Flow bench?

[ja_cain]

I know. And the bench is super expensive....


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My buddy built one for a fraction of the cost. I'll see if I can dig up a video of it.

 

[Morgan@Midwest Diesel & Auto]

Piezo's are crazy fast. Fast enough to have multiple injection pulses per compression event.

I like emptying 750hp worth of fuel only hp at 1100US....


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[N2GN2]

I thought I had two of those labjacks at work, but could only find one. Ill look again on Monday when I'm at work. If I can find the non-pro model, I'd be willing to send it to you as long as you promise to follow through on this project. Let me know if you think you would like to use it and I will see if I can find the other one.

There's a stand up guy! Thanks ja_cain, I'll keep that in mind.

 

[N2GN2]

I think you need to keep CID and FDCS in the same routine. Those cannot be run in seperate routines and everything work out in my experience. They are tied at the hip.

You know the "off time" on the FDCS is in between injectors, and the injector pulsewidth is defined by the time that FDCS is high after the leading edge of each event right? You don't pick the low, you pick the high and the low is just what's left before the next injector at the rpm in question.

Building a flowbench, pulsewidth and shot count are the bible.

In my sketch the 1st and 5th FDCS are linked with the CI state change. It'll make more sense to me once I see the scope shots of the test truck.

 

[Morgan@Midwest Diesel & Auto]

My buddy built one for a fraction of the cost. I'll see if I can dig up a video of it.

Lmk!


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[Charles]

This is probably going to sound dumb, but ID is short for identification. I keep getting momentarily hung up each time I'm either reading your code or your descriptions and run into "CI". Put the D on there. It's CID for cylinder identification. Otherwise the brain wants to read compression ignition or something else other than cylinder identification. Not to mention, all documentation specifically dealing with this communication link by Ford references CID. That includes wiring schematics, pin diagrams, so on and so forth. Best to have your brain aligned with the status quo.

And you can drive the IDM with very cheap processors. The first one I used for the flowbench project still sells for less than $40, and that's dreadfully expensive! lol

I later did much more involved work with a chip that was around $14 and it had a bazillion times the capability. You had to add your own eeprom and voltage regulation, but come on, what, $15 or $16 total?

Somebody who knew what they were doing could probably run an IDM for $10, easy.


Point being, the price isn't a problem or barrier. With electronics and programming it's always just knowledge. You can have as much of that as you have time. As long as time is cheap, stuff like this can be conquered easily.

Get your scope on a truck. And I would recommend not running your laptop on the truck alternator while you scope the truck if you plan on using that USB scope.

 

[N2GN2]

I agree the sketch is hard to read because of all the abbreviations. A friend had his truck put on the scope. I'm just waiting for those files. The bench controller is the only thing holding up completion of this project. I'm eager to see the cause and effect of injector modification. This is similar to doing your own tuning and having your own dyno.

 

[ja_cain]

Lmk!


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He doesn't have the video anymore, but will make another when he is off vacation. I'll post it up once he sends it to me.

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[N2GN2]

Any idea why we're getting this from pin 16 and 17 (CID/FDCS)? This is at 1000 RPM and 2.8 PW

 

[Charles]

I don't have the first clue what you're using for a pull-down on the IDM signals, but whatever you're using for the red line on your scope it is insufficient. If it's a transistor, then you're not feeding it enough signal to snap it on and off. Do you have some capacitance or too much resistance in your signal circuits to the gates by chance?

Your control is slow. It draws down slowly, and releases slowly. Like a hydraulic valve with a hose way too small on the pilot.

IDM will reject that, as I'm sure you're seeing.

 

[Charles]

Take a simple toggle switch and connect it to the same signal from the IDM and send it to ground through a resistor to verify that you can in fact have a crisp square wave. Then figure out why your circuit can't replicate the simple toggle switch.

 

[N2GN2]

Take a look at the last image I posted. I expect to see two square waves from the PCM to the IDM for CID and FDCS, but instead of CID were getting what looks like IDM to injector signal. We double check the pins and wire from the PCM to IDM.

 

[Charles]

Take a look at the last image I posted. I expect to see two square waves from the PCM to the IDM for CID and FDCS, but instead of CID were getting what looks like IDM to injector signal. We double check the pins and wire from the PCM to IDM.

Did you read post #90?

Btw, you are making those two signals, so anything you don't like, it's all you to fix it. The IDM just has a pull-up resistor IIRC. It's your job to sink them down to form the waves.

 

[N2GN2]

The photo is from a running truck. That is where my question is.

 

[Charles]

My bad, in that case you've got something wrong with the scope. Wrong pin (I know.... you checked.... check again...)

Otherwise, you don't have the probe grounded or something. Looks like you're just picking up noise on channel 2 from channel 1.

How are you connecting to the truck? Read in ONLY the circuit you have in red with the probe you have in blue if you haven't already.

Scope problem, wiring problem, grounding problem, or you're on the wrong pin would be my guesses.

What you're seeing isn't actually happening. You should be seeing a square wave on the first channel too btw. Why do we only see one event???

What scope are you using? Plenty of frequency?


On Edit:

And why is the picture so damn small?

 

[Rvaautodiagnostics]

Is a square wave of 0.69v to 13.66v normal for a fdcs? Got a 2000 ford with intermittent cut off. Signal stops when vehicle cuts off, pauses, then shoots one last square wave right before the idm goes to 0v.