AOS mileage drop?

[MrTris]

After adding the JLOSC AOS/Catch Can, I'm noticing a significant drop in milage - anyone else experienced this? Do we know why this happens?

 

[Joseph Garcia]

I've had a catch can installed for a few years now, J&L/JLT catch can, and I have not noticed any decrease in gas mileage.

 

[Marky Dissod]

After adding the JLOSC AOS/Catch Can, I'm noticing a significant drop in milage - anyone else experienced this?
Do we know why this happens?

Most likely, you've unintentionally added a vacuum leak.
Fix that & MpG will be restored.

 

[MrTris]

That's kinda what I'm thinking, but, I don't understand how that piece itself could be a vacuum leak, since it's the only part that was added.

I think what I'll do is disconnect the neg terminal and do a soft reset, see if that changes anything, and then barring that, I'll switch back to the stock hose.

I don't have any diagnostic tools/readers for this platform, yet, so, no way to look at ST/LTFTs or AFRs to confirm.

It's a JL - I can't see the quality being such that it'd do this - hoses are properly seated on their connections, like, it doesn't look like it's an issue.

Should I get hose clamps for the valve cover connections to the intake? They didn't have em, before, but, of course, they were the stock connections..

 

[Marky Dissod]

Were I you, I'd temporarily uninstall the catch can stuff (for diagnostic purposes) and restore it to 'previous'.
Then very meticulously inspect all of the catch can stuff with a fine tooth comb, so to speak;
goal being to find any hidden quality control defects, especially unintended GAPS.

Drive for ONE FULL DAY with it uninstalled, see if MpG is restored. If so, very carefully reinstall.
If MpG is still 'wrong', seriously consider a smoke test, or a starter fluid test?

 

[MrTris]

It's not just mileage - throttle response and shift points, too.

Put the stock pipe back on and all of those things improved.

I really wanted to like this thing, too.

After about 25-30mi I had a ~1-2ml in the can, so, it definitely works!

But that juice is just not worth this squeeze.

 

[Joseph Garcia]

That is really bazaar. Something has to be defective in the can/hoses/connections.

 

[MrTris]

That is really bizarre. Something has to be defective in the can/hoses/connections.

I've emailed JL, they responded with a video to inspect the o-rings in the hoses, as sometimes they can come unseated. Mine were fine, upon inspection.

They're sending a replacement and I'll send mine back for inspection.

 

[MrTris]

So, this turned into a doozy..

Symptoms disappeared when I reverted back to the stock hose.

Today, while running errands, all symptoms returned, rather mysteriously.

Additionally, oil pressure is now closing in on 20psi at idle at stoplights.. Didn't used to do that, and did appear during the time I ran the AOS, but, has now reappeared.

Could I possibly have a stuck PCV which was uncovered and exacerbated by the AOS?

 

[Joseph Garcia]

So, this turned into a doozy..

Symptoms disappeared when I reverted back to the stock hose.

Today, while running errands, all symptoms returned, rather mysteriously.

Additionally, oil pressure is now closing in on 20psi at idle at stoplights.. Didn't used to do that, and did appear during the time I ran the AOS, but, has now reappeared.

Could I possibly have a stuck PCV which was uncovered and exacerbated by the AOS?

It is probably time to check that out, before trying anything else.

 

[Marky Dissod]

So, this turned into a doozy ...
Symptoms disappeared when I reverted back to the stock hose.
Today, while running errands, all symptoms returned, rather mysteriously.
Additionally, oil pressure is now closing in on 20psi at idle at stoplights.
Didn't used to do that, and did appear during the time I ran the AOS, but, has now reappeared.

Could I possibly have a stuck PCV which was uncovered and exacerbated by the AOS?

More likely a hose is compromised or a grommet or plastic nipple has a crack in it,
or something like that, something easily overlooked / non-obvious til it gets looked at with a magnifying glass.

 

[Fless]

Put a scanner on it and look at the short- and long-term fuel trims, both at idle and at 1800 rpm or so. Then post them up here.

 

[MrTris]

I think I have a proximate cause : Fuel dilution.

Last long highway cruise was about a week after I got the truck, in July.

Since then, it's had probably 1000mi at least, of short trips. After an ECU reset, the shifting and driveability issues went away (so far, fingers crossed) but I'm getting some oil pressure fluctuations down to about 20psi while hot and idling in traffic.

Got an oil change scheduled, shortly, so, that should give them an opportunity to inspect things as well as likely solve the oil pressure issue due to fuel dilution, which, as I understand, is common in the L86.

