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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Stewart G Griffin on September 26, 2015, 07:23:40 pm

Title: Won't idle below 900rpm (almost there)
Post by: Stewart G Griffin on September 26, 2015, 07:23:40 pm
WE are almost there.

i can't get it to idle below around 900-800-700 rpm without giving it gas.   It will idle at 1300-1200-1100 all day.   

I've advanced the timing a little with no effect so i don't think that is the problem.

Choke works fine and i just got that working today.

i know this is taking a long time, but other stuff came up.
Title: Re: Won't idle below 900rpm (almost there)
Post by: Irish_Alley on September 26, 2015, 10:48:57 pm
vacuum leak?
Title: Re: Won't idle below 900rpm (almost there)
Post by: FlatBlack77 on September 27, 2015, 09:35:01 am
vacuum leak?

my thoughts exactly

how far did you advance the timing?
Title: Re: Won't idle below 900rpm (almost there)
Post by: Stewart G Griffin on September 27, 2015, 05:51:32 pm
vacuum leak?

my thoughts exactly

how far did you advance the timing?

Not sure----am doing it visually.

Now, i can't get it to go below 1000---even with the fast idle set pretty low---apparently the fast idle DOES have an effect on curb if you set it high enough you won't be able to get curb down low.

i think the problem before was i wasn't letting it warm up enough.

i think i can live with the 1000 for now---in gear it will probably be 900-800.  And then order a good reman.
Title: Re: Won't idle below 900rpm (almost there)
Post by: blazer74 on September 27, 2015, 06:21:20 pm
Make sure the secondaries are closed all the way, the bottom butterflies
Back out the curb idle all the way and make sure the choke is completed of the linkage.     What carb?


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Title: Re: Won't idle below 900rpm (almost there)
Post by: Stewart G Griffin on September 27, 2015, 06:49:59 pm
Make sure the secondaries are closed all the way, the bottom butterflies
Back out the curb idle all the way and make sure the choke is completed of the linkage.     What carb?


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It's a quadrajet.

Problem basically solved good enough for now.   It will idle at like 900-ish.   Idle isn't really solid but i think i need a new carb anyways.  Kinda knew this going in.
Title: Re: Won't idle below 900rpm (almost there)
Post by: Stewart G Griffin on September 27, 2015, 07:01:40 pm
P.S.
i know someone mentioned that the torque converters for the v-6 and 8 might be different;  when i first put it into gear from about 1000 rpm the trans took it down to about 500rpm!
Title: Re: Won't idle below 900rpm (almost there)
Post by: VileZambonie on September 27, 2015, 07:05:54 pm
Post more details when you start a new thread Stuart otherwise everyone is just going to start throwing out things to you. What are we working with and what have you done/where are you at?
Title: Re: Won't idle below 900rpm (almost there)
Post by: Stewart G Griffin on September 30, 2015, 09:46:08 pm
Post more details when you start a new thread Stuart otherwise everyone is just going to start throwing out things to you. What are we working with and what have you done/where are you at?

It's the stock 4.3 that i just put into the truck.   Everything stock.  Non-computer quadrajet and HEI ignition.

UPdate:
Plugged the pcv line going to the carb---because i heard this is a common problem,  backed off the timing a little and turned the idle-mixture screws in one turn(they were originally 4 turns out because i thought i might be lean)

After it warms up---around 180 to 190 degrees i can now get it to idle in gear no problems---all the way down to 600rpm.

Title: Re: Won't idle below 900rpm (almost there)
Post by: Irish_Alley on October 01, 2015, 12:59:39 am
you still have a major vacuum leak.