I recently decided to change my spark plugs to the e3 diamond fire plugs for added efficiency. Immediately after changing my plugs my car ran just fine, but when I started it this morning it began to misfire. It wouldn't drive over 20mph, and I pulled a plug out to check it and it was black. I changed back to my old spark plugs and the problem persisted, misfiring and all. I pulled the old plug back out and it was also black (soot not oil). Now my car won't start at all, only when I hit the gas it will get a few sparks but it sounds terrible. Is there something I did wrong? I checked the firing pattern and it is correct. I searched the forums and couldn't find help. Any advice would be appreciated. (Go easy on me I'm a new member lol)

 

Update, I had a mechanic come take a look at it and he said it's an internal seal that has failed on my carburetor. Could this be correct? He said me changing my spark plugs was irrelevant to the issue. When I start my car, the carburetor backfires and the engine will only run for a few seconds, misfiring.

1985 S10 Blazer 2.8l v6 4x4

 

It sounds like your mechanic could be correct. The soot would indicated that the air-fuel mixture is overly rich resulting in lots of carbon deposits. Sometimes there are coincidences like this.

Don't know anything about the carbs on those rigs. In principle, a basic carb rebuild would be the thing to do.

 

Thanks for the response. The carburetor I have is a rebuilt Rochester 2SE Varajet. My question is, is it just a coincidence that it began to flood and misfire right after I changed my plugs? I also added a new heat riser pipe, but it doesn't seem like that would be the issue since the problem persists with the air cleaner removed. The spark plug wires look new as well. My mechanic checked my ignition coil and distributor and they both functioned correctly. I might return my carburetor to advance auto parts and get a new one under warranty, but I would like to check if it could be a secondary issue causing it to flood. My mechanic had very basic knowledge of carburetor functionality, and it seemed like he wasn't sure about his answer.

 

It very well could be a coincidence. I'm not normally an advocate of swapping out parts as a diagnostic tool, but based on what you have written, I would say that getting a replacement carb could be appropriate.

What you could do is remove the current carburetor and then reinstall it following the installation directions exactly. You might find that something that should be attached has come off or an adjustment has slipped. I could imagine these happening as a consequence of just messing around the engine compartment and something inadvertently being knocked loose.

Another thing to consider is that if something is to fail, it is not uncommon such a thing to fail soon after it is first put into service. This might be what is happening with the carb.

 

Well... I installed a new carburetor, put new spark plugs in, new fuel filter, and it's still flooding. I also installed an in line fuel pressure gauge, it's reading 6 - 7.5lbs which should be good. I've checked the firing pattern from the distributor and it's correct, and I'm getting spark. Still spewing gas from the air horn and soaking the choke valve, sputtering and backfiring through the carb. I just don't get it. This is the third carb I've put on it, they can't all be bad. I don't have a fuel pressure regulator so it can't be that. Next thing I'm going to double check is my vacuum lines. It was running just fine then all of a sudden this happens. Not sure what to do, and any advice would be very appreciated! Thanks!

 

Varajets are a PIA. work good when they do and a royal pain when they don't - Your warranty carb may have a stuck float from being tossed around during shipping, try tapping on the top of the carb above the float area, if it's stuck it may jossle the float loose