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wont idle, vacuum leak?

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Old 03-25-07, 04:54 PM
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wont idle, vacuum leak?

just got it all together, turbo everything onto a NA block. LIM port matched to na block. ETC, ETC.

wont idle, i can hold it above anywhere above 1.5k, but it bounces around on its own before settling down. if i start it and let it go itll go to 1500 for a second and then die out, same if i am holding it and just let it off.

got it to stay at 2k, spraying starter fluid around the LIM to block flange makes it rev up.

I had just used RTV and no gasket before between the lim and engine, and thought it was the problem so i ordered a brand new gasket and replaced it, but its still doing it.

spraying in that area it still revs up, but i cant pinpoint exactly where the leak is.
is it possible that the new gasket is leaking? or do i have a vacuum leak from somewhere else?
Old 03-25-07, 07:59 PM
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also if i keep it alive till it warms up, i get a little white smoke out the back and off of the downpipe and exhaust side of the turbo, could that be coolant or oil not circulating right?
Old 03-25-07, 08:24 PM
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I had the same problem with my N/A once, I had disassembled the UIM to replace my pulsation damper. I used an Atkins intake gasket and I immediately had a rough idle which I didn't have before. I use propane to check for vacuum leaks and there it was.....leaking at the manifold flange. I took it back apart, compared the Atkins gasket to the OEM one that I had replaced, and noticed the Atkins gasket was about half as thick as the OEM one. I picked up a new gasket from Mazda, re-assembled it, and I had a perfect idle again. Not all aftermarket gaskets are right for the job. I would imagine that the manifold flanges warp a bit during assembly, requiring a thicker gasket.
Old 03-25-07, 08:30 PM
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As for the white smoke, is it coming out the tailpipe or just around the turbo/ downpipe area?...there's a coolant hose that connects to the rear side housing that goes to the throttle body or bac valve. You might have disturbed the hose and caused it to crack and leak.
Old 03-25-07, 08:57 PM
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Same happened to me turboing my N/A...I used stock Turbo manifolds (ported)... I made my own gasket and rtv'd the block around the ports, and on the manifold around the ports and then torqued the bolts down....Idled like a charm
Old 03-25-07, 10:14 PM
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smoke is coming out of the tailpipe barely and off the turbo/dp area, theres a pinhole in the rubber feed hose i ran but i put the clamp over it temporarily till i get the idle fixed, it doesnt leak but i think its steaming out of there maybe? tailpipe might be something else. not sure really. i ran the bac feed as the turbo feed and the bac return as the turbo return, im thinking it might not be returning and is just cooking in the turbo, im not really sure. maybe ill try running it somewhere else?

on the LIM, ive used jsut rtv once and just a gasket now, im not sure my leaks coming from there as spraying anywhere under the UIM makes it idle up. i sitll have oil injectors, theyre just capped off with caps on the vacuum nipple and the oil lines going to them. maybe the caps are leaking?

the uim to lim gasket is some kinda blue paperish one i got with the manifolds, dude said it was a new mazda gasket.

ive taken off the uim a million times though, maybe it wont seal after its been torqued a few times? ill try a little rtv next time on each side.

and i guess if i cant track down something else leaking under the uim, ill tear it apart and do the lim to block with rtv and gasket.
Old 03-26-07, 08:17 AM
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Are you premixing?...the reason I ask is that the oil injector nipples are not supposed to be capped off.....if I remember correctly, the hoses are there as a vent to allow the injectors to flow oil. The OMP is a low-pressure pump and there needs to be a vent there to allow flow. Much the same as ketchup flowing from the bottle....it would flow better if there were a hole in the bottom of the bottle ( but who ever does that lol) well you get the jist anyway.

EDIT: I just noticed in your post that you said the injector oil lines were capped as well, so disregard my blah blah blah lol.

As for the turbo being the culprit on your white smoke, doubtful. The coolant passage in the turbo's center housing is separated from the shaft seals. If the housing were cracked, for instance, you might get some coolant into the oil return or perhaps an external leak, but not likely out the exhaust pipe. You could temporarily route the coolant around the turbo (bypass it) to test if the smoking stops. it won't hurt the turbo, as a lot of aftermarket turbos are oil-cooled only. Engine coolant seals are a possibility, so read up on checking those.

Last edited by scrip7; 03-26-07 at 08:35 AM.
Old 03-26-07, 01:43 PM
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so its probably leaking on the turbo and burning up, makes sense.

or the engines smoking and i have an exhaust leak, either one i usppose.

i guess ill replace the oil injectors with bolts, maybe those caps are leaking.

vacuum leaks are frustrating.
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