4K EFI Test Rig - IAC Valve

[Banjo]

Hi Kayzz,

               You'll be pleased to know, I've been able to turn a K series "Bosch" distributor housing, into a Camshaft driven trigger wheel, & CAS signal.

The technique that Altezzaclub suggested of retrieving the "tooth wheels" from the 4AGE dissy, & "turning them down to fit the narrow K series dissy; was a good one, but not having a lathe, I settled to fit an aluminium disc to the large K series Bosch dissy, which was more doable.

It was not without some setbacks along the way.  The disc could not be fitted in the large top section of the dissy, as the sensors would have to be fitted upside down, in the base of the narrow section, where adjustment of air gaps etc, would be difficult. 

I therefore turned the disc down, & was only able to fit 18 off magnets around the disc. The rare earth magnets are beautiful, but working out the right distance between them, & the best air gap; so they will turn off, can be frustrating. I eventually reverted to "assymetrical" rare earth magnets, that have their north & south poles on the same face of the magnet, rather than at each end.  I've had it running on the bench, driven by a variable speed electric motor, & the results are excellent. The oscilloscope traces of the two streams of pulses, show crisp clean & sharp pulses.

Have no doubt it will work well, on the 5K engine, when I get around to hopefully fitting it, on the upcoming weekend.

Here are a few pictures I took along the way, as a picture tells a thousand words; so they say.

 

The only proviso I have at the moment, is whether there will be any "jitter" in the RPM speed update to the ECU, as the holes in the aluminium disc for pressing in the magnets, was not carried out on a CNC machine; but by my steady hand.

Also there could be some "timing scatter" from the CAS signal, as it mounted on the cam drive, which could have a couple of degrees of slop, in worn chain, sprockets & gears etc., to the crankshaft.

But that's another subject, which I believe I have a solution for. Let's get it running on an engine, & then the strobe light steadiness; will depict, how stable the RPM update, & CAS signals are.

Cheers Banjo

 

  

Edited February 12, 2025 by Banjo

[Ke555555]

On 2/1/2025 at 5:00 PM, altezzaclub said:

I was thinking the Hall Effect sensor on the pin at 2o'clock, like this

Chop the plate down to just an arm holding the post and mount the sensor through the wall near it. You may not even need the post, just the end of the arm swinging past might be enough to activate the Hall sensor. Banjo will know!

That gives you a cam position signal to tell the ECU that #1 is the next cylinder to fire.

The crank position signal is the hard one, the more teeth you have to read the more resolution the computer has. So the 4AGE uses 24, but others use 36 and some use less. Finding what is essentially a gear wheel to mount above the cam sensor will be the hard part, either find a steel one from a distributor, or make one out of an alloy disc and put magnets in it. You can see the factory one in that image of the distributor I posted above, lots of gear teeth close together.

That disc gets mounted on the shaft further up, and that Hall sensor goes in the side or through the lid.

Manufacturers used this idea for a while in the 80s and 90s, a cam & a crank sensor built into a distributor and a rotor and plug leads on top. Those are the dizzys you want to look inside at a wreckers, the later ones did away with a distributor altogether and ran Coil Over Plug systems with remote sensors.

Here's a Camry one from then, I've never looked at one, but it has the 24tooth wheel in there, the part 19235 picture.

https://www.amayama.com/en/catalogs/toyota/camry/3-sedan-right-v30-1990-2407/engine-fuel-system-and-tools-1/distributor-34

4AFE motors, the most common engine back then, have them too. Wouldn't it be nice if this shaft and gears fitted easily.

$40 buys a 2JZ one, somewhere in the world.

https://wardautoracing.com/products/2jz-ge-distributor

Otherwise, its alloy disc and magnets time.

What if you come straight down the top 

[Ke555555]

Does the gap size matter? 

[Banjo]

Couple of questions !  What is the model number of the Hall Sensor You are using ?   Is it a model that detects north or south poles of magnets; or is it one that detects ferrous metal targets ?  Does the Hall Effect sensor have an LED light, built into the rear, where the cable enters the Hall Sensor.

The setup You have there, maybe permanently switched on, depending on how sensitive the Hall Sensor is, & whether the "steel base", from which the pin protrudes is too close to the sensor, whilst it rotates.

