1970 Jeep Rebuild

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Already checked with 9 volt, and yes they cycle.

 

This is what I’m thinking, doesn’t seem like it’s getting a signal from the crank sensor.

 

I’m getting power when key is on and while cranking.
I am going to check grounds to make sure they are good, but I think they are because the fuel pump is cycling when I turn key on.
Pink wire is to the battery.

 

How much clearance do you have between the end of the crank position sensor (CPS) and the 3 bolts you are using to trigger the sensor?

 

I set the clearance between .035-.040

 

Good. I was concerned you may have set to clearance at something greater than .050" which is generally recommended distance. Still wondering if you see the pulses signal at the ECM input.

 

Today I started by moving my ground wires to another bolt hole in the head, after I took grinder and knocked off the paint around it.
I checked volts to the hot wire to the ECM, getting 12.35 with key on and 11.12 while motor is cranking over.
Checked diagnostic port and code 12 is only thing coming up, that’s what’s supposed to be there.
Getting 12.34 volts to fuel pump when I turn on key for 2-3 seconds. Getting nothing while cranking, so no pulse.
watched both injectors while motor cranking over and nothing coming out, knocked on them several times with handle of screw driver and still nothing.
Probed both injector leads with test light and both get a light that stays on. Checked both with a noid test light while cranking and get nothing.
Probed CAM sensor purple wire and get nothing while cranking motor. Should be 5 volts.

Called and talked to Troy at Howell and he seems to think I have a bad ECM, so he’s gonna send out a new one.

 

Im still not convinced it’s not in the wiring harness, going to the CAM sensor.

 

So why is it that we don't have a dislike option?

 

I have been following along using a factory ECM wiring diagram. This ECM does not use a CAM sensor so I am confused. The only purple wire that I know of is used with the o2 sensor. The wire you are referring to terminates on which ECM terminal?

 

I didn’t probe it back at ECM I probed it at the sensor. It’s a 3-wire plug with tan wire that has same voltage as battery, green wire in center that is ground and purple wire that shows 5 volts when open and shuts down to 0 when it is closed, (when bolts pass over it on crank).
I’m still looking for a good pdf of the wires coming out of the ECM. I’m still learning this stuff and am reading everything I can to familiarize myself with the system so I understand it.

 

Reading Kyle’s thread on his install
Sensor A: 5volt on C14
Sensor B: Low Rev on B3
Sensor C: Signal on B5

 

I’m trying to find a schematic that has the pins mapped out, (numbered) so I know exactly where the wires are pinned, do you have a source?

 

Join Gearhead-EFI - GearHead EFI Forums .The very top heading in the forum is: GM EFI Systems. Sellect it. In the Sub-Forums section click on:
GM ECM - Bins - TunerPro Definition Files - Wiring Diagrams = Tuner Info!. Look down the page to about the 4th entry: 1227747 ECM Information $42 [The 7digit number is GM's designation for your ECM, $42 refers the mask (program) used by the ECM to control your throttle body system.] Open that section and you will not only find 8 wiring diagrams but additional data that is used by the ECM. At this point, most all of the other data will look like Greek to you. Bookmark this web site. If you ever want to get into programing your ECM the members can be very helpful.

 

Thank you!
I just joined that site, waiting on permission to be able to pull up those schematics.

 

Just texted you the ECM pin outs.

 

Didn’t do a lot today, cleaned up some wiring and built a shelf for the ECM that’s mounted under the dash.


no pics of it mounted, also ran some camper tape for the ECM to sit on. Waiting on new ECM to show up.

Totally ripped this off from Norcal69

 

Man you guys are neat, building things like this. If it were me I would have the ECM swinging off the steering column by a zip tie.

 

Easy access

 

At least tape it to the firewall or toss it in the glove box.

But seriously, I don't know how you guys are running these pcms without a weather proof enclosure. Dust, mist, alligator swamps all seem to attack my nice things.

Mine's taped up inside an oversized glove box. I've gone through a bunch of relays and had to move them into the glove box as well.