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Old 08-17-2012, 02:08 AM   #1
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Unhappy Rough idle and engine noise after turbo install

Hey guys so i recently installed my turbo and now my car is acting weird! Im using an older flyin miata manifold and downpipe and an older fm2 intercooler im also running 1.8 injectors and a 12:1 vortech fmu and msd the turbo is a garrett t25
What happens is that when i turn on the car the rpms go down and the car strugles to stay on the rpms bounce up and down. Also it makes a very loud noise i thought it was my exhaust manifold gasket so i replaced it again and that wasnt it. I called flying miata and i was told to check my cylinders by unpluging the plugs each one by one and the plug 4 didnt make a difference o the cars behavior when unplugged there was also a small amount of oil on the plug so i redid my valve cover gasket and cleaned it all up. I thought maybe the wire was bad so i borrowed my cusins wire from his miata and that didnt make a difference. I swaped the plugs too and that made no difference them i checked the wire with a light and it light up meaning its working ok. Im out of ideas as to what can be wrong can some one please help????
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Old 08-17-2012, 02:26 AM   #2
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What air fuel ratio is it idling at when its struggling to stay on? You might want to give info on what the car is..
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Old 08-17-2012, 02:28 AM   #3
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Its a 1992 miata1.6 and im not sure because my wideband has not came in im running the stock afm

I ordered an aem wideband from fm

Last edited by curly; 08-17-2012 at 09:40 PM.
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Old 08-17-2012, 08:34 AM   #4
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Get the wideband in, but it sounds like you've nuked cylinder 4. If it was my car I'd be throwing the compression tested on it.
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Old 08-17-2012, 08:54 AM   #5
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Do you have a boost gauge? What's the vac. showing at idle? Did you check the gap on the plug? How did the top of the plug look compared to the other plugs?
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Old 08-17-2012, 04:47 PM   #6
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I just checked my plugs and they are all at 0.045 inches and my boost gauge bounces between 10-15 vac when its strugling to stay on then at times will idle fine untill i hit the gas all the plugs looked the same the one from cyl 4 didnt look any different im going o run. Compression test first thing tomorow morning
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Old 08-17-2012, 05:21 PM   #7
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Http://youtu.be/XMqO_XpdeUw

Http://youtu.be/2MCoVQgi7_Y

Its worth mentioning that i had another turbo manifold and downpipe before this started happening and i upgraded to this setup i have now with my other turbo it wasnt doing this but i upgraded because my turbo was going bad and i found this kit on cl so decided to upgrade everything. Only thing different is i added 1.8 injectors and used a different modified 02 sensor (longer in order to reach) and added intercooler but the car was running ok before this. It wasnt loud and didnt idle like this just the turbo was busted.

Last edited by curly; 08-17-2012 at 09:40 PM.
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Old 08-17-2012, 05:45 PM   #8
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How much bigger are 1.8 injectors?
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Old 08-17-2012, 05:49 PM   #9
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1.8s are 260ccs.

the baby blue 1.6 injectors are 210ccs.

.045 sounds like a big space on the plugs, most people here run .030-.035 on stock coils.

See what the compression test shows.
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Old 08-17-2012, 05:51 PM   #10
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I installed them because i started the car and was doing that so intjought maybe it wasnt gettig enough gas but it did it with 1.6 injectors too
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Old 08-17-2012, 05:52 PM   #11
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Soo... 25% more fuel with nothing to control it.


Either way, i agree with a compression test.
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Old 08-17-2012, 05:54 PM   #12
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Im running vortech fmu 12:1. I thought that gap was too much!! Im gonna replace them and do comression test
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Old 08-17-2012, 05:56 PM   #13
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Quote:
Originally Posted by 7j0rdan7 View Post
Im running vortech fmu 12:1. I thought that gap was too much!! Im gonna replace them and do comression test
That's not what i meant.

You have a MINIMUM of 25% more fuel at any point than you did before, and no way to control it.
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Old 08-17-2012, 05:59 PM   #14
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Oo ok so should i go back to 1.6 inj?? I have emb just bot hooked up bcus idk how to tune it
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Old 08-17-2012, 06:01 PM   #15
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Quote:
Originally Posted by 7j0rdan7 View Post
Oo ok so should i go back to 1.6 inj?? I have emb just bot hooked up bcus idk how to tune it
I doubt it's going to fix your problem, but i wouldn't suggest adding more potential problems into the mix at this point.

I don't know what the rest of your post meant, sorry.
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Old 08-17-2012, 06:03 PM   #16
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I have e manage blue i havent installed et because i dont know how to tune it amd the guy that sold it to me said it was tuned for 11 psi
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Old 08-17-2012, 06:04 PM   #17
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It takes a lot of reading but if you had installed it (properly) you wouldnt be having this problem. Hope you didnt bomb your engine.
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Old 08-17-2012, 06:18 PM   #18
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The weird thing is it was running fine with my last turbo not much is different just manifold downpipe turbo intercooler o2 sensor. After i replaced all those parts it started acting up before i even ran it once then i changed the injectors and it made no difference. So idk gow i could have nuked it...

I dont understand how i could have nuked it if it was running turbo before without theese problems and all i changed was manifold downpipe turbo added intercooler made the o2 sensor longer inorder to reach and i turned it on and it was acting like this so i changed my injectors and it made no difference so i changed exhaust manifold gasket again and redid my valve cover gaskets but it was running fine before its just i had a turbo with shaft play

Last edited by curly; 08-17-2012 at 09:41 PM.
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Old 08-17-2012, 06:49 PM   #19
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In other words before it could have been a dog setup and now its running a lot better pumping much more air however the fuel system was untouched in the process... leaving you with a lean setup in boost.
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Old 08-17-2012, 06:58 PM   #20
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It should be running alot better now but its running worse then before at idle it ahould be normal tho even with the ammount of fuel its getting because its nt under boost right?? I ran it alittle just aroud my block and i got about 4 psi boost and whenever i left it in gear and let the car keep going without giving gas it would quiet down and as soon as i gave it gas it would be super loud again
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