Nomally, You connect the DC supply voltage across the two (2) wires, that supply the Hall Sensor, with a DC voltage between 5-12V DC.  Then rotate the dissy, & see whether the LED turns on & off, when the vertical pin passes the sensing face of the Hall Sensor.  If You have model number for the Hall sensor, then list it here, & I can look it up, & see what type it is.

Be careful when connection it up; as some Hall Effect sensor colour codes are a bit unusual. I've got some here, where the "brown" wire is +12Vdc, "black", is the output wire; & blue is the -ve wire.

Cheers Banjo 

Edited August 3, 2025 by Banjo

[Ke555555]

Does the gap size matter? 

1 hour ago, Banjo said:

Couple of questions !  What is the model number of the Hall Sensor You are using ?   Is it a model that detects north or south poles of magnets; or is it one that detects ferrous metal targets ?  Does the Hall Effect sensor have an LED light, built into the rear, where the cable enters the Hall Sensor.

The setup You have there, maybe permanently switched on, depending on how sensitive the Hall Sensor is, & whether the "steel base", from which the pin protrudes is too close to the sensor, whilst it rotates.

Nomally, You connect the DC supply voltage across the twi wires, that supply the Hall Sensor, with a DC voltage between 5-12V DC.  Then rotate the dissy, & see whether the LED turns on & off, when the vertical pin passes the sensing face of the Hall Sensor.  If You have model number for the Hall sensor, then list it here, & I can look it up, & see what type it is.

Be careful when connection it up; as some Hall Effect sensor colour codes are a bit unusual. I've got some here, where the "brown" wire is +12Vdc, "black", is the output wire; & blue is the -ve wire.

Cheers Banjo 

It’s a Hall sensor that detects metal part number HAL-502

[Banjo]

The Cherry ZF sensor You have purchased, is one of the best available, & usually very expensive here in Australia.

It does not however, come with a built-in LED to indicate it is working & producing an output, when You place the sensing face close to a ferrous metal object like your vertical pin. They are generally utilised to sense ferrous teeth on a trigger disk, as depicted on the spec sheet.  As your ferrous pin, has a curved surface facing the sensing surface of the Hall Sensor, it may well need to be a bit closer to the pin, than the 1.5mm, the spec sheet indicates for the gap.

The only way, is to test it. As the Cherry unit does not have a built-in LED, You are going to have to hook up an external one, across the output of the Cheery Hall Sensor, as per my sketch below.  You will need a small 6 or 12 volt battery to power it.  The frequecy response of the Cherry Hall Sensor of 15kHz, makes it idea for this application.  Most commonly, these sensors are used to pick up ferrous 30-60 teeth on a trigger wheel, attached to the crankshaft pulley. However, in an application like distributor body, where the distributor rotates at half the speed of the crank; & only has one tooth per rotation to sense, it is more than suitable for your application.

So get yourself an automotive LED bezel lamp, suitable for 12 volts, at an auto store. These will already have a resistor, inside the lamp, in series with the LED, as the LED only needs 2-3 volts across it; (depending what colour they are), to light up.

Detach the Hall Sensor from the dissy body, & then place various sized bolt heads, washers etc., close to the sensing face, & get a feel for how close it has to be, before the lamp is turned on fully.

Then put it back into the dissy, & move it as close as necessary, to get the LED light to come on reliably & consistently.

Let us know how You go.

Cheers Banjo 

 

Edited April 24, 2025 by Banjo

[Banjo]

I've had some success, in the next stage of the development of a Trigger Wheel, & CAS signal, from within a K Series dissy.  The Bosch K Series dissy was used, because they are physically larger in diameter, than the more common K series dissy body.  The rings of rare earth magnets worked, but did present some issues.

There are a couple of incremental rotary encoders used in industry; & the education industry, that provide an identical output to the rare earth magnets & Hall Sensors, but are a "drop in" item.

Rotary encoders, can provide outputs, that can be used to indicate the rotational speed of the encoder; the direction of travel of the encoder; & the actual angular position, at any time. 

An industrial grade absolute encoder, can be quite expensived, but the small "educational" incremental ones, for teaching concepts; are less than $ 30.00 ea. As can be seen in the three pics below; they are relatively easy to mount, in the dissy. 

