2G serious vacuum leak problem!!

[richard5309]

So, i got a cyclone intake manifold for my 98 gsx and tore down my stock manifold to put it on but then decided against it after realizing the vacuum set up on it was too confusing.

I put all my stock stuff back on and correctly to my knowledge but apparently my knowledge failed me.

I have a serious vacuum leak and i cant find it. My car is idling at 1800 then drops to 1200 and repeats. i sprayed carb/cloke cleaner everywhere and still nothing has been found.

Are there vacuum lines that are easy to cross and/or forget?

Please help! I have to go to work tomorrow and that isnt going to happen if i cant fix this!!!

 

[lastshark08]

Did you by chance put a new gasket in when you did this? I had the same problem when i was going back together. I couldnt get my engine to rev with the choke cleaner anywhere up top, but my leak turned out to be on the lower part of the intake manifold. So maybe you ripped a gasket going back in or something.

 

[LiquidX]

Try doing a boost leak test and spray around with soapy water. You'll be looking for bubbles and you might be able to hear the leak as well to help pin point it. You should do one regardless since you removed intake parts.

 

[lastshark08]

I dont think it would be a boost leak problem do to the reving. That is usually associated with extra air entering after the throttle body.

 

[LiquidX]

Hense doing a boost leak test... You'll pressurize the system and any holes will leak out the pressurized air. When not pressurized, those same holes can suck in air post MAF and cause the issues described above. Granted there are some vacuum leaks that would seal up during positive pressure but generally they will leak during both ends of the spectrum.

 

[richard5309]

Did you by chance put a new gasket in when you did this? I had the same problem when i was going back together. I couldnt get my engine to rev with the choke cleaner anywhere up top, but my leak turned out to be on the lower part of the intake manifold. So maybe you ripped a gasket going back in or something.

yes they are all new gaskets. thats why i am so confused about this.

 

[LiquidX]

I know you are new, do a boost leak test and you will find your problem. It very well could be something small that you missed or it could just be a plug that isn't seated in the whole way. Regardless, anytime the intake system is messed with a BLT should always be performed to at least 20psi with the crank at 30* ATDC to ensure the intake valves are closed.

If you want to persure this more, searching for "idle surge" will help out. Here are 2 links to get you started.
Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge)
Idle Surge FAQ

 

[luv2rallye]

I think you mean 30* BTDC: http://www.dsmtuners.com/forums/attachment.php?attachmentid=121912&d=1303187520

 

[LiquidX]

Which ever, I was thinking the "A" was for after.

 

[1990AWD]

Is the cyclone manifold your putting on the one made for the 6 bolt head?

 

[afoster98GSX]

I would try rerunning the vacuum lines may have made a mistake

 

[newTSIguy]

I went down to my buddy richards house yesterday and helped him sort this problem out, it turned out we had to adjust the tps, and biss, and rerout his vaccum lines. Thanks to the wisemen and all others for your help and advice.

 

[luv2rallye]

Which ever, I was thinking the "A" was for after.

"A" is for after. But 2 cyls intake valves are open "after" which is why you want it before top dead center.

 

[LiquidX]

Oh I was under the impression it was supposed to be after. Thank you for the clarification

 

[lastshark08]

I went down to my buddy richards house yesterday and helped him sort this problem out, it turned out we had to adjust the tps, and biss, and rerout his vaccum lines. Thanks to the wisemen and all others for your help and advice.

Ha that tps can be a pain. Good to hear you solved it.

 

[richard5309]

Yup! Got it all fixed. Lol, except for today I found out the hard way that we didnt tighten one of the hardpiping clamps all the way and popped it out of the couple on the freeway hahaha. But other than that it is all fixed.

 

[hoby0316]

Hense doing a boost leak test... You'll pressurize the system and any holes will leak out the pressurized air. When not pressurized, those same holes can suck in air post MAF and cause the issues described above. Granted there are some vacuum leaks that would seal up during positive pressure but generally they will leak during both ends of the spectrum.

I second this. ^ Do a boost leak test.

 

[newTSIguy]

Yup! Got it all fixed. Lol, except for today I found out the hard way that we didnt tighten one of the hardpiping clamps all the way and popped it out of the couple on the freeway hahaha. But other than that it is all fixed.

better than that coolent line

 

[richard5309]

better than that coolent line

hahahaha yeah thats true