I stumbled upon an auction last night for a 1999 L21 out of a heavy-duty truck chassis.

This looks as if it had to be controlled by a 411 PCM.
- Distributor housing used for sensor only
- Coil per plug ignition
- Drive by wire throttle body

The biggest questions in my mind all revolve around how the PCM is getting crank position. I don't know where exactly a reluctor ring is on an 8100, it's somewhere in the rear and has a sensor very difficult to get to and prone to failure. The 8100 doesn't have a position sensor on the cam that I know of, so it would have to have a non-symetrical crank reluctor so the PCM could distinguish between cylinders. This version of the Vortec 454 though clearly has a sensor in what's left of the distributor. There's only one lobe in the Vortec distributor, meaning the combination of the distributor sensor and the crank sensor on the symetrical ring could be used by the 411 to control coil packs! We already know that these two sensors together are enough for even the old bloack box PCM to know what cylinder each power stroke belongs to - it needs that for misfire codes. Seems to me the crank would need more than a full rotation for the PCM to figure out where it is when started.
Coil packs are cool, I have some interest in putting them to work on my setup with a 454CID-calibrated 411 PCM. The file from a truck like this would be a mess with a manual trans and drive by wire, but I think we could learn from it.
If anyone encounters a 1998-2000 Chevy/GMC 6000/7000 series gas-powered truck and has TunerCATs with the right definition files, hook up!

Here's the auction:
http://cgi.ebay.com/ebaymotors/454-Chevy-Big-Block-GEN-VI-BBC-Low-Miles_W0QQcmdZViewItemQQcategoryZ33615QQihZ024QQitemZ370047033458QQrdZ1QQsspagenameZWDVW#ebayphotohosting

Photos from the auction:













Last edited by James B. on Sun Dec 28, 2008 11:43 am; edited 3 times in total

Hey James,

I am in the process of "trying" CNP right now. I had a new balancer machined to accept a 24x wheel. I will use the Vortec dist. for the CMP. I am trying to work out a holder for the CKP sensor. I have a tune worked out that I think will work. I wasn't going to post anything about this project until I had it working. I am trying to find time to work on the crank sensor.

Jeff

Ignition System Overview

The electronic ignition system controls fuel combustion by providing a spark to ignite the compressed air/fuel mixture at the correct time. To provide optimum engine performance, fuel economy, and control of exhaust emissions, the PCM controls the spark advance of the ignition system. The Electronic ignition system has the following advantages over a mechanical distributor system:

• No moving parts

• Less maintenance

• Remote mounting capability

• No mechanical load on the engine

• More coil cool down time between firing events

• Elimination of mechanical timing adjustments

• Increased available ignition coil saturation time

The electronic ignition system does not use the conventional distributor and coil. The ignition system consists of the following components/circuits:

• Eight ignition coils/modules

• Eight ignition control (IC) circuits

• Camshaft position (CMP) sensor

• 1X Camshaft reluctor wheel

• Crankshaft position (CKP) sensor

• 24X crankshaft reluctor wheel

• Related connecting wires

• Powertrain control module (PCM)

Crankshaft Position Sensor and Reluctor Wheel




(1) Crankshaft
(2) Bolt
(3) CKP Sensor

Crankshaft Position Sensor Reluctor Ring




(1) Key
(2) Crankshaft
(3) Crankshaft Position Sensor Reluctor Ring

The crankshaft position (CKP) sensor is located under the front engine cover. The CKP sensor is a dual magneto resistive type sensor. This sensor is not speed dependent. The dual micro switches monitor both notches of the reluctor wheel for more accuracy. The CKP sensor works in-conjunction with a 24X reluctor wheel. The reluctor wheel is mounted on the rear of the crankshaft. The 24X reluctor wheel uses two different width notches that are 15 degrees apart. This Pulse Width Encoded pattern allows cylinder position identification within 90 degrees of crankshaft rotation. In some cases, cylinder identification can be located in 45 degrees of crankshaft rotation. This reluctor wheel also has dual track notches that are 180 degrees out of phase. The dual track design allows for quicker starts and accuracy.

