USRB25S13

Ok I am going to replace my stock RB25 MAF with a Q45 I have sitting in my tool box. I got the wiring figured out. What I want to know is if I am going to have to retune the Maps for the larger MAF or will the Power FC be able to use the same maps with the MAF voltage adjusted to the Q45's values. Right now the car runs great but the Check engine light flashes and the MAF voltage goes well over 5V's. Also the Q45 MAF is shown as 4.1 on the MAF selection chart right?

Ok I turned off the F/B control and the car feels much better at crusing. I guess there isn't any way to control what the ECU does in Closed Loop mode? The O2 sensor seems to be working properly. The voltage goes up and down like it should while driving in closed loop.

Ya that covers most questions I have soo far. Thanks Now as for the stalling problem when the engine revs down. I have an HKS SSQ BOV on the car and ever since I put my larger turbo on it stalls. I can't get the BOV back into the intake because I made my own intake and my external wastegate gets in the way of the recirculation pipe.

What is the F/B control O2 in the function menu? When I turn it off the car doesn't surge as much but it won't idle at all. Also what does the little Jappens writing mean next to the different functions? Is it on/off? I know when I first started the car the check engine light was on and when I went in and turned the Boost option to what I think is off then the light went out. I left the other things alone (Knock, injector warening) But funny thing is I have never seen the knock turn on the check engine light. At what point is that supose to happen? BlueRB240: I am using 94 Oct fuel. Gotta love living in PA.

You got PM I was out doing some test pulls at lunch. First thing I checked was my A/F ratio. It was nice and rich compaired to the stock ECU. With the stock ECU I was seeing 11.5-11.1. Now with the PFC in place I see 10.8-10.5 So I got plenty of fuel. I also saw that the knock wasn't going above 13 on the PFC display. So I layed into it in 3rd gear till about 7K. Knock was still below 13 and car felt pretty strong. Injector pulse max was 85.8% with my A/F ratio in the mid 10's. I did another pull and looked at the moniter. It showed knock at 83!! I guess the stock SMIC must be getting heat soaked or my timing is a little bit advanced? I am only running 10 PSI BTW. So could somone explain the #'s for the injectors on the map? I assume lowering the # will lower the amount of fuel in that cell. Sorry for all the questions it's just being in the US there isn't anyone here who would have a clue of how to tune this setup. But I do have my own resources as to tuning myself (Wideband, Ears, and a good friend to ride with me to moniter things) I still haven't taken care of the weird surging problem at cruising. My TPS voltage is constant, Air flow isn't jumping. The only thing I can say that is wierd is the A/F goes from 13.8:1-16:1 while crusing which I think it a bit much. I think with the Stock ECU it was going from 14:1-15:1. I don't know how I can adjust that though since it's in closed loop. Any ideas?

I have a .63 exhaust housing on my turbo. But since my exhast wheel is a stage 5 wheel vs a stage 3. I don't see full boost till 4200 RPM's. I am running an external wastegate. The compressor is a T04E .6 AR compressor with 56 trim compressor wheel rated at 65lbs/min of flow.

Well My setup doesn't make full boost till after 4,000 RPM's. I am running a 56 Trim T3/T4 with a stage 5 exhaust wheel .63 housing. So at 3K there isn't any boost. What kinda A/F's should I target while crusing? Right now it's 14.2-15.1 and it goes back and fourth. As for the manuel Apexi-USA doesn't have a manuel to navitgate the Comander menu. It just shows how to hook it up.

Idle right now is better. I set the idle to 1100 and it holds it steady. It will still shut off if you let the revs drop to quick but it did the same with the stock ECU. Now the weird crusing problem is pretty bad. It's very hard to go down the highway at a constant speed. The car surges on/off a bit. It's not sudden but very noticalbe to me. I don't think my passangers can tell but with my foot on the throttle at a constant speed the car will feel like the brakes are being lightly applied and then released. It's the feels the worst around 3000 RPM's which is highway speed in 5th gear. One idea I have is it may have somthing to do with going between open/closed loop. Is there anything on the PFC to control it or moniter it. My timing maps where as high as 42 BTDC. I set them back to 30 degrees for now. With the knock moniters on I didn't get much of a reading. But I turned the timing back just to be safe. The A/F's look good. 11.5:1 and richer under boost.

Well if anyone remebers from my last post I got a new PFC and it wasn't working for me. So I sent it back to Japan only to find I was missing a power feed in my ECU connectors. Now I got it back today and hooked it up. Car fired up with the check engine light illuminated. I went to the setup menu and turned off the boost controllers option. First thing I noticed is the idle was funny. It sounds like a miss but after monitering the Ing timming I see it goes from 18-20 BTDC and drops to 3-9 BTDC. It's like the ECU is retarding timing maybee to get the idle down? I did adjust the idle screw up to keep the car from stalling when it comes down from a high rev. Maybe the idle control valve is shut all the way but the ECU is trying to get the idle down by retarding the timing? Also what kinda timing do I want to see under boost? When crusing around I see 30-38 BTDC. I haven't gotten on the car much yet for I want to get it to a dyno ASAP. I also find that when crusing under light throttle the throttle feels like an on/off switch and if I get it just right the car will bog off and on. Should I look at My TPS voltage? What should it be at closed throttle? Where can I find a manuel in English?

