Engine Misses

Question: [GU] "I have a 351 svo crate engine, its a Ford 1998 Explorer block. Edelbrock rpm performer intake, edelbrock 750 carb., mallory LED mech. advance distributor. The problem is when I get to 4000 RPM under full throttle the engine misses like the plug wires, or plugs are crossing, or breaking down. No detectible miss up to 4000 RPM. Also smell gas from time to time, checked the lines, and no leaks. Tried to adjust the carb. idle screws and the drivers side screw didn't effect the idle at all. All the way out or in no change. Passenger side idle screw works fine, set it at 2 1/2 turns out. the timing is supposed to be 36 degrees BTDC at 5000 RPM. So I set it at 10 degrees BTDC at idle, this should make it 36 at 5000. The timing metal indicator has three places that look like it could be the place to use, first a circle ( hole ) then a "C" place then a pointer type part at the top. This is where I set the timing to, the top pointer thing. Plugs are dark on the ends. Any suggestions??"

Answers and Suggestions:

[Dino] "if I'm not mistaken, the crate engine has gt40x heads...I don't think they like, or need a lot of timing. The first thing I would do is back the timing off in 2 degree increments and see what happens. Also sounds like you may be getting too much gas...the plugs shouldn't be black. Are they wet black or dry black."

[ST] "I had a problem with an RPM related miss one time. It turned out to be vibration related within the electrical system (a loose condenser in a points type system). Very hard to diagnose. I would carefully check all of the wiring within the ignition system before messing with the carb."

[C] "does it do it on tip in acceleration or after it is floored? If it falls on its face, it is usually fuel related. If it is very direct and pops a little, it is usually electrical.

I think its electrical. Check your cap and rotor, make sure there are no cracks. Make sure your plug wires are not touching anything. How new are the plugs? what kind? what gap? If your gap is too wide, it could cause the problem. Also, you could try retarding or advancing the timing to see if it makes a difference. If you can with your timing light, check your timing above 4000 rpm. It could be way too advanced."

[Jam] "my guess on the miss is ignition . I would agree to check the cap/rotor/plug gap/wires etc. Check all the connects on your Mallory ignition and perhaps you could even try a run without the rev limiter chip.
I once found a loose fitting chip caused a miss because if vibrated around at certain rpms."

[GU] "I found that part of the miss was timing. But it still fluttered and missed when pulling hard over 4000 RPM. I found out it was my air cleaner, take the air cleaner off and, no miss. I had a triangle shaped air cleaner, it was the only thing that would fit under the hood. This air cleaner had a metal bar that went across the top of the carb. to hold the base of the air cleaner on. This bar was partially blocking the air flow over the secondaries on the passenger side. Only thing that I can figure is, the air flow was so turbulent that no fuel was being drawn into the secondaries on that side. As they require vacuum to draw in fuel, and that vacuum is provided by the air rushing past the fuel opening. Thus, only missed when WFO, and over 4000 RPM when LOTS of air is flowing into the engine.
"

First Run Issue:

Question: [TM] "Well, I couldn't wait any longer! Still can't get the fuel pump to work without by-passing the relay, and still waiting to get the passenger side pipe back from being coated. So I bolted up the drivers side pipe and had my son hold the jumper wire on the fuel pump relay and cranked up FFR 2336! Started up after the second rotation. Ran great but I shut her down after a couple of minutes due to the fact the oil pressure gauge was still on zero. Probably getting pressure any way (filter was full of oil) but don't want to run it until I can get the gauge to work. Still have the original gauges in the original pod. I noticed a small broken resistor on the back of the pod, in line to the oil pressure gauge. Does any one know if this resistor can be by-passed? I really want to go for that first ride!"

Responses:

[WP] "You REALLY need to check the oil lines from the engine to the remote filter to assure proper routing, as a mistake will result in 0 oil pressure!!!"

[JB] "If your fuel pump isn't working, make sure you have the green connector on the computer harness connected to the dash harness."

[dino] "DO NOT RUN THAT PUPPY WITH NO OIL PRESSURE!!! Unless you have big bucks and like to replace bearings!!! Check to make sure you have the oil lines run correctly to the remote oil filter...VERY IMPORTANT!!!! I would also suggest you "prime" the engine to double check you're getting oil pressure. You can do this by removing a valve cover, then remove the distributor and spin the oil pump with a drill and a fitting (which I believe you can buy from discount auto...autozone, etc) Oil should spurt out of the rocker arms."

[RO] "The arrows on the block side of the filter kit do not run the same if you see one arrow pointing up/out and you think that the inlet on the other side is in you are wrong the arrows indicate in and out, not flow direction. The arrows point at or away from each other. NO OP is very bad. Keep working on the wiring. Check the solenoid and make sure you have a groud around it. It is very easy to put the ground to power and not have the pump work. The wire is black with blue I think."

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