Hunting idle, vacuum leak from JLT CF tube?

[Klinsmann18]

Got car last Monday and drove it home, everything was fine. Didn't drive it again until tonight when I took the wife for a spin. Had 55 miles on it. Over the weekend I did the full detail, installed the NXT hood struts, catch can, JLT CF intake tube, and Airraid dry, blue filter.

The total drive wasn't more than 10 miles, we took it to pick up dinner, however, I noticed that the idle seemed to be hunting and other times the RPMs seemed high or surging. There was also quite a bit of "rocking" from the engine, similar to if a car had a lopey cam. When I got home and put the car in neutral (parking brake on), I got out to pop the hood and listen underneath...the car stalled out on it's own.

I checked the catch can hoses and intake connections and all clamps are tight, immobile. The JLT CF tube is butted against the throttle body and the connection to the air filter guard. Perhaps I need to remove and reinstall? My guess is there is a vacuum leak? I looked at the boost gauge on the cluster at idle and it was reading 20mmHg. The two hoses to the intake are connected, but the larger one does seem as though its plug in the intake tube is "loose". Also, there was hardly any whine from the SC that I could hear when getting on it, but there was definitely power. What do you guys think?

P.S. I have learned quick that you need to respect this beast. Nothing near a crash or anything like that, but the rear of the car WILL get loose on you real quick even in a straight line.

 

[Devious_Snake]

Im not sure of the issue, have the same setup and have not seen or experienced that. and yes the car is a monster!

I would reinstall the intake tube, make sure you have the right gaping on either end. Also pose this question in the GT500 section, some of those guys have experienced this from what I read on previous models

 

[flyby763]

Check your connections...you have a vacuum leak somewhere...

 

[Chuck@Evolution]

Who did your tune?

 

[Zeroescence]

Who did your tune?

He shouldn't have needed a tune.

 

[91svtbird]

Most likely a leak in the CF tube where it clamps on to the TB. I've seen the CF tube distort from being tightened too much and I've also seen them come loose from not being tight enough.
If this happens un-metered air will enter the engine causing the MAF readings to be off thus the idle issues as well as a potential lean condition throughout the power band.

IMO This is an inherent problem with going with the CF tube and why I don't like it over the hard plastic tubes or OEM molded rubber ones. IMO You just never know if or when it may come loose or be distorted causing an air leak.

They do look nice though...lol

 

[Dick Lyon]

I got my fit from JLT and noted in their instructions that without a "tune" to go with the install serious damage to the engine may result. This was after I read on the forum of installs and "no need for a tune" comments. I talked to JLT yesterday and they reiterated that a tune "is neccesary"......For now the Big Air kit remains in the box.....

 

[flyby763]

I got my fit from JLT and noted in their instructions that without a "tune" to go with the install serious damage to the engine may result. This was after I read on the forum of installs and "no need for a tune" comments. I talked to JLT yesterday and they reiterated that a tune "is neccesary"......For now the Big Air kit remains in the box.....

That's a different kit than what he has. They make the big air kit and a basic resonator delete.

 

[91svtbird]

I got my fit from JLT and noted in their instructions that without a "tune" to go with the install serious damage to the engine may result. This was after I read on the forum of installs and "no need for a tune" comments. I talked to JLT yesterday and they reiterated that a tune "is neccesary"......For now the Big Air kit remains in the box.....

Does the JLT new tube for the 13's also house the sensor like the older 07-9's or does it just replace the tube between the TB and the meter tube/sensor (like a resonator delete does)? If the latter then it won't require a tune.

 

[Zeroescence]

Does the JLT new tube for the 13's also house the sensor like the older 07-9's or does it just replace the tube between the TB and the meter tube/sensor (like a resonator delete does)? If the latter then it won't require a tune.

Its the latter, its the same one used on the 10-12. It does not require a tune.

 

[0mineralgrey3]

Lund told me that if you have an intake you MUST have a tune. Also...there is a factory retangular gasket on the MAF. Did you remove that and use the new gasket from jlt?

 

[Klinsmann18]

Who did your tune?

