Hi, I have a 1995 chevy blazer 4.3 cmfi vortec. I had an issue recently where I thought my spider was bad and ended up being a new weak pump. Replaced both and the new spider caused it to misfire although it passed a leak down test. Put the old o e back in and it fixed the problem. Couple of days later i started smelling gas and had hardly any acceleration and low idle while I was driving around town also it was bellowing raw gas and smoke out of the tailpipe. I took the upper plenum off and found the nut kit was loose on the spider and intake so I replaced them and the external sending and return lines. Went to start it up and I had the same issue. Now, before I did the repair I had it towed home and was gonna start it up to move it to a better working spot, it sounded like a back fire or detonation when I tried to start it so i just left it. Had to reset the computer to get the starter motor to fully turn.

Any ideas as to why i still have low idle and gas spewing out the tailpipe?

Recently swapped motor from a jimmy of the same year and i gave it a new oil pump, seals and gaskets, timing gears and chain. Plugs wires cap n rotor. Did not service heads or anything to extensive.

 

That sounds like your engine got hydro-locked by fuel.
Check for fuel in the oil. (Might be so much that the oil stick smells)
Leaking injector?
Fuel in the plenum?

 

Yeah the oil was very gassy. Is there any way to evap that gas out of the cylinders?

 

There was fuel in the plenum when I replaced the nut kit. I guess I thought that was the only problem I had at the time. My buddy says to start it and let it run a minute to see if it'll clear itself up and another friend suggested I take the spark plugs out and hold a micro torch by the holes.. not sure either of those are right

 

😂😂😂

 

Anything that involves fuel and open fire, sparks or any other means of ignition should be handled very carefully!

For once I'm at a loss on what to suggest.
I'd go and find out why it leaked into a cylinder in the first place but that's not so easy.
Then determine how long the engine had been run on too much fuel. (Tends to wash down the oil film from the cylinder wall, which in turn leads to damage to the rings and cylinder.)
Spark plugs out and slowly turning by hand to check for presence of fuel. Careful it can gush out if it had been "filled".

Complete oil change as fuel breaks down the oil.

Suggestions somebody else?

 

Sounds like a leaking fuel pressure regulator to me, but it's doubtful that it would pass the leakdown test if that were the problem.

 

There are 2 small holes in the bottom of the intake where the fuel seeped through so as not to be a mini gas can on top of motor. The holes lead to the lifter valley which is indeed where it would've mixed into the oil. Not through the cylinders. The nut kit wasn't on tightly which Is where majority of the fuel came from. The pressure regulator was also leaking and my fuel pump all went out at the same time. Will update after I hang the tank again today

 

If it has not been running for long an oil and oil-filter change should do the job.