Hard to Start When Hot, and "Coughs" When Cold - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Mike Quillici · 10-27-2009, 02:17 AM

Maybe someone out there can provide some insight. When I start my truck and she is stone cold, I get a very slight quasi-backfire. I typically let off the key at this point. Then I turn the key again and she starts right up. That's Symptom 1. Symptom 2 is that when she is hot, I have a difficult time getting her to start. She either cranks for 5+ seconds until she catches, or I give her a little gas and she starts right up.

I don't know if these two are related, but maybe you all do. Thanks.

67ChevyRedneck · 10-27-2009, 02:21 AM

My first thoughts are that your timing is off, or your carb is bad or needs to be tuned... or a combo of both?

Do you have HEI or points? If you have HEI, be sure that is has a wire with a full 12 volts going to it. Most people use the IGN UNFUSED terminal on the fuse block under the dash.

Mike Quillici · 10-27-2009, 02:37 AM

Ah. . .I just upgraded to HEI, but didn't replace the wire. Does the wire that plugs into the distributor run to the fuse block, or to the ignition switch? I bet that's it!

67ChevyRedneck · 10-27-2009, 02:48 AM

I, and most people, run it to the fuse block. The wire that used to run the points only has 8 volts to it.

mclairmo · 10-27-2009, 03:29 AM

Put your mulitmeter/voltmeter on that wire and see what it reads. Should be 12 volts with ignition switch turned to ON.

Mike Quillici · 10-27-2009, 09:53 AM

I will check tonight. I just upgraded 2 weeks ago, and I know the timing and carb are good. I will report back soon!

Mike Quillici · 10-28-2009, 12:07 AM

So, I don't have a multimeter, but I know that I need to replace the wire anyway. My question is, do I just replace the wire from the fuse block to the distributor? Also, how do I up the voltage for the new wire?

Mike Quillici · 10-29-2009, 01:24 AM

Ran a new wire this evening, and she started right up. Haven't driven her yet, but the quick, smooth start was a good sign. I used a 14 gauge wire. Hopefully that's good enough. Thanks for the help everyone!

67ChevyRedneck · 10-29-2009, 02:27 AM

Sweet!

67ChevyRedneck · 10-31-2009, 02:28 AM

It is still running right?

Mike Quillici · 10-31-2009, 01:30 PM

So far so good! I think I need to double check the timing now that I've replaced that wire. Because once in a while I get a hesitation when I hit the gas (usually when warming up), but other than that, she runs like a champ.

67ChevyRedneck · 10-31-2009, 02:10 PM

10-27-2009, 02:17 AM	#1
Mike Quillici Registered User Join Date: Oct 2009 Location: Sacramento, CA Posts: 161	Hard to Start When Hot, and "Coughs" When Cold Maybe someone out there can provide some insight. When I start my truck and she is stone cold, I get a very slight quasi-backfire. I typically let off the key at this point. Then I turn the key again and she starts right up. That's Symptom 1. Symptom 2 is that when she is hot, I have a difficult time getting her to start. She either cranks for 5+ seconds until she catches, or I give her a little gas and she starts right up. I don't know if these two are related, but maybe you all do. Thanks. __________________ 1972 Chevy C-10 ~ 188,000 miles give or take

10-27-2009, 02:21 AM	#2
67ChevyRedneck Hittin E-Z Street on Mud Tires Join Date: Nov 2004 Location: Greenville, SC Posts: 23,090	Re: Hard to Start When Hot, and "Coughs" When Cold My first thoughts are that your timing is off, or your carb is bad or needs to be tuned... or a combo of both? Do you have HEI or points? If you have HEI, be sure that is has a wire with a full 12 volts going to it. Most people use the IGN UNFUSED terminal on the fuse block under the dash. __________________ Jesse James 1967 C10 SWB Stepside: 350/700R4/3.73 1965 Ford Mustang: 289/T5-5spd/3.25 Trac-Loc 1968 Pontiac Firebird: Project Fire Chicken! 2015 Silverado Double Cab 5.3L Z71 2001 Jeep Wrangler Sport 4.0L 5spd 2020 Chevrolet Equinox Premium 2.0L Turbo 2011 Mustang V6 ~ Wife's ride American Born, Country by the Grace of God 1967 CST Shop Truck Rebuild! My 1967 C-10 Build Thread My Vintage Air A/C Install Project "On a Dime" Trying my hand at Home Renovation! 1965 Mustang Modifications! Last edited by 67ChevyRedneck; 10-27-2009 at 02:23 AM.

10-27-2009, 02:37 AM	#3
Mike Quillici Registered User Join Date: Oct 2009 Location: Sacramento, CA Posts: 161	Re: Hard to Start When Hot, and "Coughs" When Cold Ah. . .I just upgraded to HEI, but didn't replace the wire. Does the wire that plugs into the distributor run to the fuse block, or to the ignition switch? I bet that's it! __________________ 1972 Chevy C-10 ~ 188,000 miles give or take

10-27-2009, 02:48 AM	#4
67ChevyRedneck Hittin E-Z Street on Mud Tires Join Date: Nov 2004 Location: Greenville, SC Posts: 23,090	Re: Hard to Start When Hot, and "Coughs" When Cold I, and most people, run it to the fuse block. The wire that used to run the points only has 8 volts to it. __________________ Jesse James 1967 C10 SWB Stepside: 350/700R4/3.73 1965 Ford Mustang: 289/T5-5spd/3.25 Trac-Loc 1968 Pontiac Firebird: Project Fire Chicken! 2015 Silverado Double Cab 5.3L Z71 2001 Jeep Wrangler Sport 4.0L 5spd 2020 Chevrolet Equinox Premium 2.0L Turbo 2011 Mustang V6 ~ Wife's ride American Born, Country by the Grace of God 1967 CST Shop Truck Rebuild! My 1967 C-10 Build Thread My Vintage Air A/C Install Project "On a Dime" Trying my hand at Home Renovation! 1965 Mustang Modifications!