TLDR, I probably just need to drive the damn thing more.

 

[Marky Dissod]

How often do you 'normally' change your oil? WHEN do you experience oil consumption?

Doubt I'll convert anyone, but my experience says anything over 0.5qt of oil consumption = time for an oil & filter change already,
don't give a schidt how many miles, or what the oil life monitor says.

 

[MrTris]

Got the oil changed and no change to oil pressure at hot idle - still hovering around 20psi, according to the gauge.

Dealership did the change and a, "multipoint inspection," and came back with nothing wrong. They're the ones warrantying it when there's a catastrophic failure, so, if there was anything wrong, they'd have said something.

Actually had a great experience with the dealership, too, so that was a big plus.

I'm probably getting stressed out over nothing. Truck drives fine, hot idle is at 20 and that's apparently where it's supposed to be. Is what it is.

Their stories are nuts, though. People are.. Ugh. People. Like, your vehicle is your freedom -- don't you want it to work every time? Then why is going in for an oil change every 6mos at least, a, "hassle?"

 

[Joseph Garcia]

20+ psi at fully hot oil idle for a stock motor is normal for these trucks. Even my modified truck motor holds 20+ psi at fully hot oil idle.

You do want to see a significant jump in oil pressure at 2000 rpms, though.

 

[MrTris]

Much of this is probably, "new parent syndrome," but, I'm used seeing the oil pressure no lower than 30, so, when the temp is hotter, water temp is in the middle at 210, and I see the oil pressure drop down further than I've seen in the 3mos I've had it, I'm gonna start asking some questions.

It definitely goes back up to 40 or higher with throttle inputs, so, it's doing what it's supposed to, there.

In the Subaru world, we'd call the AccessPort the AnxietyPort because with the extra gauges and readouts, if you're not entirely familiar with the nominal ranges, something can seem amiss..

I'll get around to installing the replacement AOS next weekend when I get back from getting married.. We'll see how it goes.

 

[Joseph Garcia]

Much of this is probably, "new parent syndrome," but, I'm used seeing the oil pressure no lower than 30, so, when the temp is hotter, water temp is in the middle at 210, and I see the oil pressure drop down further than I've seen in the 3mos I've had it, I'm gonna start asking some questions.

It definitely goes back up to 40 or higher with throttle inputs, so, it's doing what it's supposed to, there.

In the Subaru world, we'd call the AccessPort the AnxietyPort because with the extra gauges and readouts, if you're not entirely familiar with the nominal ranges, something can seem amiss..

I'll get around to installing the replacement AOS next weekend when I get back from getting married.. We'll see how it goes.

Getting Married? Congratulations!

I hope that your wrenching days are not over.

 

[MrTris]

Getting Married? Congratulations!

I hope that your wrenching days are not over.

Thanks!

Getting married for the first time at 40 is.. Interesting. I would love for us to be even ten years younger, but, I had some real growing to do in that time period to be ready for this. Our own personal history is important, which is why I have few regrets.

She absolutely lets me do Guy Stuff and even encourages it - I got a good one, I know.


Evidence : First time we went shооting, I picked up her Cerakote'd AR (that I built for her) from my FFL that was in the area we were staying and we went out to run it. One of his buddies was also on this (private) range and had offered to let her run it with one of his cans. Not a huge fan of loud noises, so obviously, she thought it was pretty neat and asks, "How soon can you get me one?"

I simultaneously breathed a sigh of relief, but also sarcastically thanked dude for putting me out at least another 4k, lol.

That said, we haven't yet combined finances, and I'm not (able to) buying anything in this ****** state, but will likely pick 'em up once we move down south.

Realized too late that I probably should have done a generic, non-Amazon registry so I could ask for cases of ammo..

 

[MrTris]

So, I haven't reinstalled the new AOS, one thing at a time, here, but, I did want to address something that's not entirely visible from the pics - vacuum leak.

The intake came with new hoses and connections for the valve breathers, but, they're not sealed, at least, not well. The hoses come off pretty easily, which means, when we're talking physics, air will choose the path of least resistance - in this case, a loose hose connection.

I ordered some spring clamps, Hillman 59741, 15/16ths spring clamp. They're not gray, but rather real close to ODG, which, luckily is also my jam, and only a minor concern because this is top engine, visible stuff.

Applied four of the twelve clamps (for which I think I paid about $12) and started up. Idle smoothed down seemingly quicker.. Took it for a little romp.. Throttle response and intake noise sounds.. More correct.

I'll put this one in the W column.


Probably wait until next weekend, just for the sake of, "science," before adding the AOS..