Retrofit cam position sensor onto B20b series engine?

"Sally O'Broder" (KojiroT)
10/16/2014 at 14:16 • Filed to: None

Hey everyone,

I'm trying to be cheap. I'm really in the weeds at the moment and pictures forthcoming for my awesome build progress, but I have a retrofit question that is burning up my brain.

I've figured out several solid ways of replacing the stupid Honda stock ignition, but I need to know if I've stumbled onto the cheapest .

Looking at the AEM Engine Position Module, it's just...a sensor that you cram where your dizzy should go, right? Hell, why can't I do that with some cheaper OEM sensor and just figure out the wiring myself? Considering this will be going to either an ignition box or a Microsquirt?

Also as an aside I find it that replacing crap parts is turning my CRV racecar despite just wanting better fuel economy out of it and at this point being hilariously stubborn.

I've already started to save money, though, so THERE.

DISCUSSION (8)

Mattbob > Sally O'Broder
10/16/2014 at 14:20

there could be issues with electrical compatibility. Voltage levels etc... Specs like that are kind of tricky to find on the googles for individual oem sensors. You might be okay, but on something like ignition timing you should be sure.

Sally O'Broder > Mattbob
10/16/2014 at 14:25

I'm just looking to send the timing signal to a CDI box, which will then be driving CDI coils for Coil On Plug.

That is unless someone else has a better idea and I can just forgo the coil on plug or the CDI parts.

Mattbob > Sally O'Broder
10/16/2014 at 14:33

yeah, I'm just saying to be wary of whether or not the part you are supposed to use has the same voltage output and logic as the one you want to use. What you said makes sense. Check if it is a 12V or 5V signal. If it's supposed to be normally high, or low. I would just watch out for that. Maybe get a real cheap one from the junk yard and play around with it. Would you be making up the physical mounting of the sensor?

Sally O'Broder > Mattbob
10/16/2014 at 14:43

I'll figure out the mounting later; I come from a computer modding background, so that's whatever. I just need to be able to stick something in there that will fit and provide a timing signal, letting near-universal aftermarket compatibility take it from there. Hell, even if it needs a particular voltage, I can just go down to RadioShack or whatever.

If it fits inside I will be able to make this work. That's the key; I got the rest.

BoulderZ > Sally O'Broder
10/16/2014 at 15:27

FWIW, I replaced the entire fueling and ignition system on my '89 Toyota truck (miserable late 80s carburetor...) with the SDS fueling and ignition (think it was called the 4FE or something?). Anyway, it was very easy, and effective. The ignition control was done with two tiny rare earth magnets (about 1 mm by 3 mm cylinders) that you drill and epoxy in to the back of the harmonic damper (crank pulley), one at TDC, and the other was at something like 20 degrees BTDC. The sensor is just a two-wire affair on a plate bracket that you adjust to run very close to the back of the pulley. Super easy. Really, it's a glorified version of the sensors used on cycling computers. Pass a magnet by a coil, get a pulse of current. Then, just tell time and count pulses and you get your speed, and with two magnets you get position. Anyway, SDS has all their docs online if you want to see how they do it. Good luck!

Sally O'Broder > BoulderZ
10/16/2014 at 15:34

This is brilliant but I immediately recognize it as perhaps too delicate for me; I'm not that far into DIY yet. I just need something I can plug into the engine and then into my box man >_>;

How well did your ignition work out for you?

BoulderZ > Sally O'Broder
10/16/2014 at 17:32

Ah, yeah, the SDS system would be a bit more comprehensive/advanced. The ignition and fueling both worked out really well. It uses a two coil-pack system (1 and 3, 2 and 4, batch firing), that mounts on the fender under the hood. The ECU mounted behind a trim panel in the passenger footwell, and I routed all the wiring through the existing loom passage above the front right fender. I added a turbo, and the adjustability of the timing is fantastic. You can get your boost, fueling, and advance all right how you want them. It even passes emissions handily. The only mistake I made was I didn't put enough slack in my wiring harness for the MAP sensor, and eventually the wires broke from the engine movement relative to the body. It was an easy fix, just bought a new WeatherPack connector and soldered it in with longer leads.

Sally O'Broder > BoulderZ
10/17/2014 at 14:06

Awesome! I'm a real lightweight - a Honda makes more torque than I weigh - and so I should make note that I try to avoid the harmonic balancer like the horrible plague of my life that it is.

What I'm going to do is get some smart coils once I figure out the distributor problem. Then it's just a matter of the ECU, and I think I'm going to just have to go ahead and save up for a Microsquirt or luck out on eBay.