Eliminate VSS for Vortec 8.1 liter / Turbo 400

[dave w]

If I ZERO out the Abuse Mode Disable Speed, can I use a Turbo 400 without a VSS for a Vortec 8.1 liter V8? I'm using the '0411 PCM.

Thanks,
dave w

[Taz]

Hello Dave,

Probably the best option, to promote driveability, is to use a 8.1 L tune with a manual transmission. If you are using a cable speedometer, an in line pulse generator can be installed to provide the PCM with an accurate vehicle speed.

Helped out another member with an in line pulse generator - attached below ..

http://forum.efilive.com/showthread.php?14646-speed-sensor

Regards,
Taz

[dave w]

Taz,
Thanks for the reply.

I attached the current tune I'm working with, 8.1 with auto. I'm not ready to install the engine into the vehicle. I built my own harness. I want to get the engine running on the engine stand first. One of my goals with the engine on the stand is to complete a crank position learn. I'm also becoming more familiar with EFI Live with the engine on the stand.

I found some useful information on this tread.
http://forum.efilive.com/showthread.php?11961-Vortec-7.4-0411-PCM-Standalone-Harness...got-a

I made some transmission segment changes to the 8.1 tune attached, based on the tune ss.tun in the above thread.

dave w

[Taz]

Hello Dave,

Checking the forum remotely .. no access to tuning software until I get home later today ... will have a look at your tune then. You are using OS 12208322 .. if you haven't done so already, you can use the software to "swap" in the transmission calibration and diagnostic segments from a manual transmission tune of the same OS.

Once installed in the project vehicle, a cable driven pulse generator should provide the PCM with an accurate VSS input.

I have never done a crank relearn on an engine stand. When you try it, if it doesn't seem to work, it may require the addition of a brake input signal.

All 8.1 L engines used DBW (Drive by Wire) throttle bodies ... there is no OEM 8.1 L DBC (Drive by Cable) tune ... FYI.

Regards,
Taz

[dave w]

Hello Dave,

Checking the forum remotely .. no access to tuning software until I get home later today ... will have a look at your tune then. You are using OS 12208322 .. if you haven't done so already, you can use the software to "swap" in the transmission calibration and diagnostic segments from a manual transmission tune of the same OS.

Once installed in the project vehicle, a cable driven pulse generator should provide the PCM with an accurate VSS input.

I have never done a crank relearn on an engine stand. When you try it, if it doesn't seem to work, it may require the addition of a brake input signal.

All 8.1 L engines used DBW (Drive by Wire) throttle bodies ... there is no OEM 8.1 L DBC (Drive by Cable) tune ... FYI.

Regards,
Taz

Hi Taz,
I've done many hours of planning and homework on my '0411 project. I'm actually going to use a L31 5.7 Vortec distributor instead of "per coil". I set the "Low Resolution Crank" to YES and set the Electronic Throttle to "NO". I made a test bench that allows me "Sync" both the cam position sensor and crank position sensor. I think making a test bench for my '0411 project might move my status to "Head of the Class" but not quite to the "Advanced Class" of project builders?

I decided on the 8.1 .tun mostly because the MAF / MAP / Timing tables should be a good starter .tun for the 8.1 engine I'm using. Because I decided not to use DBW, Electronic Automatic Trans, and Per Coil ignition, I have made many changes to the 8.1 .tun I posted above (which is still work in progress). I think my 8.1 .tun file looks more like an Express Van 5.7 Vortec .tun in many parameters.

I'm thinking I can figure something out about the brake input for the PCM to get a crank learn done. I think the hard part for me doing a crank learn, is me learning to use the V2 for bi-directional communication. One reason I decided to use an engine test stand was for me to be able to figure out this EFI Live stuff, before placing the engine into a vehicle.

Regards,
dave w

[joecar]

Dave, welcome to the forum :cheers:

[Taz]

That’s one interesting and unique project you have on the go !

Want to address a couple of things to help get you going. In a way you’re doing what is often referred to a “0411” swap – using an LS1-B PCM to control a distributor and low resolution crank sensor.

As with the typical 0411 swap you will need to begin with a 2001 – 2002 5.7 L Vortec tune – which is written for a 4x CKP sensor (low resolution) and a 1x CMP (distributor) sensor. There are several of these on the Holdencrazy site available for download.

Simple changing the values in G1207 in your current 8.1 L tune – from DBW to DBC, and to low resolution crank won’t work – as these features are not present in the “base” code of the tune.

In the thread you referenced in post #3, the gentlemen had done a 0411 swap on a 7.4 L, and used a 5.7 L Vortec (Express) tune as a starting point.

Also, is the photo you posted a prototype CKP sensor ? If so, it looks like it may generate more than the required 4 pulses.


Regards,
Taz

[dave w]

That’s one interesting and unique project you have on the go !

Want to address a couple of things to help get you going. In a way you’re doing what is often referred to a “0411” swap – using an LS1-B PCM to control a distributor and low resolution crank sensor.

As with the typical 0411 swap you will need to begin with a 2001 – 2002 5.7 L Vortec tune – which is written for a 4x CKP sensor (low resolution) and a 1x CMP (distributor) sensor. There are several of these on the Holdencrazy site available for download.

Simple changing the values in G1207 in your current 8.1 L tune – from DBW to DBC, and to low resolution crank won’t work – as these features are not present in the “base” code of the tune.

