454 RUNS POORLY

[TAYLOR454]

I HAVE A 454 W/HOLLEY DOUBLE PUMPER, NEW MSD BILLET DISTRIBUTER AND COIL WITH NEW ACCEL WIRES. IT SEEMS AS CYLINDER # 2 AND 4 ARE NOT RUNNING. THE SPARKS ARE GOOD AND THEY BOTH HAVE COMPRESSION SEEMINGLY COMPARABLE TO 6 AND 8. IDEAS WOULD BE A BIG HELP. THANKS.

[rwhite]

Tell us what you have done to determine that 2 and 4 aren't firing? Also what do you mean by seemingly comparable? Have you ran compression test? With all the new stuff you say is on it my first inclination would be to trace every plug wire to insure its right and also make sure the distributor isn't 180 off (though it wouldn't likely run if that was the case). Just because everything is firing doesn't mean it's in the right order.

[grampadirt]

Double pumper?As in carburetor?What have you done to this engine?

[TAYLOR454]

Thanks for seeing and answering my post!

 

1.pulled plugs as it ran to see when engine would stutter/saw plug condition on #2 in particular it was clean/could see exahaust emission on that side of engine was showing incomplete combustion.

2. i pulled plugs on 6 and 8 to compare, I also had to find TDC for #1 to install the distributer [i do not yet own a compression tester so I went by what I felt, I do have pretty good access to the sparkplug holes].

3. yeah I thought wiring order first suspect, the order is pretty easy to get correct tho. I am sure it is ok. #2 is conterclockwise to #1 and it and 4 are good. I pulled the new plugs and reinstalled the old ones, the ran the wires to the new plugs to ensure that the new plugs were sparking and they are good. The engine seems to run and start good except for those two cylinders.

 

 

 

4. yeah, a holley double pumper carb and have modified nothing on the engine.

[grampadirt]

What do you have the IAC motor & the TPS connected to?

 

Some info on the truck please.

[TAYLOR454]

Grampadirt, there is no IAC motor or TPS. This is an old school engine.

[grampadirt]

Sorry I was going by the forum you posted in.

[rwhite]

Thanks for seeing and answering my post!

 

1.pulled plugs as it ran to see when engine would stutter/saw plug condition on #2 in particular it was clean/could see exahaust emission on that side of engine was showing incomplete combustion.

2. i pulled plugs on 6 and 8 to compare, I also had to find TDC for #1 to install the distributer [i do not yet own a compression tester so I went by what I felt, I do have pretty good access to the sparkplug holes].

3. yeah I thought wiring order first suspect, the order is pretty easy to get correct tho. I am sure it is ok. #2 is conterclockwise to #1 and it and 4 are good. I pulled the new plugs and reinstalled the old ones, the ran the wires to the new plugs to ensure that the new plugs were sparking and they are good. The engine seems to run and start good except for those two cylinders.

 

 

 

4. yeah, a holley double pumper carb and have modified nothing on the engine.

So was it running proper prior to the wire and distributor install. I have never gotten a chevy to run 180 off but I have heard it can be done. I doubt that's your issue. You might be better served to ask an admin to move this thread to the proper forum. This link may help http://www.mre-books.com/chevy/engines/firing_order.html all chevy v8s have same order but distributor position is different.

[Cody Hall]

check to make sure distributor and wires are installed correctly and i would check your valve adjustment thats a big deal in the operation of the old style chevy bad valve adjustment willmake a motor run poorly and lead you to belive its something else most speed shops sell little clips that clip to the rocker over the push rod to keep oil from going every where so you can see if there are any loose spots in the cyclinder cycle while it runs with valve covers off the make sure the cyclinder is at tdc on compresion stroke to adjust