If You want to read more about encoders, in general, then head across to this link.   https://en.wikipedia.org/wiki/Rotary_encoder

These encoders come in a variety of models, with different numbers of pulses per single rotation.  Because we are interested in angular movement of the distributor, & everything ECU wise is related to degrees BTDC etc.; I chose, & ordered; an encoder that provided 360 pulses per rotation. The encoder has two of these outputs, slightly off-set angularly, so that it is possible to work out which direction, the encoder is rotating in; although that is of no interest to us, in this dissy application, as the dissy only rotates in a clockwise direction. (more on that second output later) 

However, most ECUs accept pulse trains from trigger wheels, that produce pulses of 24/36/60/72 pulses per single rotation, of the crankshaft.  As the dissy only rotates once per two (2) revolutions of the crankshaft, then we are only interested using 180 of those dissy encoder pulses, & we set the ECU up, as if these pulses are being derived, from the crankshaft.

I then decided to see if I could divide the 180 pulses per "effective crankshaft revolution", down to one of these above common ECU trigger wheel numbers, for a crank shaft rotation. Pulse chains in electronics, can only be easily divided by whole numbers. 180 divided by those trigger wheel numbers are (180/24 = 7.5; 180/36 = 5; 180/60 = 3; & 180/72 = 2.5;  180/4 = 45. We can only easily divide by whole numbers in electrionics, so dividing the pulse train by 3 or 5 produced the equivalent of a 60 or 36 tooth crank trigger wheel. Most ECU manufacturers, advise that crankshaft trigger wheels between 24 to 60 teeth, provide best resolution. So it didn't take long to then produce these switchable trigger outputs, to an ECU. Oscilloscope grabs of the primary (360) & divided by 3 & 5 pulses, are below.

I had left my single CAS magnet & Hall Effect sensor in the base of the dissy body, so do have a working system.  However, the rotational encoder sits up pretty high, so I cannot create my low profile dissy, with my "jam jar" lid. 

Could I possibly, use that second pulse chain of the encoder, to produce a single CAS signal ?  Unfortunately; not with this particular encoder, but could be possible with a absolute positional encoder, where each of the 360 pulses per rotation, creates a unique number. We could only look for just one number, & use that pulse as the CAS pulse. However, it may be simpler than that, as an absolute rotary encoder has a single pulse per revolution, that resets the counters. That may make a perfect CAS signal, if brought to the outside of the encoder.  All I've got to do, is find an "absolute" rotary encoder, in a small footprint, at a reasonable price.

Simon down in Tassie, is sending me up a K Series Bosch dissy, so I can then try this theory out, in practice.  It may be; that ultimately, we may be able to even accomodate this angular encoder, into one of the "narrower", olde K Series dissies.

All good fun !

Cheers Banjo 

 

 

 

 

Edited April 24, 2025 by Banjo

[Banjo]

MkII dissy, with a "incremental" encoder, is now underway.  Research yesterday, indicated two    "road-blocks"; with the concept of using an "absolute", rotary encoder.

1. One was the cost.  The "absolute", type of rotary encoder are far more complicated; "internally", & more difficult to manufacture; hence the increase in cost.

2. Second, was the need for a lot more electronics; & possibly a small micro processor & coding, to indentify & grab that one pulse, to utilise, as a CAS signal to the ECU. 

Bear in mind, that I haven't considered using this dissy in a "wasted spark" system. I have tackled the sequential control of injection & ignition initially.  You can easily make a "sequential" system, operate in 'wasted spark"; but not necessarily; the other way around.

Altezzaclub & I had discussed this previously; & He suggested that as the second output of the "incremental" rotary encoder was not utilised; that maybe, we could "block out, 359, of the 360 windows for the optical encoder, & just use the remaining one, & it optical sensor, as the CAS signal.  I resisted this suggestion; knowing how relatively tiny the 360 "windows" will be; within a disk or ribon, fitted inside a circular structure, that is just 35mm in outside diameter.

However, I've decided to take the step, & dissemble the existing incremental encoder, & take a look, & see if this is a possible alternative.

I bit of reading, on the net, revealed that some incremental rotary encoders, have a single "Z" output, for internal use, to zero the processing, once per revolution. (Not the one I purchased)

If that output, is accessible, & brought out, it may in fact, be utilised as a CAS signal.  Fingers crossed. !   - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - -- - - - - - - - - - - - - - - - - - - - - -   A few hours later - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

I dissembled my incremental rotary encoder, & my suspicions were immediately realised.  The disk was so small; the slots were so tiny; & there was not a single slot in sight with a light sensor, that could create a single pulse pulse per revolution. I carefully put it back together.  This encoder I had ordered had 360 slots in a circle.  However, you could order them, with 1000 slots; so I just cannot imagine, how narrow they must be.  I was however, bolstered by the fact, that the bearing in the incremmental encoder, I've be using, was very substanial, & could work reliably in a distributor on an engine, with lots of vibrations.   After a cup of coffee, I decided to see if any manufacturers, produced a incremmental rotary encoder, with a Z single pulse.  There were quite a few, but they were all hundreds of dollars each.

