Author Topic: hard starts 20+ mins after shutting off hot  (Read 12435 times)

Offline blazer74

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Re: hard starts 20+ mins after shutting off hot
« Reply #15 on: May 27, 2017, 01:08:06 PM »
My C10 ~always~ and I mean ~always~ needs to be cranked WOT for a hot re-start.  And I've gone through the entire fuel and ignition system thoroughly.  The more volatile fuels of today boil inside the carb, flooding the engine.  Crank wide open throttle (flood-clear), and it will fire after a bit.

Shouldn't be that hard to hot/warm start. Been thru that. Too much fuel pressure from aftermarket pump. Heat expansion overcomes needle is one possibility.
I found mine by plumbing in a fuel pressure gage at the carb inlet and watch it happen over about a 10/15 min period.

Offline Joec123able

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Re: hard starts 20+ mins after shutting off hot
« Reply #16 on: May 27, 2017, 02:45:03 PM »
My C10 ~always~ and I mean ~always~ needs to be cranked WOT for a hot re-start.  And I've gone through the entire fuel and ignition system thoroughly.  The more volatile fuels of today boil inside the carb, flooding the engine.  Crank wide open throttle (flood-clear), and it will fire after a bit.

Shouldn't be that hard to hot/warm start. Been thru that. Too much fuel pressure from aftermarket pump. Heat expansion overcomes needle is one possibility.
I found mine by plumbing in a fuel pressure gage at the carb inlet and watch it happen over about a 10/15 min period.

My truck actually has a "starting procedure" on the sun visor and it says "for hot starts, hold the gas pedal halfway then crank til it fires."

Offline blazer74

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Re: hard starts 20+ mins after shutting off hot
« Reply #17 on: May 27, 2017, 03:10:21 PM »
Yep, factory service manual also.

Offline Dr_Snooz

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Re: hard starts 20+ mins after shutting off hot
« Reply #18 on: May 28, 2017, 12:12:15 AM »
Just swap to EFI. LOL
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Offline SkinnyG

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Re: hard starts 20+ mins after shutting off hot
« Reply #19 on: May 28, 2017, 12:34:54 AM »
+1

My truck is a solid VR signal away from being EFI - everything is already in the truck, just a 1-hour swap and then tune away.

'Cept it's my daily.....

.... Next long weekend!
The Crusty Chevy: 1977 Silverado, shortboxed & dropped, potato-potato.

Offline Monkey Uncle

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Re: hard starts 20+ mins after shutting off hot
« Reply #20 on: May 28, 2017, 05:44:02 AM »
My C10 ~always~ and I mean ~always~ needs to be cranked WOT for a hot re-start.  And I've gone through the entire fuel and ignition system thoroughly.  The more volatile fuels of today boil inside the carb, flooding the engine.  Crank wide open throttle (flood-clear), and it will fire after a bit.

Same here.  New quadrajet on an old stock 350.  If it sits more than 10-15 minutes after shut-off, I always have trouble re-starting.  But if I just hold the ignition on and pump the accelerator, it will start and run normally after 10 seconds or so of cranking.

Offline roundhouse

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Re: hard starts 20+ mins after shutting off hot
« Reply #21 on: May 28, 2017, 07:52:38 AM »
I would insulate the fuel lines under the hood
To help keep them cool

Maybe a wood spacer under the carb if you have room
And the factory type hose to bring in cool air to the air filter


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Offline VileZambonie

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Re: hard starts 20+ mins after shutting off hot
« Reply #22 on: May 28, 2017, 08:46:10 AM »
Get it so the condition occurs and shut the engine off. Let it sit for the 20 minutes, remove the air cleaner and verify the choke is fully open. Looking down through the air horn actuate the throttle and verify fuel is discharged from the accelerator pump nozzles.

How is your distributor advance connected, ported or manifold vacuum? What is the base timing set at?

My vacuum advanced isn't even hooked up. The port for it is plugged on the carb. idk what the timing is set at or how to check.

You need to dial in your timing and your carburetor adjustments or you will continue to have issues.
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Offline 1979SIERRAGRANDE

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Re: hard starts 20+ mins after shutting off hot
« Reply #23 on: May 28, 2017, 03:13:10 PM »
I had the same issues with mine right down to the grey smoke  and carb way I fixed mine was I bought a rebuild kit for the carb EDL-1477 and a nitrile rubber heat divider EDL-9266 recommended by edelbrock  seems to be a common problem with them . my accelerator pump gasket was shot and had a bunch of rust from the previous owner running the truck without a filter and as vile was saying check the timing . I would check the condition of the spark plugs see if it's running rich may have fouled them


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Offline 1979SIERRAGRANDE

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Re: hard starts 20+ mins after shutting off hot
« Reply #24 on: May 28, 2017, 03:13:35 PM »
Is your intake the original cast iron or an aluminum ?


