Miata Turbo Forum - Boost cars, acquire cats.

Miata Turbo Forum - Boost cars, acquire cats. (https://www.miataturbo.net/)
-   DIY Turbo Discussion (https://www.miataturbo.net/diy-turbo-discussion-14/)
-   -   Leaning out (https://www.miataturbo.net/diy-turbo-discussion-14/leaning-out-93106/)

devonthedude1234 05-07-2017 08:17 PM

There aren't any puddles, and I keep an eye on the afr gauge all the time. It never leans out with no boost pressure. Before I put the turbo on, it would richen up to about 12.8 at WOT. I've told you pretty much all I've done to the car. what else do you need to know?

Bronson M 05-07-2017 08:21 PM

Let's start with how you converted to a return style system, I assume you removed the in tank regulator? How exactly did you plumb the FMU? How are you monitoring fuel pressure? Any way to tape said fuel pressure guage to the windshield so you can watch FP as you make a pull?

devonthedude1234 05-07-2017 08:28 PM

I used this link https://www.miataturbo.net/diy-turbo...l-style-74629/ . Yes, the in tank regulator was removed. So here's how my fuel system is plumbed: fuel tank, fuel pump, fuel filter, rail, isr fuel rail adapter, afpr, fmu, back to the tank. The only way I can see the fuel pressure is on the afpr. And it's pointed towards the front of the car.

Bronson M 05-07-2017 08:37 PM

Since we're driving finishing nails with a rock...... Point a go pro at the guage and take a drive. Or start throwing parts at it.

devonthedude1234 05-07-2017 08:40 PM

Okay. I'll report back when I figure out what it's doing. Thanks

devonthedude1234 05-07-2017 09:06 PM

I just got done watching the video. The pressure is not dropping. It looks like it's going up a very small amount. I would say 10psi max.

Bronson M 05-07-2017 09:42 PM

So you've verified that things are working in the right direction.

Looking at this link Vortech Fuel Management Units | JEGS

You'll see there are different rising rate settings. Again with the lack of data you've provided I'm assuming that was 5 psi of boost and you saw 10 PSI rise so that would be 2 to 1 and that isn't one of the options. you need to keep cranking up the fuel pressure till you're not lean. If u come back and say you have it setup for 5 to 1 then your fuel pump isn't keeping up . This is assuming you understand that fuel pressure is less than the set point under vaccum, equal to set point at 100kpa and rises at the FMU rate in boost. What actual pressures are you seeing.

devonthedude1234 05-07-2017 09:59 PM

I have an 8:1 disk. I plan to cut a12:1 (2.72") disk tomorrow at work to see if that changes anything... and honestly i didn't watch the boost gauge. As soon as I saw the afr at 16 I stopped. It didn't feel like there was any boost at all though. I didn't rev past 4K

if I crank up the fuel pressure it will only get me to 75ish psi. I think it would still be running lean but I can go try it

with the video I took it was hard to tell... all I can tell is that it's at 60psi at idle and got to about 70psi when I tried to get on it.

sixshooter 05-07-2017 10:14 PM

I like cats.

Bronson M 05-07-2017 10:45 PM

At this point you're lean with 60 to 70 psi something is wrong and honestly there is no good way to trouble shoot it with a FMU. You're left to guessing and checking and doing rediculouse things to try to log data. This is why you got a bunch of snarky smart ass responses when you started this thread. It's expected that you take the advise of those with a high post count or their names in green. I also understand that simply accepting the "because I said so" reasoning behind the short answers is tough to swallow. I'm pissing off the old guard by spoon feeding you but it was obvious your weren't going to figure it out yourself.

Just so you're aware the correct way to deal with this is to wire in a pressure transducer into the fuel system and log it through your megasquirt. This is what I did, I discovered an issue with my fuel pump and corrected it in literally one log and a single click on Amazon for a new fuel pump.

At some point you have to ask yourself, what's my time worth?

devonthedude1234 05-07-2017 10:53 PM

well I don't want to bother anyone anymore. Thanks for the help.

Schuyler 05-07-2017 11:03 PM


Originally Posted by DNMakinson (Post 1412018)
Welcome back, @Schuyler! Seeing you post again is the redemption of this thread.

Thanks David! I am in China this week, but work is slowing down some. I've been spending ~1 week a month at my house lately. Hopefully going to start putting some time in to the car here soon and begin posting once again in my own build thread. I'll post my to-do list once I'm back state-side. I have a track day scheduled in July, as well as a travel freeze for that month. So, I'm running out of excuses to not get working on the car.

I may be reaching out to you regarding some MS stuff in the coming weeks.

DNMakinson 05-08-2017 11:13 AM


Originally Posted by Schuyler (Post 1412080)
Thanks David! I am in China this week, but work is slowing down some. I've been spending ~1 week a month at my house lately. Hopefully going to start putting some time in to the car here soon and begin posting once again in my own build thread. I'll post my to-do list once I'm back state-side. I have a track day scheduled in July, as well as a travel freeze for that month. So, I'm running out of excuses to not get working on the car.

I may be reaching out to you regarding some MS stuff in the coming weeks.

Sure. Remind me where you are located now. What track would you be running?


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