ECM Test Bench

[Six_Shooter]

I have made and ECM test bench, that has been useful for testing code and learning about how ECMs function.

I started with a MegaSquirt JimStim 2.0, and have made some jumper harnesses for different GM ECMs. I plan to use this to learn about other manufacturers ECMs as well.

I started with the JimStim 2.0, since it had trigger wheel simulation, for simulating engine RPM.

Here are some old pictures, I will get some new ones soon.

http://domestic.3400z24.com/sixshooter/Tuning/Test%20Bench/desk01.jpg

http://domestic.3400z24.com/sixshooter/Tuning/Test%20Bench/desk03.jpg

http://domestic.3400z24.com/sixshooter/Tuning/Test%20Bench/v1stimnecm.jpg

Anyone else use a test bench?

[EagleMark]

Yeah I got one! Been building wiring harness on the bench and needed to test them, looked up some information and found that you had been doing ECMs on the bench.

I added a JimStim stimulater to give some readings for sensors I couldn't get from the origanal test bench which was a TBI intake manifold. I used a distributor and a 3/8 drill to spin it.

Been very handy both ways.

http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1812&d=1330739286

[EagleMark]

Here's a picture of one that Mark M, author of tunerPro uses. The stimulater was available years ago and is no longer available. But very cool set up!

http://tunerpro.net/images/TestBench.jpg

[Six_Shooter]

Yeah, at one point, I was trying to find one of those, when I realized they were already long out of production.

The JimStim works great though. Just needs a few more circuits.

[EagleMark]

The JimStim has been a great help but you have to add an EST like the one pictured above uses. You can get a tach signal without it but that's it, no knock or ESC. And if you hook up a 12 volt signal from the ECM to the JimStim you burn up a chip and a capiciter. (Don't ask how I know?) :roll:

Have you seen the stimulater on Moates site for the Honda ECMs?

[Six_Shooter]

I just have the ESC pulled own to ground through a resistor. I'm not so worried about testing ESC, at this point.

Yeah, I've seen that stim, a bit pricey IMO, especially when a JimStim is so cheap and can do the same and more.

[dave w]

Here is mine. I just plug everything in and spin the distributor with a hand drill. I use a hand vacuum pump on the Map Sensor, a heat gun on the temp sensor, and data log with the aldl connector. I ground a spark plug from the coil, and connect a noid light to the injector connector. The batteries are Sealed Lead Acid 12 Volt 10 amp / hour. I got the batteries from the recycle bin at work when the emergency lighting batteries were replaced.

dave w

http://i239.photobucket.com/albums/ff290/buildabot2002/TBI%20TEST%20BENCH/DSCN2730.jpg

http://i239.photobucket.com/albums/ff290/buildabot2002/TBI%20TEST%20BENCH/DSCN2735.jpg

http://i239.photobucket.com/albums/ff290/buildabot2002/TBI%20TEST%20BENCH/DSCN2731.jpg

http://i239.photobucket.com/albums/ff290/buildabot2002/TBI%20TEST%20BENCH/DSCN2732.jpg

[Lucky]

Now THAT looks like something I would do Dave :thumbsup:

no offense intended ...

[EagleMark]

Here's a look at my power supply. Just a lawn mower batterey $22. and my batterey charger when needed. I also ran some power junctions to the benchtop when I am working. Jumper cable clamps at the batterey as I usually leave it disconnected when not in use.
[attachment=0:wktck2b4]Power.jpg[/attachment:wktck2b4]


Here is a close up of my JimStim wiring mess...
[attachment=1:wktck2b4]JimStim.jpg[/attachment:wktck2b4]

[RobertISaar]

so how is everybody simulating an O2 sensor? that's about my only holdup ATM.

i want to be able to control high/low time ratio and swing frequency independantly, so a 555 is pretty much out of the question.

[dave w]

so how is everybody simulating an O2 sensor? that's about my only holdup ATM.

i want to be able to control high/low time ratio and swing frequency independantly, so a 555 is pretty much out of the question.

