Tune up needs another going over

[tonyiiiafl]

Brought the old gal up the river to winter storage. Ran great, or so I thought. Started fine, idled supreme and moved along at 3,000 perfectly. I thought I would give a burst of WOT and that is when bad stuff happened. Port engine went up to 3950-4000. About normal with the full tankage and weight. Starboard stumbled between 3200 and finally made it up to 3700 but was misfiring, so I backed it off. I replaced new plugs (NGK was in there) new Quick Silver wires and cap. I wires are close together, but small wire separators. The wires weren’t what I thought as for a full custom set. Just 4 short wires and 4 Long, so the long ones dangle some. Ran great at speed before tune up. Starboard engine ran fine, just on teh 1200 hour port. Thinking of checking wires for proper placement, but I replaced 1 at a time. I usually dont do an entire tune up at once. I usually do plugs, then run it to see if there is a proble, then cap, then wires. Starboard cap was worn badly on inside, but port looked almost new. Ideas?

[km1125]

If it was running good up to 3200 then I seriously don't think it's a miswiring or even a cross-fire situation.

Loose wire(s) somewhere? maybe.

[g36]

Had you had them both upto wot recently before the tune up? What bout fuel filters change during tune up?

[tonyiiiafl]

Both were up to WOT before the tune up and hit 4000. I did not change fuel filter yet, as it ran good before the tune up, just started hard. Now starts easily, as plugs were gapped at .030 on starboard . I gapped at .035. The wires I got were Qucksilver. However, there were 4 short and 4 long wires for each engine, rather than 4 custom sizes. This is what I bought:

I used die electric on each wire. Starboard did get up to 3900, but port stumbled. It did surge up to 3900, but dropped right back.

[tonyiiiafl]

DOes anyone have the part number for wires for a 1994 454 Gen V with Thunderbolt ignition?

[bud37]

Just go back and check all your wire connections at the plugs and the cap.....if you put dielectric on there they could have slipped loose if not on just right.

[Viper]

Post a serial number Tony

[Cooler]

It is real easy to cross wires. Also, if your engines are Crusader, that plug gap might be .045. er

[Viper]

Thunderbolt ignition would make them Mercs

[tonyiiiafl]

Going down this week to get a serial number. I did see that Sierra had custom wires. Since that one was running pretty good at the time, and I saved the cap and rotor (looked like new) I may put old cap back on after checking the wires.