I'm going through the typical vacuum hose job and trouble shooting because my secondary turbo is not working right (I have a 10-8-5 pattern), and I wanted to know how much of the emissions and/or maybe double throttle I can eliminate without getting a PFC at this time.

Can anyone help guide me here.

I live in Idaho where we don't care too much about emissions stuff, so eventually, I plan on cutting everything down to the simplified sequential setup with a PFC, but if I can eliminate any of the mess while I'm in there right now, I'd like to pull out whatever is not necessary.

 

search box is your best friend........
i practically built my fd from the ground up repacing everything on that car by hitting search button and google

 

the short answer is all of it, but search so you can figure out how to do it w/o the ecu throwing codes, there is a way, I dd mine that way.

 

Really? I thought that I had read that taking out the EGR would put the computer into limp mode.

 

Basic idea is you have to put resistors where the solenoids use to plug into to trick the ECU for it not to throw codes.

Haven't heard anything about that EGR thing? I have a JDM engine so mine doesn't have an EGR anyway.

As far as how much you can delete, you can delete everything. From my research unless you have a PFC, the only problem you should have are going to be with idling. And you will probably have to raise your idle to something like 1k.

 

I removed my double throttle and it resulted in the 3k rpm hesitation getting a lot worse. Removing the air pump screws up your idle and also throttle response at lower rpms. Don't know about anything else though.

 

Eliminating the EGR system altogether would create a CEL, unless you install a circuit that sends a signal simulating the EGR function sensor back to the ECU. I did it back in 2008 with the circuit shown below. The circuit easily mounts next to the PCME (ECU).

Incidentally, our '94 just passed emissions in CA with a lot of margin on all parameters, with the EGR stuff completely gone.

 

Hmmm.

I'm thinking that I'm not interested in resisters and all of that right now.

In the future, I think I'm going to get a PFC and pull out all of the EGR, air pump, and maybe even the cat, but for right now, I don't want to create more problems for myself. I just want it to work correctly.

Why does pulling out the double throttle make it hesitate at 3000 rpm?

 

Actually I think there are two effects going on.

One is that the response of the PCME and fuel injectors is not quite as fast as needed to perfectly follow the throttle butterfly's response to your foot on the accelerator pedal. The A/F mixture would momentarily go too lean if you tromped on it and the secondary throttles opened in sync with your foot. Mazda built in a delay there to hold off the jump in air pressure in the manifold. At least that is how they describe the need for the double throttle. But that could happen not just at 3K rpm but elsewhere as well.

The "3000 rpm miss" seems to be associated with the ECU itself, and may be an electrical problem. If you look at Mazda's technical bulletin posted in Post #42 of this forum thread, you can read their take on grounding issues. In post #47 I indicated that their fix cured my 3K rpm miss.

 

One thing that I just noticed.

There are white paint markings on some of the lines and solenoids. Is that done at the factory? I didn't think anyone had been in there.

 

I'm starting to see why everyone hates vacuum lines.

So far, all of mine seem to be okay, but I know there is a bad one cuz I'm not getting any secondary.


GRRRRRRRRR......

 

i don't know what you guys are smoking but the ECU doesn't throw codes on the USDM models with a power FC because the ECU doesn't send a check engine light signal to the check engine light anymore. the signal is sent to the "overheat exhaust" relay which only triggers if there is a hard fault with the system.

in short you can ditch everything under the hood with the exception of the:
injectors(durr)
TPS
MAP
crank triggers
IAT
coolant temp sender


that's it, many people run big singles with the powerFC with little to no ill effects.

 

He's NOT using a PFC. He's using the stock ECU. He's asking what he can do "without" a PFC (which was answered by asianguy02).

 

Well, I finally got back to trouble shooting.

I must have the only car out there without bad vacuum hoses. I checked and checked, and didn't find any leaks.

Finally I found out that my Turbo Control Actuator seems to be leaking. The pressure side will not hold. You can pump it up to 10 PSI, and it moves like it should, but it leaks out somewhere and will not hold the air pressure. The vacuum side holds, but the pressure side leaks; especially at higher pressures. (approaching 10 psi) I guess that would explain my 10-8-5 boost pattern.

I'm guessing that I'll just have to replace the actuator, but that sure doesn't look like fun.

Has anyone else had this same problem?

 

Yeah, you'd have to replace the actuator to fix that. Just work from the bottom of the car and use 1/4" drive ratchets, yeah its small, but that should make life a little easier for you. It's about on par with pulling the OMP when the engine's installed. It's a PITA, but doable with some patience, and quickly learned finger dexterity. best of luck and have fun.

 

+1! have you done this with an FC, i'd let you use my FC as a ginnypig to try if you havnt

 

I think I'm going to leave all of my vacuum lines for now.

They don't seem to be leaking, so I'm not going to replace them until I have to, or until I get a PFC and go simplified sequential.

If I can replace just the Turbo Control Actuator, and get it running right, I'll be overjoyed.

 

Well, I'm just now getting around to looking for a Turbo Control Actuator, and it turns out that a new one is $560, and it might be hard to get one.

Anyone got a leftover used one?

I know there are a lot of guys that have gone single or non-sequential, so there should be a lot of those actuators floating around.

 

Heh, just sold one last week. Sorry!

 

Anybody else?