Got my new Blackwing Installed tonight and went fine and runs great. My only question is now its got an erratic idle. When i pushing the clutch and pull it out of gear to coast to a stop, the idle tanks down to 400 rpms and then bounces up to 700 or so where its more stable. Its even cut off once or twice. Question, will this go away once the computer learns the new air box? I checked the codes and don't have any current. Any ideas?
Ed

 

Humm thats weird. Mine never did anything like that. Double check everything and make sure all seals are 100% tight dont want any leaks. I found it best to mount the complete blackwing to MAF and air bridge then install on car. That way you know the critical seals are good.

If you know all is good maybe do a search on idle relearn procedure (although I found this doesnt seem to do anything). Or just let the car learn and see what happens.

 

The Blackwing does not significantly deviate from a "stock" air-flow pattern to cause these issues.

In most cases, faulty installation is to blame; re-check all fittings, couplers, etc. for leaks.

 

I did assemble the whole blackwing unit outside with the bellows and then reinstall to the throttle body. I will go in though and recheck all the hose clamps and fittings for a tight seal. I had a tough time getting it to slide back over the TB, the angle seems to have changes slightly. So possibly there is a small leak there. I'll retighten the hose clamps and see if that helps clear it up.
ED

 

If that does not work disconnect the battery for 30 minutes then reconnect it let it warm at idle for a while and take it for a cruise

 

go through these steps.

http://www.c5forum.com/diy/idlerelearn.php

 

I'd like to know what this is too. My '99 is dead stock and has started doing the exact thing. Seemingly, when cold it fast idles correctly but once warm coming to a stop, pushing in the clutch it will (only sometimes) drop the idle to 3 or 4 hundred then picks back up to about 600.

Idle relearn had no effect. Battery is a new red-top, seems to be no voltage problems, have seen many posts along the lines of "rough idle", "erratic idle", "low idle". Never seen anything definitive...

 

Did you change the airfilter or did it just start happening? I was extra carefull, but I hope its not the MAF sensor? Anyway to know?
Ed

 

if I were to guess, I would say it sounds like some kind of vaccum leak. In the past when dealing with vaccum leaks, I put together a solution of water and dish soap (3:1) in a spray bottle and where I could (staying away from electrical components), I would spray the solution on hoses, air lines, etc and sometimes I would find bubbles where it was leaking. Worth a try or easier still just listening for the hissing...but erratic idle sounds like the engines computer is trying to adjustments on the fly and finding the right fuel/air mixture which it will never be able to do if it can't hold vaccum...just my 2 cents worth

 

Got tired of it tonight, have done an "idle relearn" procedure driven it a 100 miles or so. Gave up, reinstalled the stock air box, everything is fine! No surging at cruise and the low idle is stable and staying between 700 and 800 when taken out of gear. As opposed to dipping down to 300 or 400 and sometimes stalling out. Im at a loss!

Dumb questions, should the filter be oiled prior to use? The instructions didn't say you have to, I assume it was pre-oiled. Any ideas? I emailed Corvettes of Houston to see if they had any insight?
Ed

 

Please post a solution when you get it. My 99 just started doing this yesterday - I've made no changes?

 

ttt

 

I know this post is old now but the funny thing is I replied to this post saying mine has never done that. Well guess what I noticed today while coasting down from 60mph in nuetral (6spd)? idle was bouncing all over the place from as low as like 400-500 then surges back up. When the car gets to a stop it idles fine (little ruff but it always seems to have done that). Maybe I will re-install my stock air box and see what happens.
Any more info is appreciated.
Thanks

 

JTS, what type of airbox did you have on it? I did take mine to a local tuner who specializes in corvettes. He adjusted most of my idle problem out. Its much more stable now. He also tuned it a bit and managed to get 331 rwhp and 340 rwtq. Not bad for a stock ls1 with only a Blackwing.
Ed

 

Ed, over the history of that air intake it has been known to cause that problem on some cars. You did the best thing you could have by taking it off and saving yourself the headache. That kind of is not worth 10 HP or so.

VR

 

The other day after noticing my idle doing weird things during deceleration (not to mention horribly choppy idle since day one of blackwing install) I installed the stock airbox again. Not thats it hard only took 20 minutes or so. Anyway I put stock air box back in and did the correct idle relearn procedure. The car no longer surges and my idle is VERY smooth now. Infact I cant believe that I left the blackwing in long as I did. Cant notice much power difference maybe mid range but overall full throttle still seems very strong. I guess for now I will leave stock air box in and if it stays this good when the computer fully learns I will just sell my blackwing.

 

Don't give up, try this...

I had trouble with the Blackwing on my '03. It would sometimes die if I pushed the clutch in at freeway speeds, and it idled rough. The problem was I had a leak after the MAF that was only showing up with the hood closed. No codes, just a crappy idle and it would sometimes die.

What I found was the air bridge grommets didn't seat down all the way into the two posts that stick up, one on either side of the air bridge, and when the hood was closed it was pushing down on the air bridge, creating an air leak after the MAF. That raises hell with the computer.

I finally figured out that the snout of the Blackwing was simply too long.

So I marked it, and took a hack saw and carefully cut off about 1/4 inch of the Blackwing inlet snout and it bolted up just fine after that. There was still plenty of snout to mount the coupler to, and the air bridge grommets seated all the way down on the posts.

Voila! No more problems!

When I bought my '04, the first thing I did was buy a blackwing, and sure enough, it didn't fit right either. I knew what to look for with this one, and I could tell I had the same problem when the two air bridge grommets didn't seat down all the way onto the pegs. So I cut 1/4" off the inlet snout of the Blackwing and VOILA! It fit like a glove.

So check to see if the air bridge grommets are seated all the way down, and if they aren't, you might want to try my mod.

If you do this, make sure to stuff a bunch of rags inside the blackwing so you don't get any filings down in there. You don't want plastic particles in your intake.

Make sure you cut evenly and don't cut off too much! 1/4" should do.

Good luck.

 

Thanks Steve,
That could be the cause! I've noticed that once it was mounted, it didn't sit down flush on the radiator shroud and I couldn't get the studs back in, I just accepted it and didn't think closing the hood would be flexing it enough to cause a gap. I'll try it.
Ed

 

Not the case for me. My blackwing was seated all the way down on the radiator shroud tabs and I know for a fact I had no leaks. Heck, just sit at idle in the car with hood up and it made no difference. Stock air box is in and car idle perfectly smooth. Not sure what else to say. Not sure what it id about the blackwing the car does not like.

 

I fought with that Blackwing and the leaness it caused in the A/F mixture (and resulting ping) from the day I installed it on my otherwise stock '04.

I finally removed it in favor of the stock airbox and like others have said, the surging and the pinging vanished...AND the airbridge fit right once again.

Another thing I noticed in the posts here is that while those who have installed this gadget in other threads, openly brag about the seat-of-the-pants improvement it made....no one so far has mentioned any such "seat-of-the-pants' degradation in the level of performance by removing it.



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