No power all of a sudden - The 1947 - Present Chevrolet & GMC Truck Message Board Network

tino0217 · 10-23-2020, 03:56 AM

My 71 C10 350 sb, after finding a short from an after market tach installed for timing purposes led to changing my hei distributor, coil and module also found my radiator was shot so I replaced it. I went through the timing like I did before, 3 yrs ago, 12° advanced and it ran like a champ. While I was trying to figure out why I wasn't getting any power I found there was a intake leak so I replaced the gasket. Now with everything done hoping to fix any gitty-up set backs, I find myself back at square one. The engine sounds a lot more powerful with good compression better than it ever did but I can't get any power when I give it gas. I'm getting some slight backfiring in the exhaust and was able to take that down by adjusting the carb air-gas mixture. The only thing that I need to look at, as of now, is my automatic choke because it doesn't seem to be working the way it did after everything I've done. Could this be part of the problem? Any suggestions would be appreciated.

68bbc/20 · 10-23-2020, 06:44 AM

i'd check tdc for #1 cylinder again, sounds like it was 180degrees off.

geezer#99 · 10-23-2020, 09:29 AM

Quote:

Originally Posted by 68bbc/20

i'd check tdc for #1 cylinder again, sounds like it was 180degrees off.

You do know it can’t run if it’s 180 degrees off!

geezer#99 · 10-23-2020, 09:30 AM

Quote:

Originally Posted by tino0217

My 71 C10 350 sb, after finding a short from an after market tach installed for timing purposes led to changing my hei distributor, coil and module also found my radiator was shot so I replaced it. I went through the timing like I did before, 3 yrs ago, 12° advanced and it ran like a champ. While I was trying to figure out why I wasn't getting any power I found there was a intake leak so I replaced the gasket. Now with everything done hoping to fix any gitty-up set backs, I find myself back at square one. The engine sounds a lot more powerful with good compression better than it ever did but I can't get any power when I give it gas. I'm getting some slight backfiring in the exhaust and was able to take that down by adjusting the carb air-gas mixture. The only thing that I need to look at, as of now, is my automatic choke because it doesn't seem to be working the way it did after everything I've done. Could this be part of the problem? Any suggestions would be appreciated.

Post some pics of your choke and all around your carb.

truckster · 10-23-2020, 10:43 AM

Are you sure you got the plug wires in the same positions? If they're off, it could still run but would be very advanced or retarded, depending on which direction they're off.

68bbc/20 · 10-23-2020, 11:48 AM

If its wired for 180 degrees off, number 1 back on number 6 position it will run and not have any power! Ive pulled the distributor and got every thing back corrected on a couple different truck before.

**HO455** · 10-23-2020, 01:46 PM

Double check that the plug wires are properly installed. I think I it is 5 and 7 that can be swapped and the engine will run ok but it will be low on power. The PO of my Burban had two wires swapped when I bought it.
And as Geezer asked, please post some pictures so we can better help.

Lee H · 10-23-2020, 06:43 PM

Distributor, GM, aftermarket? Did you check to see if the weights were free? What is your timing with vacuum at idle and about 1,500 rpms? Are you using ported or manifold vacuum?

**Corts60** · 10-25-2020, 08:50 AM

popping through the exhaust = too advanced timing / rich
popping through the intake = too retarded timing / lean

As everyone mentioned, triple check your distributor was dropped in correctly.

10-23-2020, 06:44 AM	#2
68bbc/20 Registered User Join Date: Dec 2018 Location: greencastle indiana Posts: 105	Re: No power all of a sudden i'd check tdc for #1 cylinder again, sounds like it was 180degrees off.

10-23-2020, 10:43 AM	#5
truckster Registered User Join Date: Jan 2001 Location: Orem, Utah Posts: 7,985	Re: No power all of a sudden Are you sure you got the plug wires in the same positions? If they're off, it could still run but would be very advanced or retarded, depending on which direction they're off. __________________ I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson

10-23-2020, 11:48 AM	#6
68bbc/20 Registered User Join Date: Dec 2018 Location: greencastle indiana Posts: 105	Re: No power all of a sudden If its wired for 180 degrees off, number 1 back on number 6 position it will run and not have any power! Ive pulled the distributor and got every thing back corrected on a couple different truck before.

10-23-2020, 01:46 PM	#7
HO455 Post Whore Join Date: Feb 2016 Location: Portland Oregon Posts: 11,415	Re: No power all of a sudden Double check that the plug wires are properly installed. I think I it is 5 and 7 that can be swapped and the engine will run ok but it will be low on power. The PO of my Burban had two wires swapped when I bought it. And as Geezer asked, please post some pictures so we can better help. __________________ Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377

10-23-2020, 06:43 PM	#8
Lee H Registered User Join Date: Jun 2010 Location: Upland Ca Posts: 4,148	Re: No power all of a sudden Distributor, GM, aftermarket? Did you check to see if the weights were free? What is your timing with vacuum at idle and about 1,500 rpms? Are you using ported or manifold vacuum? __________________ 1972 C10 SWB, Air, PS, PB, 350/350THM. Second owner. 1965 Corvette roadster, 44K miles, 327/365 SHP, 4 speed, side exhaust, knockoffs, teak, second owner (bought in 1970), Have ALL numbers matching components. My frame off restoration thread: http://67-72chevytrucks.com/vboard/s...d.php?t=556703

10-23-2020, 03:56 AM	#1
tino0217 Registered User Join Date: May 2017 Location: Seatac, wa Posts: 172	No power all of a sudden My 71 C10 350 sb, after finding a short from an after market tach installed for timing purposes led to changing my hei distributor, coil and module also found my radiator was shot so I replaced it. I went through the timing like I did before, 3 yrs ago, 12° advanced and it ran like a champ. While I was trying to figure out why I wasn't getting any power I found there was a intake leak so I replaced the gasket. Now with everything done hoping to fix any gitty-up set backs, I find myself back at square one. The engine sounds a lot more powerful with good compression better than it ever did but I can't get any power when I give it gas. I'm getting some slight backfiring in the exhaust and was able to take that down by adjusting the carb air-gas mixture. The only thing that I need to look at, as of now, is my automatic choke because it doesn't seem to be working the way it did after everything I've done. Could this be part of the problem? Any suggestions would be appreciated.

10-25-2020, 08:50 AM	#9
Corts60 Just here to tinker Join Date: Jun 2008 Location: Holland, MI Posts: 3,697	Re: No power all of a sudden popping through the exhaust = too advanced timing / rich popping through the intake = too retarded timing / lean As everyone mentioned, triple check your distributor was dropped in correctly. __________________ 78 C10 SWB Diesel #1 (wrecked)http://67-72chevytrucks.com/vboard/s...1978+silverado 78 C10 SWB Diesel #2 (sold)http://67-72chevytrucks.com/vboard/s...d.php?t=650751 60 GMC Suburban (sold)http://67-72chevytrucks.com/vboard/s...d.php?t=445526 60 GMC 1000 (sold)http://67-72chevytrucks.com/vboard/showthread.php?t=298235 67 GMC 1500 (sold) http://67-72chevytrucks.com/vboard/s...d.php?t=803695 73 Chevy C20(Daily)http://67-72chevytrucks.com/vboard/s...d.php?t=852767 86 Suburban(summer unit) http://67-72chevytrucks.com/vboard/s...d.php?t=810697 88 Suburban 4x4(sold)



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