2003 sxt - rusEfi test mule

russian · Post by **russian** » Thu Oct 30, 2014 12:44 pm

My 2003 sxt is a test mule for my open source ECU project.

I hope I've got a great deal - less then $1k for a 101K miles manual with current inspection. Looks like there was a hit into one of the rear wheels or something since the bearing and strut mount are shot, but that's an easy fix.

As for the ECU project, the board is ready

I've already extracted a connector from a donor used ECU

So now it's the question of simply wiring everything up.

See also: http://forums.neons.org/viewtopic.php?f=18&t=410462

Gnuserup · Post by **Gnuserup** » Thu Oct 30, 2014 2:24 pm

interesting, what are your plans ?

russian · Post by **russian** » Thu Oct 30, 2014 2:27 pm

Gnuserup wrote:interesting, what are your plans ?

When I've started this two years ago I did not realize that making an ECU from scratch would take so long. At this point I am just enjoying this as a hobby, hopefully I will run this ECU at a Lemons (amateur endurance road racing) race in 2015 or 2016. We'll see

Post by **occasional demons** » Thu Oct 30, 2014 10:17 pm

Maybe link your thread from neons.org. We don't really have any issues with sharing info from other forums here. (If that's why you didn't)

The more knowledge the better.

russian · Post by **russian** » Sun Nov 02, 2014 7:22 pm

neons link added into first post

Also I've finally started this thing today!

Ops, no youtube embedding here?

http://www.youtube.com/watch?v=PhIWAPaUnYM

russian · Post by **russian** » Wed Nov 12, 2014 10:49 pm

So my 2ng gen does not have a timing mark right? I've made my own mark more or less where TDC should be - that's the longer mark. the other marks are 10 degree apart (at least I hope they are - 16mm should be 10 degrees considering 93mm pulley radius)
http://www.youtube.com/watch?v=QHzr-K8jmqA

that's rusEfi idling
http://www.youtube.com/watch?v=xcxzZYOdPJs

russian · Post by **russian** » Fri Dec 05, 2014 11:27 pm

http://www.youtube.com/watch?v=14n-xKUQg5E

Does anyone know anything about alternator field wire? Is it ground or battery +, is it on/off or PWM?

fixit · Post by **fixit** » Sat Dec 06, 2014 9:04 am

pwm to ground.
might be easier to go with an external regulator

http://www.msextra.com/forums/viewtopic ... 31&t=54320

russian · Post by **russian** » Sat Dec 06, 2014 9:47 am

fixit wrote:pwm to ground.
might be easier to go with an external regulator

http://www.msextra.com/forums/viewtopic ... 31&t=54320

Great link but they do not specify if 1st gen or 2nd gen

Looks like 2nd gen the wire goes to battery, not ground.

Post by **occasional demons** » Sat Dec 06, 2014 11:41 am

I think they changed it in 2003.

russian · Post by **russian** » Tue Dec 09, 2014 11:31 am

It's hard not to understand electronics, so far I am failing to control the alternator with my ecu. Here are the details:

Resistance between field wire and ground: 12 Ohm

With the car running with rusEfi, if I manually connect field wire directly to battery positive terminal I can see how the car RPMs go up (load goes up?) and the voltage goes from 12v to 16v. This tells me that's the right wire I am messing with

Next step - I am trying to control the alternator with my ecu.

I have 400Hz PWM via the hi-side TC4427 chips. I've tried 60% (~7v), 80% and 95% (~11v) PWM connected to alternator wire to no avail - the alternator does not seem to engage.

Now that I've typed this I've realized that I have a 100Ohm resistor after the TC4427 chip.

I guess my next step would be replacing that resistor with a 0ohm and hoping for the best.

Post by **occasional demons** » Tue Dec 09, 2014 8:57 pm

russian wrote:
I have 400Hz PWM via the hi-side TC4427 chips. I've tried 60% (~7v), 80% and 95% (~11v) PWM connected to alternator wire to no avail - the alternator does not seem to engage.

Now that I've typed this I've realized that I have a 100Ohm resistor after the TC4427 chip.

Are the voltages above actual measured at the field connector, or just mathematical equations?

russian · Post by **russian** » Tue Dec 09, 2014 10:58 pm

occasional demons wrote:Are the voltages above actual measured at the field connector, or just mathematical equations?

that's actual voltage measured on my control wire while it's not connected to alternator (the pieces are not connected yet since I am still trying to figure this out)

I've removed the 100R resistance but it looks like I cannot provide enough current into this wire through my control transistor:

idling with rusEfi, +12V on battery => DMM => alternator field wire: 6.5A - engine is jerking up, probably charging. pretty large spark

idling with rusEfi, rusEfi control field control wire => DMM => alternator field wire: 0.5A - engine is maybe reacting a bit, not sure. the spark is pretty tiny. voltage on the battery does not change so I guess no charging

Post by **occasional demons** » Wed Dec 10, 2014 12:20 am

I wonder if you could use a mosfet to handle the current. The rusEfi control could switch the mosfet for PWM. Mosfets have been successfully used to switch COP ignitions, so the alternator field shouldn't be an issue.

russian · Post by **russian** » Wed Dec 10, 2014 8:04 am

occasional demons wrote:I wonder if you could use a mosfet to handle the current. The rusEfi control could switch the mosfet for PWM.

I am using a mosfet right now - TC4427 - but looks like it's just too weak with it's 1.5A peak rating. What's your favorite mosfet for this application?

I have a DPAK breakout module I can maybe use:

Post by **occasional demons** » Wed Dec 10, 2014 7:46 pm

The BIP373's are what are used for COP set ups.

http://www.diyautotune.com/catalog/bosc ... p-230.html

http://megamanual.com/ms2/bip373_datasheet.pdf

Hopefully this is helpful.

I know on neons.org they have suggested going with the older external VR, but I can understand your desire to have it all in one package.

russian · Post by **russian** » Wed Dec 10, 2014 7:52 pm

Is not this BIP373 low side (N-channel)? It looks like I would need a hi-side for alternator control.

My electrical engineer is busy at the moment, I hope he gets back to me or I would order FQB12P20TM just as a random P-channel

russian · Post by **russian** » Sat Dec 20, 2014 9:12 pm

first rusEfi dyno run.

Stock ECU run: 121hp/127 lb-ft
1st rusEfi run ever - wooping 44hp/69 lb-ft. Right, 12 degrees advance does not work so cool
8 runs later: 123hp/128 lb-ft. More then stock ECU! better timing.

We did not tune fuel at all (Speed Density with default table), the plan for the day was to get close to stock values and just test everything. Mission accomplished

full logs

ragek23 · Post by **ragek23** » Sun Dec 21, 2014 8:47 pm

nice job!