Trouble starting 72 pickup - The 1947 - Present Chevrolet & GMC Truck Message Board Network

colyank · 05-30-2018, 05:55 PM

Having trouble starting my 72 Chevy Pickup lately and can’t seem to figure out what the problem is. I had the truck running smoothly about 6 months ago after I had rebuilt the carburetor. About last month it has had lots of trouble starting and it took dumping gas into the carb to be able to start it and then had lots of trouble staying running. Now it won’t even start, I took apart the carb again and made sure everything was good, didn’t make a difference. NNext I’m going to try checking all 8 spark plugs to see if that could be the problem. It kinda sounds like while it trying to start and run, there’s some type of timing issue while cranking on it. Anyone have any idea on what could be wrong?

**WorkinLonghorn** · 05-30-2018, 06:03 PM

I had an old motor with a similar problem and it turned out that the timing chain was worn so bad that it skipped a tooth. Wasn't a chevy but same could be true for yours. But since you just did carb work, then I would triple check that system including the fuel filter, fuel pump, etc. -BA

**Steeveedee** · 05-30-2018, 09:18 PM

In my experience as a mechanic, 99% of the trouble with vehicles of this vintage is electrical. HEI went a long way to correcting that. Check and see if you have spark on cranking. I've seen where the wire on the "R" terminal was corroded or loose and the coil didn't get enough energy to fire the plugs.

It looks like you may have a choke issue, though, if it won't start cold and the spark is good.

CC69Rat · 05-31-2018, 08:33 PM

Quote:

It looks like you may have a choke issue, though, if it won't start cold and the spark is good.

My thoughts too. I'm a Holley guy .. So, I'm giving you Holley guy direction here. .. If it's electric choke, make sure the choke pulloff is clocked all the way back as far as it will go. You'll see three small screws on the choke pulloff housing. Loosen them about half way out and turn that choke pulloff housing all the way clockwise until it stops. Then turn it back just barely, maybe 1/8 of an inch, then tighten your screws back down.

Bet you a dollar it fires up. Have a flat screwdriver ready because you will likely be adjusting the idle too.

05-30-2018, 05:55 PM	#1
colyank Registered User Join Date: Dec 2017 Location: Oakfield, Wisconsin Posts: 13	Trouble starting 72 pickup Having trouble starting my 72 Chevy Pickup lately and can’t seem to figure out what the problem is. I had the truck running smoothly about 6 months ago after I had rebuilt the carburetor. About last month it has had lots of trouble starting and it took dumping gas into the carb to be able to start it and then had lots of trouble staying running. Now it won’t even start, I took apart the carb again and made sure everything was good, didn’t make a difference. NNext I’m going to try checking all 8 spark plugs to see if that could be the problem. It kinda sounds like while it trying to start and run, there’s some type of timing issue while cranking on it. Anyone have any idea on what could be wrong?

05-30-2018, 06:03 PM	#2
WorkinLonghorn Senior Member Join Date: Dec 2006 Location: Studio City, Calif. Posts: 2,883	Re: Trouble starting 72 pickup I had an old motor with a similar problem and it turned out that the timing chain was worn so bad that it skipped a tooth. Wasn't a chevy but same could be true for yours. But since you just did carb work, then I would triple check that system including the fuel filter, fuel pump, etc. -BA __________________ '69 GMC C2500 Custom Camper, 8 1/2' bed, New GM 350, NP 435 Close Ratio 4spd. Trans., 3.73 Dana-60 open.Camper and Trailer wiring, PS, PB, AC, tach , three gas tanks, stereo speakers, 2nd owner, Work-Truck supreme.

05-30-2018, 09:18 PM	#3
Steeveedee Who Changed This? Join Date: Jan 2013 Location: Simi Valley, CA Posts: 10,676	Re: Trouble starting 72 pickup In my experience as a mechanic, 99% of the trouble with vehicles of this vintage is electrical. HEI went a long way to correcting that. Check and see if you have spark on cranking. I've seen where the wire on the "R" terminal was corroded or loose and the coil didn't get enough energy to fire the plugs. It looks like you may have a choke issue, though, if it won't start cold and the spark is good. __________________ ~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.