I’m Stumped Microsquirt LS Guidance Needed

Let me tell you a story.

Two months ago before my wife and I had a family expansion I decided to knock a ringland out of the second 4.8 this summer. 

So I did what any cheap enthusiast would do, I took a good piston out of one motor and slapped it in motor number two.

Upon installation of motor number two my battery was dead and I did a bad thing. I tried to jump start my truck using the boost function on my tiny battery charger and fried the 5v circuit in my microsquirt. Sent it back to efi source and they fixed it up for me and shipped it back to me.

Now that the trucks all back together I can't get it to idle or run well. If I hold it at 5-10% throttle it will run, its pig rich pegging the wideband at 10:1. 

I know the truck isn't firing on all cylinders . I have checked the coils, they are all firing. Hodgepodge motor has compression.  All sensor reading look fine with the only thing altering fuel is warm up enrichment.

I smoke tested the intake tonight, no leaks. I ensured efi source hadn't loaded another base tune , and they did not.

I'm at a loss for what to check next. 

Plug your laptop into it and access every available map you can with TunerStudio.

I made this video a while back after I fried EvanB's MSPnP in his Miata, and had to send it in to DIYAutotune to be repaired.

Notice how it runs like crap?  That is why the video ends where it does.   After a lot of screwing around trying to figure out why it was not working right (I forget if it was not firing the injectors, or double-firing them, or what) I finally went in to the computer with TunerStudio to see WTF was going on in there, just for datalogging.  The maps themselves weren't corrupted but somehow there was weird things going on with the MS not registering RPM correctly or something.  And every time I'd open a different table, things would look wrong, then sort of hiccup and look right.

I have no idea what happened, but somehow repairing the board made things go sideways for a bit, and like Wile E. Coyote not falling until he looks down and realizes he's walked off a cliff, the MS didn't work right until I looked at all the maps and verified that they were correct.

Two days later, no retuning

In reply to Knurled. :

Will try that, I've had the fuel map open but not sure if I have opened the timing map yet. 
Either way it's an easy box to tick off so I'll do it.

Connect and check all the sensor readings. Use test mode to verify spark and injector outputs. If that all looks good, reflash the firmware and reload last known good tune. 

In reply to Paul_VR6 :

All sensor reading look normal. Nothing out of whack.

My spark tester shows fire at each coil and my wires are quite new. I have power at injectors which seems to be confirmed by my running pig rich.

I will try re loading the firmware this afternoon. I tried going to a saved tune from 2 months ago and that made no change.

Can you plug a spare injector in and use test mode to see if they are stuck open? The inj should have 12v on the power side but be floating on the control side unless commanded to open. 

In reply to Paul_VR6 :

I had the intake off to check for leaks and when I cycled the motor before re installing the intake I forgot to remove the injector fuses...they are pulsing. 
Also my injectors use a ford style uscar plug. They are the only ones I owned like that 

In reply to Paul_VR6 :

I think you hit the nail on the head Paul, I loaded up the firmware and went back to a sloppy base tune and despite it running rich it seems to be running alright.

Thanks for the help!

For all the others, I hope to have the truck out for a test drive in the next couple days weather permitting.

Verify injector impedance is NOT low.

Verify Sensor ground has no continuity to ground with the MS unplugged < see 3.2 of TFM

Verify there are no 12v devices using Sensor ground (Example - Innovate O2 controller must not use sensor ground)

Ground coils to the motor with a short path.

Do not use a USB cable to connect to the MS. No USB cable is best.  https://www.diyautotune.com/product/usb-to-serial-adapter-works-with-tunerstudio/

DO NOT over-dwell LS coils some will dump early if they get "too full" Bad JuJu.

Do not run it under load if you are seeing any sync loss or resets. < zero tolerance

Keep us posted. 

Whelp, false hope after the new firmware.

https://youtu.be/1ckh1GMZOvI

bentwrench I'll check the sensor ground next, but nothing has changed as far as ground locations go from the last set up that ran fine.

coils are grounded to the head for each bank.

I have tried my old tune and the sloppy mechanics base tune. Motor runs like Poop on both. 

Have you re-calibrated your sensors under the tools drop down.

Looking at your video the motor has too much cam or not enough spark timing.

You can't tune speed density with a poor vacuum signal (80kpa at 1000 rpm is not going to do).

AFR of 10:1 is dead rich and probably smoking like a diesel (not helping)

If you can't get the vacuum higher (lower kpa) you should consider changing to AlphaN fuel control. (or a blended setup).

