Providing engine specific crank/cam trigger signal Via Tacho

[BaldTurboFreak]

I have a H6 Subaru project in the works, and Im brainstorming about the integration with the factory WRX electonics. Since MS3/3x will be in charge of running the engine itself, I need not worry about a large portion of the factory outputs. However, since the EZ30 or EG33 dont share a common crank/cam trigger with the H4 so I cant keep the factory ecm inthe loop to run emissions related componenets, A/C controls, Idle Valve,Purge canister, Dash, Etc.
The solution to the problem would either be:
1) to use the Jimstim chip circuit stripped down on a little card, and the frequency controlled by an output from MS3
or
2) (yuck) mount the H4 triggerwheel off the front of the damper on the H6, and use it to drive a factory cam pulley. That will give me an accesory drive (scavenge pumps maybe?) and a place to provide a second set of cam/Crank triggers to run the aforementioned needs.
or
3) 2 unused outputs on MS3x (or the mainboard inJ for that matter).



Im no Code writer, but what is the feasability of implementing the same drop down trigger settings into the Tacho/spare outputs. So a guy like me can drop a H6 where a H4 was and keep all the nessicary hardware happy by providing it with the crank/cam triggers the factory ecm wants to "see".= Happy OBD2dash.

Or a guy or gal who's arse is married to the CAN bus in the vehicle and has no choice but to keep the factory ecm on board. Like Dropping a LSx in a Rx8 etc. Or a VVti 2jz where a non VVt was? 2Jz where a V8 toyota was? The ability to engine swap then becomes much much easier. I can't be the first guy to think of this

So as a formal feature request I would like to see
All the current triggers for the input side of MS availible as a "Jimstim like" output on the Tacho/spare output in Crank/Cam fashion. With realtime RPM correlation Input/output
Is it possible? or would a daughtercard with the Jimstim chipset/dipset, frequency controlled by the tacho output on the 3X and 2 "VR or 12v sq" outputs be a better solution? ( Paging Jean Belanger!)

[BaldTurboFreak]

Anyone? is this feasable or should I begin working harder on a jimstim based solution to this?

[Matt Cramer]

This may need to wait for V2.0's angle clock.

[BaldTurboFreak]

This will be an outstanding feature, unique in the tuning world. It will certainly put the MS3 in a class of it's own in terms of adaptability and use, by solving this typically significant hurdle for engine swaps.

[BaldTurboFreak]

I have my EG33 WRX swap running and driving. Now I really really need to get on providing the factory ecm (still in car and running all emissions/obd2 devices) for the EJ205 and rpm signal from said 4cyl.
As it stands right now, how feasable is it to have my MS3x output the trigger wheel patterns for the ej205 (2002 wrx) WRT rpm? Im going to try and rig up the jimstim to the factory ecm and see if that gets the party started, but Id really like to button up the rest of the loose ends. State inspection being one of them and that will require RPM input.
My last resort is to use the 4cyl trigger wheel mounted on the front of the damper with a VR wired to the OEM ecu.Possible have to run the cam side too, id like to avoid it if I could.

Can anyone code this up? I'll pay for your time!

Jean Belanger, is there a way your jimstim board could be modified to use the tach signal from MS3 to drive the rpm pot semi accuratly?

[racingmini_mtl]

Jean Belanger, is there a way your jimstim board could be modified to use the tach signal from MS3 to drive the rpm pot semi accuratly?

You could probably make a frequency-to-voltage circuit but how accurate it would be and what exactly you'd need in the circuit, I can't say.

Jean

[frank_ster]

i have similar issue. i have buick v6 in my 05 legacy.

the stock ecm is looking for the drvers side cam sinc even with all the codes disabled using ecu flash. if i disable the p code for the drivers side cam sensor the ecm wont let the engine run. because the code sets a backup function.

BUT the 2.5 i (n/a) legacys dont do this. so switching the computer to a n/a version i should be able to have the ecm fully happy with cel off.
i did make a subaru crank trigger wheel

[frank_ster]

the subaru ecm is looking for this kind of wave ( jpg attached) and its a vr sensor so more that a 5 v pulse. so having mega squirt making this kind of signal may be complicated. yes a square wave may work but but would probably need more that 5 v.

