MS3 Pro LQ4 No RPM Signal

[Bolt-on]

Just got everything hooked up today on a turbo LQ4 project and have no rpm indication while cranking. No injector pulse width or engine start either. I did my best to search for answers before posting here. I read about soldering errors and adjusting pots, but the MS3 Pro is sealed so I doubt that's the issue. I read about triggering flood clear mode, but the MS3 doesn't seem to know the engine is rotating.

I installed the terminals on an unfinished harness that came with the MS3. The CKP and CMP signal and ground wire pairs were shielded, and I added a 12v power wire per instructions. I made the basic LS1 24x settings in Tunerstudio. My elevation is 6,000' and the pressure is only 73.5 kPa, so I reset the MAP lower limit to 70. I am fairly new to this but checked the rest of the settings as best I could. I tried swapping in a used crank sensor from another motor, and checked for power at the connectors. What else should I check?

I'm using MS3 Release 1.3.4 and Tunerstudio MS v2.6.19. I've attached a copy of the tune, a datalog of it cranking, and a screen shot of the Tuner Studio dash. Sorry if this has been answered here and I missed it.

[Bolt-on]

I found some problems. When I made the connections, I used the writing on the harness wires to locate the circuits, and never checked the wire routing to the connectors. I followed a LS1 basic sensor wiring diagram which shows:

CKP+ to white 6 (CKP+)
CKP- to white 18 (sensor return)
CKP supply to +12v

CMP+ to white 26 (CMP+)
CMP- to white 18 (sensor return)
CMP supply to +12v

I had:
CKP+ to white 6 (CKP+)
CKP- to white 15 (CKP-)
CKP supply to +12v

CMP+ to white 3 (injector out J) EDIT: I had the connector upside down when I checked this. It was on pin 26 (CMP+) where it was supposed to be.
CMP- to white 16 (logic ground)
CMP supply to +12v

And I hadn't grounded white 15 and 16 to the head as instructed.

Should I take CKP- to pin 15 (CKP-), pin 18 (sensor return), or pin 16 (logic ground)? Does it matter? What about CMP-? I assume CMP+ should go to pin 26 (CMP+), probably by re-pinning it in the white connector so I keep the shielding. I checked the rest of the routing on the white connector that is being used. It was correct.

[jsmcortina]

Have you read the manual?
http://www.ms3pro.com/_downloads/ms3pro ... agrams.pdf

James

[Bolt-on]

I used the diagrams and settings in that link, except that I went with the writing on the wires and didn't check that the wires went where they were labelled. Is there another manual I should read?

For a 24x LS1/LQ4, where do CKP- and CMP- go? Pin 18 white connector as it says in the manual you linked, or pin 15 (CKP-) and pin 27 (CMP-) as it says in the MS3 Pro pinouts? Do I ground white connector pins 16 and 17 to the head as it says on the pinout page?

[jsmcortina]

The CMP- and CKP- inputs on the MS3-Pro should not be connected to anything.

The ground pin on each sensor should be connected to Sensor Ground as shown in the diagram.
Pin 16 on the white connector must be grounded as shown in the diagram.
Pin 17 on the white connector is part of the RS232 serial connection.

James

[Bolt-on]

I will do that. Thanks!

[Bolt-on]

I connected CMP- and CKP- to white connector pin 18 (sensor ground), and ran a ground from the pin 16 (logic ground) wire to the cylinder head, then found an intermittent connection at the crank position connector. I had spliced in a pigtail connector with a bad crimp. Soldered that and it has an rpm signal now. It fired a few times but didn't start.

I made a timing pointer and a positive stop, and made a TDC mark on the lower pulley. Cylinder 1 is firing about 13 degrees before BOTTOM dead center. Made me realize that I didn't check the coil sequence when I re-used the factory sub-harnesses for the coils. I'll check that tomorrow. And my timing light inductive pickup only gets a signal when the arrow that is supposed to be pointing toward the plug is pointing away from it. ?

[Matt Cramer]

Do not ground CKP- and CMP-. They need to be left floating.

