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Old 11-19-2008, 09:47 PM   #1
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Question Troubleshoot Jumpy RPMs - MSII

I've been attempting to troubleshoot my MSII running MS2-Extra code for a while now. After reading just about every thread mentioning RPM and/or MSII, I'm still stuck. I followed the B&G MSII with 3.0 build docs supplemented by the MS2-Extra 4g63 for the input/output circuits.

When connected to the Jimstim, I get what appears to be a constant oscillation between 0 and 1 RPM and sync/nosync. It was only tonight that I discovered something that gave me a glimmer of hope. Every so often a realistic number would flash onto the RPM gauge. This number appropriately changed as I twiddled the RPM pots on the Jimstim. I was able to capture this behavior in a datalog.

I've attached my .msq and datalog. I'm hoping someone can show me how to troubleshoot the input circuits beyond triple-checking the physical assembly and directions that I followed.

I'm attempting to run stand-alone.
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Old 11-19-2008, 09:58 PM   #2
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Post everything about your car, year, setup, mods, etc etc. More info the better. Have you tried it on the car yet?
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Old 11-19-2008, 10:10 PM   #3
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Quote:
Originally Posted by patsmx5 View Post
Post everything about your car, year, setup, mods, etc etc. More info the better. Have you tried it on the car yet?
Thought I had put that in my sig. Guess not.

'93 N/A, intake, header, exhaust, no CAT. GM IAT, Stock coolant sensor. JAW wideband O2. Bosch Wideband o2 sensor. 4g63 CAS.

Tried it on the car when I originally used DIY's miata instructions for a MSI. Just cranked, but in hindsight, I'd expect nothing more. Have not tried it since MS2-Extra 4g63 mods done. Wanted to get it working on Jimstim first. CLT and IAT gauges read good. O2 is not reading, but I think it's because I'm never above the RPM threshold.
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Old 11-20-2008, 11:24 AM   #4
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Default Some more info

MSExtra 2.0.1 code. MegaTune 225p4
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Old 11-20-2008, 03:59 PM   #5
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That sound like the problem I'm having!!!!

Does the 'Burn to ECU' window stay open once you've burnt it?

I've also got the two outer LED's on constantly and the Jim Stim only has the power LED on.

You get an interesting reaction on both Jim Stim and the Engine RPM if you alter the spark output to 'going low'!

I think there's something simple we're missing but I'm lost!

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Old 11-20-2008, 04:22 PM   #6
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Hmm. I looked through the msq and datalog. Didn't see anything obvious. What's a 4g63 CAS? Is that the regular miata CAS?

Funny, I had a similar problem with my MS2 in a regular stim. With the miata mods to read the factory sensors, I wouldn't get a reading. But if I sat there and "twiddled" the RPM pot, I would get random signals, just like you are showing.

Have you put this on the car and seen if it will get an RPM reading?
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Old 11-20-2008, 04:49 PM   #7
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Quote:
Originally Posted by patsmx5 View Post
Hmm. I looked through the msq and datalog. Didn't see anything obvious. What's a 4g63 CAS? Is that the regular miata CAS?

Funny, I had a similar problem with my MS2 in a regular stim. With the miata mods to read the factory sensors, I wouldn't get a reading. But if I sat there and "twiddled" the RPM pot, I would get random signals, just like you are showing.

Have you put this on the car and seen if it will get an RPM reading?
4g63 is the regular miata CAS. I do have the Jimstim set for the 4g63 wheel type and have the 2nd tach. input jumpered. I'll give it a shot on the car but won't have time to try until Fri. Evening.

A16BBR - I saw your thread as soon as I posted mine. I have the 2 outer lights and only the power LED on the Jimstim as well, but no issues with burning to the ECU other than MegaTune becoming unresponsive until the burn is complete.

If the mods want to merge the threads, that'd be fine with me.
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Old 11-21-2008, 03:18 AM   #8
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No probs merging either - the more replies the better!

I don't think we're alone here!!!

Rich
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Old 11-23-2008, 03:28 PM   #9
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I finally got a chance to try it out on the car today. Still the same RPM symptoms. The car did sputter a few times. The CPU also experienced resets on at least 4 occasions. I've attached the current .msq and datalog from the attempts.

I did read where Joe Perez suggested that the trigger angle may need to be modified to a number likely in the 60s or 70s. I started out at 10 as the MS2-Extra 4g63 manual shows, but then I tried 60, 65, 70, 79,and I think 62. There was no sputtering at 10. Low 60s seem to be the best, but without a steady RPM, I'm guessing it's just coincidence that fuel and spark came together a few times.
Attached Files
File Type: msq 2008-11-23 - First Start Attempt.msq (47.7 KB, 64 views)
File Type: xls 2008-11-23 - First start attempt.xls (416.9 KB, 56 views)
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Old 11-23-2008, 03:37 PM   #10
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Quote:
Originally Posted by mj71 View Post
I finally got a chance to try it out on the car today. Still the same RPM symptoms. The car did sputter a few times. The CPU also experienced resets on at least 4 occasions. I've attached the current .msq and datalog from the attempts.

I did read where Joe Perez suggested that the trigger angle may need to be modified to a number likely in the 60s or 70s. I started out at 10 as the MS2-Extra 4g63 manual shows, but then I tried 60, 65, 70, 79,and I think 62. There was no sputtering at 10. Low 60s seem to be the best, but without a steady RPM, I'm guessing it's just coincidence that fuel and spark came together a few times.
Go into megatune and click "basic settings" / "injector characteristics" Then enable bank two and make sure all the numbers match bank 1. Also dig through the megamanual and make sure those settings are correct for your fuel injectors (high or low ohm?)

