97 Suburban stalls after restart on warm engine

Tiny
VMAX4800
  • MEMBER
  • 1997 CHEVROLET SUBURBAN
1997 Chevy Subruban K1500 4X4 AUTO about 97K miles. I can drive the truck for minutes or hours but when I do stop and shut the motor off, if I go to restart the engine in anything less than an hour the truck will start and quickly stall. After that I have to wait a period of several hours and truck will start normally. ALSO sometimes while driving the truck above 20MPH the truck seems like it wants to stall upon acceleration but does not, this will happen again in a minute or two then go away. Truck gives NO CODES and check engine never lights. RELEVENT INFO --entire fuel system has been replaced within the last year

If after a stall I check codes--I find none but do an erase codes anyway the truck will start. ANY IDEAS?
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Tuesday, November 20th, 2007 AT 5:09 PM

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Tiny
PEAR69
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Ideas? No! Lets find the amswer. When you had the entire fuel system changed I am assuming the fuel pump was changed. AHHH HAAA another one! There is a problem with the connectors on these fuel pumps. And there is realy no way to determine if your problem is the connector other than this. The next time the engine stalls jump out, crawl under the truck, and wiggle the fuel pump wireing harness. Then try to start the engine. You could also jump out the fuel pump, wiggle the wires, and see if the pump turns on and off. To jump out the fuel pump--unplug the fuel pump relay--look the relay located just behind the left front wheel well under the hood, and observe the wire diagram on the relay--with a small wire, jump out terminal 85 and 86 only. This will directly run your fuel pump with or without the key in the on position.
The loose connection is caused by a flaw in the design of the chassy fuel pump harness connector. The prongs inside the connector pry open when you unplug the fuel pump connector. This causes the connection to be loose. When you are driving air is flowing all around your suburban. This may be the cause. Vibration also may be it. Anyway, this loose connection will eventualy began to arc--thus melting the connector--and it could cause a fire at your fuel tank. This problem will also NOT send any type of trouble code to the computer. Let me know how you make out Good luck
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Wednesday, November 21st, 2007 AT 2:24 AM
Tiny
PEAR69
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If you carefully split apart the terminal block that the relay plugs into you will see that all the wires have terminal ends crimped onto them. If you disconnect the wire with the crimp end from the block you can replace the crimp or just squeeze the crimp end just a tiny little bit. This will make the connection tighter. Just be carefull not to squeeze too much. Do this slowly and carefully.

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Monday, December 17th, 2007 AT 7:36 PM
Tiny
VMAX4800
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I will look into this advice for the fuel pump connection again. Your help has definitely put me on the right track. I have not yet found any trouble at the fuel pump connector side yet, thus I am not sure which is the primary cause (the fuel pump connector or the relay block connector). What I do know is when the engine has stopped I can re-seat the relay and the engine will start; however the relay is EXTREMELY hot to touch. This leads me to think there still a problem at the fuel pump connection but I will have to drop the tank to find that out. TANKS - I have donated
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Wednesday, January 2nd, 2008 AT 10:50 AM
Tiny
PEAR69
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The relay is normaly hot on these tahoes. Try changing the relay if you haven't already done so. I have a 98 tahoe and I went through the same thing you are going through. My relay gets extremely hot also. I feel that this heat eventualy makes these relays fail so I just changed it. I also found out, after dropping the fuel tank 4 times and changing the fuel pump 3 times, (thinking that it was the fuel pumps' fault), that the fuel pump chassy harness connector has the defect that I described before. I know you are probably pulling your hair out, like I did.
Also check the fuel pump ground. It is one of the four wires, colored black, that goes from the fuel pump connector and terminates to the cross frame member right in front of or behind the fuel tank--mine is in front. If you follow the harness wires along the frame to where they hop up over the cross-member you will see a black wire that sticks out of the harness. This wire is the ground for the fuel pump. Make sure that this connection is clean and solid. I ran a wire all the way back to where the batterys' negitive wire connects to the chassy--under the hood--and bypassed this connection, so as not to ever have to worry about this connection again and so it is less likely to corrode. I hope this helps. Please keep me informed. Good luck and happy new year!
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Wednesday, January 2nd, 2008 AT 3:58 PM

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