[Bolt-on]

I connected the ground leads from the sensors to pin 18 as shown in the setup diagram, but left the CKP- and CMP- leads from the MS3 floating. Hope that's right.

I had to mount the coils under the heads because of the turbos. When I did, I flipped the coil sub-harnesses. Today I re-pinned the connectors to correct for that. Then I found I had entered 80 lb injectors as 80cc injectors, so that and the fuel req were way off. I fixed that and it started right up: https://youtu.be/bSkYkVF6peM

Unfortunately, it has a very fast idle. It started at just under 2000 rpm and moved to just under 3000 rpm as it warmed up. It also tends to flood and be hard to re-start. I tried blocking the IAC port and the idle dropped to stall depending how much was blocked. I removed the IAC and checked to see that it was moving when the MS3 was powered, which it was. On power-up it goes in and out a bit then goes out and stops. I had a spare IAC so I tried that, but it made no difference. I haven't connected the alternator electric leads yet so there is no load there, but that doesn't seem like it would be enough to slow it down 2000 rpm. I attached a data log and the tune. Any ideas?

[billr]

Increase the IAC "homing" steps, I use 500. You want more than enough to stall the IAC stepper for establishing home. Then go to the test mode in TS and see how the idle responds to various "run" settings. You may find you have the motor running/homing backwards. If you prefer to do some testing with the engine not running, then remove the IAC valve, leaving it connected to the harness, an play with it in test mode and simply watch to see ho the pintle is moving. Be sure to restrain the pintle from going too far out if "homing closed", use a some tape wrapped around the end of the pintle.

[Bolt-on]

Thanks! I'll go try that. I didn't know there was a test mode.

Is homing the motion the IAC does when MS is powered up? Is stalling what it does when it stops? The IAC goes full open on power-up, wiggles, then closes about half way and stops. If I am understanding correctly, how do I reverse it if it is homing open and should be homing closed? Reverse the terminals? I have the throttle body off, so I may as well leave the IAC in the throttle body as a stop. I think I can look into the opening and see it moving.

[Bolt-on]

I checked the IAC in test mode. It is homing open when set to homing direction close, and closed when set to open. How do I change that?

The IAC resistance between the center pins is infinite. It's connected as follows:
IAC pin to MS3 gray:
A to 31
B to 30
C to 33
D to 32

The connector terminals release to the front, so would have to be cut off to re-pin.

How is the idle target determined? There is a run position setting in test mode, but I haven't found a way to set idle or set a run position for the IAC anywhere else.

[billr]

Reverse the wires to just one IAC motor coil, that will reverse motor direction.

[Bolt-on]

I reversed two of the wires. That did it. Thanks!

It's funny, it starts and idles well if it homes open, but not if it homes closed. I still wonder where the idle target is set.

[billr]

Increase the "cranking idle steps". If it then fires OK, but soon dies, then increase the "warm-up idle steps" too. The last I saw, your MSQ was set for open-loop idle, so that "warm-up idle" table is your main (only?) idle target.

[Bolt-on]

The Riviera been starting and running well. I have an acceptable rough tune, and have driven it about 150 miles checking things out and breaking in the engine.

Recently Tunerstudio on my Windows 8 laptop started to disconnect erratically, and now won't connect at all. I'm using Shadow Dash with a Bluetooth serial adapter, and it works fine.

I tried switching usb cables, and I tried another computer with Windows 10. The computer and cable will connect to a couple of other Megasquirt ECU's I'm working on, but not to the MS3 Pro. I tried to see if the Windows 10 laptop would connect with Bluetooth, but it couldn't see the adapter.

I haven't spent much time on this yet, but I'm looking for ideas.

[jsmcortina]

The Riviera been starting and running well. I have an acceptable rough tune, and have driven it about 150 miles checking things out and breaking in the engine.

Good!

Recently Tunerstudio on my Windows 8 laptop started to disconnect erratically, and now won't connect at all. I'm using Shadow Dash with a Bluetooth serial adapter, and it works fine.

It may be best to post these specific questions in a new topic in the TunerStudio sub-forum.

James

[Bolt-on]

I did a port test and tried again and it connected. If it happens again I'll move the thread.