Distributor-less ignition (DLI)?
1 - 3 of 3 Posts
Joined
·
5,055 Posts
all FWD models had DLI.
DLI has no distributor..... to understand how DLI works you need to understand how a distributor works and the purpose of it.....
A distributor has a specific location that it needs to be set at in relation to the cam. Newer motors have them keyed a specific way to make this easier. Older versions have multi-toothed wheels that mesh with the cams and they can be difficult to set.
Anyways, the distribor spins 1:1 with the cam. It is set at "top dead center" for #1... which means when piston #1 is pointied perfectly at the top of it's rotation. The distributor has many things on the shaft internally -- most toyota distribors have 2 toothed wheels and all have a "rotor" at the end. The rotor just spins on the shaft, moving spark from the coil-in button and moving it to the lead for the spark plug wire. That part is only a slight portion of how your ignition works.
Like I said, most have 2 toothed wheels. Each wheel has a specific number of teeth -- usually it is symmetrical. Static within the distributor, there are magnetic pickups that "read" where the tooth is -- it does this by seeing whether the magnetic field is there (a tooth of the wheel is passing by) or whether there is not a magnetic field (a space between the teeth is passing by). In this system the ecu is actually "dumb" and has no idea what cylinder is #1, #2, #3, and #4 is. As the magnetic pickup gets a signal, it sends it to the ignitor which translate it and send it to the ecu... the ecu sees that the engine is moving at XXXX rpm and needs to send a signal to fire the coil, and also to fire a batch of injectors. The ignitor gets this signal, sends it to the coil, the coil fires, and the spark runs through the carbon button in the middle of the cap, across the rotor, to the spark plug wire lead to the plug.
You can see that this system is pretty basic and also complicating to those who don't understand. When someone says to check your timing, that means that even if your distributor is meshed into the correct location, the distributor housing can still be rotated -- which means that the "static" parts move with the housing when the shaft stays put. Meaning, when the ecu sees the signal and when the spark arcs across to the lead can be changed within a specific number of Degrees (360* is one full rotation).
Now.... if you understand all of that.... DLI is actually smarter and less complicated.
Usually in DLI you have something similar to the toothed wheels and some sort of magnetic or hall effect sensor. However, in this situation you have either specific coils for each spark plug or you have "batches" of coils -- usually run in pairs.
Batches of coils is called a waste spark setup. In a 4age, the timing is 1-3-4-2. So you would have coils setup as 1&4 and 3 & 2. Any time a spark is sent to #1, #4 receives a spark as well. The opposite is true... whenever #4 gets a spark so does #1. This is also the case for other coilpacks. This system actually helps burn off excess gasses in the combustion chamber and should take place at bottom dead center (meaning there's no compressed air to move the piston).
So you know that these are sparked off in batches, but how does the ecu know when to spark them? Instead of having a distributor DLI cars can have a crank angle sensor and/or a cam angle sensor. Usually coil on plug (each plug wire gets it's individual coil) will have both whereas a setup that has just one will be a waste spark setup.
Usually there is a toothed wheel and a sensor -- however, what is different is that the toothed wheel is attached to the crank (or cam) and has a missing tooth. The purpose of the missing tooth is so that the ecu actually knows where the engine is in relation to #1 TDC.
You can get your car setup on DLI, but not with the stock electronics. I use Megasquirt for my aftermarket ecu's and run fords EDIS (because it's simple to wire and Megasquirt can manipulate it easily.... plus it's very common in junkyards and very cheap). My 4agze is using an MS with EDIS4 running a waste spark setup, utilizing a 36-1 (36 teeth, one missing) wheel, a hall effect sensor, and the factory 4agze coilpacks. A 36-1 toothed wheel on the crank just makes sense -- in one full rotation of the crank there are 360* and 360/36 = 10*... meaning for each tooth there is 10* of change on the crank (or 10* timing).
DLI has no distributor..... to understand how DLI works you need to understand how a distributor works and the purpose of it.....
A distributor has a specific location that it needs to be set at in relation to the cam. Newer motors have them keyed a specific way to make this easier. Older versions have multi-toothed wheels that mesh with the cams and they can be difficult to set.