I then thought, there has got to be someone in China, making these incemental rotary encoders, with 360 pulses per revolution, & a "Z" pulse.  So off to ebay, & there they were; in a variety of different pulses per revolution, but with a Z pulse once per revolution, which came out in the wiring harness/lead.

Things were looking up, so I read as much as I could, about this particular brand series.  They were dearer than the one I had, but I did manage, to find one, with the exact specs I wanted, in China, with Speedpak delivery, for about $ 45.00.  So it's ordered, & should be here in 1-2 weeks time.

When I looked up this rotary encoders outside dimensions, it is almost the same size as the current one I'm using. As I had the one here; now out of the distributor, I took it over to the shed, & found a gutted K series dissy case, which we refer to as the "narrow" one.  It fitted inside, with room to spare.  So don't throw out any olde K Series dissies, You might have. They may yet live; to find a new purpose in life.

Cheers Banjo 

 

 

Edited April 28, 2025 by Banjo

[Banjo]

It occurred to me, that there has to be someone out there in the big wide world, who has also seen the potential, of using an incremental rotary encoder, to basically be, an automotive "trigger wheel", & CAS signals, for an ECU's inputs.

I scanned the internet, & only found one . . .

https://forums.ni.com/t5/LabVIEW/Using-rotary-encoder-position-to-trigger-an-analog-pulse/td-p/2017540

If anyone reading this has come across any other similar efforts "on the web"; I'd me most grateful, if You could put a "link" in this discussion.

Cheers Banjo

Edited April 28, 2025 by Banjo

[Banjo]

I went out in the shed tonite, & found a 3K early dissy, which had the narrow, yet deep main body. This dissy was in very good condition, but I gutted it completely, so I could determine, if the incremental rotary encoder, would sit neatly inside.

Ah Yes !

I even found a jam jar lid, in my wife's kitchen cupboard, (She is out tonite) that fits perfectly, like it was made for it.

I would have liked a dissy body, with a replaceable ball race bearing at the base; like the one in the 4AGE  distributors, instead of the phosphor bronze ones fitted to all K series engines, I believe.

However, this dissy shaft & sleeve bearing are in remarkable condition, so very happy with the fact, that the two parts, manufactured, many decades apart, are so complementary.

Just have to be patient now, until the Omron incremental rotary encoder, with a single "Z" pulse per revolution arrives here, & I can take it to the next stage.

Cheers Banjo

 

 

 

Edited April 28, 2025 by Banjo

[Banjo]

Should have the incremental rotary encoder arrive here this week, with a single "Z" pulse output, I can hopefully use as a CAS signal. I've decided to fit this dissy to my 4K-U engine in my KE-30, so I can do some real road testing on it, instead of on the 5K stationary test bed engine, in my workshop.  I will need to change my single ignition coil over to COPs.

I built a COP frame for the Denso COPs, a couple of years ago.  It was a quick build in a couple of hours on a Sunday afternoon.  That one is still in use on the Test Bed 5K engine stand.

However, fitted to a road car, would require something a bit more rigid & strong, so I built one over the weekend, out of stock aluminium & few rivets & 6mm Riv-Nuts from Bunnings.

It is quite rigid; as I pick up the whole head's weight, holding onto the aluminium bracket. Those two flat bar angled brackets from the rocker cove, are actuallt stainless steel.  Just awaiting some DENSO 4 wire plugs for the COPs, so I can wire them all up.  I hope to be able to feed the 3 wires to each COP, through the aluminiun channel, to keep it neat & out of sight.

I've purposely made the COP mounting frame a little longer at each end, on purpose.  It maybe; that on the engine, the frame vibrates a bit at a particular RPM, that might coincide with a resonant frequency of the frame & it's mounting brackets. If that eventuates, I can always run a couple of support bars down from the ends of the COP bracket, to the engine block below.

Cheers Banjo

 

Edited May 12, 2025 by Banjo

[Banjo]

Well, finally got around to wiring up the COP mounting bar.  I wanted to make all the wiring from the COPs hidden, inside the rectangular section of the aluminium mounting tube.  However, as the COP shafts pass through the rectangular section; it doesn't leave much room to squeeze all the wires past COPS near the end where the wires, all exit from the tube.  I also didn't want to squib on the wiring size, for two reasons.  I wanted pretty heavy wire for the ground & +12V supplies to the COPs, as there are reasonably high currents involved, & we don't want any voltage drops.  Anyway, it all just fitted, so pleased with the result.  The alternative was to add another wiring conduit or tube; & that would have detracted from the clean lines of the COP mounting bracket.

Have powered them all up, & had them sparking perfectly with a test circuit, to fire the COPs, one after another. I also needed to identify the 4 off trigger wires, as I used the same colour (blue) for all trigger wires

Because the spark plugs on the K Series engine, were recessed into the head, I wanted to seal this area, around the COP long tube; so no rubbish got down inside there, around the spark plugs.  I couldn't find a commercial rubber bung of any kind on the nett, to accomplish this.  On the original K series distributor HT leads, this "seal" was moulded into the leads.  I cut the ends off an olde set of leads, & with a very sharp hobby knife cut out the inner part, so it left a hole to fit snuggly around the COP shaft.

Just have to now fit it to my 4KU in my KE-30, & work out where to terminate & mount a connection block for the wiring & plug & socket, so the COP assembly, can easily be removed from the engine, so the spark plugs can be removed.   It may however, be just as simple, to remove the 4 off COPs, & then remove the spark plugs, without removing the complete assembly.  Once I've got it on the engine, I'll make that decision.

I also found that the COPs mounting bolts, & the gold COP mounting frame, were not grounded !  There was about 6-7 Megohms resistance between them & the head.  The COP mounting frame, is attached to the rocker cover. The rocker cover is actually isolated from ground, via the big rubber gasket around it's bottom edge, & the two bolts that attach it to the head. I found a little earthing strap, from the rocker cover to the head, solved this issue. 

One of the common issues with COPs, on modern engines; is that they overheat. This is particularly common, in twin overhead cam engines, wher the COPs are "buried" down inside the head body, with little or no air flow around them.  This will not be an issue, with my setup, as there will be plenty of air flow over almost all the COP assembly. Once it is on the car & in use, I'll check the temperature of No:1 & No:4 COP bodies, & see whether there is any difference.

Cheers Banjo

Edited August 4, 2025 by Banjo

[Banjo]

Haven't had a lot of time, to persue this project lately, & have run into a few issues with my Rotary Encoder with a Z Pulse.

The first one, with a "Z" pulse output, that I purchased; I accidentally killed with an incorrect connection, whilst testing it.  I had to await a second one to arrived, & that worked; but I could not get nice stable pulses from it. I tried all sorts of ways to stabilise it, but came to the conclusion; that the "timing jitter" & unsteadness, of the CRO traces, were in fact a result of the vibration, inside the rotary encoder itself.  This encoder, was pimarily utilised, because I had discovered, they were available with an additional single "Z" pulse, per revolution.  Maybe all rotary encoders are not all built equally.  I did not remember, having this issue, with the very first rotary encoder I purchased; that did not have, the single "Z" pulse, per revolution.

At the weekend I pulled out the original Bosch dissy I had fitted this encoder to, along with the single CAS pulse I had built in the base of the dissy.

 

 

The whole aim of using an encoder, with a "Z" pulse; was to avoid having to create a CAS pulse, & to fit the rotary encoder, completely, deep inside a narrow Corolla dissy.

As it turned out, the rotary encoder, still stuck out high a bit; as I I had to fit a tiny rotary flexible  shaft joiner, between the rotary encoder & the dissy shaft, which had to be turned down a bit.  Getting the two shafts, which are slightly different in diameter; to be completely concentric, needed patience.

Got it all working well, & there is no jitter or instability from the 360/6 pulses per dissy revolution; which just goes to prove that all rotary encoders are not built the same.

