is there a ecu that is reprogrqamable that will fit an 90 rx7 yes or no...

 

Yes PowerFC, you need the Banzai Racing Harness

 

Yes. Also the RTek, but it's far more limited.

But what you really want is a full standalone that lets you dump that old Mazda wiring harness for something new that won't cause you problems.

 

Really? Why are you convinced there is something wrong with his engine harness? How can you tell that he "really wants" to spend days if not weeks rewiring his entire car just to find out that he read the wiring diagram incorrectly? Are you really that convinced that he wants to run premix?

I am truely amazed that you were able to establish what the OP "really wants" from such limited information. If your argument is that his harness is crispy, how do you know? Because it is 20 years old? I have installed 50+ PFCs into S4s and S5s here at the shop and have not had one issue with the wiring harness at all. We have sold hundreds of installation kits all over the world an have yet to hear of anyone having an issue. There are lots of people out there that "really want" to have a standalone engine management installed in 1-2hrs without having to rewire their entire car.........What they "really want" is the Power FC...

 

90% of FC harnesses I deal with are trash. I would never use one if planning to seriously upgrade the car. Using a new harness does not preclude the use of a PowerFC. I guess in Florida there aren't any salty winters and wild temperature swings, so it's more likely that the harness is in better shape. But 18 years of baking in an engine bay turns any harness into junk.

That said, I don't know if either of us really say what is best for him as he's provided no information on his goals with the car. It's not even mentioned whether the car is an NA or TII (though his username would indicate TII).

For all we know, the standalone/PowerFC/RTek is going onto a bone stock NA.

You're exaggerating a bit when you say "rewire the entire car". It's really "rewire emissions harness".

 

well my car is an na but i will soon be wanting to buy a turbo II to swap it in and i want a tuneable ecu cause i got the car a month ago and the guy said he upgraded the injectors and its got a third gen fuel pump. plus the car is running rich and i cant tune that with the stock ecu. and thanks for your help.

 

I will gaurantee you, that I see more cars than you do. I have 6 FCs and 5 FDs in the shop right now not one of them has a crispy harness.

Emissions harness only? Say what? Every haltech , microtech etc requires fuel pump, ignition coils, everything to be rewired right down to the windshield wipers (or do you consider those emissions?)

There are more than a few N/A's running around with PFCs by the way.

However the original poster only needs a S-AFC at this point and it will allow you to dial out enough fuel to get your car running correctly. There was no reason to upgrade the injectors in an N/A.

 

Find out what injectors it has and get the ECU chipped. Rtek 1.7/1.8 or the tuneable 2.1 will due. www.pocketlogger.com.

 

OK, so instead of trying to fix the previous owner's mistake, put the car back to stock. Install the proper injectors and the correct fuel pump. You don't need all that fuel as an NA and it's just going to cause you hassle to make it work correctly with an S-AFC.

Without a doubt, you see more cars then I do. I don't tend to work on other people's cars anymore because I found it to be too much of a pain. Too many people bring real shitboxes in and expect a first class car to be built in a 3rd class budget. However I've probably only seen one or two FCs (one of them was mine) that had engine/emissions harnesses worth using.

The harness coming from the ECU that drapes over the engine and does 90% of the EFI work on the stock setup is called the "emissions" harness in the FSM. Yes, it also contains the wiper harness but it's about a 5 minute operation to separate the two assuming the wiper harness is in good shape. The fuel pump is two wires to the back of the car, and the ignition is three wires to the existing front harness. Of course on the NAs the alternator wiring is also on the emissions harness, and both the TII and NA have the coolant temp sensor on the same harness. So yes, there is a bit of rewiring but it's not the entire car by any means and the advantage is clear.

OK...

Yep.

 

ok let me rephase this again i want to buy a ecu that i can just plug in and have to tune it. i saw the powerfc and it looks like a plug n play situation but i dont know that so if you have one let me know if its like that cause i want one that i can hook up to my laptop and change the tunning on it. and so that i can put a turbo on the stock na and run around 5lbs of boost (until it eventually give out and have to rebuild it) and to end this discussion on the cars harness its not in that bad a shape its clean and there aren't any cut wires or anything on it. and if it does give me a problem i got another harness in the garage which i can just swap it out..

 

Aaron- You really like to use 90% as your reference don't you.

This means that you have only dealt with 10 maybe 20 FCs according to your 90%, the 1-2 good harnesses is what doubles the figure obviously. This is not a large enough sampling size for you to be telling anyone that they need to replace their " old Mazda wiring harness for something new that won't cause you problems"


I know exactly which harness is the "emmisions harness", It is the one that we have been discussing since you decided to tell everyone that 90% of them are "junk".

Funny enough, when installing an EMS with a flying lead, 90% of the installations reuse the same old original connectors from the "junk" harness. I have bad Microtech and Haltech installs towed to my shop all the time, one is being trailered in today (Sat.) owner can't get it to start. Oddly 90% of the time it is a wiring issue with their brand new flying lead. The cars ran perfect with the stock harness and someone like you told them that if they want to modify their car what they "really want is a full standalone ".

