As I was going full throttle, my engine started cuttin out, I know normally the fuel cuts off to the 2nd rotor at 8 psi, without fuel cut defenser... but I have a fuel cut defenser and it shouldn't be.... any ideas? I'm confused

 

Ok, nvm... thank you...

 

I was being sarcastic I still need help! haha!

 

So at what boost is it cutting? If it's at 8-9psi it could be a bad FCD. If it's above or below that it's something else. Is it a hard cut or a rough misfire?

 

I only have stock boost gauge, so I'm not totally sure how much I'm pusing. I'm going to be getting one of the manual boost gauges and checking it at the engine. and my lil cousin is giving me one of his other boost gauges.... so yeah I'm going to be checking it in the next couple of days.

But when I am boosting it cuts out...... Its definately not a misfire...

 

IF YOU ARE RUNNING STOCK ECU IT WILL DO THAT BECAUSE OF THE COMUTER

 

No It Wont He Has An Fcd

 

Usually you can locate the pot in the FCD and make an adjustment there. Ususally they *try* to cover the slot in the screw head with wax to discourage this.

What you could do, is monitor the pin 2B on a series four car while boosting and see what the max output to 2B from the FCD is. Then if it's cutting out, adjust the pot in the direction to LOWER the voltage to the ECU from the boost sensor.

It helps to have a meter that can capture the lowest and highest reading, but it's not required.

I adjusted one from Rotary Peformance that in my opinion was inputting too low a voltage at it's peak. The engine wasn't hitting fuel cut but was set at tooooo low a voltage. In other words wasn't at the optimum.

 

Hailers, I'm sorry to say, but that didn't help to well. If you are talking about an aftermarket FCD, which I assume you are... I think I have a home made one. lol, sorry bought it with it on there already. So yeah..... can you speak in a little less out of the book context... Sorry, but thank you.

 

I once had a similar problem.

It felt like I hit a brick wall in 2nd gear or higher at 5k RPM.


It ended up being a dirty air filter (stock airbox, stock TID, 2.5" DP, stock main cat and stock catback)

And not all FCDs work all the same. From what I understand, most of them trick the boost sensor into thinking you're running lower boost, so essentially you could still hit the fuel cut when you're at a higher boost than the boost sensor reeads.
And then some lock the signal once it gets just below fuel cut point.

What mods do you have?

-Ben Martin

 

It'll still be adjustable, they have to be. It's possibly one made from Paul Stokes' instructions. Read this and follow the tuning instctions.

http://www.teamfc3s.org/info/articles/fcd/diy_fcd.htm

 

Nope. I made a Paul Stokes FCD before I bought the FCD from Rotary Performance. That's how I knew how to adjust the clamping voltage on the one from Rotary Performance (Racing Beat one, I think).

All I really know about FCD and all, is that the boost sensor puts out a voltage that increases as the boost goes up. When the ECU sees a certain voltage, it starts cutting fuel to the rear rotor.

So what a FCD does, is *clamp* the voltage output to the ECU, once it reaches a certain voltage level, even though the boost is still a rising.

Like on the Paul Stokes one I made, I set it at 3.65vdc as the max voltage output to the ECU. If the FCD was not there, the voltage would rise up to ??????over 4vdc I suppose.

I reset the *clamping* voltage by using a MittyVac. I put the MittyVac on the boost sensors input nipple and just pumped that sucker up to over 10psi, while at the same time I was looking at a digital meter that was backprobing the output wire (BrR) of the boost sensor. I just turned the tiny screw in the RB pot til the voltage was where I wanted it. I thnk I set it closer to 3.65vdc. IF memory serves, they, RB, had it clamped at 3.2 vdc or so. A little too soon to be clamping imho.

What MIGHT be happening to yours, is the *clamping* voltage ***THEY*** set it to is too high a voltage or something else has gone wrong with it.

Then again, we might be mis diagnosing your cars problem altogether and have you on a wild goose chase.

Later I'll dig out that old RB FCD and open it up to show the screw. Might did the old home made PS FCD out too but I potted the guts of that little jewel with RTV to keep things from rattling around and I kinda doubt I could show the tiny screw in its pot.

Don't worry about not understanding what I write. Mostly it's just disjointed ramblinigs that I don't even understand when I read it the next day.

Hey. What YEAR RX-7 is your car?????? Series four or five?

 

This post probably won't do anymore than put your thread back on the top. Shown in the jps is what I think is a RB FCD and I point out where the screw in the pot is on it.

The second is my homemade one with clear RTV all over the darn place and I can't show you the pot in it. Mine is almost twice the size of the RB one, but it worked like a champ.

I've a couple of RTEK 2.0 now so I don't use FCD's anymore.