What kind of trigger and home sensors do our motors have?

[bszopi]

Which hi-res sensor? All of the sensors for the ignition are on that diagram. As far as where that diagram came from, its from a 66U PCM (3100SFI) GM STG book I picked up on eBay awhile back.

[evilmiata]

The crank has two sensors: a low-resolution (7x) reluctor in the block and a high-res (24x) pickup (can't remember the technical term).

The other thing that bugs me is that the low-res has seven trigger points, but the diagram calls it a 3x and only shows six.

[RacerX11]

The 7X low-res sensor feeds into the ignition module, not the ECM. The ignition module uses the 7th pulse to determine TDC of cylinder #1. The 6-pulse waveform shown in the above diagram is the reference pulses sent by the ignition module to the ECM. It effectively removes the 7th reference pulse from the raw crank sensor signal, and sends a 6X waveform to the ECM.

The ECM uses the hi-res 24X signal from the crankshaft to determine engine speed (there is no reference tooth on this sensor, so no engine position can be determined from it, only engine speed). The cam reference pulse signal is used to synch up engine position with engine speed to allow sequential injection.

You have a couple options:
1. Use the GM DIS module, like it is documented on DOHCFiero.com (I still don't understand why you aren't going this route, but whatever)
2. Use a combination of 24X crank signal and 1/2X cam signal to determine engine speed/position
3. Modify the 24X trigger wheel in the damper by removing one 'notch", thus creating a 24X-1 signal. You could then synch off this position (I'm not sure if this type of signal is compatible with the Haltech or not).

Marty

[evilmiata]

Re: What kind of trigger and home sensors do our motors have

RacerX11,

I am not using the GM ignition module because

dohcfiero.com is down.

and

Dude, I don't have a car, let alone a computer/harness to test. Click on my house. In fact, I've never even been under the hood of a running 60*V.

The Haltech totally replaces the ignition module. The IM just another piece of junk that adds weight (superficial) and wiring issues. Besides, EVEN if I used the ignition module, I would still have the same questions.

Because the Haltech is so streamlined, I picked your #2 option

I'm using the high res crank sensor (93-95 f-body, if it matters) as trigger and cam sensor as home.

[evilmiata]

RE: Re: What kind of trigger and home sensors do our motors

FYI: Clip side up, 1st pin PCM 2nd pin 12v 3rd pin Ground. I had the PCM and the 12v reversed. I should be able to figure out the rising/falling edges real fast once I switch up my wiring. I'll post with my findings in case anyone else ever searches for this info.

Brad, I truly appreciate your help and effort. I know what its worth to go out of one's way for a stranger these days.

[bszopi]

RE: Re: What kind of trigger and home sensors do our motors

Should be 5v, not 12v. All of the sensors for this engine run off a 5v reference. Sorry I never got a chance to do any more for you. Its been hectic around here lately trying to adapt to a new town and job.

[evilmiata]

RE: Re: What kind of trigger and home sensors do our motors

My wiring diagram shows 5v at the A/C Evaporator Temperature sensor, A/C Refrigerent Pressure Sensor, Map sensor, and Throttle position sensor.

The Ignition control unit, automatic transmission, Camshaft Position sensor, and crankshaft postion sensor all share the same fuse under the hood. I'm betting that's 12 volts.

[bszopi]

RE: Re: What kind of trigger and home sensors do our motors

Interesting... I guess you are right. I never really paid attention that much, just knew that majority of the sensors used a 5v reference. But know that I look at the diagrams I have up on the site (http://www.60degreev6.com/images/Wiring_Diagrams/), it does look like they would be 12v.