The PCM also receives a 4X signal from the crankshaft position sensor. The PCM utilizes the 4X signal for the following:

• Tachometer output

• Spark control

• Fuel control

• Certain diagnostics

The CKP signal must be available for the engine to start. The CMP signal is not needed to start and operate the engine. The PCM can determine when a particular cylinder is on either a firing or exhaust stroke by the 24X signal. The CMP sensor is to determine what stroke the engine is on. The system will attempt synchronized and look for an increase in the MAF signal. An increase in the MAF signal indicates the engine has started. If the PCM does not detect an increase in the MAF signal, a re-sync will occur to the opposite cam position. A slightly longer cranking time may be a symptom of this condition.

Camshaft Position Sensor




(1) Bolt
(2) Camshaft Position Sensor
(3) Lower Intake Manifold

The Camshaft Position (CMP) sensor is mounted through the top of the engine block at the rear of the valley cover. The CMP sensor works in-conjunction with a 1X reluctor wheel. The reluctor wheel is located under the cap of the camshaft. The CMP sensor is used to determine whether a cylinder is on the firing or the exhaust stroke. As the camshaft rotates, the reluctor wheel interrupts a magnetic field produced by a magnet within the sensor. The CMP sensor internal circuitry detects this and produces a signal which is used by the PCM. The PCM uses this signal in combination with the CKP 24X signal to determine crankshaft position and stroke.

The CKP signal must be available for the engine to start. The CMP signal is not needed to start and operate the engine. The PCM can determine when a particular cylinder is on either a firing or exhaust stroke by the 24X signal. The CMP sensor is to determine what stroke the engine is on. The system will attempt synchronized and look for an increase in the MAF signal. An increase in the MAF signal indicates the engine has started. If the PCM does not detect an increase in the MAF signal, a re-sync will occur to the opposite cam position. A slightly longer cranking time may be a symptom of this condition.


Powertrain Control Module Description

I added this just because. Hmmmmmm 411?

The powertrain control module (PCM) is designed to maintain exhaust emission levels while maintaining excellent driveability and fuel efficiency. The PCM controls the following operations:

• Fuel control

• Ignition control (IC)

• Knock sensor (KS) system

• Automatic transmission shift functions

• Evaporative emission (EVAP) urge

• Exhaust gas recirculation (EGR)





(1) Connector C1 (Red) opposite the manufacturer's logo
(2) Connector C2 (Blue) same side as the manufacturer's logo

The powertrain control module (PCM) is located in the engine compartment.

The PCM constantly looks at the information from various sensors, and controls the systems that affect vehicle performance. The PCM also performs the diagnostic function of the system. It can recognize operational problems. The PCM also alerts the driver through the malfunction indicator lamp (MIL). When the PCM detects a malfunction, it stores a diagnostic trouble code (DTC). A DTC stored, will identify the problem areas. This will aid the technician in making repairs.

The PCM supplies either 5.0 or 12.0 volts to power various sensors or switches. This is done through resistances in the PCM. The resistance is so high in value that a test lamp will not illuminate when connected to the circuit. In some cases, even an ordinary shop voltmeter will not give an accurate reading because its resistance is too low. Therefore, a DMM with at least 10 megaohms input impedance is required to ensure accurate voltage readings.

The PCM controls output circuits such as the injectors, cooling fan relays, etc. by controlling the ground or the power feed circuit through transistors or a device called an output driver module.

Caleditor, got any part numbers for that reluctor ring or distributor assy? I'm guessing that reluctor ring would only fit the big block (larger diameter snout)? I don't suppose they ever made a reluctor like this for any small blocks? Excellent stuff... very interesting.

