Car will not idle after MAF relocation

[G.Chetcuti]

Hi everyone, this is my first post on this forum as I couldn't find any help on the internet and even asking friends. I have a 2006 Yaris 1.3 and I would like to replace the airbox and air filter with a sleaker "cold air intake". My main motivation in doing so is to achieve the desired induction growl and to have a nicer engine bay (once I clean it up as it is a bit messy right now). Anyways back to the point. I have installed the intake but in order to connect the intake directly to the throttle body I had to relocate the MAF (which is usually in the air box, just above the throttle body) a bit further down the pipe away from the throttle body. Now the car will not idle and will die. It will start up but the revs will just drop and the car will stall. I do not know why as I do not think moving the MAF should affect the car's operation. The diameter of the new MAF housing is slightly larger than the original and I have tried inserting the MAF in different directions but it still doesn't make a difference. I have also tried running the car without the filter but the result is the same. Somehow the car is running rich rather than lean, as the exhaust is smelling very fouly and smells more of petrol. Could anybody perhaps know why this is the case and why it won't idle? In the meantime to keep my car running I have reinstalled the original airbox and the car runs fine so the MAF is working when in it's original condition. Should I attempt this again and disconnect the battery so that the MAF can relearn the new air flow? I really am struggling as I do not know why it will not work. Any help will be appreciated. Thanks

[06YarisRS]

Hmmm...very interesting. I have been researching a turbo application for my car (not by any means committed to doing it) but just the other day I wondered about how relocating or placing the MAF into charge pipe might affect the signal/operation. I know that it would be affected by forced induction and the electronic management of the aftermarket ECU/piggyback would clamp the MAF to keep voltages within acceptable paramaters. It's a bit of a different scenario, but I'll be watching your thread closely for the outcome.

[WeeYari]

I've seen many instances in the past in which the maf is seriously thrown off by any change in intake tubing diameter. You cannot deviate from the inside diameter of the stock maf housing as it affects the volumn of air flowing over the sensor.

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[myfirstyota]

I've seen many instances in the past in which the maf is seriously thrown off by any change in intake tubing diameter. You cannot deviate from the inside diameter of the stock maf housing as it affects the volumn of air flowing over the sensor.

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Yep. As far as I know, the maf relies on the diameter of the intake to make a proper calculation as to how much air is actually entering the engine.

[G.Chetcuti]

Thanks for the input. I guess that is the reason why, unless a retune or ECU/MAF flash is conducted, you can't run my setup as the MAF is calibrated to function only within the stock diameter. I managed to attach the pod filter and piping directly to the existing airbox and got the desired sound, however it would be cooler (and lighter) to attach it directly to the throttle body as intended

[myfirstyota]

I'm not sure about the 1.3 engine as we simply don't have those available in the yaris here in North America. But on the 2zr swap I did, the maf and the pipe it mounts to is removable. You'll end up with a section of pipe about 4" long with the maf mounted in it. If this happens to be your setup, maybe that oem maf tube could be integrated into the cold air setup.

[bob225]

It should of been ok, but you will need to do an idle/tps relearn

[G.Chetcuti]

I'm not sure about the 1.3 engine as we simply don't have those available in the yaris here in North America. But on the 2zr swap I did, the maf and the pipe it mounts to is removable. You'll end up with a section of pipe about 4" long with the maf mounted in it. If this happens to be your setup, maybe that oem maf tube could be integrated into the cold air setup.

Yeah unfortunately the 1.3 setup has the MAF sensor integrated into the airbox which is located right above the throttle body, so I didnt have much room to play with, because the bonnet space is already pretty limited so adding a 90 degree bend over the existing MAF housing in the airbox wouldn't fit. Hence why I opted to relocate the MAF. Alas the car is working fine as I have just driven it :smile::smile:

[G.Chetcuti]

It should of been ok, but you will need to do an idle/tps relearn

You're right, but it didn't work or I didnt do it correctly. I removed the battery and reconnected it after an hour, turned key to ON position,waited 10 seconds then turned the key off, then reinserted the key and started the car but it still wouldn't idle. Do you know how to to an idle/tps relearn? Thanks :smile:

[WeeYari]

You need to drive the car non-stop for about 30 minutes in order to have ecu relearn.

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[G.Chetcuti]

You need to drive the car non-stop for about 30 minutes in order to have ecu relearn.

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Well, the car coudln't even idle so driving it wouldbe a problem in the short roads we have in Malta, but thanks for the idea. I'll get back to this again in a few weeks and give it another go :w00t:

[praivo]

You need to drive the car non-stop for about 30 minutes in order to have ecu relearn.

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No. There is nothing to for it to relearn if the system is set up properly. And given the construction on the intake on the SZ engines (NOT in a circular pipe & very close to the throttle body) I really can't think of a simple way to alter it without affecting its function. The NZs are FAR better in this regard.

[bob225]

You need a scan tool with bi-directional controls to do a relearn correctly

You can also check the airflow of the MAF

[praivo]

How would you check the airflow if the engine won't run with the sensor connected?