Idle ???

[chief77]

Hello all, first off I would like to say I have monitored your forum for quite sometime now as a guest, and have gotten allot of good info, from just reading the posts, and I decided it was time to join this "brother hood" and in some cases "sister hood" of Blazer “gurus” as a member.



I will begin my initial post with a question that may have already been posted, so please bear with me; here is my problem I recently bought a 1977 K5 Cheyenne near Ft. Benning, Ga for a good deal, and soon after the head gasket “blew” I looked like a steam engine going down the road, but anyway I decided it would be wiser to get a “crate 350”, from GM Depot, and I had it installed at a local garage, by a guy who said he could do it with no problem. So here are the systems I am having:



During first start up’s after sitting overnight it will “tach” around 1500-1700, and will idle down to around a “grand” after a hard push of the gas pedal, this I believe is by design for the Edelbrock Carb. (electric choke #1406), but as soon as I get to the end of the drive way it will some times “tach” back up to 1500-1700, or it will idle in drive around 500 rpm’s thus trying to stall out, I have wondered if it is a problem with the timing, or if its “carb” related, so has anyone besides me had problems like this???



Thanx: chief77

 

[Poohbair]

sounds like your choke might be f-ed up

 

[milspec]

You can always do the basics on the older engines. Replace all fuel filters including the one in the carburator. If you didn't use a new fuel pump, make sure its working properly. The local parts store can supply the timing. You can watch the choke open as the engine warms and see if it is working. When you first start the car by deprecessing the acellerator you set the fast idle. As the engine warms and smooths out you hit the gas slightly again which releases the fast idle cam on the carb. Follow the linkage to the carb and you will see the setup. Make sure you don't have any vacuum leaks. Leaks below throttle plain will cause high idle. Any hose below the level of the throttle linkage is primary.

 

[chief77]

Thanks "milspec", I have had the vacuum lines checked and all seem in working order, and the fuel pump was replaced with the new engine; “the reason I know; I had to regulate the fuel pressure down to 5.5 psi for the "carb" from 10-15 psi for it to work, the way it is supposed to. I for the “life of me”, don’t understand how even when the engine is at operating temp. can still be running at high idle??????



“anywho”, thanks for the suggestions……………………………………



Chief77

 

[BIG*RED]

mine does the same, sounds like in the morning you don't let it warm up enough. my does everything you said yours does, when i rush the warm up..and mine also at times jumps back up on the idle after it has been warmed up..i have driven it for like an hour, turned it off ran into a gas station bought a soda came back out and it starts up on the higher idle..but only for a min or two..beleave it or not even though it gets really hot under the hood, the choke can cool down relativly quick..in the summer when the air temp is also warm or hot like a 95 degree day, my truck doesn't do this anymore..only durning the winter when the air is cool and moist....just a thought

 

[chief77]

Hey "sheoldeblaze", I know sometimes I don’t allow it to warm up before hitting the road, but not often, and it still displays the sporadic idle when it has ran for 5-10 minutes before heading off to work.



I don’t know this may just be a symptom for the “ole gal”, during the winter months…… maybe when the weather warms up a little she will do better.



Thanx for all that responded.



Chief77

 

[southernspeed]

I used to have that set up and had those problems. If you adjust the choke to stay on longer (turn the black plastic 'drum') and then bend the rod that controls the fast idle so that it doesn't rev so hard you can drive on choke for longer without it screaming its nuts off. As the choke is set to be on for longer it won't try to kick off by the end of your drive.

 

[chief77]

If you adjust the choke to stay on longer (turn the black plastic 'drum')

The plastic drum? are you talking about the coil, where the power and ground wires run into the "carb"?

thanx: chief77

 

[southernspeed]

Yeah , mine had a black cover on it. You can adjust the time by slackening off the lock tab and turning it a bit. There's a + and- sign on there with an arrow...at least there was on my carter which is the same thing!

 

[chief77]

Hey “southernspeed”,



"Ok", I went out and checked it out, and mine has a black drum, so do I adjust to the + or - side? Or both ways till works.........



Thanx: chief77

 

[southernspeed]

+ will make it stay on longer but you'll have to tweek the high idle bar to lower the revs a bit.