Quote:

The crankshaft position (CKP) sensor is located under the front engine cover.
The CKP sensor is a dual magneto resistive type sensor.
This sensor is not speed dependent.
The dual micro switches monitor both notches of the reluctor wheel for more accuracy.
The CKP sensor works in-conjunction with a 24X reluctor wheel.
The reluctor wheel is mounted on the rear of the crankshaft.
The 24X reluctor wheel uses two different width notches that are 15 degrees apart.
This Pulse Width Encoded pattern allows cylinder position identification within 90 degrees of crankshaft rotation.
In some cases, cylinder identification can be located in 45 degrees of crankshaft rotation.
This reluctor wheel also has dual track notches that are 180 degrees out of phase.
The dual track design allows for quicker starts and accuracy.

The PCM also receives a 4X signal from the crankshaft position sensor. The PCM utilizes the 4X signal for the following:

The reluctor wheel is mounted on the rear of the crankshaft.

I think this is a misprint

That PCM they show in the picture is the predecessor of the 0411, it was used in 97-98 LS1 cars.

James B. wrote:

I stumbled upon an auction last night for a 1999 L29 out of a heavy-duty truck chassis.

This looks as if it had to be controlled by a 411 PCM.
- Distributor housing used for sensor only
- Coil per plug ignition
- Drive by wire throttle body

The biggest questions in my mind all revolve around how the PCM is getting crank position. I don't know where exactly a reluctor ring is on an 8100, it's somewhere in the rear and has a sensor very difficult to get to and prone to failure. The 8100 doesn't have a position sensor on the cam that I know of, so it would have to have a non-symetrical crank reluctor so the PCM could distinguish between cylinders. This version of the L29 though clearly has a sensor in what's left of the distributor. There's only one lobe in the Vortec distributor, meaning the combination of the distributor sensor and the crank sensor on the symetrical ring could be used by the 411 to control coil packs! We already know that these two sensors together are enough for even the old bloack box PCM to know what cylinder each power stroke belongs to - it needs that for misfire codes. Seems to me the crank would need more than a full rotation for the PCM to figure out where it is when started.
Coil packs are cool, I have some interest in putting them to work on my setup with a L29-calibrated 411 PCM. The file from a truck like this would be a mess with a manual trans and drive by wire, but I think we could learn from it.
If anyone encounters a 1998-2000 Chevy/GMC 6000/7000 series gas-powered truck and has TunerCATs with the right definition files, hook up!

Here's the auction:
http://cgi.ebay.com/ebaymotors/454-Chevy-Big-Block-GEN-VI-BBC-Low-Miles_W0QQcmdZViewItemQQcategoryZ33615QQihZ024QQitemZ370047033458QQrdZ1QQsspagenameZWDVW#ebayphotohosting

Photos from the auction:

ok.........seriously...............get out of my head!!

i have been watching that same motor for the last few weeks to see how it does (might even get it - dunno yet)

but i have also been looking at the fact that it is CNP.

been wanting to do some research on that, i think that it could be possible to a similar setup on even an L31.

i have too many people in my head as it is - man its getting crowded in there.

James, the computer's only going to care that it gets the signal, not where it comes from. Since you've had the L31 and the big block apart, would it be possible to put the reluctor up front and use L31 parts? Seems to me like that would fix the "unreliable part in a hard to reach place" problem you say that big block has. I'd love to see you make one of those work as I'm still living vicariously through you where high performance rigs are concerned. Well, at least for another year or so.

It's only the Mark-VII (tall-deck 8100) that has the reluctor in the back with the problematic sensor. The Mark-VI L29 uses a 4-tooth symetrical reluctor wheel like the L31 up front between the timing gear and balancer on the crankshaft behind the timing cover. The sensor looks to be the same as the L31 sensor and is very reliable.

THen if you were to do this Mark VII block, you should be able to just move the L29 reluctor parts over. Excellent.

EFI Connection has been taking a similar approach to what the C7500 454 engine does (and I wasn't aware of this until just minutes ago, wow!), but for the small block. Keep the reluctor inside the timing cover and use the distributor for a cam signal only. This is prototype material here, but it's coming together quickly. The engine is a 350 TPI converted to a Ram Jet 350 and Corvette electronic throttle body and coils. Should be running (at least attempted) in the upcoming weeks.

