. Remove it, clean it up, charge it and test it if OK or not AND check and grease the end cables at battery or replace them as called for.


Fuel goes bad, battery can't just sit and low fuel if so can kill a new fuel pump so pressure check mandatory and new fuel filter again after three years not a waste IMO anyway if you wish,


T



Hammer Time
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Oct 12, 2015, 1:59 AM

Post #5 of 16 (876 views)
Re: 96 Gmc Savana 5.7L 96K mi intermitent no start Sign In

We need to know the exact fuel pressure.



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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.



ghross
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Oct 12, 2015, 5:56 AM

Post #6 of 16 (867 views)
Re: 96 Gmc Savana 5.7L 96K mi intermitent no start Sign In


In Reply To
You need to check for actual pressure not just if it leaks a bit of fuel or not. It's not a fuel filter by all chances if it can run at all.


Battery if not tended to is probably junk after 3 years of sitting around. Remove it, clean it up, charge it and test it if OK or not AND check and grease the end cables at battery or replace them as called for.


Fuel goes bad, battery can't just sit and low fuel if so can kill a new fuel pump so pressure check mandatory and new fuel filter again after three years not a waste IMO anyway if you wish,


T




Battery was good and all connections are clean. Fuel was fresh---will see what I need to chk the pressure and let you know


Tom Greenleaf
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Oct 12, 2015, 6:12 AM

Post #7 of 16 (866 views)
Re: 96 Gmc Savana 5.7L 96K mi intermitent no start Sign In

From first post you said new pump and it was run for up to 1/2 hour sometimes which if enough should charge a battery up but if it stalled out long enough would kill the battery if unattended. Then with a jump (you said that) it would start right up with ether (starting fluid is ether) and run again.
Notes: GM side posts can look great and stink. There's an eyelet inside that can fail hidden by the rubber.
It sat for 3 years with I guess this battery so it that old plus how old it was and has been run low or dead - a warning of bad battery now to be verified.


Fuel pressure is critical to these if an "R" code Vortec engine requires high pressure or won't start well or at all but might run with tricks like ether.
I take it you aren't sure how to check for fuel pressure nor have a gauge so here you go. If a Vortec (not sure anything else in a 5.7 was used) it has a rail and like tire cap under hood on passenger's side. Takes a gauge meant for fuel pressure testing right there. First KOEO (key on to Run position, Engine Off), known charged battery BTW and should quickly come up to full pressure spec and stay there for a good time. That # and again when running is needed.


So - maybe places like Autozone now rent fuel testing gauges - ask locally. Check on buying one just for this vehicle without tons of adaptors some are not too expensive. YOU NEED THIS INFO.


It would be no surprise that pump new or not even if fuel not gone sour if run out or low too much could fail that easily but need to know first by pressure it can make and hold,


T



ghross
User

Oct 16, 2015, 1:19 PM

Post #8 of 16 (839 views)
Re: 96 Gmc Savana 5.7L 96K mi intermitent no start Sign In

Well, off to Autozone for the third time----first two testers were defecrive----near as I can tell at the moment, I have 40 PSI at KOEO, and 60 at start, drops to steady 50 PSI while running.------as I said all connections are clean and tight, and fuel(10 gal) is fresh.
will update once I can obtain a pressure tester that actually works.--------I do apologize, I am an old school mechanic(pre-electronics and computers)---ready to sell the tool box, as I can't afford to buy all the specialty tools needed to work on todays engines!-----and then places likje Autozone , who loan you broken tools !!


(This post was edited by ghross on Oct 16, 2015, 1:23 PM)


Tom Greenleaf
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Oct 16, 2015, 2:51 PM

Post #9 of 16 (829 views)
Re: 96 Gmc Savana 5.7L 96K mi intermitent no start Sign In

I don't trust those #s if this is an "R" code Vortec it wouldn't be running or starting at 40PSI or stay running at 50PSI. Even 60 is below spec but would start probably second try if it stayed there.


In short this all smacks of low fuel pressure making it to the port where you check but these can't do all you said or I misread it?


IDK - if battery voltage is way too low while cranking and somehow starts and doesn't give proper voltage or excessive voltage drops it's a factor for fuel pressure too but it's all over the place and shouldn't be running when say below 58 lousy and 57 about quits.


If unsure of which engine check 8th digit of VIN# should be an "R" spec for fuel from memory is 62>66 PSI or within a pound of that,


T



Hammer Time
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Oct 16, 2015, 3:11 PM

Post #10 of 16 (823 views)
Re: 96 Gmc Savana 5.7L 96K mi intermitent no start Sign In

Fuel Pressure Specifications:

Central SFI 415 - 455 kPa (60 - 66 psi)
SFI 385 - 430 kPa (56 - 62 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.



ghross
User

Oct 19, 2015, 9:35 AM

Post #11 of 16 (804 views)
Re: 96 Gmc Savana 5.7L 96K mi intermitent no start Sign In

  OK here we go--broke down and bought a tester-----Initial KOEO pressure is 63--after few seconds drops to and holds at 58-----------starts(yes second try)runs at 53.


Hammer Time
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Oct 19, 2015, 9:51 AM

Post #12 of 16 (800 views)
Re: 96 Gmc Savana 5.7L 96K mi intermitent no start Sign In

Something is wrong there. It should be running higher than that. Most of these won't even run under 55PSI



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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.



Tom Greenleaf
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Oct 19, 2015, 10:01 AM

Post #13 of 16 (799 views)
Re: 96 Gmc Savana 5.7L 96K mi intermitent no start Sign In

Drop to 58 on a Vortec "R" code 5.7 seems close but they really don't like that. If test is valid and it really holds I blame the pump again newer or not for that.


Good pumps (GM OE especially) + whole units really can put out plenty even with other issues but hold in range exactly posted by Hammer Time.


I can't explain why it runs at all at 53 and if so you notice a lot of drop in power.


Said - IF A VORTEC ''R'' CODE ENGINE!


T



ghross
User

Oct 19, 2015, 11:44 AM

Post #14 of 16 (792 views)
Re: 96 Gmc Savana 5.7L 96K mi intermitent no start Sign In

  
Yes, it is an "R" code. ---also, original post I was using starting fluid to start it, found I had some corrosion in the fuel relay socket-----cleaned that up,so now I get pump to cycle at KOEO.
Van has other issues needed to be addressed before it is roadworthy so can"t tell where we stand power wise!----anything else I should be looking at?


Hammer Time
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Oct 19, 2015, 11:56 AM

Post #15 of 16 (790 views)
Re: 96 Gmc Savana 5.7L 96K mi intermitent no start Sign In

They have a known problem with the contacts at the plug near the pump also.
You might have to do a voltage drop test to determine if you have resistance issues in the circuit.



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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.



(This post was edited by Hammer Time on Oct 19, 2015, 11:57 AM)


ghross
User

Oct 19, 2015, 1:16 PM

Post #16 of 16 (787 views)
Re: 96 Gmc Savana 5.7L 96K mi intermitent no start Sign In

Pump was from Delphi---came with updated harness for pump supposed to crimp splice into old harness-------as In said I am old school---don"t trust crimp connectors, so I spliced & soldered & shrink insulated all four wires in the harness---don't think there"s an issue there !







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