I would have to say that our 91 Vert w/ SP 13B-RE and GT35R is "seriously upgraded", this is all done on a stock S5 TII engine harness with an FD Power FC: http://www.banzai-racing.com/br_projects_vert_pg5.htm




Fast2G- Have you ever tuned a car? A PFC will not run the VDI or the port actuators on your car, (neither would a Haltech or Microtech) so just to get it to function properly you would have to disable those. The PFC requires an interface called a datalogit fo you to plug in a laptop and tune. Another investment is a wideband, you would need this with any EMS to be able to tune properly. So the quick answer is "yes" you could install it, but the longer answer is that if you have no experience tuning, it is not as easy as it may appear and to go with a complete EMS is going to be expensive any way you look at it.

A S-AFC is a piggyback that wires in to the stock ECU and allows for changes in fuel mixture, this is a good place to start if you have never tuned before.

 

Wow, I've never seen anyone make such a big deal out of making a wiring harness; honestly it doesn't take very long if you can read a simple diagram and the benefits far outweigh the few hours it takes to assemble.

 

There are two plug and play ECUs: the PowerFC and the Zeal Megasquirt.

I don't know much about the PowerFC. That's Banzai-Racing's territory and he would be the person to ask.

The Megasquirt is a good option but it really does rely on the CAS wiring being in perfect shape. Even if your harness is great I'd suggest running a high quality double shielded 4 conductor cable to the CAS if you go with the 'Squirt.

All ECU options will require tuning.

Do you know how much work it is to turbo the NA? It's not worth doing so to run only 5 PSI.


It's an awesome number that covers 90% of situations.

I lost count of the number of FCs I've dealt with a long time ago, but it's certainly more then 20. Yeah, the numbers don't add up but I didn't spend a lot of time calculating how many FCs I've seen vs. how many have bad harnesses. I'll put it this way though: The majority of the FCs I have dealt with have emission harnesses bad enough that I would never want to put a standalone on them.


Yeah, but that's just wrong. To install a new wiring harness but reuse the old connectors is just crazy. Especially the injector connectors which almost always fall apart. I think that should be filed under "installer error". I can't account for installer error and I've been there as well. Several standalone installs I have had to fix and started by ordering a new flying lead harness because the first had been butchered so badly. It's incredibly frustrating to then have the argument with the owner as to why I am starting over when it was "totally wired but I can't start it". Honestly I don't know how you can do it day in and day out. After a few years, I lost all interest because of the BS.

Well yes, but I'm betting you started with a good harness to begin with.

 

ok so the zeal megasquirt ecu heres my question can it be hooked up to a laptop and also if you say 5 psi is not worth the trouble then what would be a good number for a stock na with 149xxx original miles... and yes i have tuned cars with reprogramable ecu with the laptop and im sure the difference from a civic, eclipse and rotary is not that different so i know how to work with the tunning

 

Ok I am not quoting information here, but a rotary is a horse of a different color


...................................Civic.......... .....Rotary

Ignition System(s)........1.....................2
Waste Spark...............No...................Yes
Split Timing..................No...................Yes
Fuel Inj Staging..........No.....................Yes
Different Size Inj...........No...................Yes
Knock (Sm or Lg).....No Damage......Rebuild Time
Proper AFRs...............Normal..............Way Rich
Aux Ports...............Elec VTEC..........Mach. Ports
OMP............................Nope............... .O Yea



That is about all i can think of at the moment.

 

Yes. It wouldn't be much good otherwise. Check out the Megasquirt forum on this website. There isn't much specifically about the Zeal, but it will give you a lot of info on the Megasquirt.

On the stock turbo, run about 10-12 PSI for 250 RWHP or so. Any less and it's not worth the trouble to fabricate the system. But there are far better choices then the HT-18.

Uh, you're in for a bit of a surprise. The rotary uses a staged injection system. There are three coils, the leading fires wastespark and the trailings fire independently. Two ignition triggers are required from the ECU, as well as a trailing toggle. "Split" is the time between when the leading and trailing fires and is measured in degrees. Mazda uses a progressive throttle body. The NAs have three sets of ports which open sequentially, controlled by the throttle body and aux actuators. Your S5 also has a variable length intake system called "VDI".

Aside from the mechanical differences, your rotary will make safe power at a much richer AFR then a Honda (when talking forced induction). It will require a LOT more fuel then you think and if you detonate it, you'll be rebuilding the engine.

So in sort, it's a bit different.

 

alright thank you guys for helping me out

 

okay last question seriously... whats the worst that can happen if i start boosting my car with the na ecu... i have been told that the car going to run like crap. would you guys suggest it if not throw me some options

 

The NA ECU can be used under boost if you have some way of adding fuel (ie. larger injectors and an S-AFC). But I don't suggest doing this unless you know what you are doing.