For a simple 1 wire O2 sensor I use an LM317 DC voltage regulator for 0vdc - 1vdc. http://www.national.com/mpf/LM/LM317.html#Overview

[Six_Shooter]

Just a variable 10K resistor (pot), that is manually adjusted.

[EagleMark]

so how is everybody simulating an O2 sensor? that's about my only holdup ATM.

i want to be able to control high/low time ratio and swing frequency independantly, so a 555 is pretty much out of the question.
JimStim does narrow and wide band.

[RobertISaar]

Just a variable 10K resistor (pot), that is manually adjusted.


For a simple 1 wire O2 sensor I use an LM317 DC voltage regulator for 0vdc - 1vdc. http://www.national.com/mpf/LM/LM317.html#Overview" onclick="window.open(this.href);return false;

neither of these options would make the O2 swing though.... just provide an static mV value until manually adjusted.


JimStim does narrow and wide band.

and i'm piecing this together bit by bit, since it will be incredibly cheaper and will allow me to tailor the bench specifically to the target ECM's capabilities.

[Six_Shooter]

Test benches aren't meant to simulate a running engine, that would take much more complex processors and sim software than is readily available. This would require math that would simulate burn rates and changes within a cylinder, accounting for dynamics of a running engine.
Test benches are meant to simulate static conditions that are otherwise impossible with a real engine to verify code changes or reactions of code to specific conditions.

For the $59 (or so in kit form) from diyautotune.com, the JimStim is worth it to use as a base, since it can simulate quite a few different trigger wheels, though you really only need one, since most GM ECMs use the same ignition signals. That's why I started with the JimStim and have added on to it.

[RobertISaar]

RBob/Dimented24x7 have been guiding me along and it sounds like i have a good option cooked up now that will allow me to make somewhere between a square and sine wave for the O2, which is what happens IRL, which is exactly what i want... and with the ability to adjust frequency independantly of duty cycle, which meets my initial requirements. it would also seem that i can now change the center point of where the "O2" switches, which will allow futher fine tuning....

[rts91tsi]

You all have some excellent test bench setups! I have been interested in setting up a test bench for a while, and was unsure how exactly to go about doing so, until I stumbled on the JimStim info in the TunerPro thread. It is great that there is such a tool available, and I plan to not only use it to verify ECU repair work, but also use it to try to further modify and verify code modifications.

Before I learned of the JimStim, I was planning to use a spare engine wiring harness and some sort of multiple DC voltage power supply, and who knows what else, to create a test bench of sorts. Hell, I even though of using a battery operated Tens Unit to create electrical pulses to mimic the sensors that use those types of signals.

For those of you using batteries for power supply, have any of you tried using the power supply listed as an accessory?

[EagleMark]

I used the optional power supply for the JimStim and it worked fine. But didn't need it as I have a 12 volt lawn mower battery I use for powering the other entire system. That has a battery tender, like a trickle charger to keep it charged.

If you look at that picture in TP thread IIRC Mark has a electronics power supply...

[Six_Shooter]

I use a 5amp 12volt power supply. I plan to add a battery, but to be more of a filter, than something to power the system from.

[EagleMark]

Exactly why I use a 12 volt battery!

Electrical noise from Ignition Coil, spark plug wires etc... has to be looked at carfully whe doing a conversion. First one I did with front distributor, (Chevy has rear distributor) had issues! Found them with my Osiliscope and changed wiring path of harness to fix the noise! Actually I moved the coil!

[rts91tsi]

I see what you guys are saying about using a battery as the power source, instead of the plug in wall unit. Since the wavelength of the AC current is broad, its output would be more inconsistent than a true DC power supply. An electronics power supply, oscilloscope, and a meter that can measure capacitance are definitely on my list of things to eventually add to my bench setup, but for the time being, the basic necessities will have to do.

[1project2many]

The "no longer available" stimulator looks like one designed by (I think) Bob Ward? He was on thirdgen last I knew. If my memory's any good he had an old Malibu with twin blowers from a junkyard. He said he built that after looking at my test bench and deciding there was no way he wanted something so big and clumsy.