[BaldTurboFreak]

I bench tested the stim on the car's factory H4 turbo ecm, Success! it recognized the 36-2-2-2 immediatly and showed up Aok in the software. CEL's turned off and everything is working.
Now I have the choice between making a electronics based solution or just mounting the 36-2-2-2 wheel to the front of the damper and calling it done.

[BaldTurboFreak]

http://www.google.com/imgres?imgurl=htt ... A&dur=1445

I was thinking this circuit built to feed the jimstim componenets. Thoughts?

[jsmcortina]

You could possibly use a generic PWM output and a resistor/capacitor low-pass filter to generate the signal from the MS3. Use the PT4 output. I would add a Zener diode at the JimStim end though to ensure 3.3V is never exceeded.

James

[racingmini_mtl]

One problem with using the JimStim that way is that you will need 2 analog signals: one for the coarse pot and one for the fine pot. The fine pot has a range of 512RPM with a granularity of 1RPM while the coarse pot has a range of 16128RPM with a granularity of 256RPM. If having the RPM value jump by 256 up or down is not a problem then you could use only one signal. Otherwise, you'll need to use two signals and coordinate them to get a continuous RPM reading.

There is a mode where you send an RPM value over the JimStim serial port but that would require something else that can read the RPM off the MS3 and write it to the JimStim. It's not complicated but it doesn't exist as such and would need to be done.

Jean

[frank_ster]

what year is the car your doing this to ? i guess it does not have the cam advance thingy ?

[BaldTurboFreak]

It's an 2002 wrx Frank, no variable cam advance no. You can just disable it with opensource/romraider in your leggy.
Jean, d*** I didnt think about the fact that it has 2 pots to run RPM. Is there another method of running that chip? Or is there another style chip that could be used to accomplish what we are doing with the engine swaps? Id be the first guy to buy it, our shop specializes in MS installs and many of them are engine/family swap related. Unforutnatly we still ahve to pass obd2 inspection and in my case this is the last piece of the puzzle

[frank_ster]

well you might get away with only 256 rpm resolution.

i cannot disable that p code in my legacy i have tried. its because mine had the intake cam advance. there is a checking that checks that the cam is correctly timed. if you had a subaru with the cam advance and the timming belt was off by a tooth the ecm would not let it start.
however if you unplug the sensor you can run the engine with one tooth off. but in cranking the engine will turn 3-4 times before it sets the code and allows spark and fuel. with my car i need to crank the engine extra long for the tach to finally jump up. its very bizzar.
and when i disable that p code it does not set the default action for not having the cam sensor. but this is not the case with the same year legacy with non turbo engine. but the computer is wired differently so i need to make a few changes to switch that ecm.

but the next question the jim stim if you simulate starting the car with the pots. and if you can simply use the rough correction and rev it up and down a bunch of times and the ecm is not freaking out you should be able to do the same via megasquirt. i realy doubt the stock ecm is looking for rpm smoothness.

also the jim stim does it put out a 5 v square wave ? i would like to do the same if possible.

[racingmini_mtl]

also the jim stim does it put out a 5 v square wave ? i would like to do the same if possible.

You can set it for that.

Is there another method of running that chip?

As I mentioned, you can set the JimStim in a specific mode and send it an RPM value through the serial port. What could be done is to use one of my TinyIOx and get the RPM from the MS3 through CAN and send this value to the JimStim CPU through the serial port. That would require writing a special function for the TinyIOx but I could probably do that.

Jean

[BaldTurboFreak]

Is the TInyIox board this one: http://www.jbperf.com/io_extender/index.html ?
if so I'll place an order for one with components immediatly. I definitly want to follow thru on this feature for MS. As I said, this will put MS in a class of it's own with respect to standalones and adaptability/integration with engine swaps. Providing the factory ecm with the original cam/crank inputs opens the door for alot of folks with engine family swaps.

[racingmini_mtl]

Actually it's this board: http://forum.jbperf.com/viewtopic.php?f=14&t=1032. It's a smaller derivative of the one you linked but it's more than enough for what you want to do. Having said that, the current firmware does not support this option of talking to the JimStim so it would be a bit premature to get one right now.

Jean

[frank_ster]

yes i second that thought! would br great for engine swaps to different familys. sincemost new cars are using can comunication to the cluster and everything else removing the stock ecm would be a big undertaking.

[frank_ster]

what about puting the jim stim componets into the proto area of the megasuirt?