In the thread you referenced in post #3, the gentlemen had done a 0411 swap on a 7.4 L, and used a 5.7 L Vortec (Express) tune as a starting point.

Also, is the photo use posted a prototype CKP sensor ? If so, it looks like it may generate more than the required 4 pulses.


Regards,
Taz

Taz,
I really appreciate the input and time you are spending with me on this tread!

Ok, I will Flash a modified Express Van Vortec 5.7 .tun file into the PCM. I wired the '0411 wiring harness using the Express Van wiring schematics. The modified 8.1 .tun seems to be working. I can read TPS from 0 ~ 100%, RPM, Vacuum KPA, CTS, IAT, timing, injector BPW and MAF on the Scan Tool screen. I don't know enough about the '0411 PCM, so I'll accept your advice and use a modified Express Van .tun.

The one problem I am having, is a few injectors (3,4, & 6) are not responding to Noid Light testing. When I hand turn the crank position, injectors (3,4, & 6) will flash for a couple rotations then not flash any more. The other injectors are consistent and flash the Noid Light on every rotation when hand turning the crank position. Hand turning the crank position = about 450 ~ 500 RPM's with the way I have the test fixture set up. When I use an electric drill motor to turn the crank position, I can read up to about 2500 RPM's. I might have a faulty PCM? It's seems simple enough to change the PCM flash to the Express Van flash and see if all the injectors work the Noid Light? I've checked the wiring to / from the PCM / Injectors and checked for voltage at the injector connector ... all good. I really like finding / solving problems like this on a test bench!

One question I have about flashing another PCM, will I need to use a license to flash other PCM? If I can't seem to figure out any other solution to the injectors not flashing the Noid Light I'm thinking I'll need to flash another PCM to figure out if the current PCM I'm using is the problem?

On the topic of the prototype CKP sensor. For the test bench, the 8 position reluctor wheel is required to "Sync" the Crank Position Sensor and Cam Position sensor. The crank turns 720 degrees to the distributor's 360 degrees. For the test bench, I've placed the crank position sensor directly to the distributor. I agree, a harmonic balancer mounted crank reluctor wheel will require 4 positions (about 30 degrees high / about 60 degrees low).



dave w

[dave w]

I re-flashed the PCM with an Express Van L31 Vortec .tun. operating system and calibrations.

So the Noid Light problem has changed some. Now only #2 is not working, but #2 was working with the 8.1 .tun. I'm not sure if anyone can help with this injector not firing the Noid Light problem, but I thought I'd pass the information on that changing the flash changed the problem to a different cylinder.

dave w

[Taz]

When you mentioned building an “engine test stand” I had envisioned the 8.1 L running on this fixture. It sounds like you have constructed a fixture(s) to mimic the engine turning over at various RPMs, while observing the input / output of various sensors.

Regarding the injector Noid light observations …. with the 8.1 L tune you had issues with 3 of the injectors … with the low resolution Vortec tune you now only have an issue with one injector. This seems to indicate the Vortec tune is better able to interpret the improvised low resolution CKP sensor signal.

With only one injector “acting up”, I would wonder if there is an issue with signal (CKP & CMP) for that particular injector. As you already know, your “fixtures” will need to be symmetrical for all “pulses”, and properly synchronized.

I have absolutely no practical experience with this type of project !!


Regards,
Taz

[dave w]

When you mentioned building an “engine test stand” I had envisioned the 8.1 L running on this fixture. It sounds like you have constructed a fixture(s) to mimic the engine turning over at various RPMs, while observing the input / output of various sensors.

Regarding the injector Noid light observations …. with the 8.1 L tune you had issues with 3 of the injectors … with the low resolution Vortec tune you now only have an issue with one injector. This seems to indicate the Vortec tune is better able to interpret the improvised low resolution CKP sensor signal.

With only one injector “acting up”, I would wonder if there is an issue with signal (CKP & CMP) for that particular injector. As you already know, your “fixtures” will need to be symmetrical for all “pulses”, and properly synchronized.

I have absolutely no practical experience with this type of project !!


Regards,
Taz

Taz,
Everything works now. I made a very minor adjustment to "Sync" the CKP & CMP. I was maybe off by about 3 or 4 degrees.

Let me say "Thank You" again for the advice to use the Express Van .tun file. I don't know where someone would ever find “base” code of the tune information? I'm not new to EFI, just new to the LSx PCM's. Older ECM's & PCM's are not as complex, so I figured (based on knowledge learned from older EFI systems) just changing the G1207 setting would be all I would need to do.

Engines are expensive, and can be damaged very easily with incorrect PCM programming or an incorrectly built wiring harness. The test bench I built is like you described "mimic the engine turning over at various RPMs, while observing the input / output of various sensors". With the information observed from the various sensors when testing the EFI system on a test bench, the likely hood of damaging the 8.1 Liter engine is greatly reduced. The test bench is a cool way of learning EFI Live Software / Hardware also.

dave w

[ScarabEpic22]

Glad you got it sorted out Dave!

(BTW, where in WA are you located? Im from Seattle and my parents live there but spend the school year in Spokane)

[dave w]

(BTW, where in WA are you located? Im from Seattle and my parents live there but spend the school year in Spokane)

I live in that northern suburb of Portland Oregon, Vancouver WA (USA)

dave w