I have the same problem as you. But I still have the stock ECU and MAF. When I put my larger turbo on I couldn't use the stock intake piping so I put my HKS SSQ back on. I never had idle problems with the HKS and stock turbo. I found with the larger turbo it stalls out if I let the revs drop too fast. It's a real PITA! I noticed my A/F ratio goes to 10:1 when the RPM's are droping down. I think the stalling problem has to do with there being much less volume of Air between the MAF and Turbo.

Just to clear somthing up here. The ECU doesn't read the boost pressure correct? It caculates it from Air flow. So it is possable to hit boost cut with out running alot of boost say if you put a larger turbo and IC on. I know I have hit the cut in my car at 9 PSI.

I have an RB25DET I am running a 56 Trim T3/T04E (Flows 65 lbs/min). It's got a .60 compressor housing, .63 AR exhaust housing, and a stage IV 76 Trim exhaust wheel. It's got a standerd Bushing center housing. Runing Stock exhaust manifold with an adaptor box for the 38 MM external wastegate. I don't see boost till 3K (5 PSI) and full boost comes on at 4200 in 3rd gear. It comes on really strong all the power at once! I am only running 10 PSI and still running the stock RB25 SMIC intercooler. Once My PFC and Q45 MAF comes I am going to fit my FMIC on and run more boost till the injectors are maxed out. I guess a Ball bearing Turbo will make boost 500+ RPM's sooner. Must be nice. How about an adjustable cam gear? How much would that help?

So I could use my standerd PFC and set the rev limit to 8K and then use an aftermarket ignition rev limiter to let me flat shift. Sounds like a plan to me.

I am trying to figure some thing out here. I recently put an RB25DET in my S13. I had to of course wire up the stock ECM harness so it would run. It turns out I never ran a wire for the battery backup for the ECU 12v+ constant. My car has ran just fine now for 5 months. But last week I got an Apexi Power FC and it wouldn't work at all. I think I know why now. Too bad I sent it back to be checked out. The Pin # on the ECU that I found out to be battery backup is pin 58 it's a white/black wire. I am correct on that right? My engine is a Series II RB25DET

Ok. I am going over my cars wiring at the ECU to make sure there isn't a power or ground missing from mine that the PFC would need. I am having problems finding correct ECU pinouts. The one diagram I have show pin # 58 being backup power. At pin 58 there is a white/black wire but there is no power on it. I would think without power there my stock ECU wouldn't work right at all. So does anyone have a good power/ground pinout for an RB25DET series II motor?

I tried to ground the ECU with a ground cable and it didn't make any difference. As for the wiring with the swap, all the engine wiring is untouched. I only had to extent the wires for the O2 sensor and MAF. And since the stock ECU works without any problems I would think my wiring should be ok. I sent the ECU back the Japan where It will be sent to Apexi and tested. I sure hope they find a problem with it.

Since the PFC isn't doing anything at all I can't change any settings. The comander screen is blank. I still don't think the ECM housing needs to be grouned. There is no place on the ECU housing to bolt it down. They give you double sided velcro tape to fasen the unit down.

Before the ground was put in the loom did the ECU work? Mine doesn't do anything at all. I tried running a ground wire to the ECU case and it didn't make any difference. So how did you figure to run the wire. Did you have to add an extra wire in the ECU conector?

So the unit needs to be grounded? Can anyone comfrim this? Since the way they tell you to secure the ECU is to use the velcro tape they send with the ECU I don't beleave that. But I will give it a try.

I see how the plug can cause some difficulty. If the stock ECU is working before and after I try the PFC that would tell me the power/grounds are ok. What would a locked PFC do?

I see how the plug can cause some difficulty. If the stock ECU is working before and after I try the PFC that would tell me the power/grounds are ok.

It was brand new from jap parts specialist. http://www.jappartsspecialist.com/ I emailed him and he told me he would help me out with shipping to Apexi if needed.

The plug is going in all the way. I am a mechanic by the way.

Well I just got my New Apex Power FC in the mail this morning and I went out pulled to stock ECU and pluged the PFC in. When I turned to key on nothing happend at all. No Check engine light illuminated and the comander isn't lighting up or showing anything at all. I checked the Model # to make sure it's the right one for my car. Crank the engine and it wouldn't start. Is there somthing that needs to be done to the unit before it will work? I looked at the english manule from the Apexi webpage and didn't see any steps I missed.

Ok. I have a techedge wideband already. I guess the datalogit is the only way to go then. Is the R33 GTS system out yet?