Idle hanging bad after Roush AB install ???

So I got the JLT CAI installed, had some issues getting the tune to work but worked with Lund on getting that squared away. As expected, they said once my Roush arrived I could install it with no changes to the tune. Well I installed it over a week ago and love the sound, but for some reason my car developed a bad idle hanging. I can't guarantee 100% it wasn't there before the exhaust, but I surely notice it now and it's driving me nuts! It hangs for s good few seconds and all the way at up to 2k, so it's very annoying!

I asked Lund about it, and he said the tune won't cause idle hanging, which I find odd but he's the expert He told me to try clearing the KAMs via the X4, which I did, and that seemed to actually make it worse. He then said to try to do idle re-learn via the owners manual instructions, which I haven't done yet but the instructions are odd as it just seems like you idle and drive the car like I normally do everyday anyway Plus, the instructions are pretty specific about being in Park and Drive so I'm not sure what exactly I need to do for a manual transmission I did load a new tune that Lund gave me to return the fans to stock operation per my request, hoping the new tune would fix it, but alas it still has the same issue :(

I'm on vacation now so I can't mess with the car, but would like to see if anyone else has seen this issue especially with similar mods as I have. All else fails I will start taking off mods one at a time to figure out the cause, first being to try the SCT canned tune for JLT, then taking off the JLT altogether if that doesn't work. I hate to do that but this really sucks.

Crap video but best one that shows the idle hanging....

I don't think the exhaust caused an issue, but you likely hear it more easily.

Just watched your video, sounds pretty good. I think the easiest thing to try is just drive it and put some miles on it to see if it can correct itself.

Check vacuum lines...

Here is my car after my Roush AB install just a few days ago. That is the only mod to my car unlike your JLT and tune.

[ame]

Grimace427 said:

I don't think the exhaust caused an issue, but you likely hear it more easily.

Just watched your video, sounds pretty good. I think the easiest thing to try is just drive it and put some miles on it to see if it can correct itself.

Click to expand...

I've done that, and seems to have gotten worse. Not sure how long/how many miles this sort of thing takes??

1g4my2g said:

Check vacuum lines...

Click to expand...

Will do when I get back. Plan to check on the whole CAI and oil separator since those are my only engine mods (besides tune of course)

Have you tried putting back the factory tune? This is one of the reasons that i won't go the tuning route before the warranty expires! I ll be installing the same exhaust this weekend and let you know if i end up anything but a healthy growl!

What issues did you have with the Lund tune? I have a tune ready to go on but amd waiting for my intake to arrive.

Tunes usually fix all the hanging idles once the ecu learns again. It can take a full tank of gas actually for it to do this procedure.

By owning a 2015 GT myself and being a service advisor at a Ford dealership, I have not only experienced this with my car but have seen it on others. The most common thing that I am seeing is rev hang after a high RPM rev or pull. All that I have seen so far is that emissions control system will keep the throttle body open for >3 seconds to burn off any excess fuel that may be sent to the engine when you take your foot off of the gas.

*This may not be your concern and I am not trying to diagnose it over the computer, but I hope this may at least point you in the right direction!

BTW: Car sounds awesome!:clap2:

-Tyler

As with any car with an electronic TB the computer has to relearn after a flash/reset. Drive the car for a few days and see if it gets better.

My car was reflashed by the dealer through a PCM update, and I had the same symptoms. It went away and got progressively better every morning I cranked it up. I wouldnt worry about it unless it does it consistently for a while.

Sasuketr said:

Have you tried putting back the factory tune? This is one of the reasons that i won't go the tuning route before the warranty expires! I ll be installing the same exhaust this weekend and let you know if i end up anything but a healthy growl!

Click to expand...

Can't really unless I take off the JLT (won't run right with factory tune)

anotherneon said:

What issues did you have with the Lund tune? I have a tune ready to go on but amd waiting for my intake to arrive.

Click to expand...

It was just a compatibility issue with my car, possibly a strategy issue? Had to call SCT and have them send me a file, because it wouldn't let me load the Lund to my car. SCT got it all straightened out and now they load fine.

T.DUKES said:

By owning a 2015 GT myself and being a service advisor at a Ford dealership, I have not only experienced this with my car but have seen it on others. The most common thing that I am seeing is rev hang after a high RPM rev or pull. All that I have seen so far is that emissions control system will keep the throttle body open for >3 seconds to burn off any excess fuel that may be sent to the engine when you take your foot off of the gas.

*This may not be your concern and I am not trying to diagnose it over the computer, but I hope this may at least point you in the right direction!

BTW: Car sounds awesome!:clap2:

-Tyler

Click to expand...

Thanks that's good info! Is this just accepted behavior or is there a fix/workaround?

5.0GT said:

Tunes usually fix all the hanging idles once the ecu learns again. It can take a full tank of gas actually for it to do this procedure.

Click to expand...

Vinny@JLT said:

As with any car with an electronic TB the computer has to relearn after a flash/reset. Drive the car for a few days and see if it gets better.

Click to expand...

Hmmm...I think I did do about a tankful since the JLT install. Put on the Roush about a week after and have noticed it since then (a few weeks ago now, though I only drive the car on nice days). Just loaded a new tune from Lund (just to change the cooling fan parameters) so I'll let it relearn for a few days and see what she does.

I have the Roush AB on my 2015 GT and I don't have an idle hang. I had them on my 2012, 2013, and 2014 and they never had an idle hang

My car has the SW catback, JLT, and the X-4 tuner. I was surprised to see when I got the SCT X-4 that there was already a file on it for the JLT. Even with the tune added and the increased throttle response and overall better drivability, I still experience the rev-hang I talked about earlier. I'm sure with custom tuning (which I plan on going with the Lund tunes soon) they could get a bit more specific and possibly fix or at least improve the rev-hang. Hope this info helps!

-Tyler

T.DUKES said:

My car has the SW catback, JLT, and the X-4 tuner. I was surprised to see when I got the SCT X-4 that there was already a file on it for the JLT. Even with the tune added and the increased throttle response and overall better drivability, I still experience the rev-hang I talked about earlier. I'm sure with custom tuning (which I plan on going with the Lund tunes soon) they could get a bit more specific and possibly fix or at least improve the rev-hang. Hope this info helps!

-Tyler

Click to expand...

Yeah my next step is to use that SCT tune for JLT and see if that helps. John Lund told me the tune has nothing to do with the idle hanging, which I find to be an odd statement but I'm not the expert. I'm hoping that it'll just fix itself with some more driving time. :shrug: