Readings from vrg3 Scan tool

georryan · Post by **georryan** » Wed May 05, 2004 6:56 am

Ok, I'm not sure where this goes, most is purtanent to the engine forum, but not all, so I just thought since it is electrical readings from the ECU it may go here.

I want some clarification.

1)
1 torr = 0.0193367747 pounds per square inch, right? (thanks google)

Does our car hit full boost in second or third gear? I was only getting about up to 344 tor which equates to about 6.6 psi. It wasn't even really consistant. My brother said that even during acceleration the numbers were jumping around by about 100 torr all over the place, but he thinks it peaked at 344.

2)
Fuel Trims:

What do you guys get at idle? What should it be? Mine was ranging from -.78 to 0 and up to 1.56. At that time my idle was loping a little, but not as bad as it has been.

3)
Idle Timing:
This I guess I could look up, but my idle timing is 15 degrees. Is that normal?

4)
The injector pluse on my car at idle was 2.048, and it was pretty steady. Is that were it should be?

5)
System voltage. What should that be while idling with no AC on and the headlights on, or even without the headlights? With the headlights I was had a system voltage of...hmm..didn't write it down. It was 13.8 something I think. I know that when I turned on the ac it dropped to 12 point something.

If you guys can answer any of these questions that would be absolutely great.

Thanks again to vrg3, who is a hardware genious and subaru Einstein. I'm hoping this will help me figure out my idle and accelleration problems.

TheSubaruJunkie · Post by **TheSubaruJunkie** » Wed May 05, 2004 7:58 am

Ryan. We need to get together and set this up on both of our cars so we can monitor and compare in real-time. Im sure we both could learn alot about our engines that way.

This program looks very sweet. Are there any others like it? or do the same thing? Is VRG3 the author of the software? I'd like to know if there'd be anyway to dump the readings to a .txt file and have a running log of the info? For comparison and what-not.

I'm going to start searching for a cheap laptop Saturday. Hopefully i can find something (or hell... maybe even a motherboard/CPU and powersupply).

-Brian

mikec · Post by **mikec** » Wed May 05, 2004 12:10 pm

The idle timing is set to 15 degrees by the ECU as soon as it sees the neutral switch (I read that in the FSM) - so thats right. The voltage without A/C and the injector pulse timing sound good. Dunno what the voltage should be when you turn the A/C on, but that sounds okay. Did the voltage come back up once the idle had stabilized after you turned the A/C on?

I asked Vikash what the fuel trim meant, and his guess is that its an indication of how the ECU is changing the amount of fuel from its preprogrammed base map. So you should be seeing it change as the ECU adjusts the amount of fuel as it tries to maintain a steady idle. If you unplug your O2 sensor, you'll see they stay at 0, because the ECU has no way of knowing how much to change the fuel trim. I've been getting much larger changes in my idle fuel trims (up to 15% at times), but I am chasing a sometimes erratic idle.

Can't help you with the boost, as I'm having problems with mine.

vrg3 · Post by **vrg3** » Wed May 05, 2004 5:55 pm

Ryan, this thread is a good idea.

Your manifold pressure readings shouldn't bounce around by 100 torr, I don't think... that's a little weird. I wonder if your pressure sensor is okay. Do you have a boost gauge? What did it say was going on?

Brian, yes, I'm the author. I posted it originally in this thread:
http://bbs.legacycentral.org/viewtopic.php?t=16219

There's currently no way to log the readings. The program actually doesn't use any DOS system calls at all, since I originally meant it to run without an operating system. Maybe in a future version though...

As far as I know there isn't any other software out there to monitor our ECUs. Certainly not free, anyway. Some third-party scan tools probably can do it, though, like the Snap-On OBD stuff.

TheSubaruJunkie · Post by **TheSubaruJunkie** » Wed May 05, 2004 6:47 pm

Are you done working on this software? I would really love to be able to log the variables and be able to create a graph to really see whats going on.

-Brian

vrg3 · Post by **vrg3** » Wed May 05, 2004 7:51 pm

See the original thread for my comments, but in brief:

- I'm not likely to make any big changes any time in the next month or so since I have more important software to work on.
- You can't log multiple channels simultaneously, so the best you could do would be to round-robin several parameters or just look at one.
- There are spurious incorrect readings with this scan tool. They usually only last one sample, so you usually don't even notice them when watching with your eyes, but they'd show up as spikes or dips in a log.

georryan · Post by **georryan** » Wed May 05, 2004 9:35 pm

Well to answer vrg3, I don't have a boost gauge. I wish I did. I know what you mean by it being weird to bounce around so much. I can say that I have felt my car seem to pull back when accelerating, hesistate a minute then pull, as if the amount of boost is jumping around. I didn't feel that at all last night driving around, nad feeling that is rather rare. I will try driving around in test mode later and see if I get the "fuel-cut-in-test-mode-without-codes" issue.

The atmosphere reading was rock solid, it never changed ( don't know if that will mean anything or not). Was there a reading for hte pressure sensor?

Oh, the purge boolean value, is that referencing the purge solenoid? If so then it is registering on the scan tool even if it isn't bad enough to flip a CEL. Something to be aware of.

I checked throttle position voltage readings also, according to the post in the engine forum recently, it looks like with a voltmeter you should see 4.6 at open throttle was it(?), and 0 at closed.

Either way, I was seeing 4.8 with the pedal untouched, and at full throttle I still had 1.0 volt being read on the scan tool. Should it be at zero with the scan tool??

georryan · Post by **georryan** » Wed May 05, 2004 9:37 pm

Oh, also, does anyone with a boost gauge or knowledge know if our cars hit full boost ever in 1-3? Thanks.

Brat4by4 · Post by **Brat4by4** » Wed May 05, 2004 9:45 pm

Yes, 2-5 will hit full boost all the time. Occassionally if you take off just right the ecu lets the car hit dang near full boost in 1st gear (car normally runs off wastegate in 1st, correct?)

georryan · Post by **georryan** » Wed May 05, 2004 9:52 pm

Yeah I think your right about first. Thanks for the info Brat, that means that I should have seen greater than 6.5 psi in second and third.

BAC5.2 · Post by **BAC5.2** » Wed May 05, 2004 10:07 pm

My 1st gear never peaks over like 6psi IIRC. 2nd, and 3rd hit full tilt on my gauge.

georryan · Post by **georryan** » Thu May 06, 2004 12:21 am

For those using the tool, if your at full boost (8.7 psi that is) then you'll be looking for something near 450 torr. This will adjust as your elevation changes.

THAWA · Post by **THAWA** » Thu May 06, 2004 12:39 am

that would explain the 17 times then eh ryan.

TheSubaruJunkie · Post by **TheSubaruJunkie** » Thu May 06, 2004 12:53 am

Cool VRG, the program is pretty sweet as is, just wondering if v2.0 was on its way

I was thinking of splicing into the harness and instead of having 1 parrallel port, have like 3 of them and 3 laptops, all running the software that way i can view more than 1 variable at a time. Think it could be done?

Also, can the software be modified? I know how programers can get, and im not sure how protective of this you are... but it looks like there maybe room for improvement and this could be a good starting point for another programmer to start from.

-Brian

georryan · Post by **georryan** » Thu May 06, 2004 1:20 am

Thawa: yeah that would explain my timse alright.

SubaruJunkie: By programmers I hope your not referring to me

Assembly is cool and all, but it isn't one of my spare time enjoyments. haha

THAWA · Post by **THAWA** » Thu May 06, 2004 1:31 am

now all you gotta do is figure out why

vrg3 · Post by **vrg3** » Thu May 06, 2004 2:10 am

The ECU doesn't continuously monitor barometric pressure. The atmospheric pressure reading can only change when the ECU uses the pressure exchange solenoid to sample barometric pressure. It does this every time you go on boost and also every couple of minutes even if you don't go on boost.

The FSM says at WOT the TPS should read 0.7 to 1.6 volts, so 1 volt seems good.

