Something is wrong.....
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Senior User
Joined: Mar 2004
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From: Tankville
Something is wrong.....
My 390 4v will idle fine but will not run properly when I get on the gas unless I floor it, even then it still doesn't run all that great and lacks power at WOT. Its sorta like when the vacuum advance leaks, apply throttle and the engine doesn't respond.
IVe got the brake booster plugged and the vacuum advance hose to the carb plugged and it still acts real weird.... IS my carb messed ? or an intake gasket??
I need some ideas because I don't have an extra carb to check if thats the problem first before I whip the intake off. All else is sealed tight.
IVe got the brake booster plugged and the vacuum advance hose to the carb plugged and it still acts real weird.... IS my carb messed ? or an intake gasket??
I need some ideas because I don't have an extra carb to check if thats the problem first before I whip the intake off. All else is sealed tight.
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Joined: Nov 2003
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From: Planet Earth
Originally Posted by Fritolay
use a can of wd40 spray around the base of the carb listen to see if the idle changes also spray around any vacume caps on the carb see where it may be sucking air.
samckernan
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Joined: Apr 2002
Posts: 3,613
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From: Coal country
Even better: Use a handlheld propane torch. Don't light it, and play the fumes around spots where intake leaks can occur.
The gas will dissapate quickly, preventing a fire hazard, but will easily tell you if there is a leak.
The RPMs will go up (possibly down if you are running too rich) when the propane gets sucked into an intake leak.
The gas will dissapate quickly, preventing a fire hazard, but will easily tell you if there is a leak.
The RPMs will go up (possibly down if you are running too rich) when the propane gets sucked into an intake leak.
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Senior User
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From: Tankville
I got a can of WD 40 sitting right next to my truck, think I'm gonna try that out.... Funny thing is it still idles fine, you'd think it wouldn't idle properly with a busted intake gasket or a vacuum leak of other sorts??
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Joined: Jan 2004
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From: in the springs
only reason i said wd 40 is almost everybody has a can of it laying around not everyone has the propane torch, and i dont like using ether cuz its just to flammable and i dont like what it does to engines.
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Joined: Jul 2004
Posts: 938
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From: North Carolina
You need to go through all the proper checks. How old is your carb? Has it been rebuilt recently? Make sure timing is set to specs. Check for vacum leaks, you can buy a vacum gauge from the store that will tell you a TON about your engine. You can diaaonsde all lot of things with a vacum gauge. Also, can you feel the secnadarys open when you floor it? They may not be opening, thereby giving you crappy high-end power. Keep us posted.
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From: Tankville
The truck is still not working, it idles fine, when I lay into the gas pedal nothing happens..... It aluva sudden acts like it got a vacuum leak. Exactly like what happens when the distributer vacuum diaphragm is busted, only problem is it still acts that way with the vacuum hose is plugged.
THis is a rebuilt carb.... CAn the insides of the carb be leaking or something?
THis is a rebuilt carb.... CAn the insides of the carb be leaking or something?
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Joined: Sep 2004
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From: Sacramento, CA
Originally Posted by the tank
The truck is still not working, it idles fine, when I lay into the gas pedal nothing happens..... It aluva sudden acts like it got a vacuum leak. Exactly like what happens when the distributer vacuum diaphragm is busted, only problem is it still acts that way with the vacuum hose is plugged.
THis is a rebuilt carb.... CAn the insides of the carb be leaking or something?
THis is a rebuilt carb.... CAn the insides of the carb be leaking or something?
Junior User
Joined: Jun 2003
Posts: 96
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From: North Carolina
Also check your float in the carb. Mine did the same thing once and it was the the float valve staying shut letting no or very little gas in. Just enough to idle, but touch the gas and it died.