Massive temporary power loss? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Project1970 · 04-07-2002, 01:56 PM

Here's what happens sometimes - right now, it only happens on hot days after pulling out of parking lots and not even all the time then, but it might get worse as the summer starts; it happened last year too but forgot about it. =P

Anyway, when the engine gets a bit hot (above that second tick mark and on its way up to 1/2 hot, I've gotta pull and rod the radiator) sometimes if I get on it a little, it starts to pick up...well, like the last time it happened. Got on it, pulled okay from 2000 to 3000, then WHAM...not even just falling on its face but it's like someone just kicked it square in the family jewels! It just goes WAY flat and even though I've got the throttle wide open at this point, drops all the way back down to 2000RPM, then sputters up/down for a few more seconds before it regains its composure and comes back to life...

Fuel delivery problem? It's an Edelbrock #1901 Q-jet on my 350...

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Project 1970 - soon to be seen at http://milhouse.treylis.org:81/

CoryM · 04-07-2002, 02:31 PM

Vapour lock maybe? Not sure, doesnt get nearly hot enough here to worry about that.
How close to the exhaust is the fuel line routed? Or maybe your choke is NFG and when its already 100F out it still turns on? Any black smoke?

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1970 heavy duty C-10 fleetside sport truck. Vancouver B.C. Canada
http://www.geocities.com/chevroletc1070

"Take up our quarrel with the foe:
To you from failing hands we throw
The torch; be yours to hold it high."
Lieutenant Colonel John McCrae, Canadian Army

O'l Buck · 04-07-2002, 03:28 PM

sounds like vapor lock to me, the engine temp will rise after the trucks been sitting shut off, then cool down, sometimes the heat differential is enough to heat up the fuel in the pump and vapor lock, try dumping water on the fuel pump next time it does this and see if it helps.

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'72 Chevy 1/2T 4x4 shortbox stepside 350/350auto on '84
ralleys and 31/10.5s

67 Cutlass convertible
330, 3spd stick

90 GMC Jimmy
350/auto
Chad Stephens
Orleans,NE

Project1970 · 04-07-2002, 05:09 PM

I was thinking hot fuel myself, but the thing is, at least before it gets REALLY hot, it won't do it for more than about 10 seconds (and it really doesn't make itself known until I start to lean into the secondaries...hmm...)

Basically, it does it just long enough to embarass me a bit. =P

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Project 1970 - soon to be seen at http://milhouse.treylis.org:81/

04-07-2002, 02:31 PM	#2
CoryM Registered User Join Date: Dec 1999 Location: Surrey, B.C. , Canada Posts: 874	Vapour lock maybe? Not sure, doesnt get nearly hot enough here to worry about that. How close to the exhaust is the fuel line routed? Or maybe your choke is NFG and when its already 100F out it still turns on? Any black smoke? ------------------ 1970 heavy duty C-10 fleetside sport truck. Vancouver B.C. Canada http://www.geocities.com/chevroletc1070 "Take up our quarrel with the foe: To you from failing hands we throw The torch; be yours to hold it high." Lieutenant Colonel John McCrae, Canadian Army __________________ 1970 heavy duty C-10 fleetside sport truck. Vancouver B.C. Canada http://www.geocities.com/chevroletc1070 "Take up our quarrel with the foe: To you from failing hands we throw The torch; be yours to hold it high." Lieutenant Colonel John McCrae, Canadian Army

04-07-2002, 03:28 PM	#3
O'l Buck Recovering Truck Driver Join Date: Mar 2002 Location: Orleans, NE USA Posts: 1,883	sounds like vapor lock to me, the engine temp will rise after the trucks been sitting shut off, then cool down, sometimes the heat differential is enough to heat up the fuel in the pump and vapor lock, try dumping water on the fuel pump next time it does this and see if it helps. ------------------ '72 Chevy 1/2T 4x4 shortbox stepside 350/350auto on '84 ralleys and 31/10.5s 67 Cutlass convertible 330, 3spd stick 90 GMC Jimmy 350/auto Chad Stephens Orleans,NE __________________ 67 K-20 350, SM465, Eaton rear, 4.56 no spin option 00 Dodge 2500 4x4, 24V cummins, 5 speed Chad South Central Nebraska

04-07-2002, 05:09 PM	#4
Project1970 14.1 @ 96MPH Join Date: Jul 2001 Location: Mesa, AZ Posts: 2,811	I was thinking hot fuel myself, but the thing is, at least before it gets REALLY hot, it won't do it for more than about 10 seconds (and it really doesn't make itself known until I start to lean into the secondaries...hmm...) Basically, it does it just long enough to embarass me a bit. =P ------------------ Project 1970 - soon to be seen at http://milhouse.treylis.org:81/ __________________ Project1970 - LS1 Swap Complete!

04-07-2002, 01:56 PM	#1
Project1970 14.1 @ 96MPH Join Date: Jul 2001 Location: Mesa, AZ Posts: 2,811	Massive temporary power loss? Here's what happens sometimes - right now, it only happens on hot days after pulling out of parking lots and not even all the time then, but it might get worse as the summer starts; it happened last year too but forgot about it. =P Anyway, when the engine gets a bit hot (above that second tick mark and on its way up to 1/2 hot, I've gotta pull and rod the radiator) sometimes if I get on it a little, it starts to pick up...well, like the last time it happened. Got on it, pulled okay from 2000 to 3000, then WHAM...not even just falling on its face but it's like someone just kicked it square in the family jewels! It just goes WAY flat and even though I've got the throttle wide open at this point, drops all the way back down to 2000RPM, then sputters up/down for a few more seconds before it regains its composure and comes back to life... Fuel delivery problem? It's an Edelbrock #1901 Q-jet on my 350... ------------------ Project 1970 - soon to be seen at http://milhouse.treylis.org:81/ __________________ Project1970 - LS1 Swap Complete!



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