Hello all,
I'm new here and I got a '93 S-10 Blazer with a 4.3l Vortec for next to nothing that has some engine issues that I want to get sorted out. The original owner told me that it had started running rough and that it started pulsing real bad and blowing black smoke through the breather tube and then it had backfired bad enough to literally blow both of the valve cover gaskets completely out and both valve covers are bent and broken where the mounting bolts go through them.
I started checking obvious things like compression which is good. I couldn't see any signs of jumped timing as cylinder 1 at TDC brings the dist. rotor to the proper position. The coolant looks good and shows no signs of oil and the oil shows no signs of water so I don't think it's head gaskets. I did however notice a small puddle of coolant on top of the intake. Has anyone here ever had this happen? And what does it sound like it might be? The only money I have in this thing so far is $60.00 for a battery so I could check the compression. Also, it will start up and run but of course it runs roughly. After I let it run for a little bit, I checked the plugs and all but 2 plugs were firing. The plug in cylinder 5 was carbon fouled and was cold to the touch and cylinder 6 was wet with gas and was cold to the touch so I'm sure those 2 plugs were not firing. I have a budget of about $300.00 for parts and I will be doing the work myself. Any help or advice would be greatly appreciated.

Thanks in advance,
Shawn

 

I would pull of the upper plenum and have a look at the fuel system. It's possible that the problem was caused by a fuel leak internal to the plenum.

 

if plugs 2-4-6 are fouled or showing a rich condition then the fuel regulator might be leaking. The regulator is positioned on the left side of the CPI unit and if it leaks it will cause a rich condition on those cylinders. The main injector and fuel lines will be on the right side and the same condition, fouling, of 1-3-5 could point to a leak. Spose there could have a fuel leak large enough to cause a backfire, but I have never heard of a backfire tossing gaskets and bending metal - must have been huge. I think it's best to just pull the plenum and have a look. How many miles on this engine? Do you know if there was any head work done by the original owner?

 

Hey guys thanks for the replies.
The mileage is 102,000 and according to the original owner,
No head work has ever been done. Nor has it ever had any major engine or trans. Work other than normal maint.
But he did mention that there was a strong fuel smell right before it backfired.
So, I will take a look under the plenum this weekend and see if the fuel "spider" as I call it is leaking and I'll check the regulator as well and let you guys know what I find.

Thanks again for the suggestions.

Shawn