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Plugs in Drivers Side Bank Fouled

FridayGt

FridayGt

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So, I was having carb flooding problems (I thought) and it was causing my plugs to foul out on me. I got a brand new carb and replaced it and it sounded like the engine just exploded to life. The next day I changed all of the plugs out so that I would have a fresh set to judge the mixture with. They were all fouled or close to it from the previous carb. When I took it for a test drive, I nearly melted the one tire completely off with my 2.76 grovery getting one wheeler peeler diff in the back. Driving the car around the other day I could tell that I had fouled plugs again. Getting into it, I pulled the #2 and #8 plugs and they had that perfect tan that you want to see along with the change in color right in the apex of the bend telling me my timing is about right if I'm not mistaken. However, when I started pulling the plugs on the drivers side bank, every single one of them was fouled. Pitch black fouled and it looked like carbon fouling, but I'm not the most versed. I verified the firing order was correct. Anyone have any thoughts on what to check next? I replaced the plugs and will see how they do again tomorrow. If they all foul on me again, does anyone have an idea of what it could be?

MSD Ignition and coil
Autolite 85 plugs
Just recently cut new Accel wires
Tan cap distributor
 
Anyone ever have this happen to them?
 
Yes, I had the electric choke set wrong and most all of the plugs oil fouled, got choke set right and goo to go now.
 
Very odd to have an enitre side of the engine foul plugs. Have you done a compression test?
 
bigmanjbmopar said:
Yes, I had the electric choke set wrong and most all of the plugs oil fouled, got choke set right and goo to go now.
Click to expand...
Hmmmm, didn't think of that. Think it's still a possibility with a manual choke? Not much to mess up on those it seems. I defenitely make sure it's all the way in and not pulling on the choke assembly on the carb before I drive.

dryheat said:
Very odd to have an enitre side of the engine foul plugs. Have you done a compression test?
Click to expand...

That's what I was thinking. Did a compression test on about half the cylinders, two from each bank. All were over 100, but very close to each other, around within 5% I believe. I'll check them all again when I get home from picking up parts. Better to be detailed with info when asking for help.
 
Strange its just one side. I have found on my stuff if I dont use a fuel pressure regulator on the carb inlet I get bad fouling from too much fuel. Most carbs dont require much fuel pressure usually abot 4 pounds, and most pumps are putting out at least nine. Edelbrock carbs are mainly what I use and they dont work well with too high of a pressure on the inlet.
 
what intake are you running?a split plane intake seperates left from right sides of motor.it also divides left and right sides of carb.i have seen,with older intakes,haveing to jet carb diff from side to side because of this.its fairly rare,but it does happen.
 
welder47 said:
Strange its just one side. I have found on my stuff if I dont use a fuel pressure regulator on the carb inlet I get bad fouling from too much fuel. Most carbs dont require much fuel pressure usually abot 4 pounds, and most pumps are putting out at least nine. Edelbrock carbs are mainly what I use and they dont work well with too high of a pressure on the inlet.
Click to expand...

I'm using an Edelbrock 1407 carb and I used to have a fuel pressure issue until we vented the gas cap. Now it's about no higher than 6 pounds.

67 coronet said:
what intake are you running?a split plane intake seperates left from right sides of motor.it also divides left and right sides of carb.i have seen,with older intakes,haveing to jet carb diff from side to side because of this.its fairly rare,but it does happen.
Click to expand...

It's an Edelbrock preformer intake for the 440. I just picked up a calibration kit, so we'll see if that's the case, thanks for the suggestion!
 
If all the plugs are fouling on one bank, but not on the other bank, it doesn't sound like a carb problem to me. I've had that happen when there was leakage from the valley pan gasket that seals the intake manifold to the head. Since then I've always used a thin bead of sealant around each port on both sides of the valley pan gasket.
 
So, very odd, and not sure what difference this may or may not make. I got back from the shop getting a sheared bolt removed from my valve cover and only one plug in that bank was fouled this time. The #7 cylinder plug, the one that I had problems with before when an inproperly crimped spark plug wire connector on the distributor side caused the connector to get scorched and constantly fry plugs. The connector and that plug were replaced, not the wire. So, I changed the oil as I had been planning to and went for a drive. Flawless performance this time. No fouled plugs.

Is it possible that there was so much residual gunk from before that it just blasted the new plugs when I fired it up the first time? This would be me hoping for the absolute best! Lol.

Now, when I pulled the fouled #7 plug, the insulator was still very light colored, except for the small section that was black and scorched. As I'm describing this to you guys I am regretting throwing it away without a picture big time... Lol.
 
Just a comment. A dual plane intake does not separate bank to bank. That would be a divided plenum single plane like the old small block intakes. Are the plugs flat black in color (soot) or kind of greasy and shiny? Sooty would be rich, otherwise you might be looking at oil fouling. I have a 750 Eddy carb and I'm running a Holley pump with 7.5 PSI and no issues. As some have suggested make sure your choke is not closing on you. What is your idle vacuum?
 
