3tgteu cam sync sensor for progamable ECU?

[turbotoy]

I thought of modding the valve cover to hold a VR sensor to read the cam lobe.

[thechuckster]

cam lobe is too gradual a curve - even for a VR sensor - a sharp-edged tooth will give you a better zero-crossing point for any sensor-signal analysis.

attach a trigger wheel to the front of one of the cam chain pulleys and then shove a VR sensor thru the timing cover. Getting it aligned and with the right tooth/sensor gap will be a challenge.

It will probably have to be VR sensor as the heat from the oil will eventually kill any epoxy holding a magnet onto a trigger wheel.

Is there a reason why you need sequential injection? Unless it's for emissions compliance, i'd suggest that it's of little benefit except at idle.

[turbotoy]

Exactly. I need/want it at idle. I am running 550cc injectors. At idle I have pules width set so low the injectors wont keep up and it still runs rich. I also want the ability to trim each cylinder for max HP.

[thechuckster]

what injection-duration resolution do you get with the Haltech?

if you drive them as two banks and fire the injectors 2 times per 720 degrees you might get the duration needed?


otherwise you gotta attach a trigger wheel to a cam somehow. Perhaps take a leaf out of the 1/2J cams - they have a trigger tooth about halfway down the cam and a VR sensor poking thru the head looking directly at the cam (and incredibly hard to unplug unless you remove the intake manifold)

Rip the intake cam out and where the dizzi drive was, get small steel peg 'fixed' (e.g. drill small hole, cut thread in hole with tap and die, get suitably-sized steel bolt with inset hex head, mill sides to produce square not round cross-section, screw into hole and use very heavy loctite to keep it there) at a known crank position and then shove a VR sensor down the dizzi mount hole and fix it safely/securely.

I'm assuming that you're getting headers with O2 bungs in each runner?

[3jcelica]

For the hassel of getting a cam sensor without a dizzy and the complexity-cost of trying to tune each cylinder power, manifold work (bungs in each runner), cost of coils etc I think you would be better off staying with wasted spark as opposed to Coil On Plug.

As the chuckster says look at the firing aragangement of the injectors, and the injectors you are using. I know a lot of people using 550cc RX7 injectors and 660cc Mitsibish injectors that have no idle problems on smaller engines i.e 1600cc.

Rich idle is not so much of a problem, idle needs to be smooth and at lowest manifold pressure possible for best throttle response. Some engine like it a little rich during idle, other don't. I think mine runs ~13:1 during idle, but is smooth.

rather than trying to bodge something up through the rocker cover I would be looking to get a standrad 3tgte intake cam reground if possible and use the bottom of the 3tggt dizzy removing three of the vanes.

What pulse width do you have at idle? It could be the cams you are running causing the pulsing due to map sensor signal pulsing. Map signal moving around much?

Roger

[turbotoy]

I talked with Haltech. They said I could use a MSD pn8914 Cam Sync Generator this will give one the proper signals to run full sequential. Basically it uses an induction pickup from #1 to give a signal to the Haltech for #1 TDC. So now I will be upgrading from a E6S to E6X on my 3tgte.

[thechuckster]

do they mean an inductive pickup on spark #1? (edit: yes they do)

wont that home signal 'move' about as your timing map goes thru changes in advance/retard? this will make accurate injector phasing difficult?

[turbotoy]

Good point I thought about that too. But from what I understand all the ECU needs is something to tell it the difference between TDC intake and TDC exhaust. All timing calculations are based on the crankshaft position sensor.
I am switching from a flying magnet setup of two magnets to a 36-1 wheel to give me better resolution.

[turbotoy]

do they mean an inductive pickup on spark #1? (edit: yes they do)

wont that home signal 'move' about as your timing map goes thru changes in advance/retard? this will make accurate injector phasing difficult?

Confirmed with Haltech. The ecu need only to differentiate between TDC intake/TDC exhaust. All timing calculations come from crank trigger input.

[thechuckster]

is a novel way of doing cam positioning - certainly saves on fabricating another sensor setup.

I wonder if you could make one up with the inductive pickup wiring from a timing gun?

only issue I can see is that the ECU can't start with seq injection as it needs a proper combustion event for a waste-spark coil pack to favour one cylinder. E.g. ECU starts in batch mode then up-shifts to sequential once it works out the cam position?

[turbotoy]

only issue I can see is that the ECU can't start with seq injection as it needs a proper combustion event for a waste-spark coil pack to favour one cylinder. E.g. ECU starts in batch mode then up-shifts to sequential once it works out the cam position?

True but from my experience most ECUs don't turn on the injectors until they figure out the timing. Shouldn't take but 2 to 3 revolutions.

I am glad I don't have to do anymore fab work!!!!!

As long as the output from the timing light is a square wave or can be converted to a square wave I don't see why not.

[turbotoy]

Well after experimenting with the MSD box. I have come to the conclusion that it will not work with my setup. From what I can gather with a scope I am getting to much inductive interference from the duel post coils. So I have ditched the box.

I have decided to stop messing around a just drill a hole in the head to accommodate a hall effect sensor to give me a signal off the cam lobe itself. WORKS GREAT. I am so excited.
Full sequential direct fire waste spark 3tgteu!!!!!

P.S. For all those that don't understand why I want sequential injection it is simple. Just because I can, and I want it!!!!!!!!!!!

[RA35GT]

Dood, the inductive sensor doesn't work on waste spark ignition because each cylinder gets a spark twice in the cycle. So you will still have an issue of knowing when #1 is at compression. (Since it would also fire on #1 during exhaust).

[turbotoy]

The MSD box compensates for that. It is designed for waste spark ignition. It uses an inductive pickup along with input from the cpu.

[RA35GT]

Ahh, just read the pdf, looks like it must detect the voltage at the lead (the cylinder under compression normally needs a higher voltage to spark then the cylinder in exhaust).