DVT with the 411 PCM

[FeetDry]

I'm trying to troubleshoot a fuel delivery problem with a V2 on a 411 PCM.

Inside Scan 7.5, @ the DVT tab, @ the Engine Ctrl tab, I active and select Activate Fuel Inj Ctrl,.... Then nothing. I click the many All & Cyl buttons, and I'm not getting any response. I'm trying to do a static test of the individual inj's, by measuring voltage at the Inj control lines. (Engine not running.)

I know I am connected as I can control the fuel pump.

I suspect I'm not using this Fuel Inj Ctrl correctly. I'm not finding anything about DVT in the PDF manual. Is it documented somewhere? (Where?)

Does Fuel Inj Ctrl work for the 411 PCM?
Can I use this control to manually test the Inj flow, like a Tech2 would do?
Do I need the engine running to get this control to do something?
Does "Cyl 5 off" mean, make #5 a dead cyl?

I see there is an Inj balance test in the bi-dir menu. (I have not done this yet.)

Thanks

[joecar]

You are correct, that's not how the injector control works.

No you cannot use it to test injector flow as shown in the service manual using a Tech2 (I ask Paul for this test).

This is how it works:
- with engine running at warm idle;
- when you click Cyl 1 Off, the PCM turns off injector 1;
- when you click Cyl 2 Off, the PCM turns on the previous off injector and turns off injector 2;
- and so on for each Cyl n Off button;
- click All Cyl On to turn on the last off injector;

You can do this while logging, the log should show RPM dropped while each injector is off (i.e. an rpm rise indicates a non-firing cylinder), this is the manual handraulic version of the balance test.

Paul said he will eventually put the automated balance test back in.

[FeetDry]

I'm having a hard time doing the manual balance test. I'm not sure if I'm doing it wrong or interpreting it wrong.
When looking at the data, I can't tell when I switch from one cyl to the next. The RPM barely changes. I've had to record each cyl seperately, then look at the narrow & wide band O2 voltage to try and figure out when I turn the inj off. (Is there some way to add a bookmark/marker to the recorded data? Something that say's "Mark this spot".)

When listening to the exhaust, it is real easy to hear a dropped cyl. When looking at the data, there is no real change in rpm. I'm seeing drops of 10-20 RPM, which is basically nothing. I'm using the "Active Idle Control" in the DVT tab. More specifically I set the RPM to 1200. I'm thinking this the problem. I should be using the IAC, (doesn't have ETC).

I know there is a problem w/ Cyl 1&2, as there is no RPM or sound difference when these cyl's are dropped. The wide band goes rich when these are dropped. When the other cyls are dropped, the WB goes lean. I'm also seeing switch activity on the bank1 narrow-band O2 when I drop a bank2 cyl. (Unless I have crossed some wires, this can't happen.) I'm thinking this is because I'm use RPM in the Active Idle Ctrl. As in, the PCM is compensating for the dropped cyl.

What is the difference between the Fuel Inj Ctrl: AFR & AllCylOn? (AllCylOn doesn't look at the O2 signals? The Inj Pulse Width doesn't change?)

BTW the Recorder screws up the DVT setting. When I stop recording, and save the file, I loose the Idle Ctrl. I have to uncheck then recheck the DVT Idle Ctrl box to get the RPM back up. I'm not sure if Blacky intended it to be this way.

[joecar]

If auto trans, hold it stopped with brakes, put vehicle in Drive, and repeat manual balance test, you should see a drop of at least 200-300 rpm.

Try leaving Active Idle Control un-activated. What is your normal commanded idle speed...?

AFR = command specific AFR

AllCylOn = turn on all injectors (since you had turned one injector off a few moments ago), i.e. terminate the off-ness of the previous injector you turned off.

[FeetDry]

Commanded Idle is 580.
With approach described above,.. (in gear, no active idleCtrl)
I'm seeing drops of 80-100RPM. It is still hard to spot in the RPM data. The missing cyl shows up as a sawtooth wave. As in, you can see the miss in the RPM data of a healthy cyl. The dead cyls, they are just flat.

I was using an idle speed of 1200, but that was even more difficult to spot the dropped cyl.

[joecar]

You can change the range of the RPM chart from 0-8000 to 0-800, it will help to make the RPM drop more visible.

[FeetDry]

Yes, I keep trying to change the display range, but I can't seem to find the right gizmo. It looks like I need to create a whole new VDC file. Can I temporarily change the chart? Is there an auto-range setting? (How?)

As it turns out, my inj's were working fine. The DVT screens "Cyl1" & "Cyl2", don't acutally control Cyl's 1&2. They are probably more like Cyl's 7&8. (Mine is a V6.) After I installed an expensive new MFI assembly, I had to pull the individual injector wires from the PCM to get the cyls to drop. I'm not sure if the DVT Cyl 3 is actually switching off cyl 3 or another cyl. As in, if Cyl 1 is not controlling cyl 1, why would cyl 3 be controling cyl 3?
(My PCM info: OS=12212156 Stream=LS1B)

[joecar]

You can temporarily change the chart if do not save it.

Or, you can duplicate the current chart (add the current chart so it appears twice, edit the 2nd instance, save it with a different name)... then you can choose to display or not display this chart as needed.

There is no auto-ranging ability.

Good question about the cylinder numbering, IDK the answer.

[FeetDry]

How do I change the Y-axis range?
I keep going to (right-click) chart-properties, and not finding anything there.

Thanks

Edit: never mind,... I finally found it in the "series" tab.
I didn't "Save" it, (I clicked OK), but it was changed over all further charts. (Like the change was saved.)

[FeetDry]

Here is the info for a 2002 4.3L using the 411 PCM (OS=12212156, Stream=LS1B) EFI ver 7.5.6 (build 157)
Cyl# vs (DVT)button# vs wire/pin#
1 8 Blk C1-36
2 3 LtGrn/Blk C1-76
3 4 Pnk/Blk C1-37
4 5 LtBlu/Blk C1-4
5 6 Blk/Wht C1-43
6 7 Yell/Blk C1-77