Hard to Start with Engine Kick back MSPNP2 NS8994 Ka24de

[nkldme]

Hard to Start with Engine Kick back MSPNP2 NS8994 Ka24de

I have been waiting a long time to write this because I wanted to exhaust all options of attempting to resolve this issue myself before I ask for help though I’ve slammed into a hypothetical wall. I’ve searched and searched again the forums, attempted some of the users suggestions to alter some setting and have been through the MS manual several times.


My MegaSquirt vehicle is a 1971 Datsun 510 Wagon with a 1991 Nissan 240sx S13 Ka24de engine and transmission. I’ve owned it for many years now and had it running flawlessly on all of the stock OEM hardware and decided it was time to complicate things by adding a turbocharger.

The first approach to this project was to buy a standalone ECM and learn how to program it before I even start to rip anything else apart. Quiet a bit to bite off I must say but I’ve done very well over the last 6 months. I'm down to a few little tweaks and one larger problem.

MY PROBLEM is while cranking to start, I am experiencing a long crank time 5-8seconds with the engine stumbling trying to catch no matter what the coolant temperature is. Sometimes I’ll experience a very hard kick back that will cause the engine to spin backwards and significantly drop voltage. This issue can be catastrophic and I need to resolve it immediately.


There has been a consistent theme of recommendation to adjust the Cranking PW. I have done this by increasing and decreasing by 10% and have had no luck. I have also tested a few times having the throttle all of the way open and this won’t even let the engine start which points to, to much Craning PW. I also have checked all engine grounds and sensor calibrations. There is more that I have tested but I think this may be enough to say for now.

Any help would be much appreciated.

[Matt Cramer]

Starter kickback is a timing issue, and Nissans are especially prone to this because they use a long time delay between the pulse from the distributor and the coil firing. If the engine slows down too much in that area, the spark will fire too soon.

The first way to deal with this is to try backing off the cranking timing. If that doesn't work, try our replacement trigger disc; this improves the timing accuracy.

[nkldme]

Starter kickback is a timing issue, and Nissans are especially prone to this because they use a long time delay between the pulse from the distributor and the coil firing. If the engine slows down too much in that area, the spark will fire too soon.

The first way to deal with this is to try backing off the cranking timing. If that doesn't work, try our replacement trigger disc; this improves the timing accuracy.

Hi Matt,

Thank you for the suggestion. I will look into adjusting the Crank Timing shortly. Where within Tuner Studio can I find this setting?

On another note, I did purchase the optical trigger wheel from DIY a couple of months ago and never could get the car running. I did change the perimeters in Tuner Studio as the instruction say and I even doubted my installation of the wheel being upside down. With all of these areas triple checked and I still couldn’t get it to run. I pulled the DIY trigger wheel out and installed the OEM one and the engine starts. So I’ve abandoned the DIY trigger wheel for now.

[Matt Cramer]

Let me know what firmware you're running and I will go over where this setting is located.

[nkldme]

Let me know what firmware you're running and I will go over where this setting is located.

Hi Matt,

Here is what I'm using:

MSPNP2-NS8994
Apple software - TunerStudio MS v2.6.04
Apple software - MegaLogViewer HD v3.4.11

Thanks,

Brandon

[BigLou240sx]

Those two are program versions... Matt is asking for what firmware is loaded on your megasquirt. If connected to your megasquirt, the firmware version will be shown on the top of the screen

Although, if you've had a look around the ignition settings while trying to get the DIY trigger disk setup, you've likely been on the same window as the cranking advance. You may be able to find that setting if you open up some of the ignition option windows (if you don't want to wait to report your firmware version and have Matt respond).

on the stock nissan disk, I'm using a cranking advance of 5 degrees so that the chance of kick back is reduced.

[nkldme]

Those two are program versions... Matt is asking for what firmware is loaded on your megasquirt. If connected to your megasquirt, the firmware version will be shown on the top of the screen

Although, if you've had a look around the ignition settings while trying to get the DIY trigger disk setup, you've likely been on the same window as the cranking advance. You may be able to find that setting if you open up some of the ignition option windows (if you don't want to wait to report your firmware version and have Matt respond).

on the stock nissan disk, I'm using a cranking advance of 5 degrees so that the chance of kick back is reduced.

