Popping coming from exhaust while idling

[masonmort27]

My exhaust note changed whether idling or driving. You’ll know for certain when you pull the exhaust and have a look,

So BOTH cats are hollow. I guess I was misinformed by previous owner as to what they were/ he hollowed them out. Good to know, but a dead end.

Sponsored

 

[Timbuck]

Interesting.. sure sounds like a misfire.

how is it when you hold it at higher rpm like 3500 constant ? Is the miss the same ??

id try an isolate it while engine is running. start with 6 and 7.

one coil could be a little open circuit and not giving the amps it needs for proper spark.

maybe. unclip a coil at a time and see if it will go away or then you could try moving a coil to the opposite side. see if the pop moves over to the other side.

 

[masonmort27]

Interesting.. sure sounds like a misfire.

how is it when you hold it at higher rpm like 3500 constant ? Is the miss the same ??

id try an isolate it while engine is running. start with 6 and 7.

one coil could be a little open circuit and not giving the amps it needs for proper spark.

maybe. unclip a coil at a time and see if it will go away or then you could try moving a coil to the opposite side. see if the pop moves over to the other side.

Here’s a video holding it at 2k.

I’ve thought about the coils too, but I am hesitant to switch them around because I read elsewhere on here that the computer learns them and that they become cylinder specific? And haven’t seen anything else confirming/denying this

 

[Timbuck]

There is NO learning at all with coils. Swap them to any cylinder , it’s the only way you will know if 6 and 7 are the issue.
swap the coils takes less than a few minutes and you will know straight away if there has been a change. This will be a process of elimination.

 

[Timbuck]

Man. Listening to that 2k video sure is a random soun That’s got my brain thinking

 

[masonmort27]

There is NO learning at all with coils. Swap them to any cylinder , it’s the only way you will know if 6 and 7 are the issue.
swap the coils takes less than a few minutes and you will know straight away if there has been a change. This will be a process of elimination.

All the coils are good. Swapped each one on driver side to cylinder 1 one at a time. No change in the sound at all

 

[HKusp]

I would pull the cam covers and get a look at the retaining clips and other assorted parts and pieces under them next. If all of that looks good, I believe it may be bore-scope time in the cylinders.

 

[masonmort27]

I would pull the cam covers and get a look at the retaining clips and other assorted parts and pieces under them next. If all of that looks good, I believe it may be bore-scope time in the cylinders.

Yea the shop has a theory that it’s a lash adjuster or follower, but I figure if it was that it would be loud under the engine bay. And it’s not

 

[Timbuck]

That’s good. I’m with Jason. get those valve covers off and inspect. The compression test being ok throws me a curve ball. Because it sounds like a valve problem , misfire caused from a broken spring or cam lobe. But a broken or Stuck lifter on the exhaust side would give similar symptoms as the exhaust valve would stay shut.

 

[masonmort27]

That’s good. I’m with Jason. get those valve covers off and inspect. The compression test being ok throws me a curve ball. Because it sounds like a valve problem , misfire caused from a broken spring or cam lobe. But a broken or Stuck lifter on the exhaust side would give similar symptoms as the exhaust valve would stay shut.

Yea it certainly sounds like a valve issue, but nothing is adding up. Scheduled to take it to the shop next Thursday and they are gonna pop the valve covers off. I’d love to do so myself just to get a look in there before they do, but I don’t feel confident enough in myself lmao

 

[Timbuck]

Only one way to learn mason. There is nothing you can fuck up taking valve covers off. Curiosity would kill me waiting till next Thursday.

 

[horsepower addiction]

There is a lot of complaints about those plugs, causing misfires. It’s a well-known problem with those plugs. I would put the 6510s in it and bring the gap down. also, did you check the gap on the plugs or did you just assume that the pre-gap was what it’s supposed to be. Like I said these plugs are known for misfire problems. First thing I would do is swap out those plugs with a ngk6510 with a 28 gap before I started thinking about Pulling valve cover covers.
You said a Shop tested the spark plugs exactly how did they do that? There’s not really a way to know if they’re firing right underload not underload or at temperatures or at idle bears,not really a test also these spark plugs require more current to fire those plugs are also known for overheating coils and causing more problems. I’m not saying that i100% the spark plug are your problem but I’m saying 100% you picked the wrong plug.

 

[masonmort27]

There is a lot of complaints about those plugs, causing misfires. It’s a well-known problem with those plugs. I would put the 6510s in it and bring the gap down. also, did you check the gap on the plugs or did you just assume that the pre-gap was what it’s supposed to be. Like I said these plugs are known for misfire problems. First thing I would do is swap out those plugs with a ngk6510 with a 28 gap before I started thinking about Pulling valve cover covers.
You said a Shop tested the spark plugs exactly how did they do that? There’s not really a way to know if they’re firing right underload not underload or at temperatures or at idle bears,not really a test also these spark plugs require more current to fire those plugs are also known for overheating coils and causing more problems. I’m not saying that i100% the spark plug are your problem but I’m saying 100% you picked the wrong plug.

They never tested them they just checked the gap and discoloration along with the relative compression test. I switched all of them from bank 2 to bank 1, and the sound did not move, so I don’t think it’s spark plugs. The shop has been using these ruthenium plugs for a little while and they haven’t had any issues with them.

 

[horsepower addiction]

Do a simple search of ruthenium plugs and misfires
They require more power to jump the gap so your coil might not have enough depending on what the gap is this also heats up the coil causing it to overheat. You need to run a smaller gap than 6510’s. Just because they come pregapped doesn’t mean they are right or for your setup

 

[masonmort27]

Do a simple search of ruthenium plugs and misfires

1. If it was the type of plugs themselves, I would think it’d be happening on both sides
2. If it was 1 or 2 plugs specifically, the sound would’ve moved around when I swapped em around

Sponsored