Tune it, don't just throw some canned tune at it and expect it to fly, that is just to get you started. And that is often counter productive as you are blindly accepting settings for a different install. You did not choose the settings so you don't have any clue why it doesn't work. A Sloppy tune is not bad it just won't likely match your setup. 

First off you need to verify spark timing and fuel pressure, then before you can tune you need to get the motor hot enough to open the thermostat. Then you setup the hot idle first, all modes of operation use the hot idle settings as a base. Here is a tutorial I wrote for setting up idle.

***************************

Do your required fuel calculation, this is a one time setting, not a tuning parameter (any changes here will necessitate a complete retune).

Always start tuning with the hot idle, get the motor good and hot. Thermostat must be open.

Don’t mess with any of the starting or warm up settings until you have established a hot idle. (defaults will get you going)

Make sure you are out of any trim areas WUE ASE etc. 

Remember WUE should end at 100% just before or very near the thermostat set point (you can fine tune this later)

You should not be using any of trims for hot idle, and you cant tune a cold motor,

You first tune a hot motor and then adjust the trims to make it happy when cold.

Set your Idle manually high 1500-2000 rpm and adjust VE to keep it running clean and build heat.

Now is a good time to verify spark timing, don’t try to do any tuning without first verifying spark timing.

If you can’t get the spark timing dialed in STOP and get this sorted first before moving forward.

No sync loss or misfires are tolerable.

To tune idle first disable closed loop idle control. Set idle speed manually

Disable O2 correction, & always tune on a fully warmed motor.

Add 1 or 2 degrees in the spark table below your target idle speed.

(this will help the motor recover from a sag, especially automatic trans, AC, fans, power steering)

Check that WUE ends at no less than 100% and at a temp slightly lower than thermostat opening. (100% is no change to the fuel calculation)

Make all the cells used for normal idle (a square of 9 cells) in the lower left of your VE table the same number.

Start the motor and adjust the throttle stop so the motor will run steady 700 - 900 rpm.

Then highlight all the cells in the lower left corner, and use the up or down function to change them all. 

Adjust to make the motor happy not shooting for a specific AFR.

(many try to set at 14.7, few if any motors will idle there without sequential injection)

You want the smallest number that provides a smooth stable idle (lean best)

Note the AFRs in that area and change your AFR table to that number so Auto Tune does not change them back.

(I lock out those cells when using Auto Tune, highlight and right click and select lock)

Another reason to adjust the AFR table in the idle area is O2 correction will try to steer AFRs in that direction

Then you can make final adjustments to the individual cells in the idle area to fine tune.

Always make final tuning adjustments on a fully warmed up motor (thermostat open).

Then if auto put trans in gear and fine tune again (different cells) blend/interpolate adjoining cells as needed.

Now you can enable closed loop idle and return the throttle stop to just barely open.

I set the throttle stop to just barely open because gack from the PCV will collect around the blade opening and close it up over time.

Not closed so far it sticks (if using closed loop idle).

Most all of the other adjustments use the hot motor settings as a base and modify them for different conditions. 

Now once a day you have the chance to make observations for altering WUE settings.

Also cranking squirts and ASE

In reply to bentwrench :

I wonder if the map sensor is reading wrong.  A MAP reading really high would pull timing and be pouring fuel down the engine.  (Like using a 1 bar MAP and the MS is assuming a 2.5 bar? But you would see that KOEO, the MAP would be readng something other than 95-99KPa.)

Alternatively, if the camshaft is off a tooth or two, that will cause the same symptoms of low manifold vacuum, which will be hell on a speed density tune.

You can, however, tune an engine that idles at a real 80kpa on speed density.  BTDT.   One of my engines idled at around 85-90kpa and I never had much issue.

Many in an effort to get started the easy way throw tunes at a problem and don't check the basics or take the time to learn the system.

That is why I recommended to check sensor calibration and verify spark timing first (make no assumptions).

Also I would at this point avoid exotic plugs and absolutely do not use non-resistor plugs. You can put the high dollar plugs back in later and see if they do anything. I would not use a platinum plug either as detonation will blow the platinum off and it does not give a performance advantage, the platinum is there only to slow down erosion of the electrodes.

A fouled plug (or rich missfire) will show lean on the AFR when there is actually unburned fuel in the exhaust, the O2 sensor does not measure fuel it is a calculation based on lambda.

Speed density relies on manifold pressure to calculate fueling ~100kpa is no vacuum (and what should be seen with the motor of key on). A change to only 80kpa at idle allows only 20kpa of granularity from idle to WFO! That is NOT enough to properly calculate fueling for normal driving. It might "work" in the internet sense, but even if you drove with an on off throttle it will have gaps (huge gaps). That is why AlphaN tuning was created, fuel calculation is based on throttle opening rather than manifold pressure and you will then get a much better representation of motor loading. MS Extra also provides ways to blend AlphaN and SD to get the best of both worlds. 