Thank you for the response,

I’ve attached a photo showing the window you’re describing used to change the trigger wheel. And there is the cranking advance. I found a slight change in kick back reduction when lowering the cranking advance to 9.0°, though the issue is still present. I’ve lowered the cranking advance to 5.0° as well but did not experience anything beneficial. I also increased the cranking advance to 12.0° and the engine wouldn’t even start.

Also what I did today, is I data logged about 1 hour worth of data to analyze in MLV while running a tune I have had better success with starting. The only value/s that are different is the VE table. Everything else is setup identically. After analyzing the data in MLV and loading this new tune into my MSPNP the engine is starting a WHOLE HELL OF A LOT BETTER. MLV changed values significantly in the 700 & 1000rpm range from 19.0 - 100kpa. Why would these values drastically change the way the engine starts if I am still using the ‘cranking’ program at that time? Is there anything else that I can change to further adjust the way the engine starts?

Thanks,

Brandon

[LAV1000]

Start reading om WUE, warm up enrichment.
Cold engine has different needs than a warm one.
You also have be sure about injector specs.
Best way is to measure the flow and deadtime.

[BigLou240sx]

In your screenshot, if you were connected to your megasquirt and "online", the firmware version would be shown where "go online for firmware version" is displayed.

Have you confirmed delivered spark advance versus commanded by using a strobe light to make sure they match? I use a significantly different trigger disk angle... (not saying yours should match mine exactly, but we're pretty far away from each other. Perhaps a difference between sohc/dohc engines though)

Also, what is your cranking rpm threshold?

ETA: reason I'm asking about your trigger offset settings is if your delivered timing is advanced of your commanded/expected timing, then your 10 degrees cranking advance could be much more advanced in real life leading to the difficulty starting and kickback.

[jsmcortina]

The firmware version is the important part.

James

[nkldme]

Hello everyone,

I first would like to show my appreciation to everyone that has provided inputs/suggestions regarding my issues. It is nice to be apart of a community that actually has people that are willing to help and provide opinions.

Second, I have solved all of my issues and want to share them with you. While I have remained stagnate on my response here I have been very busy working on my vehicle. I had my Tune combed over by Works at Sears Point and then Dyno’d for load tuning and then a few performance pulls. Basically most of my settings/tune were very close thanks to all of the information here on the forums to help teach me. The only portion of the tune that was pretty out of whack was my VE table. Works tuned it off and on the dyno to put it where it should be. In the end, the power my engine made was exactly where I estimated it to be at the rear wheels (140ft lbs of torque@ 4343rpm & 130hp @ 5288rpm).

After the professional tune from Works I decided to once again tackle the installation of the DIY trigger wheel knowing my tune was solid. After proper installation I again experienced the same issues I had before when the DIY trigger wheel was installed. I couldn’t get the engine to run and stay running at all. All of the settings in TunerStudio are spot on and correct. I then decided to check where my spark timing actually sits on TDC and found the distributer off by one ‘tooth’ and has been this way the whole time. Even though on the OEM trigger wheel I was able to compensate for this by manually adjusting the distributor but when the DIY trigger wheel is installed the timing marks don’t even register with the timing light. Physically removing the distributer and moving it to the correct ‘tooth’ position made all of the difference in the world and from there I was able to set my timing.

In your screenshot, if you were connected to your megasquirt and "online", the firmware version would be shown where "go online for firmware version" is displayed.

Have you confirmed delivered spark advance versus commanded by using a strobe light to make sure they match? I use a significantly different trigger disk angle... (not saying yours should match mine exactly, but we're pretty far away from each other. Perhaps a difference between sohc/dohc engines though)

Also, what is your cranking rpm threshold?

ETA: reason I'm asking about your trigger offset settings is if your delivered timing is advanced of your commanded/expected timing, then your 10 degrees cranking advance could be much more advanced in real life leading to the difficulty starting and kickback.

Third, With the new DIY trigger wheel installed and the programming/timing set I tested different degree reduction on the cranking advance and found when the cranking advance is set to 0 degrees there is no more “Hard to Start with Engine Kick back” at all and starts every time smooth as butter within 2-3 seconds.

Starter kickback is a timing issue, and Nissans are especially prone to this because they use a long time delay between the pulse from the distributor and the coil firing. If the engine slows down too much in that area, the spark will fire too soon.

The first way to deal with this is to try backing off the cranking timing. If that doesn't work, try our replacement trigger disc; this improves the timing accuracy.

[/quote]
So once again, thank you everyone for your help. I truly appreciate it.

Brandon