The CRO traces show a steady & reliable trace of pulses. The top trace is the output of the encoders 360 pulses per revolution.   The bottom trace is after the a divider has reduced that number to 60 pulses per distributor revolution.  As the distributor turns only once, for two rotations of the crankshaft, then 180 pulses divided by 6 = 30 trigger pulses for each revolution, of the crankshaft.  If it works well, I will decrese the division of the 360 off pulses to 3, which will produces 120 pulses per dissy revolution, which will equate to a 60 tooth trigger wheel, fitted to the crankshaft.  Most ECU setups, allow you to nominated whether the pulse train originates from the cam-shaft, or crankshaft.   

Just have to hook it up to the Speeduino & COPs, & setup the COPS charging rate times per system voltage table; in TunerStudio, so there is no chance of overheating the COPs.

Cheers Banjo

 

Edited August 5, 2025 by Banjo

[Banjo]

The incremental rotary encoders, I came across; with 360 pulses per revolution, seemed like a perfect way to produce a triggering system; physically small enough that it could fit inside an existing distributor body. This would mean that anyone that was handy; could "gut an olde dissy", & simply fit an encoder; & then replace the dissy on the K series engine.  When I did my experiments on a 5K engine, with various aluminium disks & magnets, with Hall effect sensors; I had an engine on a test stand in my garage; & access, was very easy. Doing the same thing, with the engine in the car, could be very difficult; as every time You needed to run it, you'd have the replace the radiator, & maybe the grill.

Simply removing the olde dissy, & replacing with another, is a relatively easy undertaking.

However, my tests with the rotary encoders, had some side effects, resulting in pulses produced that "wavered around", on their leading & trailing edges. Most ECUs, trigger off a leading edge of a pulse, not the height or width of the pulse. After all; the ECU is only interested in the frequency, or time difference between pulses, to calculate accurately; the RPM of the engine.  The incremental encoders I was using had 360 pulses per revolution, which being driven, by the camshaft, resulted in a resolution of one pulse per every 2 degrees of crankshaft revolution (which is extremely good). However, the leading edges of those pulses were not stable. This could well be the mechanics of how the pulse were developed inside the encoder; or the induced vibration; as the distributor enclosing the encoder, is firmly part of the engine block. Once I opened up an encoder, & witnessed how small the windows were in a tiny wheel, it all became very clear, to me, where the problem lay. Anyone, who has ever played with, or read about the issues with Nissan & Mitsubishi twin OHC motors; that used CAS's driven by a camshaft, will be aware of what they describe as "timing chatter". This was particularly observable; when the optical trigger S.S. disks in the CAS; had 360 little optical slots, around their outer edge.

However, others on RollaClub, have fitted the "rotary optical encoder", from Nissan SR20 CAS units to the Bosch dissy, that Toyota used on some early K series engines. It was a little wider in diameter, than the more common Denso dissy body.  The picture below, indicates, it fits, like it was made for this dissy.

Brand new optical transducers, are commonly available, on ebay, Amazon, & AliExpress, & are relatively inxpensive. These however, do not come with the 50mm S.S. laser cut, or punched slotted disk.

 

The most commonly available ones are a 24-1 & a 360-1. There are 36-1, & 60-1 models of these slotted disks, but they are very hard to find. I'm currently trying to find an overseas source.  A 72-1 or even a 120-1, would be really nice, if I can get hold of one.

50mm dia. S.S. disk    24-1 Optical

So as soon as my brand new optical sensor arrives in a week; I'll start some bench testing, with my oscilloscope, to see if the result; does not suffer the issues, I've had with the incremental rotary encoders.

 

So while awaiting this SR20 optical encoder, I wondered if what I'm proposing; is the very best way of triggering an ECU.  So I asked AI; & this is word for word; what it produced.

____________________________________________________________________________________

The Pinnacle of Triggering Systems for Aftermarket ECUs in Automotive Engines

Precision, Speed, and Reliability in Modern Engine Management

Introduction

In the pursuit of automotive performance, reliability, and efficiency, the role of the engine management system stands paramount. At the heart of any sophisticated engine control unit (ECU), whether factory or aftermarket, lies the triggering or “engine position sensing” system. For tuners, racers, and engineers seeking the utmost in accuracy and speed, the selection of a triggering system is a foundational choice. This document explores the very best, most accurate, and highest-speed triggering systems available today for aftermarket ECUs, dissecting how they work, why they excel, and which applications benefit most from their precision.

The Function and Importance of Triggering Systems

Triggering systems in automotive engines provide real-time feedback on crankshaft and camshaft positions. This information allows the ECU to precisely control ignition timing, fuel injection, variable valve timing, and other functions critical to high-performance and emissions-compliant operation. Any inaccuracy or latency in the triggering signals can result in poor engine efficiency, reduced power output, or even engine damage in extreme conditions.