At the time, I thought mine was pretty organized. I used an ignition module from a small cap dizzy to drive a small LED so I had visual confirmation that the RPM generator was working. I picked up a GM test tool from a swap meet which outputs various frequency A/C signals for testing DRAC, instrument clusters, &etc. For most of what I was doing I found a fixed RPM input was satisfactory. I've also seen people use cable driven magnetic VSS connected to an igniton module as an rpm input. I used pots for sensors and put LED's on several of the outputs and on the REF and EST lines. Having trouble finding pictures but then again, I haven't had it out for at least 5 years. Here's the DIS system I set up for testing:

1220

It's an old PC fan with notches and a crank sensor connected to an actual DIS module. A dial back light was useful in measuring delivered timing to confirm chip settings. A PC power supply for the bench worked well for most testing but the DIS module with coils attached required more current so I had an automotive "jump pack" attached along with the power supply.

[RobertISaar]

i'll have pics up tomorrow. :D

mine is currently functioning.... kinda. i'm having issues with the 3 wire sensors ATM, but i have a good idea as to why. turn A/C pressure pot, skews MAP and TPS readings... what a pain.

[Six_Shooter]

i'll have pics up tomorrow. :D

mine is currently functioning.... kinda. i'm having issues with the 3 wire sensors ATM, but i have a good idea as to why. turn A/C pressure pot, skews MAP and TPS readings... what a pain.

Yeah I have had similar issues develop after a while. I plan to improve my bench with some separate pots to hopefully get rid of that.

[RobertISaar]

mine did it immediately after i completed it, so it's likely that i skipped a resistor or hooked up the pot incorrectly.

either way, it all fits in a 6" X 8" radioshack project box... and it is quite cramped. only used about a 100 foot spool of wire as well. :laugh:

and if i had to redo it: i'd be using logarithmic pots for some things, these linear units can cause some really touchy operation.

[rts91tsi]

I've yet to get around to setting up my test bench, due to other distractions, some useful some not. Anyhow, I took an electronics fabrication class at community college this semester, which ended today, and I fabricated a variable DC power supply.

Here are some pictures:

This is the PCB I fabbed. The etchant was about on its last leg when I did my board, so due to etching time, some of the reference designators were etched away.

http://i809.photobucket.com/albums/zz12/rts91tsi/dogsandpower002.jpg

http://i809.photobucket.com/albums/zz12/rts91tsi/dogsandpower003.jpg

I used this to finish the aluminum alloy sheetmetal enclosure after sanding with 180 grit to add grain to the metal:

http://i809.photobucket.com/albums/zz12/rts91tsi/dogsandpower004.jpg

http://i809.photobucket.com/albums/zz12/rts91tsi/dogsandpower005.jpg

http://i809.photobucket.com/albums/zz12/rts91tsi/dogsandpower006.jpg

Some functionality shots:

V-min = 0 VDC
http://i809.photobucket.com/albums/zz12/rts91tsi/dogsandpower007.jpg

V-max = 14.53 VDC
http://i809.photobucket.com/albums/zz12/rts91tsi/dogsandpower008.jpg

[EagleMark]

Nice! :thumbsup:

Better then my lawn mower battrey...

[RobertISaar]

i'm just using a fairly new ATX power supply.... had no use for it since i bought a ~800 watt unit, so this one got turned into my "project power supply"...

charge batteries, power a jewelry cleaner, test car radios, power my wife's keyboard.... useful little thing, definitely worth it's money.

i should really post pics of my bench though, it's quite a simple affair, on one side exists the power supply, then the engine sim, then the PCM. i do have a few pots pulled out of it for the moment, but otherwise it's complete.

[EagleMark]

The ATX, power supply from a desktop PC? Darn, never thought of that I have a couple laying here...

[RobertISaar]

yeah, they're quite useful. and push plenty of amperage for almost any DIY project.

[Tunedperformance]

So I finally decided to do a upgrade this last week too the jimstim, Full range on rpm to ecm limit and full vss range 1-255 mph. Runs off of ecm 5v reference.

