The AUSubaru.com.au Forums

yeah, is anyone familiar with the use of the microtech hand controller and ecu ltx8?

wanna drop the fuel pressure a bit

http://www.microtechefi.com
You don't want to drop fuel pressure. The injectors and fuel pressure regulator are standard turbo items and shouldn't need changing. Easiest way to tune it is with a laptop rather than the hand controller. It has a 3d graph that shows all the fuel maps. You can click and drag to readjust the maps. Doing it this way you can see what you are doing.

If you use the hand controller you can only work on values for the length of time the injectors are open. It is a very slow way to do it. There is also an option in there where you can drop the whole fuel ratio by a percentage value. So, if it is fat right across the board you can take fuel off with one setting.

she's lean at idle to the point its surging up and down trying to idle smoothly, then gets down to the 10:1 somewhere off the gauge when you put your boot into it.

Jay you might want to contact Rotomotion. They are Mazda rotary specialists but also the WA distributer for Microtech and know just about all there is to know about them.
They have tuning people on staff so you may even want to bring the car in to them for a look-see.

Jay, you can look at the idle settings on #3 memory and write them down. Then look at the settings on #4 and do the same. Then make number 3 the same as what 4 is. I know it always idled better on #4 tune but it used a hell of a lot more fuel when driving.

If that doesn't fix it I would be looking for an air leak. It never used to idle badly before I changed the plugs before you picked it up. It would idle high at around 1000rpm but that was fine for when the air kicked in so I didn't worry about it.

Tune 4 idles smoothly and around 800rpm.

Hey Jay... I'm with Brett on this one. You DON'T want to drop the fuel pressure but you should check the the pressure is around 40 to 50psi at idle and that it should increase to around 60 to 70 under load. This is the case, if your using a standard Subaru Fuel pump. If your using and aftermarket one, pressures will be a little higher but not high enough to cause any problems.

Air/Fuel Mixture should be around 14.7:1 at idle and cruising... It must go richer as you first put your foot into it. Too rich and you'll flood the spark plugs and too little and you'll burn a hole in the piston.

I think it would be best to pay someone for some dyno time and sort it out before given it too much gas...

I have found some wideband O2 sensors and meters on the net... you should have one fitted, so after your dyno, you can keep an eye on the mixtures... and like Brett says, if it shows it leaning out, then you know it got a leak

on a turbo car ..a leak is usally quite safe as it goes rich under boost instead of lean (for a MAF based system anyway, a MAP based should handle it fine).

yeah leaning towards biting the bullet and putting it in to get re-tuned/dynoed and water/oil leaks fixed... more $$$

Wasn't it getting retuned before u bought it? Did the ECU loose it's tune or something?

think it only had a quick one, which resulted in a ****ty tune. i also did a bit of research about the jerkyness going from idle to acceleration, that relates to the tune as well. if i let it idle and try rev it in park, it won't move till it jumps to 2500rpm and its impossible to hold it between that and idle. so driving at 60 is a biatch.

I had a hesitation similar to that in the RX-7 once, it was fixed by adjusting the timing of when some of the injectors fired. Something to do with the mapping between idle and normal driving. The tuning guys did it in a few minutes with the hand controller and it's been sweet since then.
I should learn more about how to use it but touch-wood I havn't needed to with mine yet.