My first objective would be to get more idle vacuum, more spark timing (20-25°) and get the AFR better than a 10:1. The motor will be much happier. For a streetable application you may be best off to use a milder cam especially if you have boost. Boost does not like high overlap cams. A long duration cam will need more static compression to run well at low speeds. EFI is not a power adder nor will it enable you to bandaid a poor combination of parts and make them "work".

Read the setup manual front to back, and then re read anything you don't understand.

Then sit down and go through all of the steps on your HOT running motor and you will sort it out.

Idling at 80kpa doesn't mean driving in an 80-100kpa window.  My engines that had crap for idle vacuum at 1200 would still pull 50-55kpa under cruise, like anything else.

bentwrench said:

Many in an effort to get started the easy way throw tunes at a problem and don't check the basics or take the time to learn the system.

yeah I tried that.

That is why I recommended to check sensor calibration and verify spark timing first (make no assumptions).

I ran this same block and did not touch the cam so timing should not have been changed.

Also I would at this point avoid exotic plugs and absolutely do not use non-resistor plugs. You can put the high dollar plugs back in later and see if they do anything. I would not use a platinum plug either as detonation will blow the platinum off and it does not give a performance advantage, the platinum is there only to slow down erosion of the electrodes.

I am running basic ngk tr6. 

A fouled plug (or rich missfire) will show lean on the AFR when there is actually unburned fuel in the exhaust, the O2 sensor does not measure fuel it is a calculation based on lambda.

The plugs were replaced with a new gapped set. No change.

Speed density relies on manifold pressure to calculate fueling ~100kpa is no vacuum (and what should be seen with the motor of key on). A change to only 80kpa at idle allows only 20kpa of granularity from idle to WFO! That is NOT enough to properly calculate fueling for normal driving. It might "work" in the internet sense, but even if you drove with an on off throttle it will have gaps (huge gaps).

 

motor on same tune usually idles at 10 inches of vacuum. This one will stall when I let off. But as stated above I smoke tested the intake and found no leaks. Map is a gm 2 bar and is reading correctly.
 

That is why AlphaN tuning was created, fuel calculation is based on throttle opening rather than manifold pressure and you will then get a much better representation of motor loading. MS Extra also provides ways to blend AlphaN and SD to get the best of both worlds. 

My first objective would be to get more idle vacuum, more spark timing (20-25°) and get the AFR better than a 10:1. The motor will be much happier. For a streetable application you may be best off to use a milder cam especially if you have boost. Boost does not like high overlap cams. A long duration cam will need more static compression to run well at low speeds. EFI is not a power adder nor will it enable you to bandaid a poor combination of parts and make them "work".

This is stock cam motor, it ran flawlessly all summer on this exact set up. That's why I'm so confused.

 

Read the setup manual front to back, and then re read anything you don't understand.

Then sit down and go through all of the steps on your HOT running motor and you will sort it out.

In short I'm no expert but I feel I've checked the basics. I will check the sensor ground as noted earlier.

Well in the video it sounds like it has a rock and roll cam.

If not then you need to look at ignition and injectors.

If you cannot get it to run better by leaning it some the problem is probably not inside the MS.

Firing order, bad coils or wiring, dead or half dead injectors or triggering, fuel pressure, etc.

Verify spark timing with a light?

The sync loss show in the vid may just be from a rough start, if the sync loss count increases while running you have a triggering issue.

Key on engine off map reads near 100kpa (or lower at altitude)?

In reply to Paul_VR6 :

It sits right on the 100kpa cell on the fuel and spark map.

Can you host/link tune and a recent log? Or email to kandpperformance at gmail dot com

you sure the injectors arent on all the time (driver failure)?

Paul_VR6 said:

Can you host/link tune and a recent log? Or email to kandpperformance at gmail dot com

I'll see if I can sneak out to the garage tomorrow and fire it long enough to get a log.

you sure the injectors arent on all the time (driver failure)?

On second thought I'll grab 8 empty water bottles and pull the fuel rails and check.

Then re-assemble then log. 

Its a bit odd to go from working ok to disaster mode. Even just a log of key on to do a quick sensor check is helpful. 

In reply to Paul_VR6 :

Just emailed you a key on log and a short one of it running.

Also confirmed that injectors are pulsing and not static open.

Got your email will check it tomorow once you send the msq too. 

Don't look at the VE map, look at the "gauges".  Make sure the MAP is reading right, the coolant temp and air temp are reading right.

I still think your rich running is a symptom, not a cause.