Author Topic: Cold start - proper techniques?  (Read 10856 times)

Offline Ben_Greenberg

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Cold start - proper techniques?
« on: December 21, 2014, 12:25:18 pm »
Hey guys and gals!
My newish to me 78 c15 heavy half has a TON of trouble with cold starts.

When it's warm out it takes several seconds of the starter cranking and me repeatedly pressing the accelerator to get fired up and occasionally it will die, but if I start back up then it will start and idle ok.

Now that it's consistently 32 or below in northern Indiana I have to use starting fluid about 2 or three times to get the thing to fire up and stay that way.... Aka no longer practical.

What is the correct process to start my truck in cold weather?

I feel like when it was fresh off the line in 78 it would not have had this many problems. Any ideas on how I might help my old guy get back to its former glory?

Thanks everybody! Any and all thoughts are appreciated! I may post a link to a video of the cold start if I get a chance and if it would be helpful.

Offline zieg85

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Re: Cold start - proper techniques?
« Reply #1 on: December 21, 2014, 12:35:08 pm »
Typically when the carb is in good shape and the choke is set up correctly you only depress the accelerator to the floor once to set the choke and high idle.  Turn the key and it should come to life.  My 1984 C10 starts great and have no issues through warm up
Carl 
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1986 C10 under construction
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Offline rich weyand

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Re: Cold start - proper techniques?
« Reply #2 on: December 21, 2014, 12:51:31 pm »
In warm weather, I push the accelerator once to the floor, then turn the key and it's on.  In winter, I push the pedal to the floor several times to prime the manifold, turn the key and it's on.

Things to check: Is the choke working?  Is the choke adjusted properly?
Rich

"Working Girl": 1978 K-10 RCSB 350/TH350/NP203 +2/+3 Tuff Country lift

Offline Ben_Greenberg

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Re: Cold start - proper techniques?
« Reply #3 on: December 21, 2014, 01:37:43 pm »
Rich,
When I depress the accelerator once the choke does close, or at least close to being fully closed. Should it close completely?

Offline rich weyand

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Re: Cold start - proper techniques?
« Reply #4 on: December 21, 2014, 01:50:22 pm »
No, the engine needs air even when choked.

What's your timing set at?  All the air pollution crap still on it?  Have you set the idle mixture?
Rich

"Working Girl": 1978 K-10 RCSB 350/TH350/NP203 +2/+3 Tuff Country lift

Offline Ben_Greenberg

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Re: Cold start - proper techniques?
« Reply #5 on: December 21, 2014, 03:04:10 pm »
Rich,
There are a lot of questions there that I'm afraid I don't have the answers to.

When I first got the truck I took it to my mechanic that has a dedicated classic car mechanic and he noticed that I don't have a timing marker or a balancer with marks, so timing... Not so sure.

Idle mixture, also not sure. I had it tuned and timed by ear by my mechanic, but that's about it.

As far as any EGR or any other exhaust related item my truck doesn't have that.

Offline FlatBlack77

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Re: Cold start - proper techniques?
« Reply #6 on: December 21, 2014, 04:35:34 pm »
your mechanic should have tuned the idle mixture and timed it by using a vacuum gauge. not by ear

that could be a huge part of the problem
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Offline VileZambonie

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Re: Cold start - proper techniques?
« Reply #7 on: December 21, 2014, 05:25:33 pm »
For extreme cold, fully depress the pedal and depress the pedal again about 1/2 way, now crank the engine. Once it starts, foot off the pedal. This is assuming it's properly tuned, stock configuration. If it's not starting this way, you need to do a complete engine performance tune-up. Start with the ignition system, set timing and adjust idle mixture & idle speed. Allow it to cool and check/set the choke coil and fast idle speed.
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Offline 78BIG-TEN

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Re: Cold start - proper techniques?
« Reply #8 on: December 21, 2014, 05:36:04 pm »
The choke should close all the way when could,in fact it should have some tension to it in the closed position.
The colder it is the tighter it will be.Hit pedal 1 time to set it and turn the key.It should start and run at high idle.
If it starts and dies then there is not enough tension on the choke or the choke pull off is not set right pulling it open to far

Offline Ben_Greenberg

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Re: Cold start - proper techniques?
« Reply #9 on: January 17, 2015, 06:09:30 pm »
Hey guys! So I finally got a chance to mess with my 78 with apparent choke issues. So I have a few questions

Offline Ben_Greenberg

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Re: Cold start - proper techniques?
« Reply #10 on: January 17, 2015, 06:11:00 pm »
When I depress the gas, it engages the choke and it closes almost all the way. Now when I push it closed, the truck starts right up! Which is great! Now how do I make sure that I get the proper amount of tension to close the choke completely? Any helpful tips are appreciated! Thanks everyone!

Offline Stewart G Griffin

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Re: Cold start - proper techniques?
« Reply #11 on: January 18, 2015, 08:22:18 am »
Do you still have the owner's manual and can you post a pic?

In the meantime, i think this is a very good article:
http://www.chevelles.com/techref/Adjusting_Automatic_Chokes.htm

Offline Stewart G Griffin

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Re: Cold start - proper techniques?
« Reply #12 on: January 18, 2015, 08:27:47 am »
P.S.
Before i stupidly overheated my 305----and you can say what you want about 60 year old technology, my rochester 2G started up as fast as any fuel injected car.  And in some cases FASTER than some fuel injected cars---like my TBI cavalier.

Offline 78BIG-TEN

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Re: Cold start - proper techniques?
« Reply #13 on: January 18, 2015, 02:27:26 pm »
How tight the choke sets is all relevant to ambient temps.the coider it is the tighter it will shut thus taking a little longer to fully open
It should be like my 78 and have a choke stove mounted on the pass side of manifold under the carb with a rod running up to the choke plate
shaft.You can take it off and wind it some to get ckoke to close fully when cold,just be gentile with it.It may take a couple tries.Of couse
 assuming its original stuff
« Last Edit: January 18, 2015, 02:34:11 pm by 78BIG-TEN »

Offline Ben_Greenberg

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Re: Cold start - proper techniques?
« Reply #14 on: January 18, 2015, 08:07:55 pm »

How tight the choke sets is all relevant to ambient temps.the coider it is the tighter it will shut thus taking a little longer to fully open
It should be like my 78 and have a choke stove mounted on the pass side of manifold under the carb with a rod running up to the choke plate
shaft.You can take it off and wind it some to get ckoke to close fully when cold,just be gentile with it.It may take a couple tries.Of couse
 assuming its original stuff

Thank you! I will definitely check this!