Key Requirements of High-Quality Triggering

·      Accuracy: Ability to resolve crank and cam position with minimal error, down to fractions of a degree.

·      Speed: Fast response with minimal latency, especially important at high RPMs (upwards of 10,000-15,000 RPM in racing engines).

·      Noise Immunity: Reliable operation in the presence of EMI/RFI and electrical noise common in modified vehicles.

·      Compatibility: Ability to interface with a wide range of aftermarket ECUs.

·      Reliability: Robustness under temperature, vibration, and environmental stress.

Overview of Common Triggering Technologies

·      Inductive (VR) Sensors (Variable Reluctance): Generate AC signals as a toothed wheel passes a magnetic pickup. Robust and simple, but resolution and accuracy can suffer at very low or very high RPM.

·      Hall-Effect Sensors: Output a digital square wave as a ferrous target passes the sensor. Highly accurate at all speeds, with clear on/off transitions that are easy for ECUs to interpret.

·      Optical Sensors: Utilize a slotted disk and an LED-photodiode pair. Offer high resolution but can suffer from contamination and are less common in modern automotive applications.

While VR and Hall sensors are both widely used, the combination of a well-designed toothed wheel and a Hall sensor is often considered the gold standard for aftermarket high-performance ECUs.

The Best: High-Resolution Multi-Tooth Reluctor Wheels with Hall-Effect Sensors

The leading solution in the aftermarket today is a high-resolution multi-tooth crank trigger wheel (such as a 36-1, 60-2, or similar) coupled with a precision Hall-effect sensor. This setup is favored by top ECU manufacturers (Motec, Haltech, Link, Emtron, Syvecs, and others) for its blend of speed, accuracy, and robustness.

How It Works

A multi-tooth wheel (often mounted to the crankshaft) has a series of teeth (e.g., 36 or 60), with one or two teeth omitted (“missing teeth”). The Hall sensor reads the passing teeth, generating a digital signal that the ECU interprets. The missing teeth serve as a reference for the ECU, allowing it to determine absolute engine position each revolution.

When paired with a camshaft position sensor (also Hall or VR), the ECU can establish engine phase, enabling full sequential injection and ignition control.

Why This System Excels

·      Exceptional Resolution: With more teeth, the ECU can “see” the crankshaft in finer increments, allowing for precise timing adjustments—critical at high RPM.

·      High Speed: Digital Hall-effect sensors can process rapid tooth passages even at extreme engine speeds, supporting applications up to and beyond 20,000 RPM.

·      Clean Signal: Hall sensors are less susceptible to noise and are easier to wire and calibrate than inductive sensors.

·      Self-Calibrating and Adaptive: Modern ECUs automatically adapt to signal characteristics and compensate for minor variations in wheel manufacturing or installation.

Common Trigger Patterns

·      60-2: Sixty teeth on the crank, with two missing. Popular in BMW, Volkswagen, and modern performance engines.

·      36-1: Thirty-six teeth, one missing. Common in Ford and many racing applications.

·      24-1 or 24-2: Used in some Japanese performance engines.

The more teeth, the higher the resolution, but also the greater the processing demand—modern ECUs easily keep up.

Comparative Analysis: Why Not VR or Optical?

While variable reluctor (VR) sensors are robust and cheap, their analog nature can result in signal degradation, particularly at very low or very high RPMs. This can cause starting issues or misfires at high engine speeds. Optical sensors, though precise, are vulnerable to contamination and less reliable in the harsh automotive environment.

Hall-effect sensors with multi-tooth wheels strike the best balance—digital, precise, robust, and widely supported.

Integration with Aftermarket ECUs

Modern standalone ECUs such as Motec M1, Haltech Nexus, AEM Infinity, Link G4X, Syvecs S7, and Emtron KV utilize advanced digital filtering and adaptive algorithms to extract the most from high-resolution Hall-based trigger systems. They can instantly detect crank/cam direction, synchronize rapidly, and support variable valve timing and complex multi-stage ignition/injection.

