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Rough idle and engine noise after turbo install

Old 08-20-2012, 10:27 AM
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And you've triple checked all of your couplers/clamps for tears/holes/leaks?
Swapped the AFM back to the stock one?

It'll end up being something simple....
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Old 08-20-2012, 10:32 AM
  #42  
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Yupp i went through and checked everything i pretty much took it all apart and put it back together again and made sure everything was on right
Yeah i have my stock afm on
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Old 08-22-2012, 07:50 PM
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Ok so i fixed the exhaust leak today i just changed my manifold and thats good now my only issue now is how it idles. The rpms drop to the point where its barely staying on then jump back up to over 1000 rpms and it will just do this for a while sometimes it will setle at around 850rpm but as soon as you give it gas and let it idle it will do it again. Something worth mentoning is that i thought maybe my timing could have gotten moved or somethig so i went to set it and when its at 10deg it idles rough but if i advace to say 14 it idles better i tried setting the idle control while at ten deg but that didnt make anything better
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Old 08-23-2012, 06:38 AM
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Is this still with the bigger injectors that you can't actually control?
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Old 08-23-2012, 08:02 AM
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The timing marks on our cars tend to move after 20 years due to damper elastomer fatigue.
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Old 08-23-2012, 08:57 AM
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Well im running a vortech fmu for now previous owner said it had a 12:1 or 1:12 disk And according to this site Fuel Injectors - Miata Turbo FAQ my ecu should be able to handle the 1.8 tan tops im using.

I have e-manage blue ready to be hooked up tho im just looking around for a base map for it does any one have one? Or maybe a reference to a good guide on tuning it?

I didnt know that about the timing how would i check if mines like that?
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Old 08-23-2012, 09:00 AM
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Originally Posted by 7j0rdan7
I didnt know that about the timing how would i check if mines like that?
drop your dipstick in #1. turn the crank by hand until it reaches TDC, check pulley alignment to timing marks.
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Old 08-23-2012, 09:00 AM
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Could be bad IACV. Could be your car freaking out over the larger injectors with no real control. Just because it'll run or idle doesn't mean it's right.

What does your wideband say?
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Old 08-23-2012, 09:18 AM
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tan tops should be no issue.
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Old 08-23-2012, 05:51 PM
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So this morning i decided to mess with the timing beause it made my car idle abit better last time i tried it and i somehow accidetaly disconnected the bov vacuum line to throttle body and i started up my car and to my surprise it idles pretty good and i thought maybe that was because it was stilll cold so i let it warm up and i noticed it was idling above 1000 rpms but it was idling perfect and i gar it gas and it didnt struggle to stay on so i cheked te timing and it was at like 16 deg (i left it at ten yesterday) so i lowered it to ten and to my surprise it idled smooth but i could hear a vacuum leak then i noticed it was unplugged and i plugged it in and instantly it started idling bad and it lowered my timing to less then ten so i raised my timing to ten but it was idling like it has been all rough so i unplugged the bov and it idled high but smooth so i set it to ten again and plugged the vacum nipple with my finger and it idled smooth so now im thinking maybe i have a bad bov??? What do you guys think i should do?
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Old 08-24-2012, 01:17 AM
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Remove the bov and plug the hole. Are you running a vent to atmosphere bov? If you plan on sticking with the maf sensor you will have to reroute the bov to the intake just before the turbo.
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Old 08-24-2012, 07:31 AM
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Well thats the issue. Your vta bov is hanging open at idle and drawing in un-metered air. Either ditch the maf or recirculate the bov to inbetween the turbo and the maf.
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Old 08-24-2012, 07:55 AM
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Or just... you know... fix the BOV. It shouldn't be open at idle if it's a VTA.

"Yes" to recirculating post maf/pre turbo if you go that route.
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Old 08-24-2012, 02:35 PM
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Nearly all VTA bovs are open in idle. Adding a stiff enough spring to keep them closed usually results in surge.
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Old 08-24-2012, 04:51 PM
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If you don't want to plumb the BOV to recirculate the air behind the MAF to solve the problem, leave the BOV alone with no vacuum line attached. Plug vacuum line and drive the car. BOV stays closed and the car will run just fine.
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Old 08-24-2012, 04:58 PM
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And then you'll feel like you're being chased by helicopters.
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Old 08-26-2012, 03:52 PM
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Originally Posted by Leafy
And then you'll feel like you're being chased by helicopters.
Lmao thats hilarious!!!

I recirculated the bov and i can run the car now without it dying just one problem... No boost!! My boost gauge shows no boost at all but when im driving i can hear my turbo spool and i can hear the bov dumping the air when shift but theres no boost!

Also i drove it to my new house and parked it and when i went to turn it on again it was dying unless i gave it gas i thought maybe the timing had moved so i cheked it and and it was at ten but dying if i advanced it a crazy ammount it would stay on but idle at about 1200 rpms but it wouldnt shake it would run smooth and i noticed my vacuum while at ten degrees was at 8 and when i had it advanced itwould vacuum at about 15.

Also if i lowered my timing to ten degrees it would smoke like vapor from around the upper radiator hose area

Last edited by 7j0rdan7; 08-26-2012 at 07:08 PM. Reason: Added info
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Old 08-26-2012, 07:48 PM
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Dude take some pics. Somethings fucked up with your install.

There should be no smoke coming out from anywhere.
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Old 08-26-2012, 08:44 PM
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It almost sounds like you haven't adjust your idle to the proper rpms. By unplugging your BOV you're introducing more air, giving the illusion of a more open throttle. Unplug enough vacuum lines and you'll have a 7250rpm idle.

Keep everything plugged in (bov, boost gauge, etc), and with your crappy idle, adjust the idle screw to a 850rpm idle.

There could be something screwy with how you've plumbed your BOV, either to the wrong side of the throttle body or something's screwy with the recirculating parts. Like triple said, we need some pictures.
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Old 08-27-2012, 10:37 AM
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Originally Posted by triple88a
Nearly all VTA bovs are open in idle. Adding a stiff enough spring to keep them closed usually results in surge.
Well... all four that i've run on my other turbo car stay closed at idle... otherwise they act like a huge vacuum leak and the car doesn't run.

No surge issues.

Tested and proven:

Greddy Type S
Greddy Type RZ
TurboXS RFL
HKS Racing Type 1 (current)
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