[Six_Shooter]

Were you not able to go to ECM limit with the JimStim before? I have no issue going well beyond what the ECM is capable of with my JimStim.

I need to get around to building a VSS circuit...

[Tunedperformance]

I decided instead of buying a transstim to just build both in one. It cost me $25 to build. I think the transstim is $20 for the board and $15 for the parts from digikey plus shipping. The Jimstim did reach the ecm limit But I never put a tach on too see how much more it will go.

[Playtoy_18]

I built a bench harness this weekend.
Used an ATX from an old computer,relocated the switch and put it all in a pioneer reciever/dsp I gutted.
I plan to expand it with digital displays and some other stuff.
The rear rca plugs have been repurposed for the 5v power,and the speaker ports are prepped for 12v.
Still need to install led's as well as a rheostat.
http://i130.photobucket.com/albums/p275/edwinleahy/79515BEF-12EE-42F5-BBB3-C44581EB1228-232-000000719AE8BA60_zps1f5cea73.jpg

[1project2many]

You've probably checked, but the PC power supplies often provide a pulsed DC signal and sometimes it's not a very clean one. Many 12V components will work with this but it can introduce a fair amount of noise when working with ecm's and sensors. I've found old 2 way radio power supplies to be excellent for use with ECM and other 12V powered items.

Hmmm... aren't you supposed to be doing "front and face" when it's slow? Pulling apart the network terminals to make a bench cable between customers is probably frowned on.

[Tunedperformance]

for c3 and p4 ecm's im using a AC 100V-240V Converter Switching DC 12V 1A Power Supply US 5.5mm x 2.1mm works well. Thanks for the reminder I need to work on my bench ;(

[Playtoy_18]

Funny you mention radios,cause that is the main purpose for this supply :)
I needed something to run my quad band yaesu when my bench supply fried.
I didn't know it was pulsed,i'll see if I can get buddy to bring scope by.
If nothing else i've got other ways to power bench harness,just needed to get off my butt and get something started.
I am running a load resistor on the 12v side and a fan on the 5v.
Any suggestions?

Our store is among a few others that is experimenting with new hours,and we're really small town.
That night we did $20 in sales the last 2hrs,$14 of it was me. (And that was busy)
You can only do corporate policy busy crap for so long before there is nothing else to do. :)
The others bring books,I bring projects.
Not sure what your talking about with network terminals?

[1project2many]

Get the scope on the signal before you worry about how to smooth it out. The cheapie units actually produce a very bad sawtooth. A good battery charger combined with a noise filter can produce a better signal.

I don't blame you about the corporate stuff. I've dealt with it first hand. Glad you're able to do what you can though. It's such a waste to have to stand around because someone might give you a hard time for bringing a project or book.

The photograph is a little blurry and it looks like the "black box" might be an old store computer that would be tied to the company network. I was joking that things are so slow you're taking the store pc's apart to use the power supply.

[Playtoy_18]

I've got a smart charger that is mostly unused now that I have a larger shop unit,so at least I have something to use otherwise.
I'll keep updated as to what I do,this will be expanded with a full test harness I'm just looking for a spare vortec black box harness to use since I have a spare black box pcm.

As far as AZ,I'm allowed quite a bit of freedom from my former and current manager.
I keep trying to quit and they keep getting me to stay,I enjoy helping people so meh.

Funny,the old network stuff we just upgraded from was actually given to me and sat in my garage for several weeks.
I planned to use the cases for just this,ended up stripping and giving away instead of using them.

[EagleMark]

There's a ton of useful parameters in the Vortec dissasembly that have never been added to TC, EFI Live or HP Tuners. I think a lot could be done with them.

I'm still old school clean power on my bench, small tractor battery and a battery tender.

[Tunedperformance]

372637273728

[Tunedperformance]

Thank you for reminding me I need to work on my test bench. Got quite a bit done cleaning it up and making 2 cables . Still need to tidy things up and rewire my iac leds to tri-color leds and label the case and lights.

[Six_Shooter]

Why are you using the GM ICM with the JimStim?