Go into megatune and click "basic settings" / "rev limiter" and select "none"
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Old 11-23-2008, 04:29 PM   #11
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Done and done. I verified the injector settings as well. I put the Trigger Angle at 15 since that's where my car's currently timed. I know I physically have to move it back to 10 eventually.

It attempted to fire a few times with these new settings, but it was accompanied by an immediate CPU reset. Msq and logs attached.
Attached Files
File Type: msq 2008-11-23 - Second Start Attempt.msq (47.7 KB, 67 views)
File Type: xls 2008-11-23 - Second start attempt.xls (133.8 KB, 65 views)
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Old 11-24-2008, 02:06 AM   #12
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Quote:
Originally Posted by mj71 View Post
Done and done. I verified the injector settings as well. I put the Trigger Angle at 15 since that's where my car's currently timed. I know I physically have to move it back to 10 eventually.

It attempted to fire a few times with these new settings, but it was accompanied by an immediate CPU reset. Msq and logs attached.
I think the trigger angle is probably wrong. Not familiar with CAS's, but I read a lot of people run sixty something or so.

All those resets aren't right. I suspect something on the spark outputs is wrong. Specifically, I bet you have the transistors installed wrong. Every time it tries to fire, something shorts the +5V supply to ground, causing a reset. Then the CPU comes back on, reads the input circuits, tells it to spark, then it shorts the +5V to ground resetting the CPU, and the process repeats in a cycle. My uneducated guess. Anyways, take several large, clear, well focused pics of the MS board, as well as the spark output areas.
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Old 11-24-2008, 07:47 PM   #13
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I've attached pics of the front and back by quadrants. Wow. Magnified I see what a rookie I am at soldering.

[Edit: Pics removed for clarity]

Last edited by mj71; 11-29-2008 at 11:15 AM.
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Old 11-25-2008, 12:42 AM   #14
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One benefit I like about EDIS is its built in limp mode.
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Old 11-29-2008, 12:52 PM   #15
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I finally got some time last night to really check things out and I found a major issue. I had accidentally grounded the base instead of the emitter on the 2nd input circuit. Re-soldered to the correct pin and now it runs like a top on the Jimstim.

Fast-forward to this morning and testing it in the car. I now have a solid RPM cranking at about 275 RPM. I am still getting resets, which makes me believe that I have a short somewhere in the ignition circuit(s). I verified that the transistors are oriented correctly (flat side towards LEDs) and I'm pretty sure I don't have solder bridges between the pins.

I've attached the log of the last attempt.
Attached Files
File Type: xls 2008-11-29 - 5th start attempt.xls (445.9 KB, 58 views)
File Type: msq 2008-11-29 - 5th Start Attempt.msq (47.6 KB, 79 views)
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Old 11-29-2008, 01:07 PM   #16
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I got a funny feeling you got the sparkplug wires backwards. And every time it tries to crank the engine fires backwards. Try either:

1) switching the sparkplugs around. IE-put 1&4 on 2&3 and vice versa
or, 2) switch the plugs on the bottoms of the coil packs, effectively doing the same thing.

Are you getting any kind of fire, backfire, etc?
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Old 11-29-2008, 03:41 PM   #17
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Bingo! I swapped 1&4 onto the 2&3 coil and vice-versa. It now runs, but super lumpy, like maybe only one pair is firing. I attempted to change the trigger angle (started at 60) to 65, 69 maybe some other 60s value with no discernible change.

I didn't even attempt to push on the gas pedal. Datalog attached. .MSQ is the same as my previous post with the only change being the trigger angle and Req_fuel to 13.0.

Thanks!
Attached Files
File Type: xls 2008-11-29 - 6th start attempt.xls (230.5 KB, 49 views)
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Old 11-29-2008, 03:58 PM   #18
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First, remove and clean all the spark plugs. They're surely pretty wet/fouled right now. Preferably, put new plugs in and gap them at .020".

Your voltage is low. Only showing ~11.7 running. Something tells me the alternator isn't working right, OR, it's trying to charge a really dead battery. Anyways, if it's just really weak put a battery charger on it to build it back up. Probably low from cranking on it so much.

And your map signal is not working. Did you hook a vacuum line from the map sensor of the megasquirt to the intake manifold? If so, check it. It may have popped off from the previous backfires from having the sparkplug wires backwards.

Also on the next datalog hit the throttle a few times and see if the TPS is logging correctly. Coolant looks good, AIT is working, etc.
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Old 11-29-2008, 04:08 PM   #19
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Glad to hear your on the way to success.

Any chance of a photo off your revised circuit to compare with mine?

Rich
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Old 11-29-2008, 04:35 PM   #20
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Now I'm confused. Did you imply that I physically had the plug wires reversed, or something I did in the MS reversed them? They were correct for running under the stock ECU. Warmed it up this morning using the stock ECU.
For my '93 the plugs go onto the coils 3-2-1-4 when looking from the front of the engine. I now have it 4-1-2-3.

Here's where it gets strange. I pulled the plugs. 1&2 are soot black and smell like gas. 3&4 are nice and tan. That means both coils are firing but not all the time??

Lack of a MAP signal was me being a dummy last time and leaving the vac line on the passenger floor. The battery may in-fact be low. I drove it to work last week to try and give it a charge. I'll try and dig-up a charger from a neighbor.
Attached Files
File Type: xls 2008-11-29 - 7th start attempt.xls (261.6 KB, 65 views)
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