Anyways, the distribor spins 1:1 with the cam. It is set at "top dead center" for #1... which means when piston #1 is pointied perfectly at the top of it's rotation. The distributor has many things on the shaft internally -- most toyota distribors have 2 toothed wheels and all have a "rotor" at the end. The rotor just spins on the shaft, moving spark from the coil-in button and moving it to the lead for the spark plug wire. That part is only a slight portion of how your ignition works.
Like I said, most have 2 toothed wheels. Each wheel has a specific number of teeth -- usually it is symmetrical. Static within the distributor, there are magnetic pickups that "read" where the tooth is -- it does this by seeing whether the magnetic field is there (a tooth of the wheel is passing by) or whether there is not a magnetic field (a space between the teeth is passing by). In this system the ecu is actually "dumb" and has no idea what cylinder is #1, #2, #3, and #4 is. As the magnetic pickup gets a signal, it sends it to the ignitor which translate it and send it to the ecu... the ecu sees that the engine is moving at XXXX rpm and needs to send a signal to fire the coil, and also to fire a batch of injectors. The ignitor gets this signal, sends it to the coil, the coil fires, and the spark runs through the carbon button in the middle of the cap, across the rotor, to the spark plug wire lead to the plug.
You can see that this system is pretty basic and also complicating to those who don't understand. When someone says to check your timing, that means that even if your distributor is meshed into the correct location, the distributor housing can still be rotated -- which means that the "static" parts move with the housing when the shaft stays put. Meaning, when the ecu sees the signal and when the spark arcs across to the lead can be changed within a specific number of Degrees (360* is one full rotation).
Now.... if you understand all of that.... DLI is actually smarter and less complicated.
Usually in DLI you have something similar to the toothed wheels and some sort of magnetic or hall effect sensor. However, in this situation you have either specific coils for each spark plug or you have "batches" of coils -- usually run in pairs.
Batches of coils is called a waste spark setup. In a 4age, the timing is 1-3-4-2. So you would have coils setup as 1&4 and 3 & 2. Any time a spark is sent to #1, #4 receives a spark as well. The opposite is true... whenever #4 gets a spark so does #1. This is also the case for other coilpacks. This system actually helps burn off excess gasses in the combustion chamber and should take place at bottom dead center (meaning there's no compressed air to move the piston).
So you know that these are sparked off in batches, but how does the ecu know when to spark them? Instead of having a distributor DLI cars can have a crank angle sensor and/or a cam angle sensor. Usually coil on plug (each plug wire gets it's individual coil) will have both whereas a setup that has just one will be a waste spark setup.
Usually there is a toothed wheel and a sensor -- however, what is different is that the toothed wheel is attached to the crank (or cam) and has a missing tooth. The purpose of the missing tooth is so that the ecu actually knows where the engine is in relation to #1 TDC.
You can get your car setup on DLI, but not with the stock electronics. I use Megasquirt for my aftermarket ecu's and run fords EDIS (because it's simple to wire and Megasquirt can manipulate it easily.... plus it's very common in junkyards and very cheap). My 4agze is using an MS with EDIS4 running a waste spark setup, utilizing a 36-1 (36 teeth, one missing) wheel, a hall effect sensor, and the factory 4agze coilpacks. A 36-1 toothed wheel on the crank just makes sense -- in one full rotation of the crank there are 360* and 360/36 = 10*... meaning for each tooth there is 10* of change on the crank (or 10* timing).
If you want to check if a GZE runs the DLI system, then this is one of the things (together with the coilpacks) to look for. This is the DLI pickup that sits where the distributor would sit on a 'normal' 4A-GE
![]()
This pic. is of my own 2nd gen 4A-GZE
The 4A-GZE runs the waste spark setup and has 2 coilpacks sitting on the gearbox side of the cilinderhead.
Don't mess with it and you'll be fine running the stock system :lol:
This pic. is of my own 2nd gen 4A-GZE
The 4A-GZE runs the waste spark setup and has 2 coilpacks sitting on the gearbox side of the cilinderhead.
Don't mess with it and you'll be fine running the stock system :lol:
1 - 3 of 3 Posts
