Engine Won't Fire - The 1947 - Present Chevrolet & GMC Truck Message Board Network

FoxHound · 06-09-2012, 04:15 PM

Hey y'all, hoping some of you carburetor guys can help me out here. I run a 72 k5 with a 350. Right now I have an Edelbrock 1406 that's practically new. The problem is I can't get the motor to fire. It turns over fine so I know it's not the battery. There is fuel making it's way to the carb so I know there's not a lack of fuel. And I have checked my spark plugs and they look perfect.

Last week I changed the fuel pump because the fancy pressure-adjustable one I had started to leak. Right now I'm running a repro Napa auto parts mechanical pump. This problem started after I changed the pump and seems to only happen now and then. I removed the fuel pressure regulator I had and that didn't change anything. Right now, I'm thinking it may be related to the electric choke I have, but I still have a lot to learn about this stuff so any advise would be great. Thanks

FoxHound · 06-09-2012, 04:17 PM

Oh and I forgot to mention that I have timed and calibrated everything. It's not perfectly tuned but it was running great before this problem started.

davepl · 06-09-2012, 04:27 PM

Are you certain you have spark? You can try holding the plug wire, detached from the plug, close to the plug electrode to ensure you can see a spark while someone else is cranking it. Your local NAPA/Oreily/whatever should also sell a cheap little deal that plugs inline with any spark plug with a glass window that you can see the spark jump across.

As long as there is fuel in the bowl, it shouldn't need fuel pressure to fire up for a second or two. If you operate the throttle all the way while looking down the carb (engine off) you should see fuel from the accelerator pump squirting. That will confirm fuel.

If both of those things are OK, your choke should be set up so that when the engine is cold (normally below 70F) the choke plate is fully closed.

Once it fires there are adjustments for how far the choke gets pulled off to -keep- it running cold, but getting it to fire just requires that the choke is closed, so verify that.

Check those three things and get back to us!

FoxHound · 06-09-2012, 11:56 PM

Thanks dave. I checked to see if I had spark and low and behold I did not. I got the old voltmeter out and ran some tests...there's no output from the distributor. Which is a brand new performance parts. So I'll be looking into buying a new one now lol. The choke and the fuel delivery were ok. Thank you again

06-09-2012, 04:15 PM	#1
FoxHound Registered User Join Date: Mar 2009 Location: Idaho Posts: 111	Engine Won't Fire Hey y'all, hoping some of you carburetor guys can help me out here. I run a 72 k5 with a 350. Right now I have an Edelbrock 1406 that's practically new. The problem is I can't get the motor to fire. It turns over fine so I know it's not the battery. There is fuel making it's way to the carb so I know there's not a lack of fuel. And I have checked my spark plugs and they look perfect. Last week I changed the fuel pump because the fancy pressure-adjustable one I had started to leak. Right now I'm running a repro Napa auto parts mechanical pump. This problem started after I changed the pump and seems to only happen now and then. I removed the fuel pressure regulator I had and that didn't change anything. Right now, I'm thinking it may be related to the electric choke I have, but I still have a lot to learn about this stuff so any advise would be great. Thanks __________________ 1972 k/5 Blazer 350V8/TH350/NP205 "The Ox"

06-09-2012, 04:17 PM	#2
FoxHound Registered User Join Date: Mar 2009 Location: Idaho Posts: 111	Re: Engine Won't Fire Oh and I forgot to mention that I have timed and calibrated everything. It's not perfectly tuned but it was running great before this problem started. __________________ 1972 k/5 Blazer 350V8/TH350/NP205 "The Ox"

06-09-2012, 04:27 PM	#3
davepl Registered User Join Date: Aug 2006 Location: Redmond, WA Posts: 6,332	Re: Engine Won't Fire Are you certain you have spark? You can try holding the plug wire, detached from the plug, close to the plug electrode to ensure you can see a spark while someone else is cranking it. Your local NAPA/Oreily/whatever should also sell a cheap little deal that plugs inline with any spark plug with a glass window that you can see the spark jump across. As long as there is fuel in the bowl, it shouldn't need fuel pressure to fire up for a second or two. If you operate the throttle all the way while looking down the carb (engine off) you should see fuel from the accelerator pump squirting. That will confirm fuel. If both of those things are OK, your choke should be set up so that when the engine is cold (normally below 70F) the choke plate is fully closed. Once it fires there are adjustments for how far the choke gets pulled off to -keep- it running cold, but getting it to fire just requires that the choke is closed, so verify that. Check those three things and get back to us! __________________ 1970 GMC Sierra Grande Custom Camper - Built, not Bought 1969 Pontiac 2+2 427/390 4-speed Coupe 1969 Pontiac 2+2 427/390 4-speed Convertible

06-09-2012, 11:56 PM	#4
FoxHound Registered User Join Date: Mar 2009 Location: Idaho Posts: 111	Re: Engine Won't Fire Thanks dave. I checked to see if I had spark and low and behold I did not. I got the old voltmeter out and ran some tests...there's no output from the distributor. Which is a brand new performance parts. So I'll be looking into buying a new one now lol. The choke and the fuel delivery were ok. Thank you again __________________ 1972 k/5 Blazer 350V8/TH350/NP205 "The Ox"



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