My experience with boost levels is similar to Brat4by4's.

I wonder why I didn't just make the boost/vacuum function read in psi and inHg. I think I'll do that next time I touch the code.

Brian - Version 2.0?! If you've noticed my numbering scheme, you'd know that that's nearly 200 versions away

. I'll continue working on it for sure, but I make no promises about what happens when. I am also trying to finish my master's thesis.

Using more computers won't let you read more parameters; it's the ECU that only allows monitoring one parameter at a time.

Like I said in the other thread, I'm not planning on releasing the source publicly at the moment, but I might be open to getting some help from another programmer who doesn't feel nervous when he/she hears phrases like "assembling and linking," "bit-banging," and "self-modifying code."

georryan · Post by **georryan** » Thu May 06, 2004 2:32 am

Like I said in the other thread, I'm not planning on releasing the source publicly at the moment, but I might be open to getting some help from another programmer who doesn't feel nervous when he/she hears phrases like "assembling and linking," "bit-banging," and "self-modifying code."

Haha. I'm not nervous about it, and I may be willing to help you out, but I'm not going to promise anything at the moment.

So does the boolean (true/false) Purge valve value linked to the purge solenoid?

vrg3 · Post by **vrg3** » Thu May 06, 2004 2:37 am

Yes, that bit represents whether the purge solenoid is active or not.

georryan · Post by **georryan** » Thu May 06, 2004 2:41 am

By active, do you mean the same thing as acting up? Like when a CEL would get thrown, or does that mean it is doing SOMETHING, like say it's job.

vrg3 · Post by **vrg3** » Thu May 06, 2004 2:52 am

I mean the ECU is grounding its side of the solenoid.

TheSubaruJunkie · Post by **TheSubaruJunkie** » Thu May 06, 2004 5:56 am

LOL
Read my other reply on the other thread about my programming skills

No, Ryan, i wasnt reffering to you... i have alot of Friends back in Alaska, and some in WA that know a good bit about programming.

I didnt know it was the ECU that limits the program, that really sucks. I suppose the only way around something like that would be to reflash the ECU?

-Brian

vrg3 · Post by **vrg3** » Thu May 06, 2004 2:42 pm

Yeah; you'd have to change the ECU's programming.

That's another project of mine....

NemesisEJ22t · Post by **NemesisEJ22t** » Sat May 08, 2004 5:50 am

Hey everyone, i just hooked mine up a few minutes ago and took it for a drive. The thing i noticed first was that my O2 sensor will jump from ~0 to .6 volts while at idle (when its warm). Does anyone else's do this? Also, not really related, but I am using this on my laptop running XP and using a DOS boot disk with the .com file. What i did was start the comp with the DOS disk, then run the program. Is this a good way to do it? I noticed that my CPU fan is running constantly (it almost never runs at all) and that in 10 minutes it drained 15% of the battery power which usually takes 3-4 hours to deplete. Is there anyway i can make my battery last longer? I'm thinking of maybe underclocking my CPU, but i don't know if that will work when i run the DOS disk.

vrg3 · Post by **vrg3** » Sat May 08, 2004 6:01 am

Ben, if you mean the oxygen sensor signal bounces back and forth between 0 and 0.6 volts continuously, that should be right. When the engine is warm the ECU idles in closed loop, where it tries to keep an overall average fuel mixture around stoichiometric.

The way you're running the program is fine. In fact, as long as the program works, whatever method you use is fine.

Unfortunately, since it's just a simple DOS program, it doesn't do anything with regard to APM (Advanced Power Management). That's my guess as to why your fan runs continuously and the battery drains faster than usual.

If you can underclock the processor, that should help reduce power usage somewhat and shouldn't at all hurt the way the scan tool runs. Other options include reducing screen brightness and even disabling the hard drive in the BIOS.

If you plan on using this tool often, though, it might be worth buying a $20 inverter to allow you to use your laptop's usual power supply.

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Readings from vrg3 Scan tool

Readings from vrg3 Scan tool