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Offline Irish_Alley

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Re: hard starts 20+ mins after shutting off hot
« Reply #25 on: May 28, 2017, 03:13:48 PM »
My C10 ~always~ and I mean ~always~ needs to be cranked WOT for a hot re-start.  And I've gone through the entire fuel and ignition system thoroughly.  The more volatile fuels of today boil inside the carb, flooding the engine.  Crank wide open throttle (flood-clear), and it will fire after a bit.

Same here.  New quadrajet on an old stock 350.  If it sits more than 10-15 minutes after shut-off, I always have trouble re-starting.  But if I just hold the ignition on and pump the accelerator, it will start and run normally after 10 seconds or so of cranking.

how can you be ok with the 10 seconds of cranking? it would drive me nuts if mine didnt start in 3 seconds when warm. would be so scared the battery would be weak one day and it would kill it
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Offline Joec123able

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Re: hard starts 20+ mins after shutting off hot
« Reply #26 on: May 28, 2017, 10:00:21 PM »
Is your intake the original cast iron or an aluminum ?


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It's orginal intake I have an adapter for the edelbrock to work on it and a wood carb spacer.

Offline Joec123able

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Re: hard starts 20+ mins after shutting off hot
« Reply #27 on: May 28, 2017, 10:02:09 PM »
I would insulate the fuel lines under the hood
To help keep them cool

Maybe a wood spacer under the carb if you have room
And the factory type hose to bring in cool air to the air filter


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I have a wood spacer and I have the fuel line propped up so it's not touching anything hot.

Offline Monkey Uncle

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Re: hard starts 20+ mins after shutting off hot
« Reply #28 on: May 29, 2017, 05:43:25 AM »
My C10 ~always~ and I mean ~always~ needs to be cranked WOT for a hot re-start.  And I've gone through the entire fuel and ignition system thoroughly.  The more volatile fuels of today boil inside the carb, flooding the engine.  Crank wide open throttle (flood-clear), and it will fire after a bit.

Same here.  New quadrajet on an old stock 350.  If it sits more than 10-15 minutes after shut-off, I always have trouble re-starting.  But if I just hold the ignition on and pump the accelerator, it will start and run normally after 10 seconds or so of cranking.

how can you be ok with the 10 seconds of cranking? it would drive me nuts if mine didnt start in 3 seconds when warm. would be so scared the battery would be weak one day and it would kill it

Perhaps I'm exaggerating a bit on the amount of time it takes, but it's definitely not firing right up.  I'm not necessarily o.k. with it, but also not sure I'm up for chasing a phantom problem that's basically a minor annoyance.

Based on what I've seen on several forums, this appears to be a common problem with a wide variety of carb/intake/engine set-ups.  Speculation abounds as to the cause.  Some people seem to have had success with spacers or heat shields.  Many people point the finger at the volatility of modern fuel formulations.  I'd like to find some ethanol-free gas and see if that helps.
« Last Edit: May 29, 2017, 06:33:14 AM by Monkey Uncle »

Offline roundhouse

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hard starts 20+ mins after shutting off hot
« Reply #29 on: May 29, 2017, 07:51:24 AM »
I would insulate the fuel lines under the hood
To help keep them cool

Maybe a wood spacer under the carb if you have room
And the factory type hose to bring in cool air to the air filter


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I have a wood spacer and I have the fuel line propped up so it's not touching anything hot.
I was talking about actual insulation made for a fuel line

Also I've heard of people using a Fuel filter from a AMC vehicle and a return line to the tank

They were mounted between the mechanical fuel pump and the engine and had two outlets . One to the carb and one with a restrictor that went back to the tank

This keeps fuel constantly flowing through the lone to keep it cool

But you really need to narrow down your problem

A pressure gauge at the carb and a clear glass filter at the carb
And you would be able to see exactly what's happening
If when you are having hot start issues , you have 8-12 PSI at the carb , then that's good

If you have 8-12 when its cold but noticibly less when it's hot , that would indicate a vapor lock problem with too much heat getting into the fuel line

Your problem could also be caused by a weak ignition coil, or a weak condenser or if you have electronic ignition , a bad pickup in the distributor

One way of isolating a bad pickup is when it won't start to pop the dizzy cap and spray electronic computer keyboard cleaner inside
That will cool eveything down and make it work again if it's a bad computer part in the dizzy


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« Last Edit: May 29, 2017, 08:06:29 AM by roundhouse »