3100 DIS issues

[Maverick H1L]

Well, I took the entire engine harness back out last night. Turns out that the tach wire had high resistance (almost 60 ohms). I put it back in today, after (I thought) fixing the ground wire as well. Looks like I need another power connector or another terminal for the connector as I have megaohm resistance on the ground side... I'm going to ground the thing straight to the mounting bolt at the bottom so I don't have to fight with the grounds on the back of the engine. Those things are a serious PITA.

But I did get the MSII TunerPro tach to bounce! Once!

[ericjon262]

did you replace the module underneath the coils or just the coils? if you did, was the module new GM, J/Y, Parts store?

I know some ICM plugs have a "tach output" and some PCM's have a "tach output" but cars with it on the PCM don't have it on the ICM, so you may need to wire in a different plug. IIRC, the ICM plug I'm thinking you should have, will have 2 white(mine was faded, so maybe yellow, or another light color) wires coming out of it.

[Maverick H1L]

Come on, anyone? I can't fire this thing without a tach pulse!

I've replaced the entire ignition coil pack.
I've checked, re-checked, and checked the wiring again. I have less than .4 ohms resistance on all ECM wires between the ICM connector and the ECM connectors. Also checked between the ECM wiring harness connector and the DB37 MSII connector pins on the adapter card.
I have removed the MSII from the car and checked it again on the stimulator. It works, I promise.
I still have 12V at the power connector while cranking. I even added a jumper wire for the ground straight to the battery just in case that's bad. I have already verified a good 7X pulse.

I still have SPARK but NO TACH or REFERENCE PULSES.

[Maverick H1L]

Bump...

I'm looking for a scan or something out of a FSM called "Ignition System Check". I have the system to where it will spark now (didn't connect the bypass to the START circuit through a relay yet to cut off the bypass...) but I still can't get any tach pulses to either the I/P or the MSII. The only Ignition System Check chart I have is for a distributor...

If the charts are almost the same, I'm stuck at the part where the line says to connect a test light to the tach terminal, which would be C in the 6-pin connector. I can't get a light, whether or not the 6-pin is connected, but my DMM reads 12V on every terminal in the module (except D which is a ground) with the connector disconnected (cant get the light to light on ANY terminal in the module!). Yes, the light works. I checked that both at the battery and at the coil power/ground connector. I have no light whether or not the engine is being cranked, and, according to the chart I'm using, it should be blinking...

The issue is that I have spark, but I can't get a tach pulse ANYWHERE. I have already verified the wiring to the MSII with 165 adapter card, and the MSII passed all the stim tests. And have also verified the ignition setup in TunerStudio.

[Maverick H1L]

Um, I think the module may be DOA...

I have the following:

12V supply to the module
Ground
1VAC signal from the 7x while cranking

I do NOT have the following:
Reference pulses to MSII (as verified with serial connection)
Tach signal to instrument cluster
Spark at a plug connected to a loose wire and grounded to engine through shell

I need to make sure I have the module hooked up right...
6-wire connector is self-explanatory (it only goes in one hole)
Connector next to 6-wire is 7x CKP, connector has wires in first and last holes
Connector at the other end of module is 12V and ground

If that is right, is there a way to check the module without taking it in to be tested?

[caffeine]

The way I understand it the DIS ICM has complete control of spark below 400 rpm, so it should spark with power, ground, and the crank sensor signal.

[Maverick H1L]

Got the RWD 3.4 sensor yesterday. I compared it to the FWD sensor a little while ago and it indeed is about 1/2" longer. I need to let the battery charge overnight (I'll be replacing it soon enough... other things come first) before I can check for spark again.

Also, does the DIS require an ECM to be hooked up to fire off? My MSII isn't in the car yet (need to work on the case).

[Purple pit]

Yeah I took a good long look at the 24x not that long ago. I felt a need to change it do to a idle problem. Not knowing at the time that you had to put off the damper. The real problem is an upper intake leak and a vacuum leak.
Thank you for the info!

[Maverick H1L]

It's the same as yours, just different parts. If you remove the damper, you will see a pressed metal ring with teeth on the back, with the teeth pointed towards the engine. There is a 24x sensor somewhere on the timing cover that the teeth pass through to generate the signal. This is similar to the dual rings utilized on the 3800 engines (actually, I think that may be where the idea came from since the Fast Start system may have been developed first).

[Purple pit]

Ok thanks, I didn't know much about the RWD sensors.

[Maverick H1L]

I thought the 7x was in the block and the 24x was the crank.

There are 2 CKP sensors, the 7x and the 24x. The 7x uses notches cut in the center of the crank to send a signal to the ignition module for a rough position of the crank, for starting and as a backup in case the 24x fails. The 24x goes straight to the ECM for fine tuning of the ignition timing and fuel injection pulses, and uses a wheel on the back of the damper.

I have an RWD engine that doesn't have a block provision OR the crank notches for the 7x, so I had to buy an external trigger kit to use the 3100 DIS. The damper in the kit has both the crank notches (in the outer ring) and the 24x trigger on the back (as in the 3.4 RWD).

[Purple pit]

I thought the 7x was in the block and the 24x was the crank.

[caffeine]

Could just ground one post and hook up a spark tester to the other

[Maverick H1L]

I don't get it, either. Makes no sense to me. Maybe it's located in a different place because of the starter mounting being right where the other 7x sensor would mount. I also don't get how an extra inch or whatever in length warrants a $30 price jump (I paid less than 10 for mine and the cheapest one I've seen is $35 plus shipping and what not).

I guess I'll get another 7x. Anyone need one for a FWD car?

Just need to make sure that I should see a spark jump between the 2 towers of a single coil when I get everything together...

[caffeine]

Weird I never would have guessed RWD used a different sensor