As others have stated, it shouldn't require a tune. If problems persist or I do need some goodies I am not far from you guys. My In-laws live/wife grew up about 10 minutes away from your shop. My father-in-law use to work with one of your employee's Dad.

Most likely a leak in the CF tube where it clamps on to the TB. I've seen the CF tube distort from being tightened too much and I've also seen them come loose from not being tight enough.
If this happens un-metered air will enter the engine causing the MAF readings to be off thus the idle issues as well as a potential lean condition throughout the power band.

IMO This is an inherent problem with going with the CF tube and why I don't like it over the hard plastic tubes or OEM molded rubber ones. IMO You just never know if or when it may come loose or be distorted causing an air leak.

They do look nice though...lol

Interesting, did not know there was that much of an issue with distortion. I made sure not to over-tighten the clamps though so as to not crack the CF. It is snug though.

I got my fit from JLT and noted in their instructions that without a "tune" to go with the install serious damage to the engine may result. This was after I read on the forum of installs and "no need for a tune" comments. I talked to JLT yesterday and they reiterated that a tune "is neccesary"......For now the Big Air kit remains in the box....

Like a couple others said, only the Big Air kit should require a tune.

I'll try and get around to taking ti apart today, looking over its structural condition again, and reinstalling. Will report back. Thanks everyone.

 

[Dick Lyon]

Having the Big Air kit I have also ordered the Lund tuine from Lerthal....the combination should be exciting......like the car isn't exciting enough as is.

 

[Klinsmann18]

*looks around at the sky whistling*

so how about this, decided to check the oil separator after looking over intake real good before tearing it down........the drain valve was pointed down, which if standard engineering serves me correct, means it was open. I was rotating the bottom fitting once installed to better align hoses and I must have pushed it open. I double checked pics here and to be closed it should be perpendicular.

Haven't taken her for a spin, but she started fine and worked to a warm idle OK with good vacuum and A/F ratios on the gauges. DOH!

 

[Devious_Snake]

*looks around at the sky whistling*

so how about this, decided to check the oil separator after looking over intake real good before tearing it down........the drain valve was pointed down, which if standard engineering serves me correct, means it was open. I was rotating the bottom fitting once installed to better align hoses and I must have pushed it open. I double checked pics here and to be closed it should be perpendicular.

Haven't taken her for a spin, but she started fine and worked to a warm idle OK with good vacuum and A/F ratios on the gauges. DOH!

 

[Klinsmann18]

 

[91svtbird]

Lund told me that if you have an intake you MUST have a tune. Also...there is a factory retangular gasket on the MAF. Did you remove that and use the new gasket from jlt?

Maybe your taking him out of context and he meant the CAI's that replace the meter tube which houses the sensor itself. If that's the case I would agree.

 

[0mineralgrey3]

I'm sorry. I didn't realize they made just a CF replacement tube for the 13. I have the entire intake tube. I'm actually fixing to sell it as JLT just released a larger one for the 13's. I have it now and i'm going to swap it later next week.

The new intake...........IS HUGE!

 

[mullens]

*looks around at the sky whistling*

so how about this, decided to check the oil separator after looking over intake real good before tearing it down........the drain valve was pointed down, which if standard engineering serves me correct, means it was open. I was rotating the bottom fitting once installed to better align hoses and I must have pushed it open. I double checked pics here and to be closed it should be perpendicular.

Haven't taken her for a spin, but she started fine and worked to a warm idle OK with good vacuum and A/F ratios on the gauges. DOH!

Wow an open oil separator valve can cause that many issues? I'll have to keep an eye on mine!

 

[91svtbird]

*looks around at the sky whistling*

so how about this, decided to check the oil separator after looking over intake real good before tearing it down........the drain valve was pointed down, which if standard engineering serves me correct, means it was open. I was rotating the bottom fitting once installed to better align hoses and I must have pushed it open. I double checked pics here and to be closed it should be perpendicular.

Haven't taken her for a spin, but she started fine and worked to a warm idle OK with good vacuum and A/F ratios on the gauges. DOH!

LOL un-metered air for sure...glad you found it.