superman112

Man I hope someone here can help me... I have a 5-speed 05 mustang GT. Had the 1st JLT CAI, Hooker LT headers and 4'10 geaqrs. Had the CAI for about a year with no problems. Oh also have Dougs 93 Perf/trqe tunes. A few months ago I started getting a code that I was running too rich, so I called Doug and he recommended I get the JLT II. I order it and installed it last week and its been nothing but problems. When I installed the updated tune the car was a BEAST. Until I engage the clutch to downshift and make a turn. Now whenever I engage the cluth my RPM's drop way to faqst and my car stalls. Called Doug and he doesnt think its the tune (me neither) and said I might have an air leak somewhere. Well I have checked eveything from the plastic elbow by the TB to the PCV hose and nothing. Still having this same problem. Worse thing is I just order the Comp Cams stage 3'sw from Doug and now I'm worried I cant even drive me car to the shop to install the Cams. Does anyone have any suggestion??? Its really wierd, as soon as I push the clutch the rpms drop to about 500 and then jump between 500 and 750. One thos times my car has stalled while driving.. as soon as you engage the clutcdh the rpms drop to about 200-300 and the car stalls. I really hope someone can help. Thanks in advance

dustindu4

That's normal, mine does that. You should be talking to Doug not us

G.T

i had EXACTLY the same problem
it started before i even touched my car with any mod, and gradually got alot worse
eventually it turned out my TB was faulty
so i threw the stock airbox back on, flashed the stock tune and took her in for warranty repair.
got her back the next day good as new and i haven't had the problem since.

check out my old thread for more info and two videos of the RPM fluctuation (never shot a vid of it stalling though )

first observation: http://forums.bradbarnett.net/showthread.php?t=49258

complications later: http://forums.bradbarnett.net/showthread.php?t=55245

superman112

I did talk to doug and he said to just make sure there was no air leaks.

superman112

hey thanks for the links.. that second one is exactly what is happening to me.. I wonder if it could be the TB... it just would seem like a pretty wierd coincedence that as soon as I installed the new intake this happened. The hard part is once before I had this probelm and I took it to ford to get it repaired under the TB TSB and because they couldnt replicate the probelm they wouldnt repair it under warranty. So now I dont know if I should just try and reinstalled the 1st JLT or what. **** this sucks!

superman112

when you installed the JLT II did you do that procedure for the car to "re-learn" the idle? Wonder if I should try that?

G.T

nothing really helped in my case

i reflashed the tune, reset the computer alltogether and let the car relearn the idle.. no luck

anyway, both links above are threads started by me, on the same problem.

first thread was when i had no mods, and my RPM would fluctuate while idling, and drop below 400 and sometimes stall completely

the second thread was after i installed my JLT-II and had the symptoms worsen..
basically my car would stall whenever i'd let the RPM drop freely (for instance while downshifting slowly), or even if i fully depress the clutch while the car is going at a rather high speed.. then my RPM would drop to 0 and the engine would stall
fortunately being in a manual trans car, i could simply engage/disengage the clutch the engine would crank back up (if it happens to you anyway you can press the clutch, or shift into N if it's an auto, and turn the engine on with the key)

i strongly suggest you put back your stock air box and flash the stock tune then take it in for service

TillmanSpeed

There's a problem in the throttle body that we've had many times. We've adjusted the spring tension in the throttle body (which you can get to from the drives side under the plastic cap on the thottle body). It was only a temporary fix before needing to have Ford replace the throttle body after numerous failsafe modes. Problem went right away after coming back from Ford.

CR
Tillman Speed
610-497-3711

Modular81

Put the stock air box and tune back in and try to reproduce the problem. This way you can see if the problem is cold air and tune related. If the problem comes back even with the stock intake and tune back in your car then the jlt2 and tune had nothing to do with it. Go to your ford dealer and have it looked at by the pros. Good luck!

superman112

now if I put back the factory tune and air box, because I changed the gears the speedo will be all messed yup. Will they give me a problem about that>?? That's really what I am concerned with. I guess the consense is its the TB. Hey CR how exactly did you adjust the springs??

G.T

i doubt they'd even know about your rear end gear swap unless you told them about it.
since your problem is in the intake/TB.. just put your stock intake and stock tune back on.. and you should be good to go for a dealer service.

as for the spring, i believe he's referring to the retention spring inside the actuator on the right side of the TB.
don't mess with it as yet, as that's a sure way to deny your warranty claim for now

superman112

cool.. thanks G.T. I really appreciate it.. I'm installing the factory air box now. Lets see if it continues...

G.T

i struggled with this for 4 months, so it rang a bell right away

good luck Raf

superman112

well.. just installed the factory air box and tune and now the car is barely idlin g about 500 rpms. Sounds like an old crop buster now. The rpm needle now is moving in neutral.. something it wasnt doing w/ the JLT. I am letting it get to operational temp but the car sounds like its gonna die at any moment.

G.T

well that's good.
at least it means the dealership would see the problem for themselves!

http://www.iihs.net/rpm-issue/idle_fluctuation.wmv <-- this is a video i shot of the needle dancing on its own.. i wasn't touching the accellerator

superman112

you sound hear it... it actually sounds like a crop duster.. well the rpms are now steady at 500 I totally forgot what it should be on a stock car. I'm about to drive it so lets hope nothing bad happens! Quick question about the JLT II. The holes on the billet housing for the MAF, thoise didnt come with any sort of rubber gasket did it? I know the old one does.

G.T

you mean to plug the hole left behind when you removed the MAF?
no that's always been empty.. no plug comes with the series II for it

superman112

no i meant the holes where the screw goes... ok this is really wierd. I drove the car on the "factory" tune and air box and nothing happened.. i was able to make a few turns with now problems. The wired this is my speedometer wasnt messed up>> Now maybe I am thinking wrong here but since I have 4'10s in and the stock tune shouldnt my speedo have been incorrect???? also I wonder if I am running too rick cause all of a sudden my slp tips are BLACK!!! and its from today. man this is starnge.. so could it be the intake then? or maybe the tune is too rich? CR... if the tune is too rich could that have been causing me to stall when I deccelerate??

G.T

man.. you're thinking too much about it!
anyway, regarding the screw holes on the JLT.. no there are no plugs or gaskets on them.

and you won't notice the TB problem as much on the factory tune, as that has the throttle lag in place, and isn't as aggressive as the performance tune you have from bamachips or anyone else.
but essentially the problem is still there, although the symptoms don't show as bad.
furthermore, regarding your speedo.. exactly how can you tell that it's accurate? got a GPS?
anyway i wouldn't worry about that now so don't try to solve the wrong problem

finally running rich could cause you to backfire and cause carbon build up on the exhaust tips, but it will not cause your idling issues.

superman112

well when I 1st got the gears put on I had to drive around for a few days with an old tune that didnt update the gear ratio. I would be in 4th at 2000 rpms and my speedo would read 80 mph.. so it was pretty off.. now when I was going with traffic down my road we were all going around 30 and that's about what my speedo read.. so I dont thinkits dead on but it is alot closer then when I 1st got the gears. dude.. you decribed me to a tee.. I DO think and worry to much!! Ha ha I'm trying to work on it.