Blowback our of the TBI

[Schurkey]

You can also just shove your finger in the spark plug hole and bump the starter

I'd be real careful about telling someone to shove their finger "IN" the spark-plug hole. They're likely to take you literally, and get their (or their kid's) finger mangled.

How about "Put your finger OVER the spark plug hole..." or "Cover the spark plug hole with your finger...".

 

[Supercharged111]

That's the kind of mistake you make once.

 

[Buffalo90]

Think it’s the spark plugs I got. Had a set sitting around forever that I was just going to put in but they aren’t meant for aluminum heads. Not getting enough spark. I’ll see what happens when I get the recommended ones put in.

 

[Schurkey]

Think it’s the spark plugs I got... ...but they aren’t meant for aluminum heads. Not getting enough spark. I’ll see what happens when I get the recommended ones put in.

What makes a spark plug suitable--or unsuitable--for aluminum heads???

 

[Supercharged111]

What makes a spark plug suitable--or unsuitable--for aluminum heads???

I believe the depth is different in the OE stuff.

 

[Buffalo90]

What makes a spark plug suitable--or unsuitable--for aluminum heads???

Some metals don’t conduct well with others. The threads and prong are negative terminals so when the distributor sends a pulse to the plug, the electricity jumps from the center to the prongs causing a spark. If the metal in the plug doesn’t conduct well with the cylinder head metal, then the sparks will be weak or not there.

 

[SAATR]

Some metals don’t conduct well with others. The threads and prong are negative terminals so when the distributor sends a pulse to the plug, the electricity jumps from the center to the prongs causing a spark. If the metal in the plug doesn’t conduct well with the cylinder head metal, then the sparks will be weak or not there.

That's dead wrong. Every spark plug composition from copper/nickel alloy to ruthenium has been run in iron and aluminum heads with no problems or ill effects caused by the head's metallurgy. True that some ignition systems don't play well with some styles of plug, but that has nothing to do with cylinder head metallurgy or conductivity. Either the plug is specced for the heat range and application it is installed in, or it isn't.

 

[mariodave]

What he said, plugs are not the problem. Do you have battery power to the coil?

 

[Jordan Goldenberg]

just tore apart my 454 with the same issue. Mine was running okay but had a bad misfire after half throttle. Loud popping sound from the tbi. Turns out had 2 exhaust lobes on my camshaft that were ground smooth. Plus my flat tappet lifters were dished like a dinner plate. So needless to say, cylinders 1&4 werent exhausting. Coming back out the intake.

 

[PlayingWithTBI]

I believe the depth is different in the OE stuff.

Yeah mine (Summit Racing made by Trick Flow) use 3/4" depth with gasket instead of 5/8" tapered but, that wouldn't cause the OPs issue.