Features now often include:

·      Real-time diagnostics of trigger signal health

·      Automatic compensation for sensor drift or minor wheel imperfections

·      Support for multi-channel (dual cam, quad cam) setups

·      Advanced fail-safe and redundancy modes

Emerging Technologies and Future Trends

Advanced magneto-resistive (AMR) sensors and integrated digital encoders are being explored, offering even more granular resolution and self-diagnostics. Wireless trigger systems may appear in the future, but as of today, the Hall sensor plus multi-tooth wheel remains the industry’s fastest, most accurate, and most reliable choice.

Installation and Best Practices

To maximize the benefits of a high-speed, high-accuracy system:

·      Mount the trigger wheel as close to the crank centerline as possible to minimize runout.

·      Use shielded, twisted pair wiring for sensor signals to further reduce noise.

·      Always follow ECU manufacturer recommendations for sensor voltage (often 5V or 12V) and pull-up resistor values.

·      Test signal integrity across the full RPM range before tuning aggressively.

Real-World Application Examples

Motorsport – Formula One and Endurance Racing:

Modern F1 engines use proprietary high-resolution digital encoders, but for high-end club and professional motorsport, the 60-2 Hall system is the de facto standard.

Street and Track Tuners:

Cars retrofitted with ECUs like the Haltech Elite or Motec M1 see massive improvements in driveability and maximum RPM when switching from OEM VR sensors to Hall/multi-tooth setups.

Conclusion

For those seeking the ultimate in engine control, the pairing of a high-resolution multi-tooth trigger wheel (such as 36-1 or 60-2) with a premium Hall-effect sensor delivers the very best in speed, accuracy, and reliability. This combination is supported by every leading aftermarket ECU, is robust to electrical and environmental noise, and provides the foundation for precision tuning and advanced features. While technology continues to evolve, this system remains the gold standard for modern performance and racing engines.

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Cheers Banjo

 

 

  

 

 

Edited August 22, 2025 by Banjo

[Banjo]

Further, to my previous post above, I received the optical CAS module yesterday, pictured also in my previous post.  Last night, I eagerly spent some time, fitting it to a Toyota K Series "Bosch" dissy body.

I filed out the side of the dissy body, so the connection part of the module, can easily have the harness plug fitted, similarly to how it is on the Daewoo Matiz 800cc engine.  It is made by Mando & has part numbers M934 & 4G16AA on it.

 

 

These modules, were used on some Nissan, Mitsubishi, & Daewoo Matiz engines; so the wiring harness 4 way plug, are commonly available at auto parts suppliers, like EFI Solutions, where I ordered one.

However, I have one specific simple problem, that I cannot resolve; despite hours of searching the net.  I don't know what the individual 4 off connections on the Module terminal socket, are attached to.

 

I know one will be either +5V or +12V supply voltage.  One will be a chassis earth / ground.  One will be the CAS single pulse per rotation output; & one will be the RPM pulse output.  (In my case 24 pulses per revolution)

However, I don't know how they are arranged on this module. You'd think there would be a standard; but sadly, NO.

There is no paperwork or specs, with the part supplied. I pumped in every P/N I could find attached to this module, to Google; & it hasn't been able to supply the info. I really only need to know the +5V or +12V supply & Earth/Chassis terminals; as once I have it powered, I can easily check the two outputs of the remaining two terminals, with the oscilloscope, which usually have an open collector circuit, which they pull down to ground.

I even contacted the Chevrolet Club forum, in the UK last night, as the Daewoo engine was, I believed; used in the Chevrolet. Unfortunately, they could not help either.

I know this system will work, but there is one issue with these modules.  The light beam passing through the punched holes in the disc, is infra-red light, so the unit will not be affected by visible light.  However, the four tiny optics LEDs & optical sensors could be impacted, over time, by dust & fumes, & oil film on the optical sensor surfaces.  The unit, should be tightly sealed, in a real use application, in the engine bay.  Others have reported this issue, on threads I have read, on the net.

Once I get that sorted, I'll hook it up, to the small speed controlled electric motor, I have on my bench, which can achieve 3500 RPM. As this is a distributor application; that means I can test it up to 7000 RPM crankshaft speed.

I did come across this thread, of a guy that had an issue with the optical CAS distributor's electronics, with heat & poor soldering.

https://d-iy-company.blogspot.com/

Really hope, someone can help, or point me in the right direction, regarding the four terminal connections identification.

Then I can just pop it in the KE30, & try it out, with my latest COP conversion.

Cheers Banjo

 

 

 

 

 

 

Edited August 27, 2025 by Banjo