Strange sound coming from my distributor or PVC

[UGA2018]

I posted this once before but still don't have a complete resolution so I'm hoping you can help me. I did a valve adjustment the other night and when you listen to the video you'll notice I still need to do it again because we didn't do it quite right. But what has stop me is this new sound set the valve adjustment that's coming from my distributor. Or somewhere near my distributor. I thought it was the VCV valve and I replaced it today with a new one. But even after replacing it sounded not stop. You'll notice on the video that one of the nipples are the VCV valve does not have a hose pipe in. I have fixed that.


It still is making the sound even after it's been fixed. Also you may notice that the charcoal canister is not hooked up properly. However, The charcoal canister was not hooked up prior to the valve adjustment so I don't think that's the root of the problem.

The sound that you were here that I'm asking about is almost like a rustling of paper or a constant sparking sound. I can't put my finger on it. It's louder in real life than it is on this video.

I would love to have any ideas about what you may think this is. Thanks for your help!

 

[mwebfj60]

It's hard to hear the noise you are describing. Did you pull the cap back off and have a look to see if there is arcing going on inside? I remember reading you had the cap off to find #1 TDC right?

 

[UGA2018]

Yes you're correct I did pull the cap off to find TDC on #1. I have not pulled the cap back off to see if there is arcing happening. I was thinking the engine would not run with the Off. But maybe Im misunderstanding?

 

[UGA2018]

Let's see if this audio files comes thru better. It's almost like a static sound coming from the distributor or somewhere near it.

Dropbox - New Recording 2.m4a

 

[mwebfj60]

Yes you're correct I did pull the cap off to find TDC on #1. I have not pulled the cap back off to see if there is arcing happening. I was thinking the engine would not run with the Off. But maybe Im misunderstanding?

If it is arcing electrical, you should see some visible indications of that on the inside of the lid....not with the engine running. I can't really see that being the case, arcing enough to hear it and it still running ok but worth looking inside. There is a little plastic dust cover over the pickup that could possibly pop loose and be making contact with the rotor blades...I'm just throwing out ideas of what could make the sound you're describing.

Just saw the recording and the first part never posted .. That audio recording is better. I think I can hear the noise. Almost like a tapping noise but at a really high rate...above 2000 bpm at least? If my numbers are right and you are idling at 800rpm, each spark plug should be firing 400 times per minute...times 6 and we're at 2400 sparks per minute..

That's how I go about trying to figure out what a noise is anyways. Figure out its beats per minute if possible and try to match a component that does something at that frequency. YouTube metronome clips help greatly.

If you have verified timing, I would pop the cap off real quick and take a close look at everything. Check the coil wire for cracks or damaged insulation...

 

[UGA2018]

I'm glad you finally heard it and everybody doesn't think I'm crazy. . I will I will pull that distributor cap like you described. I have not done the timing on it so I'm wondering if the timing is off so bad and maybe that's what's causing this. I was on my list after the valve adjustment I haven't got to yet. Been trying to figure out this noise first.

 

[Landpimp]

Any chance any of your spark plugs are loose? They will make a clicking noise.

 

[UGA2018]

OK I think I'm making progress on this. After a good friend came by to put his ear to the engine we decided it is not coming from the distributor. We started playing with some of the vacuum lines that were right above and just to the rear of the distributor. We noticed that some of the connections seem loose and so we thought that the lines could be bad or the connections were bad. I decided to replace them with the hopes that will fix the problem. This of course is assuming we have now discovered a vacuum leak.

Unfortunately that did not stop the noise. But what I noticed is the line in the picture that goes to the bottom of the air housing unit seems to be the trigger for the noise. If I understand this correctly it's plugged into the HIC. You can see the picture that I grabbed below. Am I correct in thinking this is the HIC?

The line that I'm referring to is the one that is going to Port B in this picture. When I pull that line off of Port B the noise stops. When I put it back on the noise starts again. So it makes me think that it's not able to properly suck air through the line.

What I have unplugged it and let it just pull air from the atmosphere it works great. The engine sounds like it run smoother and the noise stops.

Any thoughts on next steps? Is this a bad HIC valve?

THANKS FOLKS!

 

[CaptClose]

Exactly what part is making the noise Mike?

A faulty HIC could cause a vacuum leak and create a rough idle or stall the engine. You can test your HIC to see if it's operating as intended. I'm not sure these guys are still available new, but you can probably pick one up in the parting out section.

If you live in a warmer climate, you may be able to delete this auxiliary system all together. The HAI brings hot air to the carb to prevent it from icing over in extreme cold weather. Some emissions guru can chime in with the possible side effects of running without it.

Questions like these really make me miss @Output Shaft

 

[UGA2018]

I've been reading more about the HIC based on what @CaptClose posted and other info I have found online. My initial thinking is the HIC is just clogged and not functioning correctly. But now I understand the airflow comes through it at different rates based on temperature.

The vacuum leak sound does not appear to be coming directly from the HIC. It is somewhere else to the left near the hoses that I put in the previous picture. However, when I pull the line off of the HIC the leak goes away.

This makes me believe that the HIC isn't functioning as it should. I am not sure why but I have one theory on that.

There is a hot air intake duct like the one in this picture on another truck. It was falling apart when we attempted the valve adjustment so I pulled it off. So now I am thinking that hot air is not going into the air housing unit and impacting the HIC. That seems too simple but I guess sometimes these things are. Would that make sense?

Any other thoughts @CaptClose @mwebfj60 @BGarcia88FJ62 @NeverGiveUpYota

Thanks!

 

[NeverGiveUpYota]

Do you have a mity vac? Maybe the diaphragm on the air horn is blown. and air is escaping down that cloth covered section... (that area is meant tho for pulling hot air up). I can see (maybe I am wrong, my truck does not have this) that the white part appears as if it should be pulled down flush with the rusty ring an inch below it.

 

[NeverGiveUpYota]

Whoops, just read that is not your truck. Sorry my mistake for skimming. I'll say I do not have this equipped on my truck and when it was running when I first got it from VT there was no issue without the hot air duct being hooked up. I "believe" its not pertinent. But someone will correct me if I am wrong.
And your saying you can hear air escaping to the left of the hoses in the pix above so you mean closer to the firewall?

 

[Landpimp]

Any chance the pcv valve is making noise?

 

[UGA2018]

Yes @NeverGiveUpYota. The sound is near the firewall. Check out the picture here that describes it a bit more.

 

[UGA2018]

Is this PCV? That is the general area of the noise?

 

[UGA2018]

@Landpimp Do you think the PCV valve would make this noise when the hose is plugged in to port B on the HIC and no noise when it is unplugged? Thanks!

 

[Landpimp]

Yes that's the pvc valve.

Possible....

 

[UGA2018]

So should I try to swap the PVC valve and see if that does it? My temptation is to believe it is something wrong with the HIC because when the hose is plugged into the HIC it makes the noise at the PVC and when it isn't plugged into the HIC it doesn't. But maybe I'm thinking about this wrong.

 

[NeverGiveUpYota]

Also I tend to wonder if the VCV there is leaking too. Have you checked it (you would put vacuum to the S port)? And the PCV can be pulled (yours is metal, which could be good, poss not) and spray the snot out of it with brake cleaner. My old one was plastic and loaded with sediment so bad it had zero movement. Once I sprayed it out and tapped it over and over on a paper towel the rusty sludge all came out and I could then see the valve inside it move up and down with motion.

 

[NeverGiveUpYota]

Also... just saying but your vac hoses on that VCV look like they have seen better days.... 3mm (~25') and 6mm (~10' or less) hose to replace all of them.