VersaTune User Forum

Hi Guys

Hope you are well.
Im having some issues with my car and I was hoping someone here could maybe help / point me in the right direction.

I just installed a new full intake with an internal diameter of 73mm. I did some calculations and found that the cross sectional diameter difference between this intake and the stock intake is 25,5%. I added this correction to the maf cal as a start. Went out, planted it and the car totally bogged. I immediately thought its overfuelling. Stopped and defaulted the MAF values. Loaded the map and planted it again. There was no bog this time.

However, the car does not really boost (less than 1bar). Also with such a bigger intake the Actual AFR is suppose to be way higher than the Desired as I did not change any MAF values. This is not the case. Also, my WGDC is very low. Its around 20-30% even when its way higher in BCS DC. Im not totally sure whats going on. Might have a weird leak somewhere or the actuator is leaking.

Please see the attached logs. Im at 5400ft, commanding 1.8 load

Thank You in advance

The log 2013_02_23_4th_new_SRI.csv was not taken properly. The columns are shifted somehow on lines 34-37. However, the maf sensor readings are null so probably you have a problem with that connector. Pull it out, spray some contact spray, let it dry, put it back in and give it another try. Make sure you have the battery disconnected while you do this.

Later edit: actually the values are ok, but the log file is totally fucked up.

Both logs look pretty normal, I can't say there's anything wrong from only these values. You didn't mention in which one you actually logged the problems. In the 4th_new_SRI? In both the desired and actual afr's are pretty close though, I doubt it's maf cal related...

At the moment im not 2 worried about the maf cal. But something is definately up. The car does not boost, doesnt even break traction which it did with the stock airbox. I have a new MAF sensor BUT its not an OEM sensor. Im going to bypass the bcs as a test to see if there is any change


Smackin a GTI while on my iPhone using Tapatalk

Not OEM MAF sensor? Well mate... FAIL. Put the OEM one back in. The signal scaling is different.

Ok, I bypassed the BCS and went out to test. Car boosted fine, hit 1.4bar boost. Thinking that maybe the wastegate is leaking or the bcs is stuffed.
I thought as much when I purchased the sensor, but wanted to make sure and test it out. Mazda charged me a ridiculous amount so I thought Id take the chance

definitely the sensor. put the OEM one back and all seems kinda normal now. Actual AFR > Desired AFR so atleast I know that's right seeing that I did not have any MAF corrections in for the 3" intake. Also, car boosted perfectly (1.35bar) with no KR. Shot for taking the time and helping me out mituc

Line 1033, actual afr: 11.45, Desired AFR 11.3, Fuel Rail Pressure going below 1600PSI. You should cap the load at like 1.9-1.92 in that RPM range because it looks like the fueling system is at its limits. This is not MAF related, ofc.

I dont even request load that high. Fp internals are on my replacement list. Also, thats the first time that the fuel pressure goes below the 1600psi mark. I logged yesterday after reinstalling the OEM maf sensor and the FP is > 1700psi most of the time. Sometimes going over 1800psi. But yes, it is a concern and is on my list of important upgrades


Smackin a GTI while on my iPhone using Tapatalk

It must have been a boost spike then, just lower the BCS DC with like 5-7% in that area...