[EagleMark]

When I had mine setup on bench I used the GM EST/ICM as well, for something, but I forget? Timing! Won't have spark Advance without it IIRC?

[Tunedperformance]

i couldlt get the jimstim to to a very good tach signal or the est error to go away so I built my own vss generator and rpm generator. The jimstim was a waste of money for building the jimstim. Im just using it for a connection to leds and the db37 and power supply.

[Six_Shooter]

I haven't had a problem getting a good tach signal from mine, with several different ECMs. The EST error is there, but I can simply get rid of that by adding a resistor that wire, just haven't got around to that yet.

[EagleMark]

But no spark advance in data without EST/ICM ref hi and low.

[Tunedperformance]

I did add a resistor so I would not get a knock error and A 1k or the orange led in the picture my mil .

[Six_Shooter]

But no spark advance in data without EST/ICM ref hi and low.

What?

I get SA data in my logs using the JimStim. FWIW, I do use both ref hi and lo.

[EagleMark]

I really don't remember why? Not sure how spark would be accurate without? Plus a error 42, glad I sold it, now I don't have to figure out why... :laugh:

[1project2many]

FWIW, I do use both ref hi and lo.
That's the correct way. REF Lo is not a "ground" wire. It's an independent return path for the REF Hi signal.

[geewhiz]

My donor TBIs came from a 1987 7.4L C20, w/auto, and another from a 1987 7.4L K30, w/auto.

Will this work for me?
Noid Light OTC7188 GM model 700 series TBI

http://www.ebay.com/itm/NEW-Noid-Light-OTC7188-GM-model-700-series-TBI-/151197731961

I would like to start cleaning up the wiring harness, and messing around with the compounds, testing the pieces and checking to see if they all function.

This looks more like the one, and half the price!
http://www.summitracing.com/parts/oes-25140/overview/

[EagleMark]

Yup, they would be fine. I got a full set with several differant noids for like $40.

[???]

http://www.amazon.com/SainSmart-Portable-Handheld-Digital-Oscilloscope/dp/B018E4AJH2?ie=UTF8&ref_=cm_sw_r_awd_7fUdxbYPQX1KW


so I picked up one of these for a project and it has a built-in wave form generator as well. it can output sign, square, saw. and selectable freq. my only wonder is how much current the ecm would need. it's a tiny little thing and I guess it wouldn't put out but a few ma.


wonder if it's worth trying to setup a test bench.

[billygraves]

Just an Old way I use to test the ECM with a Ref Pulse signal without the engine running.

When I repaired buy-back vehicles I hated to drive them and walk back. "May Walk" meaning if you drive it you may walk.

Anyway, with situations where a stall or run/stall then no-start, I used a weller 200?? watt soldering gun. I unplugged the Injectors and installed a noid lite. (It will full up a TBI Throt bore in a matter of seconds.) Unplug the coil wire on a V engine and install a Spark Plug tester ST-125. Turn the key on, hold the soldering gun near the Dist Pick up or near the crank trigger. (Watch not to melt anything) Used a Tech-1 to record RPM ect. With the time/heat sensitive problems, it took a bit but worked. With wiring and connectors that would open or short I mearly moved each section of the suspected harness/connector until the spark quit. (Some had more failures than just one)

When setting up a TCM quick test bench at home, I used a say 89 V-8 12 volt powered up dist module screwed to a alum plate, and grounded. A pick-up coil plugged into the module. I taped another pick-up coil directly to the other. On top of it. The spare pick up I soldered, and shrink tubed a 110 volt cord and plugged it into the 110 volt wall socket. If you do the math you'll see the spds. 4 pulses per rev at 60 hz a sec. Depends also on if a 8 6 or 4 cyl. I used the test for the ISS and OSS. ISS has 31 pulses per rev and the OSS has 40 pulses per rev. Verified with Tech-1.

Maybe instead of the drill to spin the distributor for your test bench, you might use the double pickup coil. It does work. (I have not tried this on the 60 deg V-6 BUT the same 6 pulse wheel with one syn was on the early 2.5L TBI engines with DIS and it worked very well. The module will get hot, so a thick heat sink)