Issues with Intake Install

[KillboyPowerhead]

Hello C5,

This weekend I finally installed my new intake (80mm TB, manifolds, spacer, all ported for the 80mm TB), however, after starting up the car the car idled poorly, like a loping fashion, fluctuating between 500 and 1000 RPM, and then when I took it for a spin, when I lay off the gas the RPMs stay where they are as if I were on cruise control. Car drives fine otherwise. From what I've read both issues could be caused by a vacuum leak but I can't find one; tried spraying intake cleaner around the whole intake, throttle body, but no change in idle; tightened down everything to spec; triple checked all nuts and bolts and connectors...

Took everything off and made sure the gaskets/surfaces were clean, reinstalled, took if for another spin but still issues. Engine light isn't on and no codes present (although maybe I didn't drive it for long enough). Put the old factory stuff back on and all is well, normal idle, RPMs drop when laying off gas.

Any ideas? Is there a way to test the new intake for leaks with it off the car?

[SIM GhostrdrZ]

Originally Posted by KillboyPowerhead

Hello C5,

This weekend I finally installed my new intake (80mm TB, manifolds, spacer, all ported for the 80mm TB), however, after starting up the car the car idled poorly, like a loping fashion, fluctuating between 500 and 1000 RPM, and then when I took it for a spin, when I lay off the gas the RPMs stay where they are as if I were on cruise control. Car drives fine otherwise. From what I've read both issues could be caused by a vacuum leak but I can't find one; tried spraying intake cleaner around the whole intake, throttle body, but no change in idle; tightened down everything to spec; triple checked all nuts and bolts and connectors...

Took everything off and made sure the gaskets/surfaces were clean, reinstalled, took if for another spin but still issues. Engine light isn't on and no codes present (although maybe I didn't drive it for long enough). Put the old factory stuff back on and all is well, normal idle, RPMs drop when laying off gas.

Any ideas? Is there a way to test the new intake for leaks with it off the car?

What tune do you have? Try the overkill tune as he is the only one to know how to tune for that set up. I have all those items and it runs great and very reliable for years now, with the correct tune in it.

[KillboyPowerhead]

No tune, just did the install today. Does this setup need a tune from the get-go or is it driveable without one? I'll be doing a tune once my high-flow cats come in (would be in if it wasn't for the COVID situation).

Did you install a tune during your intake install or did you drive around without a tune for a bit? How did the car run directly after install (if no tune right away)?

Edit: did some more messing around. Disassembled the whole intake and put it back together, made sure it was all good, still issues. Decided to remove the TB and use the ported intake/spacer with the factory TB and it idles fine; RPMs still stay a bit high but do come down, just slower than before; maybe the car just needs time to learn it? Maybe the car needs time to learn the 80mm TB too?

Edit #2: found a throttle body relearn procedure so followed that and the idle seemed much better, then took 'er for a spin and everything felt ok; RPM's still stay a bit high but do come back down; probably just needs a few more drives and all will be well.

[xstuntman]

I would like to read thru this relearn procedure if you wouldn't mind posting it.

[Kessler]

All I did was install, then drove it 700 miles. Runs great now.

Otherwise, disconnect your battery to reset the computer. It will relearn what it needs to run smooth again in about 50-100 miles.

[DSX_Camaro]

No tune? You are getting mighty close to the limit of the stock tune. My car ran okay with every bolt on but not perfectly. I'd definitely recommend tuning it, especially if you decide on high flow / no cats soon.

[Kessler]

Stuck in Calif. Cat mods are frowned upon. All ready have to change the air box just to get it smogged. Runs good for me. Breaks traction when needed on dry pavement, can't take off without spinning in wet weather. Fun to drive.

[KillboyPowerhead]

Originally Posted by xstuntman

I would like to read thru this relearn procedure if you wouldn't mind posting it.

Here you go: This is what I used.

Originally Posted by DSX_Camaro

No tune? You are getting mighty close to the limit of the stock tune. My car ran okay with every bolt on but not perfectly. I'd definitely recommend tuning it, especially if you decide on high flow / no cats soon.

Just waiting on the Solo down pipes and then off to the tuner I go! Although I'm considering the Mace cams as well and am ready to buy anytime, just seeing if the install is something I can do myself.

Originally Posted by Kessler

All I did was install, then drove it 700 miles. Runs great now.

Otherwise, disconnect your battery to reset the computer. It will relearn what it needs to run smooth again in about 50-100 miles.

Yeah, everything seems to be running fine now. I figured there'd be a learning curve but just got sketched out with the RPM's staying high, and with that and the idle loping both being symptoms of a vacuum leak I thought maybe something wasn't right. Also of all the threads I read about the 80mm TB I never once read about these same (or any) symptoms, so thought something was off on my end.

['10CamaroDude]

Originally Posted by xstuntman

I would like to read thru this relearn procedure if you wouldn't mind posting it.

You also have to pull fuse #5 and #20 to reset the Keep Alive Memory.
That is your idle timing, and fuel/timing curves.

Idle the car in park to hot.
Then turn A/C on for a minute.
Then put in gear for a minute.
Then put A/C on, in gear, for a minute.
Then back to park for a minute.


All maps are learned. I did mine, after doing plugs, VVT Solenoids,
and 2nd Cat delete, and it ran totally different.

Depending on the intake, you need a tune. If it's 3.5" and you do not
have the MAF insert, then you need a tune. My intake has a plastic
insert in front of the MAF. I can remove it, then it runs like crap, unless
I tune it.

[xstuntman]

Glad to hear it's running good and a lot of info I haven't heard before.

It's got me wondering if it's a good idea to do the relearn and pull the fuses for just about any mods done. So far I'm just a drop in dry panel filter but planning on the Laminator and a scoop in the future.

[DSX_Camaro]

I just pull the fuses like once every 3 months or so and leave it overnight. I also only ran 93 octane (before tuning, tuned for 93 now) so I wanted to try to keep as much timing as I could.

[mikeman]

Originally Posted by DSX_Camaro

I just pull the fuses like once every 3 months or so and leave it overnight. I also only ran 93 octane (before tuning, tuned for 93 now) so I wanted to try to keep as much timing as I could.

I thought this worked only on the V8 cars?

[DSX_Camaro]

Yes and no. Our cars have distinct timing tables but they cannot access them without tuning, unlike the SS. It does still reset the trims, though.

[TommyJr]

I also have all the 80mm TB goodies, and the throttle hang is there and without a tune terrible. I had Overkill tuning it, but it's still not perfect.

Idles perfect though.

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