Infamous Northstar: Crank but lost sync

[ardillo lamboman]

Megasquirters,

Finally tested all my sensors, got the flexplate and starter installed. In the process testing correct RPM, fuel pump and injectors disconnected.

Tried set up as suggested by six_shooter http://www.msextra.com/forums/viewtopic.php?t=65459

while Cranking...."RPM Sync" after 2 or 3 seconds "Not Sync", Lost Sync Counter increase to 1, even when I continue cranking
Check the logger, Sync lost Reason = 0, SO WEIRD!!!!!
RPM = 154
No spark going to the plugs
give several shots, same results.


Change the configuration to toothed wheel, dual wheel

while Cranking...."RPM Sync" after 2 or 3 seconds "Not Sync", Lost Sync Counter increase to 1,
Check the logger, Sync lost Reason = 11,
RPM = 200
No spark going to the plugs

According to the manual, sync lost count = 11 is " few teeth before next trigger"

followed the recommendation on the manual, play around, making all possible combinations with Ignition Input Capture and "Second Trigger Active On"

Same results...


can you guys shed some light

[billr]

[ardillo lamboman]

Thanks billr for the recommendation....you are right!!!


Here are the files
check the .msq file and the datalog file

[ardillo lamboman]

Guys,

Put some information together

Based on internet search crank and cam position sensors on northstar are two wire, they produce a AC signal, signal will increase amplitude and frequency with engine speed. Max amplitude (voltage) will be 2 volts.

I'm getting around 0.985 volts when cranking in each sensor and 65-70 Hz on CKP's, CMP do not register frequency; since CMP is triggered every to crank shaft rotations the generated frequency <1 HZ....make sense to me.

Based on the signals generated by the CKP's and CMP sensors, the ICM generates other sets of signals that I hooked up to MS3-Pro

Scenario 1: Ignition On, No crank
4X = 5 volts, 0 Hz
Bypass = 0 volts /0 Hz
Ignition Control = 0 volts/0 Hz
1/2 x = 0 volts/ 0 Hz
24X = 5 Volts/ 0 Hz

Scenario 2: Ignition On, cranking
4X = 5 volts, 0 Hz
Bypass = 0 volts /0 Hz
Ignition Control = 0.56 volts/0 Hz
1/2 x = 0 volts/ 0 Hz
24X = 5 Volts/ 0 Hz

Scenario 1 appears to be good according to Ignition control Module Signal description table courtesy of http://lukeskaff.com/projects/car/cadil ... m-project/

Scenario 2 looks bad, nothing match the table referenced above.

The ICM was removed from a working northstar....but just in case Murphy is around, took the ICM to Auto Zone for testing....they told me is performing like new.

Ru n out of bullets and I still have the "lost RPM sync" condition.

Check MSQ file and MSL file on previous post

[Six_Shooter]

Back to basics, how do you have the N* ICM connected to the ECU, and what internal modifications do you have?

[ardillo lamboman]

Six_shooter

Ok....I hooked it up like image in section 2.3 on the link below. No internal modifications on the ICM...straight out of factory

http://lukeskaff.com/projects/car/cadil ... m-project/

CKP-A, CKP-B and CMP are connected as factory to the ICM.

B+ (12VDC) is shared between the ICM and MS3-Pro
ground reference is also shared.

from ICM to MS3-Pro
4X signal goes to CKP(+)
1/2X Signal goes to CMP (+)
Bypass goes to Spark out B
Ignition Control goes to Spark out A
24 x Signal not used
CKP (-) and CMP (-) goes to ground reference

Results so far while cranking:
are explained in the previous post
but would like to mention, that RPM (don't know if is correct)is measured by MS3-Pro for a short period (about 3 seconds) , then "RPM sync lost" code 11.

While cranking tried to measure the #X signals at the ICM, I get constant 4.987 VDC in both 4X and in 24X (I know 24X is not connected, but just to check)
1/2X = 0 VDC


Bypass & ignition control are also 0, this supposed to happens until MS3-Pro syncs RPM and take over the ICM, then continuous 5 VDC should be registered

The ICM was tested at local parts store and is working good.

[Six_Shooter]

Ok, I'm going through some of this, I downloaded your msq, and right away there's a huge issue.

Why are you using the "Buick C3I" setting?

This should be "GM Bypass on SpkB"... Which should be connected to the bypass pin on the N* ICM... Which is sounds like you are.

Ignition control being on SpkA should be fine, though you might want to try switching that over to the Tacho output since it is a stronger output, you can then use one of the spark outputs for driving a tach, which is how I set up a friend's MS3Pro, but the ignition system was a little different and was recommended to use the higher current capable tacho output because of his MSD box. I only mention that because having a higher current capable output used for this won't hurt anything, and might solve other issues, if they are there. This will only become a factor after you get the engine running.

The 4x and cam signals look to be connected where they need to be.

Correct the MSQ and try again.

You can also disconnect the bypass wire from the module to take ECU based timing control out of the picture for testing purposes, which just means the engine will run on base timing, and not have to factor in any ECU controlled timing variables. Another way to diable the bypass, at least on the MS2 and MS3(X) is to set the GM HEI/GMDIS... etc option to "off". This should disable SpkB from allowing 5V to be present on the bypass line, verify with a DMM, like I said I haven't used the Pro with HEI type ignition (Which the N* ICM is very much based on as far as signals go), but this is what works with the other versions.