10-27-2009, 03:29 AM	#5
mclairmo Registered User Join Date: Jan 2006 Location: Take Off Posts: 1,908	Re: Hard to Start When Hot, and "Coughs" When Cold Put your mulitmeter/voltmeter on that wire and see what it reads. Should be 12 volts with ignition switch turned to ON.

10-27-2009, 09:53 AM	#6
Mike Quillici Registered User Join Date: Oct 2009 Location: Sacramento, CA Posts: 161	Re: Hard to Start When Hot, and "Coughs" When Cold I will check tonight. I just upgraded 2 weeks ago, and I know the timing and carb are good. I will report back soon! __________________ 1972 Chevy C-10 ~ 188,000 miles give or take

10-28-2009, 12:07 AM	#7
Mike Quillici Registered User Join Date: Oct 2009 Location: Sacramento, CA Posts: 161	Re: Hard to Start When Hot, and "Coughs" When Cold So, I don't have a multimeter, but I know that I need to replace the wire anyway. My question is, do I just replace the wire from the fuse block to the distributor? Also, how do I up the voltage for the new wire? __________________ 1972 Chevy C-10 ~ 188,000 miles give or take

10-29-2009, 01:24 AM	#8
Mike Quillici Registered User Join Date: Oct 2009 Location: Sacramento, CA Posts: 161	Re: Hard to Start When Hot, and "Coughs" When Cold Ran a new wire this evening, and she started right up. Haven't driven her yet, but the quick, smooth start was a good sign. I used a 14 gauge wire. Hopefully that's good enough. Thanks for the help everyone! __________________ 1972 Chevy C-10 ~ 188,000 miles give or take

10-29-2009, 02:27 AM	#9
67ChevyRedneck Hittin E-Z Street on Mud Tires Join Date: Nov 2004 Location: Greenville, SC Posts: 23,090	Re: Hard to Start When Hot, and "Coughs" When Cold Sweet! __________________ Jesse James 1967 C10 SWB Stepside: 350/700R4/3.73 1965 Ford Mustang: 289/T5-5spd/3.25 Trac-Loc 1968 Pontiac Firebird: Project Fire Chicken! 2015 Silverado Double Cab 5.3L Z71 2001 Jeep Wrangler Sport 4.0L 5spd 2020 Chevrolet Equinox Premium 2.0L Turbo 2011 Mustang V6 ~ Wife's ride American Born, Country by the Grace of God 1967 CST Shop Truck Rebuild! My 1967 C-10 Build Thread My Vintage Air A/C Install Project "On a Dime" Trying my hand at Home Renovation! 1965 Mustang Modifications!

10-31-2009, 02:28 AM	#10
67ChevyRedneck Hittin E-Z Street on Mud Tires Join Date: Nov 2004 Location: Greenville, SC Posts: 23,090	Re: Hard to Start When Hot, and "Coughs" When Cold It is still running right? __________________ Jesse James 1967 C10 SWB Stepside: 350/700R4/3.73 1965 Ford Mustang: 289/T5-5spd/3.25 Trac-Loc 1968 Pontiac Firebird: Project Fire Chicken! 2015 Silverado Double Cab 5.3L Z71 2001 Jeep Wrangler Sport 4.0L 5spd 2020 Chevrolet Equinox Premium 2.0L Turbo 2011 Mustang V6 ~ Wife's ride American Born, Country by the Grace of God 1967 CST Shop Truck Rebuild! My 1967 C-10 Build Thread My Vintage Air A/C Install Project "On a Dime" Trying my hand at Home Renovation! 1965 Mustang Modifications!

10-31-2009, 01:30 PM	#11
Mike Quillici Registered User Join Date: Oct 2009 Location: Sacramento, CA Posts: 161	Re: Hard to Start When Hot, and "Coughs" When Cold So far so good! I think I need to double check the timing now that I've replaced that wire. Because once in a while I get a hesitation when I hit the gas (usually when warming up), but other than that, she runs like a champ. __________________ 1972 Chevy C-10 ~ 188,000 miles give or take

10-31-2009, 02:10 PM	#12
67ChevyRedneck Hittin E-Z Street on Mud Tires Join Date: Nov 2004 Location: Greenville, SC Posts: 23,090	Re: Hard to Start When Hot, and "Coughs" When Cold __________________ Jesse James 1967 C10 SWB Stepside: 350/700R4/3.73 1965 Ford Mustang: 289/T5-5spd/3.25 Trac-Loc 1968 Pontiac Firebird: Project Fire Chicken! 2015 Silverado Double Cab 5.3L Z71 2001 Jeep Wrangler Sport 4.0L 5spd 2020 Chevrolet Equinox Premium 2.0L Turbo 2011 Mustang V6 ~ Wife's ride American Born, Country by the Grace of God 1967 CST Shop Truck Rebuild! My 1967 C-10 Build Thread My Vintage Air A/C Install Project "On a Dime" Trying my hand at Home Renovation! 1965 Mustang Modifications!



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