Ok so I had a tob go bad on me, I have had a slave cylinder go bad fixed both of them. Now is what I need help with. I swapped out my rev3 intake mani for a new JMF billet mani, s90 74mm tb. I noticed on my old milspec tb I lost one of my screw heads and the butterfly is loose. Thankfully it was still on the car. Problem is I had major leak and could not find it to save my life. Fast forward new stuff goes on the car and now I have really bad idle surge. I fixed all the leaks I could find, tuner telling me has to be somewhere in the tb or intake mani. I trust my tuner and reinstalled new isc being I had 3 others laying around that were known to be good. All 3 of them keep the car surgeing and idk what else to do. I hooked my tester up to the tb put 20 lbs of air and no leaking at all, put it back on the turbo and found a few small leaks but nothing around the tb. Idk what is causing this surge does anyone have any ideas.I don't know what else to do and I am out of ideas. Thanks in advance

 

if no boost leak... tuner should be able to tell you what is wrong.

 

Maybe not because might be too obvious, but eventually a defective Blow Off?

 

Thats what I thought too, but he keeps insisting that maybe my isc is bad, or there is something else wrong being there are only a few things that will make a car surge. The last isc I tried car held steady at 2000 rpms and wouldn't move or go down. I tried to adjust the bis and once I touched the tb started surging yet again. I don't have any more isc's to try but hopefully my buddy will get one off his car which I know is good, and let me try it. If it still surges then I will look at the tb more closely. When I inspected it when I put it on the car didn't look like there was anything wrong with it being it is used it looked brand new still, but I think that will be the plan.

Bov wont make the car surge. It didn't do anything like this with my old intake and tb. So with that said I will rule that out, although it did cross my mind. Thanks for the replys guys.

 

if the TB was the issue... you would catch it during the boost leak test i would think.

 

Right, which is why I am starting to think it maybe the isc. But I bought 3 used ones off a local buddy of mine who parts evos who told me they were good off running smashed evos. Thing is I went through all 3 isc's and still have this issue. I was so hung up on it being a leak I never thought it would be an isc issue till now. Every isc I have put in has had a new o ring installed with it, so that shouldn't be an issue but idk anymore. The only other guy I know with an evo out here works just as much as I do so getting to do anything with him is a *****.

 

ive put used isc on cars before... never had an issue.
hard to believer everyone of yours is bad.
i vote tune issue.

 

I agree with you on that its what I thought all along. Only thing that would make me think it wasn't tune related would be if the leak was gone after having one is the car would die instantly on startup. Being the tuner would have had to compensate for the leak in the tb. Car doesn't do that it will run but surge. I haven't had a chance to get to the car again being my job sucks and I work a **** tone of hours. This weekend I have to help the gf move, so another weekend I wont get to work on it. My tuner has looked at the tune that I have in the car from the last guy who tuned my car and he said that it has issues, but its not bad. If he wasn't in PA I would just haul it down to him and say fix it lol. I do not want to put the rest of the turbo and **** on the car when I know I have something wrong. I have a buddy going to bring me a known good isc and we are going to rule that out for sure. Idk when he will make it over but stay tuned. Thanks for all the responses guys

 

Did you recover the screw?

 

Being I did not build this motor the answer sadly is no. I do not know when it happened. I am going to guess it happened in my old motor being we had a hard time tuning it before I had Force build me an engine. Once we got the new motor in it fought us all the way. I just find it hard to believe that a screw head litterly broke off and never noticed it till after new stuff went on and since I gave it to a buddy to use