My wife and I finally got our Evo back up and running after it being down for almost 2 1/2 years. Primary difference between it's current setup and when it last ran is engine management--we previously used an AEM EMS whereas we are back to the OEM ECU (Tephra v7 w/SD). Our SD setup currently consists of an Omni 4 bar MAP sensor; we don't have an AIT sensor but just ordered one from SpoolinUp.

Our Evo has yet to be tuned and is running on a basemap for an Evo with similar mods. Obviously we are not going to boost her without proper tuning, but as most know even under partial throttle the Evo will start building boost under certain load conditions (say going up a hill). When our Evo starts building even a little bit of boost (under 5lbs), we hit what I believe to be fuel cut. Our tuning effort will take place in a month or so, and until then it would be nice if we could mildly drive our Evo around.

Any ideas as to why are Evo won't make even a small amount of boost without issue? Is the lack of an AIT sensor throwing everything off? Thanks for your feedback!

 

Probably not the IAT, you have the factory boost solenoid in? Also, do you have the fuel cut set to something that your loads are hitting? I think it's called "boost cut" or "load fuel cut" or something like that. How did you get onto SD without some amount of tuning btw?

 

Thanks for your feedback! I don't have the factory boost solenoid; I have a Hallman RS boost controller waiting to be installed when the tuning is done. Until then am simply going off of wastegate pressure (and have a FP 25psi actuator). I am not sure about the fuel cut but will check. The shop that will be fully tuning the car provided me with a map recently used on another Evo so that I could drive around a bit before going in for tuning. I will need to do some data logging but it seems like it is running lean (even though I am being told it has a generous amount of fuel.

 

Lean under boost? The thing with SD is that it's sooo "car specific" from my exp. One cars map may run totally different on another, which was why I asked how you were getting by no tune. So, you don't have access to ecuflash and a cable though I am guessing, since the shop got you a map? Do you have a wideband? What makes you think it's lean, if you don't have a wideband (if you do have one...I obviously know why you think it's lean, lol.) You said you have to do some datalogging, so it could go either way I guess.

hearing "wastegate pressure" and then seeing 25psi after it just makes my jaw drop, lol...I'm so used to my 7psi.

Since I run such low PSI, I see about 150-160 load...so this is my fuel/boost cut table. There is also other "stuff" that could be cutting, like rear O2 wired from a wideband, and fuel cut when it's outside of acceptable range....but you'd know if you had stuff like that setup. And...besides, you aren't hitting a "boost cut" cause you are on WG pressure, it would have to be fuel cut like in my attached pic.

 

I understand that SD tunes are car specific. I'd think that I'd a least be able to boost 5psi without issue though. I have Ecuflash and am borrowing a friends tatrix cable, and have loaded a few different maps from the tuner to try and resolve this issue. I have a Zentronix wideband o2 sensor that is currently not hooked up. The rear o2 sensor is disabled and I am running the heater simulator patch. I believe it is running lean simply based off of what a friend of mine believes (and he has a fair amount of experience tuning Evos). Anyways, not trying to waste anyone's time here. I am simply trying to brainstorm here. I know I need to make it to the shop for a complete tune. Not sure when exactly that will happen so I'm looking for maybe a quick fix.

 

You need to cease and desist all further driving until you get that wideband hooked up and start logging. Don't make the mistake of not.

 

Thanks for your input! I have looked for instructions on connecting a wideband sensor to the factory ECU and haven't found any definitive guidance. There is a wire from my Zentronix setup that is waiting to be plugged into the ECU somewhere. Any idea where? I have heard that it can be used instead of the front o2 sensor input (pin 71 I think), but something needs to be modified in the zentronix control box.

 

Wire the analog output from your wb02 into your rear o2 sensor input at the ecu. What software are you using to log? Speed Density itn't something you can just flash on and start driving around rolling into boost with. Too many variables. Sounds like you should stick with a maf at this point (or forever) until you have professional assistance.

 

I would put the MAF back in until you are ready to tune.

 

Forget SD if you aren't using a wideband.

 

^What he said. You could be running crazy lean or rich but there's no way to know without a wideband. You're flirting with a blown motor boosting at all. At the very least sit down and log O2 feedback at idle and check the fuel trims to see where it's trending to get some idea but I would not be boosting at all until you are able to log AF.

 

I apologize if I've made this thread appear as if I am going off making changes to my Evo with little to no direction by those considered experts. I have done very little wrenching on my Evo and zero tuning. The majority of wrenching/tuning has been done by shops like Reese Tuning and RRE. Reese Tuning will ultimately tune my Evo but the point in which that happens is unknown. I have a bunch of business travel coming up, as well as other projects I am devoting resources (time and money) towards. In the mean time my wife and I would like to be able to drive our Evo for short drives around town.

With that said, here are some responses to what you stated:

Our Evo is being tuned with EcuFlash (Tephra v7) and I use EvoScan for datalogging. I can wire the wbo2 sensor into the rear o2 sensor pin (73 I believe), but what change needs to be made to the ROM to enable the capturing of the data? I have no intention/desire to go back to MAF for a number of reasons.

 

I haven't had MAF for over 4 years and wont waste money acquiring the necessary parts for a temporary solution.

 

I have wideband...just not connected to the OEM ECU at this point. I can connect it no problem; just need to know what needs to be done to the ROM to pull data.

 

I've done that, reviewed the results with RT over the phone, and at idle everything looks fine. And please understand the very limited amount of boosting has come from simply driving up some sort of incline or other condition where more load is put on the car. I havent mashed the gas or intentionally boosted.