Project-T: Teething issue...

Wow, Boostworx was busy when I put the little monster in... After about a week or so I got a call that the team had put together the last bits! But a slight teething issue... The car won't start..!

So I made my way there with a trusty laptop loaded with the AEM FIC software and Shaun showed me their handy work! Somehow they read my mind on how I wanted the pipes to go. The Zage Yaris kit came with a pod filter but because of the layout of the Echo engine bay, the Yaris configuration wouldn't work. So I supplied Boostworx with my existing Weapon-R Secret Weapon pod filter, couplers and a new aftermarket MAF sensor mounting in hope they would position it nicely, which they did!

Anyhoo, onto the issue!

Basically, when the car cranks it would 'try' to start then just die and won't hold idle. We checked:

• Intake - looking for any blocks
• Fuel delivery - checked the pump voltages, injectors
• MAF sensor - checked whether it was installed in the correct direction
• Tune - I reverted back to the factory tune and the pre-made turbo tune I put in so I could drive it into boost out of the workshop.
• By-passed the AEM FIC via the by-pass loop to see if the FIC was the culprit.

...nothing! The monster layed dormant..!

Shaun thought that the car sounded like it was starved for fuel. So I opened up a new cal file in the AEM FIC, adjusted the injector size and allowed the software to create a base map. I then added crap loads of fuel to the idle RPM break point and....

Ch..chgg..cchhggg.....


VROOOM!!


Shaun was right! It needed more fuel! But why!?

I quickly mapped out a very conservative fuel map (with timing pulled at the top end just in case) and I was able to drive her home.

Once back in the lab, I rechecked Boostworx's excellent workmanship in the engine bay and it hit me......

...why would it need more fuel? Was there too much air coming through the engine causing a lean condition? Was there a leak somewhere? My eyes caught a glimpse of the MAF sensor and AFTERMARKET MAF sensor mount....... THE MAF SENSOR WAS MOUNTED ON A LARGER PIPE.

Stock MAF mount on the factory air filter box

The Toyota MAF sensor was designed to measure airflow in a specific diameter pipe mounted on the factory airbox. Changing the diameter of the piping changes the amount of airflow to the sensor and hence the airflow meter readings would be wrong and uncalibrated.

Since I put the MAF sensor in a  new sensor mount on larger piping (since the Weapon-R airfilter had a larger coupler), the MAF sensor was giving lower airflow readings. Does that make sense?

MAF Sensor 101: The basic MAF sensor, or Air-flow sensor works via a hot wire. As air is drawn into the sensor, the hot wire cools. This change in temperature equates to a change in electrical reading (i.e. current/voltage/resistance) which is sent to the ECU to determine how much air is flowing in.

When I increased the diameter of the piping, the same amount of air is still being passed through, but because of the additional size/volume of the pipe, it doesn't cool the hotwire enough thus giving a 'low' reading. The ECU thinks there is not much air passing through to the engine so it injects a small amount of fuel (according to the factory map).

The engine wouldn't start because there was not enough fuel. So when I bumped up the fuel, the car would start.

This holds the other way, if you decrease the diameter, you'll get a rich condition!

Anyhoo, back to the FIC tune, I hooked up the FIC. I re-adjusted all the fuel cells back to the turbo tune and looked into the MAF map (where I set a MAF clamp). I increased the voltage offsets to pump the MAF signal up and... voila! The car would start without having to tune a richer fuel map!

I then attempted to drive it and the car stalled... It looks like my whole MAF map is messed up! I followed the AEM's instructional videos to clamp my MAF but I think the Echo ECU is a different case.......

Stay tuned!