Meep-Meep said:
Just a comment. A dual plane intake does not separate bank to bank. That would be a divided plenum single plane like the old small block intakes. Are the plugs flat black in color (soot) or kind of greasy and shiny? Sooty would be rich, otherwise you might be looking at oil fouling. I have a 750 Eddy carb and I'm running a Holley pump with 7.5 PSI and no issues. As some have suggested make sure your choke is not closing on you. What is your idle vacuum?
Click to expand...

The plugs are defenitely carbon fouled with that sooty black, but the last one I pulled, being the only one fould by itself, only had that satin black on a portion of the white insulator. Not sure what my idle is at vacuum, although, that sounds like a good reason and an excuse to go buy a tool to find out! lol. I'll go warm up the road runner now, cruise her to the parts store and pick up a vacuum guage.

When I get back, I'll post the vacuum at idle and whether or not any plugs fouled this time.
 
Ok, so, today was put road runner to test day again. Drove all over the place, to the parts store to get a vacuum guage, to the recycling center to dump the spent oil, to the dog park to exahaust my puppy so I could work in peace, and this is what I got. Seemed to be running fine, but I started to get a bit more of that popping and sputtering off pedal like before. This to me screams plug. I get home, take care of some other things while it cools a bit. I pull the usual suspect plug, #7 and it looks like it *might* be fouled, so I put it back to check. I start it up, wait a minute, then start flicking water at the headers. Same cylinder, number 7, is the only one that's cold.

So, I replace the plug and start her back up again, with the vacuum guage plugged into manifold vacuum (the lower of the two smaller valves on the front of the edelbrock carb) and I'm a little concerned. Granted, not completely warmed up yet, but halfway there, it was holding at about 19 inches of vacuum. The concerning thing was that it wasn't exactly holding steady, it was vibrating in unison with the engine idle. Not certain if these old carb'ed cars are supposed to be different, but I was thinking it should have been steady. Not hovering about a good number with very short fast vibrations back and forth with idle.

Sigh. Thoughts?

*Additional Note; the distance of vibration on the guage is less than 1/4". Not as if I held a ruler to it, but by the notches on the guage, total fast vibrating motation does not travel more than 1/4" of vacuum total.
 
Last edited:
Thougths? Distributor looks clean, so I'm thinking I'll just start replacing from there out to eliminate that as a possibility. The connectors and spark plug wire.
 
FridayGt said:
Thougths? Distributor looks clean, so I'm thinking I'll just start replacing from there out to eliminate that as a possibility. The connectors and spark plug wire.
Click to expand...
sounds like you narrowed it down to one cylinder.check for any burnt spot inside of distrib cap.if you have replaced that plug several times,try replacing or swapping the plug wire to see if you get same effect.double check firing order as well,just to be sure.
 
If number 7 is the same cylinder that had the suspect plug wire connection take an inductive timing light and connect it to the #7 wire close to the spark plug and see if it pulses ... no pulse no spark ... you might want to measure the resistance also.
 
67 coronet said:
sounds like you narrowed it down to one cylinder.check for any burnt spot inside of distrib cap.if you have replaced that plug several times,try replacing or swapping the plug wire to see if you get same effect.double check firing order as well,just to be sure.
Click to expand...
I replaced the suspect connector on the wire and still am having the issue. The distributor looks brand new, and the firing order is spot on. If this new plug doesn't work out, Ill trade the wire to another cylinder.


dryheat said:
If number 7 is the same cylinder that had the suspect plug wire connection take an inductive timing light and connect it to the #7 wire close to the spark plug and see if it pulses ... no pulse no spark ... you might want to measure the resistance also.
Click to expand...
Didn't think about the timing light, I'll check that out next. Checked the resistance on the spark plug wire and the bad connector provided a little, but not enough for concern, but replaced it any way.

Went one step hotter for the plug in that cylinder to see how it handles it. Either way, the rest of the plugs are all pulling near completely white. tuning kit for the carb gets here on Monday.
 
a single cylinder wont be caused by carb adjustment,has to be electrical or mechanical.when you replaced the wire end did you make sure the metal connector had direct contact with wire core?not just crimped to outside of insulation,but core folded back on top of insulation.
 
67 coronet said:
a single cylinder wont be caused by carb adjustment,has to be electrical or mechanical.when you replaced the wire end did you make sure the metal connector had direct contact with wire core?not just crimped to outside of insulation,but core folded back on top of insulation.
Click to expand...

Yes, absolute certain, then tested the resistance from end to end.

The one step hotter plugs aren't helping either. I'm so confused as to what it could be at this point. My next step is to just start over from square one and test everything from step to step.
 
How 'bout this...

If just one hole is bad, it may be a burnt valve..

I had this on a small block Chevy once. I actually carried a box of plugs with me and woud change that one out each time I drove the car.

To check, do a compression test. Then repeat but add a bit of oil, about a tablespoon or so, into the plug hole. The oil will seal off the rings.

If the reading stays the same, you probably have a burnt intake valve. If it goes up, then he valve is OK, but you may have a ring issue.


Hope this helps,


Jeff
 
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