Miata Turbo Forum - Boost cars, acquire cats.

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-   DIY Turbo Discussion (https://www.miataturbo.net/diy-turbo-discussion-14/)
-   -   Turbo boosting 2psi only, stumped. (https://www.miataturbo.net/diy-turbo-discussion-14/turbo-boosting-2psi-only-stumped-79433/)

cjsafski 06-11-2014 02:10 AM


Originally Posted by whinin (Post 1138042)
Turbo spins freely by hand, spins for a bit after idling for a minute.

It should always be spinning. Even right after start up all my good turbos spun.

krissetsfire 06-11-2014 02:16 AM

Have you verified base timing is set? My first guess would be same as sav. wastegate issues but you say you've tested them. You also say your wide-band is reading rich.

It would have to be a SERIOUS leak that would be madly noticeable without any real testing to lose that much boost. I drove home the other day with a cracked injector o-ring and a leaking coupler. I could easily hit 6 psi. Spool took a little longer but it would get there.

Make sure your base timing is setup correctly?

chiods 06-11-2014 09:04 AM


Originally Posted by krissetsfire (Post 1138952)
Have you verified base timing is set? My first guess would be same as sav. wastegate issues but you say you've tested them. You also say your wide-band is reading rich.

It would have to be a SERIOUS leak that would be madly noticeable without any real testing to lose that much boost. I drove home the other day with a cracked injector o-ring and a leaking coupler. I could easily hit 6 psi. Spool took a little longer but it would get there.

Make sure your base timing is setup correctly?

Base timing wouldn't have that profound on an impact. After seeing where he says the turbo will spin after a minute of idling and he had tried to clock it that's the issue it's not 100% straight and the wheels don't wanna spin. Op take the housing back off and reattach it properly. Watch a YouTube video if you have to

whinin 06-11-2014 10:23 AM

It's not that either, I had this problem before I even tore the car apart. Way back 2 months ago. Even so, the only thing I did was take the vband off, and once I saw how big those c clips were I put the vband back on. I've watched videos of it.

Someone asked me to see if the turbo spinned AFTER SHUT DOWN from idle. That's what I meant when I said 'turbo spins for a bit after idling for a minute'.

I set base timing about 2 weeks ago. Had to go so far as to pop the #1 cyl plug out and crank on the crank bolt till I got it at tdc so I could see the mark on the crank pulley. Couldn't see it before because it didn't have any white out on it.

krissetsfire 06-11-2014 10:50 AM


Originally Posted by Full_Tilt_Boogie (Post 1138267)
Kinda sounds like its detonating
either that or you were driving through some gravel

When I listen I hear det too maybe i'm wrong. Timing being off a bunch wouldn't affect det would it?

Does your car run nicely with the wastegate open? As in it idles smooth and you could daily the shit out of it and flog on it? From the video it just doesn't seem right. boost or no boost. that's all.

whinin 06-11-2014 11:23 AM

Haven't tried tying the wastegate open yet, I may have to later today. It doesn't idle smooth anyways since I have a slightly bigger injectors in there.

krissetsfire 06-11-2014 11:57 AM

As you may have seen others bow out. You have bandAIDS.

1) open the wastegate and get your car running to satisfaction without boost.
2) Do some research about ECU's; invest in something.
3) Ditch the bandaids. Boost for reals.

I'm taking my bat and glove and going home. peace.

18psi 06-11-2014 12:00 PM

He really is a lost cause.

Full_Tilt_Boogie 06-11-2014 12:04 PM

I like how fixing the bandaids meant removing one.

whinin 06-11-2014 12:52 PM

Yes there are better (much better) options out there, I know this. Shit, I had a mspnp ready to go for my '96 when I had planned on turbo for it. This does not solve my problem though. My bandaid is not preventing the turbo from boosting past 2psi. I checked my piping (took it all out of the car, connected everything like it was in the car) and the piping is hold pressure. When I popped out the pvc plug I made, it popped. So it's holding pressure.

concealer404 06-11-2014 12:54 PM

I mean.. if you're detonating nice and hard, it would absolutely keep you from making boost.

dieselmiata 06-11-2014 12:55 PM

Have you disassembled the turbo and inspected the wheels? Is it possible something destroyed the vanes of the exhaust wheel and it won't catch the exhaust flow for crap?

whinin 06-11-2014 01:13 PM

I'm not detonating, I definitely know what that sounds like. I keep telling you guys, the thing that sounds like rocks in my video is my loose shit knob.

I have not taking apart the turbo, I did take a peek inside when I had everything else off the motor. I know there are parts of the wheels that hide inside the turbo that you can't see from the outside, but from what I could see they are fine.

On a note of my post above, I did forget to put my pipe in that I had made so I could hook up my IACV hose. I am leaking there. I sprayed some soapy water on it, and it shot it off the pipe, so a pretty significant leak. But my question (and I think I know the answer, Savington mentioned it) if it is leaking all the way at the throttle body, would the pressure be the same at the wastegate?

Also, I do appreciate all the help guys. I won't be able to post back in a few hours, work called me in to cover a minor shift.

concealer404 06-11-2014 01:42 PM

So... you have a gigantic boost leak.

Miater 06-11-2014 04:41 PM


Originally Posted by whinin (Post 1139118)
When I popped out the pvc plug I made, it popped. So it's holding pressure.

??? PVC plug ???

Edit; I'm guessing its for testing IC pipe.

whinin 06-11-2014 05:52 PM

Yeah I got a 1.5" pvc pipe plug, drilled a hole for a valve stem, capped one end and put that on another and used a bike pump to test pressure! Now I know what it is, I will attempt to fix it with some jb weld. Take out the brass hose barb, put some on the threads, and then some on the outside and hopefully it will hold.

If not, what do you guys use to to route your IASC valve to the intake?

concealer404 06-11-2014 05:54 PM

Pics of what you're talking about?

whinin 06-11-2014 07:10 PM

1 Attachment(s)
https://www.miataturbo.net/attachmen...ine=1402528236

The stock hose goes to the side of the crossover tube to get air for the IASC valve. This is what I made, a 90 deg brass fitting with a hose barb end and used a piece of heater hose to make the connection.

whinin 06-15-2014 06:37 PM

Everything back together, no boost leaks, double checked with hood off, soapy water sprayed around the connections. I did have one at the beginning, but fixed it. Turbo still only does 2psi.

Going to cut out my catalytic converter Tuesday and just put a straight pipe in the place for now, tie the after cat o2 sensor out of the way.

If that still doesn't solve my issue, what else could there be? Compared to my '96, there is no power, even with 2psi. It takes it forever to get to 40 mph in 2nd gear.

mlev 06-15-2014 06:39 PM

Just disconnect the exhaust behind the DP, no need to cut anything. Run straight DP dump and see if it helps.

My apologies if you meant cut figuratively.

I still think you need to check the turbo over more carefully. I spent two days chasing your exact problem and then the front fell off.


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