So, as it turns out I attempted to use a VR type sensor for my crank sensor, and it was being a humongous pain in the ass. (inconsistent and weak signal)
I switched to a hall effect sensor (mines specifically a DIYAutotune sensor, but its similar to the Holley sensor and the GM OEM sensor and all of a sudden I had a clean, strong signal, and it was working 100% fine, despite being outside the crank-case, and despite not having magnets glued to the trigger wheel.
In fact, so far as I can tell, the aftermarket seems to actually largely be geared towards using hall sensors, and not VR sensors.
Of course, that doesn't mean that I've not been having issues.
To back things up a bit, My first task for actually making the DIS conversion happen was to figure out where in the world I was going to put my LS2 coils that I had purchased some time ago.
I held the coils in various positions around the engine bay, and quickly started to narrow down on the front of the shock towers.
As it happens, with all the EFI and other upgrades I've made over the years, space is starting to come at something of a premium under the hood of the Fairlane, and the front of the shock-towers is largely un-occupied (theres a relay panel on the passenger side that's in the vicinity, but nothing on the drivers side)
The front of the shock-towers also offers some advantages as far as serviceability goes, since its fairly easy access.
I used some cardboard (Cardboard Aided Design?) to get some idea of what space is available to me, and then I transitioned over to Autodesk Inventor to design some brackets to hold the coils.
There was some design iteration, as well as alternate designs that would have had to be welded out of steel, but ultimately, I settled on a design that I could bent up out of aluminum, which has the advantage of looking nicer.
Drivers side:
Passenger Side:
I sent the design to an Orem, UT based company, called OSHCut, who laser-cut out all the detail parts from 5052 aluminum and sent them to me. Turnaround was about a week and a half, and cost was reasonable, so I was pretty pleased.
While I was waiting on my cut aluminum to arrive, I had about 60 some-odd new wires to merge into my wiring harness. Most of these wires would end up being little short ones in the vicinity of the coils themselves though (relay 12v key on hot, chassis ground, and a ECU reference ground for each coil that ended up going onto a common isolated stud, so that only 1 wire had to actually go back to the ECU)
I don't really have any pictures from when I was installing the wires since there wasn't really anything to see at this point.
When the aluminum brackets arrived, that's when the visual progress started to happen.
I started by bending them up (minus the 2 bends on each coil bracket that was not possible with the tools I have, I'll have to bend them later, if at all)
I totally messed up, and bent my crank position sensor bracket wrong, so I had to manufacture some little extensions out of 1/2 x 1/2 square stock:
(see the 2 wire VR sensor from an explorer shown here, that ultimately ends up going away later)
and installed into the car:
Coils were assembled into their brackets, and installed into the car:
And then wired up: (with bonus plug wires that I also did
When the passenger side was wired up, I ran some continuity checks, ensuring that everything was wired right (and good thing I did, I found some swapped pins in a few places)
Once my checks were complete, imagine my disappointment when after a couple straight weekends of work, and a month of design and planning, there was no fire whatsoever when I turned the key.
The issue as it happened was the crank position sensor. The VR sensor that I had decided to use was generating an inconsistent signal, despite being between .040 and .060 away from the trigger wheel.
The above datalog shows the RPM signal, as the ECU was interpreting the crank sensor signal.
The whole time of that datalog, I was on the key, and cranking. The loss of RPM as it climbed almost up to 160 RPM was due to the crank sensor signal crapping out. In the crank log, the signal looked fine, but it was quite weak. I'm sure with enough fiddling and dicking about with filtering and minimum signal voltage settings, it probably could have been made to work, but at this time, I elected instead to go with my original gut feeling, and switch to a hall effect (also, switching to hall effect was a common suggestion by Danny and others on the holley forums and elsewhere)
I ordered a sensor from
DIYAutotune and started working up a design for a bracket that I could make with the limited tools at my house in Cedar city.
The final bracket ended up looking rather like this:
When I get up to my parents place, where I've got access to way more fabrication tools, I might come up with something better that's actually more adjustable, but this will do for now.
With the hall effect installed, and wired up (I spliced into the regulated +12v signal that I was using for the cam sensor) the RPM signal was nice and strong (and steady)
I attempted then, to fire up the engine. It started but was running like dogshit (but running, that's important! it runs)
The problem is that I'm getting quite a lot of a knocking sound (which I can feel all the way into the floor BTW)
It's also backfiring a bunch, and the exhaust fumes are making my eyes burn and throat hurt (which is new, the fumes never used to be that bad, or even noticeable really)
I've checked, and all the plugs are firing, I also have good compression in all 8 cylinders (~130PSI +/- 6 psi)
I've adjusted the TDC tooth number in the EFI from the 6 tooth (which is where I'm physically installed) up as far at to the 9th tooth (it runs best on the 8th tooth, with the least backfiring and knocking, though the timing is most closely synchronized on the 7th tooth, being only about 6° retarded from the commanded timing)
Once my account at the holley forums gets approved (apparently I never made one, though I thought I did), I'm going to make a more detailed post over there about the issue, along with some datalogs I've taken.
