1987 pops and bangs
 

my 87 GMC K2500, 350 engine runs good for a bit and then it starts popping, banging and farting thru the carb. I have had it at the local GM dealer ship and spent $856 so far and it still runs like Sh!!t. replaced the dis cap set the timing, checked what few sensors there are on it, checked vacuum hoses and routing and now I am lost. anyone got any ideas?

Re: 1987 pops and bangs
 

Timing Chain or Possibly a cracked valve?????

Re: 1987 pops and bangs
 

Biker, GM had a problem with soft cams back then and was replacing them under warantee & mabey yours never got a new cam. I am surprised your local dealer couldn't fix it correctly. It's easy to check though. Put the truck in gear and throttle up. It should start poping back thru the carb right away. It will pop as if it is timed, just like if you removed a plug wire. It is not a random pop. If the truck is a stick you'll have to do it out on the street, but the symtoms will be the same pop,pop,pop,pop until you back off the gas. Let us know what you find. jim

Re: 1987 pops and bangs
 

Mine did the same. Found out the cam had a rounded lobe. It did not pop all the time at first then it popped right after I started driving it. engine is rebuilt now. NOW IT SMOKES, LONG STORY.

Big Blue

Re: 1987 pops and bangs
 

when did you get the dealer to work on it? under 3 months? if so take it back!

Re: 1987 pops and bangs
 

Not that is makes difference with a flat cam.....but shouldn't an '87 have TBI, not a carburetor?

Re: 1987 pops and bangs
 

checking around I found a ground wire behind the engine that was loose on the engine as well as the firewall tightened both and the popping and banging went away. I was so happy I could again plow snow from my driveway I had at it and destroyed the inner axle shaft on the left side so back into the garage for repair. Thanks everyone for the help.

Re: 1987 pops and bangs
 

mine had the same problem a while after I replaced the cam, turn'd out to be the same thing. the ground wire on the back of the block.