Asked by Dec 24, 2015 at 04:56 AM about the 1978 Chevrolet C10

Question type: Maintenance & Repair

My father passed away and i inharited his
1978 c10 truck and i know i need tk fix the
timing it backfires but i dont know how to fix
the timing can anyone help me

10 Answers


Its notl typical a hard job but if you don't know much about cars then it would make sense to take it to a mechanic for repair a 78 chain should be a few hundred to repair, you can purchase the part on line..

2 out of 2 people think this is helpful.
Bob Beaman

Backfiring could be a bad timing chain or it could also be caused by the spark plug wires being on the wrong terminals on the distributor cap or at the spark plugs. The distributor could also be out of time. A compression test would help you determine if the timing chain was actually the problem.

Kelly Mayo


Bob Beaman

Could be a valve and a compression test would show if it were a valve or if the timing chain has slipped or broken. If it were a valve, it would most likely be an exhaust valve causing popping in the exhaust. If timing chain is broken pulling the distributor cap to see if the rotor is turning (while cranking the engine) would be the best way to determine if that was the problem.


Then there is the carburetor...And the fuel pump. A bad fuel pump could cause back-firing. I would check the fuel pressure, it should be 5.5 to 6.5 lbs. Timing chains on Chevy's don't ordinarily go bad. Just checking and setting ignition timing is all thats needed.

3 out of 3 people think this is helpful.
Bob Beaman

and the carb.... When the carb has full fuel bowls during start up it should run okay until it runs low on gas and that will also cause popping and backfiring. Of course it could be dirty or worn out too. If I had that truck here at the house I could probably tell you in 15 or 20 minutes what was likely wrong with it, but sitting behind this screen makes it a tough call.


Well then Bob, get out and venture a bit...

3 out of 3 people think this is helpful.
Bob Beaman

LOL, heck it's probably a long ways from Kansas. Everything is.



2 out of 2 people think this is helpful.

A compression test will show if the engine has jumped timing, or a bad valve. If all cylinders test very low or zero it's jumped timing. If one cylinder tests very low or zero that cylinder has a bad valve. If it's backfiring like a gunshot out the exhaust, but only when you take your foot off the accelerator pedal, it's going to be the diverter valve for the A.I.R. (smog pump) system. HTH. -Jim

Your Answer

Add photo

Related Questions


Looking for a Used C10 in your area?

CarGurus has 135 nationwide C10 listings and the tools to find you a great deal.


Search Chevrolet C10 Questions

Chevrolet C10 Experts

#1 CaptPKelly
Reputation 440
#2 Rowefast
Reputation 160
#3 tennisshoes
Reputation 140
View All

Related Models For Sale

Used Chevrolet Camaro"
798 Great Deals out of 38,849 listings starting at $2,650
Used Ford F-150"
3,272 Great Deals out of 216,641 listings starting at $1,500
Used Chevrolet Corvette"
431 Great Deals out of 20,238 listings starting at $3,688
Used Ford Mustang"
736 Great Deals out of 41,064 listings starting at $900
Used Ford F-100"
167 listings
Used Chevrolet Impala"
928 Great Deals out of 35,693 listings starting at $1,500
Used Chevrolet Blazer"
1,650 listings starting at $1,999