Cx racing turbo kit installed now has rough idle and goes rich after start up
 

Just installed turbo on 92 Miata, currently have stock ecu, stock injectors, wide band sensor. I do plan on purchasing megasquirt ecu, and 420cc injectors. I did first start up it idles fine for about 5 seconds then goes really rich and wants to die. Any recommendations?

Take off turbo kit. Install Megasquirt. Learn to tune. Install injectors, learn to compensate for new injectors. Install turbo kit. Have a great time tuning for boost because you already learned how to do it on a stock motor. Be happy that you didn't blow up a motor using a stock ECU at first.

100% that.

You have to go ecu/wideband, learn to tune, change injectors, tune those and THEN turbo kit.

In that order. Every time, theres no other easy successful way.

Dann

In before blown engine.

How are you going to make sure you have the right amount of fuel in boost? Stock ECU does not support that.

420cc injectors on the stock ecu and it idles pig rich?
I havent a single conceivable idea why.



Did you try researching....at all...?

if he did any research, he wouldn't have bought a cxracing kit.

like others have said, you need megasquirt and injectors. Stock ecu can't run a turbo. You will blow up the motor. Very....quickly.

y'all postin in a troll fred

Who you calling fred, fred?

Well, not to knock the kit, Have it running on my 90, not using their manifold of course but had absolutely no issues so far. HOWEVER....like others have stated, you've created a bomb that you have no way of controlling. if youre really wanting to run it use vvt 265 injectors, use the stock ecu, with a fmu. BUY A MEGASQUIRT. Pm me if you need help tuning. certified efi tuner here.

who are you certified by?
on which systems?
how many megasquirts have you tuned?

Seeing you post that you prefer speeduino over megasquirt in the other thread and then seeing this made me laugh.

prefered speeduino for the pure open source nature, still running my megasquirt though ;) tuned roughly 30 megasquirts in my area, went to hpacademy online and did a haltec program. fluent in megasquirt, aem, holly, motec and some others.
but thanks for the test ;)

that wasn't a test, it was a simple question. I hope you don't think I'm impressed, I get amused when people throw out "efi certified" and "fluent in" which is the rough equivalent of "jack of all trades, master of none".

anyways, carry on.

Are you certified? Didn't expect anyone to be impressed by me doing my job lol. However I understand how loosley the words "certified" are thrown around.

BUTTT back to OP, either buy the ecu or put smaller injectors in and run low boost and pray you dont blow your stuff up. You've been warned. GL

Just run all of the boost you can and make a few real good hard pulls. Please record a video of the results and post here when done.:x:

I'm certified in spelling Holley correctly.

Wholly cow!

:laugh:
you're proving my point flawlessly, thank you.

Are you one of those people who pays more for a "certified pre-owned" car? Because that doesn't mean anything either.

"We have certified that this car is, in fact, used."

A certified tuner would not ever tell anyone to run the stock miata ecu with a turbo kit, nor would they encourage even 1%, to go ahead with run it with an fmu. They would say STOP. Do it right or don't at all.

Well seems we have a ton of tuning experts, seemed to miss the class on spelling holley though, thanks for the tip! Also knowing people will do whatever the hell they please was reasoning to offer the stock ECU option. While NOT a good option, it's not impossible. Using standalone is ALWAYS. THE. BETTER. OPTION. But if you're a broke kid and don't mind blowing your car up go for it :)

Hm. I have a 1.8 with the FM turbo kit. I just bought a MegaSquirt, and I also got a lightweight flywheel and stage 1 clutch already on the car. I didn't buy injectors though...Do I need new injectors for a low boost tune, or will the stock injectors be good enough? I'm not planning on trying to max out the car's power with the tune, but looking more for a "casual" tune I guess. Does that matter?

(big noob here, only owned the car about a week now, trying to learn as much as I can)

Thanks

Yes. You need injectors for anything more than 4-5 psi. And stock fm2 I believe runs at 7-8 psi without a boost controller.

Most here recommend flowforce 640cc injectors. $300 but well worth it.

Hm. Okay. I'll definitely look into them then, so would the car run lean without bigger injectors or? How does that work? Just out of curiosity

X amount of air needs y amount of fuel.
As you increase x so must you increase y
If x is increased and injectors are maxed out, y won't increase, creating a lean condition, ping, detonation and boom, gouged pistons, low compression, hole in the side of the block.

Moral of the story, more air needs more fuel.

Alright yeah bigger injectors it is, thanks haha

You could technically run low enough boost to not need new injectors. But once you have megasquirt and a turbo, injectors are literally the only thing between a 150whp setup and a 230whp setup.

In this sense, how much boost could I run on stock injectors until I can get bigger ones?

edit: Borka answered this question already, nevermind haha

The other issue is how low can your wastegate actuator actually go. I maxed out my stock 94 injectors with a MS1 around 4 or 5psi if I remember correctly.

I guess I'll run 4-5 psi until I can get bigger injectors.

This assumes that your wastegate actuator actually allows you for that little boost. Most stock ones are for somewhere between 6-8psi.

So how can I find out how much my wastegate can handle?

Floor the car in 2nd gear, watch the boost gauge and see how high it goes.

But you might blow the engine doing this without proper tune and fueling

You blow up your engine. That's pretty much when you know.

If the boost spikes, assuming you even heard the detonation, you would literally not be able to remove your foot from the throttle quickly enough.

At 6000 RPM the engine is turning 100 times per second. That means there are four cylinders each being fired 50 times per second, so that's a total of 200 ignition events per second. One properly lean detonation event can break a ring and piston and destroy your engine. One.

So since the car already came turbo, how is it setup by the previous owner to run?
I'm assuming you bought it in a running state?

If you can't afford a set of injectors then you can't really afford and engine either, can you?

Sounds like you aren't ready to turbo your Miata. Not being harsh just pointing it out

Damn man I got a lottt to learn. Is there a specific thread I can post everything on my car and get feedback on what Im running and if I need to change anything? I felt like my car was running safely but now I'm a little worried, smh.

So the previous owner set up a VooDoo box Piggyback on the stock ECU. The car is actually running really, really rich right now. Idling at about 11-12, WOT is 12-12.5, and cruising is 12-13 (On average). I bought a MegaSquirt but I need to cut out the Voodoo and resplice the wires I think because the car turned over but wouldnt stay on with the Piggyback still wired into the wire harness with the MegaSquirt on.

I was tying this exact response, you beat me.

One who cannot afford to go out and buy 500 bucks worth of injectors, cannot afford a turbo miata.

I bought the car with the turbo kit already on it, I'm not saying I cant afford the injectors, I'm just asking if I can RUN the car until I find which injectors I should buy, order them, and get them installed.

Yes you can run it. You will need to wire the wastegate flapper in the open position and hope that you do not have enough boost creep with the flapper open to go over your available fuel. The system will likely still generate a pound or two of positive manifold pressure. As has been the case before, sometimes you will end up with 8 or 10 lb of pressure even with the wastegate all the way open which is why people are cautious in their advice to you. Set your overboost protection at 4 or 5 lbs on your megasquirt.

Alright thanks for the info

The previous owner already ran it on the voodoo box for a while I'm assuming, so it's fairly safe to say you can drive the car without too much worry.

At wot, how many psi do you get at say 4-6k rpm?

Yeah the previous owner drove it all the time (atleast he said he did)

8psi @ WOT

This makes it sound like they either already put in larger injectors or put in an aftermarket fuel pressure regulator and just cranked the base pressure way up (or did super janky shit like crimped the return line from the regulator). There's no way stock injectors at stock pressure can hit 12.5:1 at 8psi.