We thought about mounting the ring external, but that has its own complications (rust on the ring, position of sensor, appearance, etc). The best solution was to keep the ring under the timing cover, so that is our goal. Several very skilled people put a lot of time into research and development of this ring. Vortec GM ring on the left. Custom 24x LS1 signal on the right, shrunk to the diameter of the 4x Vortec ring.



Mike
EFI Connection
http://www.eficonnection.com



Last edited by S10Wildside on Mon May 12, 2008 6:51 am; edited 2 times in total

Caleditor,

Can you get the wiring schematics for the crankshaft position sensor? The literature you posted indicates its being used for both the 24x and 4x signal. I'd like to see how this is accomplished going to the PCM.

Thanks!
Mike
EFI Connection

Speeder wrote:

Since you've had the L31 and the big block apart, would it be possible to put the reluctor up front and use L31 parts?

The 4x big block ring and 4x small block ring are nearly identical. However, the center hole is larger for the big block due to the larger crank. The keyway is slightly moved as well.

Bad info, corrected.



Last edited by Hog on Fri May 07, 2010 7:33 am; edited 1 time in total

Mike,
Have you been able to get a scope pattern test with the small 24x wheel? That will be MUCH better than running an external reluctor. Give me a call---I want one!!!!

Jeff

Lextech wrote:

Mike,
Have you been able to get a scope pattern test with the small 24x wheel? That will be MUCH better than running an external reluctor. Give me a call---I want one!!!!

Jeff

Jeff,

We made sense of the LS1 24x reluctor with a dual channel O-scope, took that data, and designed the smaller reluctor. The small ring will be studied with the O-scope while on the prototype engine in the upcoming weeks...but hopefully this weekend. We'll compare the data to our original findings. A caliper on the teeth is showing accurate cuts. After the prototype is finished (the keyway is not yet cut), we'll put our heads together for producing these. The way we made the first ring will not be cost effective. With the amount of hours into it, no one will want to buy it for what we'd have to charge. I expect to have the prototype engine running in the next two weeks without the key cut (we're brainstorming how to do this). Once the engine runs properly with the smaller reluctor, we'll determine where the keyway should go, cut it, and begin looking for a way to produce it. I've got plans for this first prototype engine...it's going in a 1991 Trans Am convertible.

Mike
EFI Connection
http://www.eficonnection.com

Hey James will the 411 PCM run this 454 you found ??

ANY BODY got part #s ??? My copy of Alldata only goes up to 3500/ 1 Ton
Help us poor souls run HI-Tech big blocks.

The only thing differentiating the L29 hardware from the L31 is that it has two knock sensors. The CA Emissions versions also have a belt-driven clutch activated smog pump instead of the electric one on the L31, but I don't think that's worthy of discussion.

All the other sensors on the L29 are identical to the L31.
- Mass Air Flow Sersor
- Intake Air Temperature Sensor
- Throttle Position Sensor
- Idle Air Control Motor
- Exhaust Gas Recirculation Valve
- Evap Purge Solenoid
- Coolant temp (manifold)
- Coolant temp (head)
- Crank Position Sensor
- Cam Position Sensor
- Ignition Module
- Coil

There is a difference on the O2 sensors my 2000 CA Emissions version from a C3500 has. What ever it is commands twice the price of the "normal" O2 sensors, different 5-wire connector.

I don't see any reason why one couldn't be made to work on an L31 bin file simply recalibrated for the big block torque and spark curves and displacement. Lots of work in the tables but should be possible to get it going with the conventional distributor. I am wondering if later versions of the medium-duty L21 did use the 411 PCM instead of its predecessor.



Last edited by James B. on Sun Dec 28, 2008 11:57 am; edited 1 time in total

Found out some more info on the 496 (L18 I think) big block ignition.
The reluctor ring on the 496 is definately in the back but, it does ALSO have a cam position sensor. It's a huge 1-tooth wheel mounted ont he front of the cam gear with a sensor in the cover to read it. This serves the same function as the distrutor sensor in the 454 that we're familiar with.



Last edited by James B. on Tue May 20, 2008 12:57 pm; edited 1 time in total