Sudden rough idle & Hesitations after parked overnight!

[Beachdrifter]

Yes it is important the hoses go to correct location because the distributor port vents when the solenoid is not feeding advance.

Rich,

Wow great info appreciate it. That bench test is pretty handy. I took the vacuum solenoid out. Performed the bench test, thankfully had everything I needed.

-hooked up 12 volts to the terminal and heard a click.
-with the valve still activated on 12 volts, attached a hand vacuum pump to center port, and it held vacuum.
-with the valve inactive, 12 volts taken off, the valve did not hold vacuum while plugging outer port. So per the bench test, failed #3.

Could this little bugger be all the heart ache?

I could attempt at this point doing a self fix by applying silicone to the base of connector as described in the bench test or order a new valve.

I actually used my own saliva as the "soapy solution " and at that point could hear the air sucking under the base of the connector.

Maybe we're onto something here or coincidence

Thanks

[Rich]

Maybe we're onto something here or coincidence

You found one of the two issues you can have with these. A vacuum leak in the connector seal or the body. Fixing it can help with an idle issue depending on how big the leak is.

That won't fix an issue with the vacuum advance. Seems like your solenoid passed the vac advance open/close test.

[Beachdrifter]

Here's an update,

So I played around with the vacuum solenoid, tried to do the temp fix on it but seems like it still leaks by. Anyways, I'm sure it's been doing that forever probably and likely isn't the cause of my rough running condition, but it was nice to know how that worked. So I ordered a NOS one from DMCH to put on later.

This morning I replaced the spark plugs anyways -- was a quick job and figured why not? It was time anyways and they looked like they needed replacing.

Started the car and still runs rough. Now I noticed a random infrequent backfire in the exhaust .

I think I've reached the point of giving up, because everything else related to vacuum advance, distributor, and anything else is beyond my skillset.
I may need to take it to DMCFL to have them give it a full look over. I'm very interested to see what this is that was caused over one night.

Basically, I give up. I admire those that have the original engine like me, but I'm seriously considering an engine swap or EFI conversion.
Any good shops in FL or any takers for a project like that?

[Rich]

Sorry it's been hard to get the engine back in shape there. This answer isn't about helping you with a fuel system swap.

It's another diagnostic question plus a recommendation for one more bit of possible troubleshooting. An easy test for the right shop.

a. Are you sure you are getting backfire at the exhaust? Not in the intake? Intake backfires are common if the engine is stumbling or misfiring badly on accel.
b. If it's in the intake then a (big) vacuum leak is high on the list of causes. That would fit with the other symptoms. If it's due to a failed component or vac hose connection then it could appear "overnight", too.
c. If it's verified as exhaust backfire then ignore this post. The only PRVs I've heard with exhaust backfiring were running with performance cams, backfiring only on hard decel.

T-shooting a vac leak: The simplest and best way to rule out or find a vacuum leak is with a smoke test. The best test will be done at a shop with a proper (>$1K) smoke test unit, very likely at DMCFL if you can't find somebody closer. Should take less than an hour including setup. The basic prep is pulling the air filter box off so they can seal the air intake on the metering unit.

....Started the car and still runs rough. Now I noticed a random infrequent backfire in the exhaust .

I think I've reached the point of giving up, because everything else related to vacuum advance, distributor, and anything else is beyond my skillset.
I may need to take it to DMCFL to have them give it a full look over. I'm very interested to see what this is that was caused over one night.

Basically, I give up. I admire those that have the original engine like me, but I'm seriously considering an engine swap or EFI conversion.
Any good shops in FL or any takers for a project like that?

[Ron]

Started the car and still runs rough. Now I noticed a random infrequent backfire in the exhaust .

Maybe try, pulling the plug wires one as a time while it is running. Listen for one that does not change the sound of the engine when you pull it.
(If you have one or more, it could be igniting fuel from misfires in the exhaust.)

===========

+1 on smoke test.

[Bitsyncmaster]

One last low cost thing to try is some injection cleaner in your tank of gas. That may help if something in you FD has gummed up.

[Beachdrifter]

Sorry it's been hard to get the engine back in shape there. This answer isn't about helping you with a fuel system swap.

It's another diagnostic question plus a recommendation for one more bit of possible troubleshooting. An easy test for the right shop.

a. Are you sure you are getting backfire at the exhaust? Not in the intake? Intake backfires are common if the engine is stumbling or misfiring badly on accel.
b. If it's in the intake then a (big) vacuum leak is high on the list of causes. That would fit with the other symptoms. If it's due to a failed component or vac hose connection then it could appear "overnight", too.
c. If it's verified as exhaust backfire then ignore this post. The only PRVs I've heard with exhaust backfiring were running with performance cams, backfiring only on hard decel.

T-shooting a vac leak: The simplest and best way to rule out or find a vacuum leak is with a smoke test. The best test will be done at a shop with a proper (>$1K) smoke test unit, very likely at DMCFL if you can't find somebody closer. Should take less than an hour including setup. The basic prep is pulling the air filter box off so they can seal the air intake on the metering unit.

Thank you Rich, appreciate your time and response. I actually took the spark plugs out again and readjusted gap to .028. I was a bit on the low side and think that was causing a random backfire. I'll restart the car tomorrow and see if that fixed it, probably was my wrong doing.

But if all else fails will take it to DMCFL for a good vacuum test.

In almost 20 years this is the first time the car has defeated me lol. I surrender.


Thanks.

[Beachdrifter]

One last low cost thing to try is some injection cleaner in your tank of gas. That may help if something in you FD has gummed up.

Thanks Dave, hey couldn't hurt, which one do you recommend? I heard seafoam is good?

Thanks

[Beachdrifter]

Maybe try, pulling the plug wires one as a time while it is running. Listen for one that does not change the sound of the engine when you pull it.
(If you have one or more, it could be igniting fuel from misfires in the exhaust.)

===========

+1 on smoke test.

Thanks Ron, will keep this in mind, when I pulled the new plugs again to adjust the gap, I saw they were all discolored slightly from use, so I assume each cylinder is firing.

[Jonathan]

I didn't read in detail all of the previous comments, but another random thing I've encountered on our cars is the air filter housing impeding the smooth movement of the air/fuel plate. I have found that if the plastic housing is not on straight, or is tightened down a little cock-eyed, it can make it hard for the plunger and plate to move freely/easily. So, a quick test would be to take it off completely and try and run the engine without it on, just to see how it is. It won't hurt anything if you're letting it idle in the driveway running without the filter.