Here's the deal:

My car is throwing a code. It's the same one Max had. 0175, system too rich. This is because of my 440cc injectors and cruising around rich. I'm tuning this car today and I keep hitting a wall and cannot make any power past 395whp. Can this code cause a screw up with tuning? I tried to clear it but I couldn't get it to clear, so right now I just disconnected the battery so it should be clear in the morning. You might say well maybe your car has hit it's peak and just won't make any more power, trust me it's not the case. I'm making about 10whp more right now with 9psi then I was making with 7psi.

I don't know if I even am making sense right now, I'm pretty pissed off and I am going to try to tune it tomorrow morning hopefully with that code gone. I honestly think this code is screwing me up. No matter what I do I can't get this one area leaned out enough, it's just sitting wayyy below 10.1:1 from 4600-6200. Any opinions or experience? Rule out the EFMU too, 3 out of the 5 sliders are at 0 or real close to it.

-Bill

 

How does your Engine Management system adjust injector pulse width? By modifying the pulse width itself, or by increasing/decreasing the voltage from the MAF??? This will help narrow things down.

 

Bill, I obviously don't have an answer but I'm curious what else you need to do when you install new injectors other than reduce the sliders on the FMU to compensate for the increased fuel input. I thought I read that the ECU needed to be programmed--but I don't know why that would be a necessity.

In other words, please throw a mechanically-challenged dog a bone here and explain what I would need to do if I ever decided to go with bigger injectors (presumably in order to safely increase boost).

Also, how hard or labor intensive is it to install injectors?

--Steve

 

I'll answer what I know for now. I don't really remember what system Bill is using (bad memory) Depending on how much bigger the injectors are from stock you can use a engine management system like Emanage to create a custom fuel injector map based on boost.

Many engine management systems adjust the voltage out from the MAF sensor. Less MAF voltage = less fuel / more MAF voltage = more fuel because the ECU thinks there is less or more air flowing into the engine. However, because the ECU is still the one supplying the fuel injectors with the pulses it's based on a percentage of change from the stock fuel map.

I've never changed the injectors on a VQ35, but it looks like you'd just have to remove the upper and lower plenum to do it. Not too terribly difficult, if you're handy with a wrench.

 

I'm using a SAFC, so it's doing what it does with the MAF. It's the same way t32gzz car is setup. He's got the RC 440cc injectors, not using the e-manage, an SAFC, a EFMU w/ an inline pump, and he is putting down 450whp. My setup is the EFMU/inline pump that came with the ATI kit, SAFC, RC 440cc injectors and the J&S Safeguard for timing. I wish I could go back to the dyno and screw around more today, but it's going to snow and I'm not driving my car in that crap. They are saying we are going to get alot of snow so I'll head back there on Monday, gives me time to think about this.

 

Steve, it's really pretty easy to install th injectors, even the RC's where you have to cut the stock connectors off and use a new set. Like Jesse said, you remove the upper and lower plenum, then unscrew the fuel rail pop out the old injectors cut the old connectors off, solder the new connectors on and I used shrink tube to cover it up, pop the new injectors in the rail, screw in the fuel rail, connect the new injectors, and reinstall the plenums and hoses etc.. It took about an hour and a half to do all this, without rushing. So where I have the sliders on the EFMU down to 0, I'm using the SAFC and am leaning out. No where am I adding fuel with the SAFC. I'm sure the ECU could use the reporgramming, but I don't mind cruisng around a little rich, I've leaned out my idle and lo throttle settings where it's not as rich as it was, so it's not that bad really.

-Bill

 

bill: you need to tune your "lo-throttle" fuel map on the s-afc2...
with the setup you, tim, and i have, the lo-throttle is for injector correction, and the hi-throttle is to fine tune the dfmu.

tim and i have been working on getting his right... today we will run some more tests...

luckily i still have stock injectors, so my lo-throttle map is just zero straight across...

will post back here.

m

 

Just curious. How is the lo throttle setting going to help me out when I'm at WOT and my throttle is at 100%? Obviously you guys have done this already and know, I'm just wondering How is Tim's EFMU setup? I'm curious because you guys are making full boost at what, 3500 RPM or so? Obviously I can't copy his, but I'm just curious to know how his sliders are setup, also where is his scaler set at. Let me know what you find.

Thanks.
Bill

 

you are getting the RICH engine code because your O2 sensors are excessively high. this can only happen in closed-loop mode (when the ecu actually cares about the o2 readings). this is why it is your lo-throttle which needs to be leaned out.

we just came back from some diagnosing of tim's car... his CEL has not come on again after clearing it, and setting the LO map to be as lean (for right now, maybe have to go leaner) than the HI map.

i will post a new topic here in a bit. bad news for boosted applications, but the MAS is getting MAXED out for us.

just curious, do you ever see the air flow % reach 100% on the super-afc2? if so, at what rpm?

m

 

Ok, so if I understand correctly (and I apologize if this is detracting from the thread), since I have the Vortech kit I could use the SplitSecond box for fuel management with larger injectors, or I could use the S-AFC II (either with or without the SS Box) to control fuel.

It appears that the S-AFC II also allows monitoring of lots of other stuff as well, but doesn't control timing.

Correct? If so, how hard is the S-AFC II install with my supercharger already installed? How many hours would it typically take a shop?

--Steve

 

I leaned it out with the LO map, but maybe not enough, honestly I haven't had much time to screw with it, I just threw these injectors on Wed night and went to dyno Thurs afternoon. So with Tim's car, has it been driven enough now that it's cleared and you leaned it out again to say it took care of the code? Just wondering if it came on quick on his car, mine came on after about 70 miles.

I had a feeling about the MAS. I honestly haven't even checked the air flow % on my car, and the next time I'll be at the dyno is on Wed I couldn't make it today with the damn snow and my boy won't be back till Wed. This weekends going to suck.

 

Steve, do you know what the G35 sedan injectors are rated at? Are they 290cc like the 350Z injectors? I honestly don't think you need new injectors with the power your making, I think you are alright the way you are. The only reason I upgraded my injectors is because I'm going to try to make 500whp on this stock motor.

If the Splitsecond can do low throttle, I don't see why you couldn't do it, but I don't know that software and haven't seen it, but I bet I could figure it out quick It took me about an hour to install the SAFC, including soldering and taking off putting on the dashboard and running the wires neat. It's only 6 wires going to the ECU. Really not that hard but my back hurt after

Bill

 

Bill, with my current boost level you are absolutely right. The only reason I am thinking about this is in the academic context of increasing my boost levels from 8psi to 10psi. Sooner or later I'd like to do that.

--Steve

 

I don't think you'll be able to do that zimbo. Reason being, the Vortech guy that surfs this board gave us some numbers your SC is running at. Basically it boils down to that the SC head itself is only capable of producing another 3/4 PSI of boost because of the max safe RPM limit on the SC head.

 

Hmmmm. Interesting. I wonder why they offer tighter belts then? I'll have to look into it.

--Steve