hi got a 1995 blazer 4x4 with the 4.3. My blazer is running rich, and occasionally the fumes smell like sulfur, and at the tip of the exhaust its black. its not smoking, the fumes just have a strong smell. The motor has a miss to it, and cranks over before it starts.And whenever it firsts starts, it misses really bad. I had the check engine light scanned, and it came up as incorrect purge flow. that was the only thing that showed up.

Recently the coil went bad, and i changed it, hoping to help the problem. i'm not sure if that could cause the spark plugs to file out or not and make it run the way it is. Never got around to changing the spark plugs because i dont want to spend the money if its not the problem. My ventline from the fuel tank is looking pretty rough.

If you have any advice for me as to why it is the way it is please help me out. Thank you.

 

Well,thing is if the plugs are fouled out,it may cause a rich condition. pull a plug while the engines cool. Look to see if its covered in black carbon,or if its just bad. Money shouldnt be much of a issue unless times are rough. You can get NGK v-powers for $2 each and these trucks love em. or ac delcos for about 2.50 each.


Also try seafoam,it might clean up the plugs enough to clear things out.

 

Thanks for the suggestion i will try that. Could there be any chance its the cpi?

 

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I would start with a fuel pressure & leak down test. Chances are you have a leak internal to the plenum.

 

Can you explain what that is?

 

A fuel pressure test & leak down test is exactly as it sounds (and as is covered in hundreds of other similar posts found throughout the forum). A test of the fuel pressure & leak down. It requires a gauge be connected to the fuel pressure test port located on the back of the intake manifold near the brake booster. Your engine requires >55psi with the key-on/engine-off and that the pressure remain above 50psi 10 minutes after the pump shuts off.

I am betting that your results will show a leak down failure meaning you have a leak in the system. The CPI engines are notorious for their poor FPR (fuel pressure regulator) design as well as the tendency for the 'nut kit' (internal fuel lines) to leak if ever disturbed.

 

i looked at a couple stores before buying my acdelco plugs, and the cheapest i found was 12$ each, and heard that anything else than delcos does not work right in s-series trucks.

also, im waiting for my cap and rotor to come in before i do my complete tune-up and i will do the seafoam treatment BEFORE changing plugs, as i heard that it can foul plugs...

 

If that is the problem how would i fix it can you like walk me through some steps so i know.. thanks alot i really appreciate this.

 

Feel free to use the search feature. This is a common problem that is covered in great detail in other posts (hint: check out the tech article section).

 

Hold it! Quit talking about plugs till you fix the problem.

Do the leakdown test first

Fouled plugs do NOT cause the symptoms described unless the engine will barely run in the first place.
This is no chicken or egg. Plugs do not foul by themselves or with age, they wear away.

The plugs will foul for one of two reasons excess oil in Combustion or excess fuel.
Oil will foul plugs dark and greasy, fuel dark and sooty.

But the KEY is what Swartlkk said.. PERHAPS if you took off the oil filler cap and sniffed. Some actually smell the dipstick.. but not smelling gas there is still not conclusive. Do the Leakdown before anything else.
OTOH, if you DO smell fuel in your oil you can pass that step until you pull the upper, find and fix the problem.. THEN do the leakdown.
And also there's the matter of
Guess what that might mean.. excess fuel
So there was no P0300, thus no evidence the plugs were misfiring, however 'fouled' they might be.
And where the hell are reg AC Delco plugs $12?!!! NGK is good brand so is Autolite.