[ardillo lamboman]

Six_shooter,

I tried your recommedations....I think the ICM is not working correctly (even when I took it to auto zone for testing)

The crank and cam signals, I can register them, so if the ICM is good, I should see the 4x and 1/2X signals too.


Buick C3I setting should work for me when doing SFI, the difference between Buick C3I and GM bypass is the cam signal reference which is for SFI.

I will get the ICM to a different store for testing, to double check.

Thanks for all your help.

[Six_Shooter]

To start with the Buick C3I setting is incorrect for your application, even for SFI. It may work, but why force incorrect settings? The Cam signal is irrelevant when it comes to the IGNITION setting. The cam signal will still be broadcast and read when using the proper settings (which you will get to later, since you should be trying batch fire right now anyway), which will likely be dual wheel in the end. I'm going to be playing with this on my own HEI based ignition with SFI setup. The Buick C3I has some peculiarities to itself and is why I say it's not correct for your use.

Keep it simple to get it running, then add in complexity when you at least can have the engine run.

Do you have spark at the plugs when cranking?

It sounds like you're getting an RPM signal to the ECU, so the output should be fine along with the sensors.

This is ON a bonefied Northstar, right, not a retrofit to some other engine?

I'd be really surprised if any parts stores can truely test the Northstar ICM, due to it's unique signals required. I'm not sure if the testing machines for ICMs even have a mode for that. That being said I've seen modules that "passed" that were bad.

[ardillo lamboman]

Six_shooter,

No spark on the plugs

Yes it is a 95' northstar

Well...that probably my situation that the ICM is bad (all the troubleshooting I'm being doing is telling me that), so I went to a local junk yard and pull an ICM, lets see how it goes whit this "new" ICM

[ardillo lamboman]

Both ICM's are behaving the same...

but I notice now in the logger that "RPM sync lost" is giving me error code = 0 instead of 11

Tried several times same error code.

Is this code 0 generated if MS register no engine running after a few seconds????

attached msl files...note how the RPM's are way different on the 3 files

[Six_Shooter]

Well, from your datalogs I can see you have one major problem, and that is battery voltage while cranking, it's dropping far too much. It should stay above 9V while cranking, any lower and the ECU will not be able to work correctly, nor will the ICM. This is likely why you have no spark.

You also have unrealistic RPM readings, which again is likely due to the voltage dropping so much.

I'd stop looking at anything else right now and figure out why the voltage is dropping so much. Old/worn out batteries can do this, a poor connection, improper grounds, ol/worn out starters (I know, the N* starter is in a dick of a spot to get to...) are other causes.

Figure this out before going any farther with worrying about the MS or MS setup.

[ardillo lamboman]

Six_shooter

I was not monitoring voltage...geeeezzzz I missed that one!!!!

Definitely there is room for improvement on my temporary connection.


Since I still need to test timing, I have the fuel pump disconnected, but what I should expect after the voltage issue is fixed?

maybe spark
what about the "RPM Synced" should be green all the time until I stop cranking?

[Six_Shooter]

Fix the voltage issue first and you should see a lot of everything improve. Get that under control, and then move on, don't worry about anything else until that's fixed.

[ardillo lamboman]

Fix the voltage issue first and you should see a lot of everything improve. Get that under control, and then move on, don't worry about anything else until that's fixed.

I fixed the voltage issue, got a solid battery, but I still in the same boat
Check the attached msl file

"RPM Synced" never turns green.
I still have the CKP's and CMP readings, no spark.

I would like to keep the ignition system "stock" but if out there is something more realiable and easy to use and install,would like to try

Let me know

[Six_Shooter]

You should have spark even without the ECM in the car.

Try disconnecting the bypass wire (tan/black) This will force the ICM to run in base timing mode, and takes any influence from the ECM out of the equation.

You also have no RPM shown in that log. I assume you tried cranking when the voltage drops to 11.2/11.3 volts?

So you have two things to figure out now, get spark, like I said you should have spark with the ECM not even connected to the car, and you have no RPM signal into the ECU, if I'm assuming correctly that you tried cranking during the log you just posted.

[ardillo lamboman]

You should have spark even without the ECM in the car.

Try disconnecting the bypass wire (tan/black) This will force the ICM to run in base timing mode, and takes any influence from the ECM out of the equation.

You also have no RPM shown in that log. I assume you tried cranking when the voltage drops to 11.2/11.3 volts?

So you have two things to figure out now, get spark, like I said you should have spark with the ECM not even connected to the car, and you have no RPM signal into the ECU, if I'm assuming correctly that you tried cranking during the log you just posted.

Six_shooter

I disconnected the bypass and ignition control from the ICM just to take MS out of the equation.
Yes I was cranking when the voltage goes down to around 11.2 V

I'm waiting now for an oscilloscope, I'll check the signal coming from the crank and cam sensors.

I know the Northstar crank and cam sensors are VR type so they will generate an AC signal, as far as I understand in this case it doesn't matter the polarity for this sensors....I'm right??? if so that could be my issue

[elutionsdesign]

Polarity matters, yes.

[ardillo lamboman]

Now I know it the hard way....good lord almost a week I wasted testing some other stuff

I change the polarity in the bottom crank sensor, I got Spark and MS is registering "RPM synced"

Thanks elutionsdesign and six_shooter for your help.

Now that RPM is steady, got spark...it is time to check for timing, then try to run the engine