Popping from intake

[Ramcharger90]

So every once and a while my 5.0 swap starts popping and it has a lot of hesitation. It does when it rains or a high humidity day. It doesn't do in all the the time so I could imagine its to lean or a timing issue, otherwise you would think it would do it all the time. I used a 90 mustang ecm and harness. I think it's the BBK mass air sensor I clean it and it won't do it but even if I dont clean it, it will only do it like 3 miles in to my 25 mile trip goes away after a mile or 2 then it's a good all day and after sitting at work for hours and hours it will run fine all the way home. Only when it's rainy/humid or near freezing.

 

[franklin2]

Humid/rainy problems in my experience are usually high voltage problems. I would pull the sparkplug wires and ohm them out, and inspect where the high voltage wire plugs into the coil. Look for green corrosion. Pull the dist cap and look for any dark streaks or cracks or corrosion in the cap or the terminals. Be careful with the sparkplug wires, it is easy to break the graphite cord inside them. If some are broke the ohmmeter usually will pick it up.

 

[Ramcharger90]

Humid/rainy problems in my experience are usually high voltage problems. I would pull the sparkplug wires and ohm them out, and inspect where the high voltage wire plugs into the coil. Look for green corrosion. Pull the dist cap and look for any dark streaks or cracks or corrosion in the cap or the terminals. Be careful with the sparkplug wires, it is easy to break the graphite cord inside them. If some are broke the ohmmeter usually will pick it up.

I'll check that. I do have a msd 6al holly sniper coil, accel ceramic end wires, msd distributor. Not sure if that will change anything.

 

[franklin2]

What are your plug gaps? With all that hotrod ignition components, you didn't widen the gaps did you? That is ok, but you have to be more diligent in checking the gaps more often if they are wider than stock. If they get too wide or the plugs get worn, the high voltage on the plug wires may find a better spot to jump to ground than the sparkplug itself, causing a miss-fire.

 

[Bgunner]

I had an old Chevy Celebrity that would have issues anytime it rained. If it rained or snowed it would start hard and skip, if I went through a puddle it would die but if it was dry it ran great. The issue with it was the ignition module in the distributor would have issues grounding. I agree it sounds like an ignition issue somewhere.

 

[Ramcharger90]

A little burnt ordered a new cap and rotor I also ordered new plugs I'll reset the gap but I have P heads im bored 30 over with a Bcam and 1.71 roller rockers with 24lb injectors so I'm not sure the .54 gap for P heads is still adequate or to much. I'll have to get a new ignition module for the distributor couldn't hurt