J-Rat

iTrader: (2)

Okay, here is the background:

The car is an 88 TII. It now has a Megasquirt installed that was built by King EFI from kingefi.com.

Now I was asked to help out, because there is no tach signal or associated spark event occurring. I am a Haltech person so I figured I could solve the issue, unfortunately that is NOT the case. There has been a 25 RPM reading that has been shown on the readout, but the tach on the dash has not moved, and there has been a few weak sparks, but they die out after a few seconds of cranking.

My questions:

1. Is it advantageous to remove the two teeth on the CAS, 180 degrees out, and run a single trigger? At present the CAS is unmodified.

2. Could an older/worn CAS cause this issue?

3. Is there any form of gain adjustment that can be made to compensate for what may be a weak CAS signal?

Caveat:

I dont know KING EFI, and I have reason to suspect the ECU, but I need to be sure to eliminate all other known issues before resorting to that.

Any help is GREATLY appreciated!

renns

J-Rat,

1.) Removing the two teeth allows one to install a near-stock MS box, rather than having to add extra signal conditioning circuitry. No use making recommendations here until what you have presently is known.

2.) If the CAS looks fine visually (no damage, sensor intact...), then the cause is likely elsewhere.

3.) If it is a V3.0 board, there will be two pots on the board that should be turned fully CCW to start with. Listen for the faint clicking sound when you reach the end of the travel.

How was the car wired? Did the MS installer build a custom harness, or adapt to the existing one?

To best sort out what this guy's got, post up a nice clear photo of the top and bottom of the circuit board. The alternative is to ask this guy what he bought. Did he specifically ask for an MS configured to work with the rotary, or did he just buy a pre-built unit to let you sort out the details? He should really be dealing with King for support first, as they are the ones that sold him the unit.

J-Rat

iTrader: (2)

Thank you for your quick response! Let me answer those questions.

It is in fact a V3 board.

That would have been my assumption, but I figured I would ask the experts if there were any quirks concerning the Megasquirt that made slightly worn CAS' unsuitable.

Am I to assume that these are the trigger gains? I already set them to the settings you mentioned.

King EFI makes what I can only assume is a rotary specific harness, which was used in the install.

I can get you those pictures asap. This was supposed to be a rotary specific harness and ECU, but when asked, this was the response from King EFI.

Also, I agree with the issue of dealing with the "king" on these issues, but sometimes (just like the haltech guys), its alot easier to ask the experts then some dude that just soldered a board together...

muythaibxr

Could you post settings here? And as renns asked for, pics of the front and back of the board would be very helpful too.

I know nothing about kingefi either, and will probably be checking to see if Bruce/Al told him he could become a megasquirt distributor.

It would probably also be good to do some sanity checking on the harness... just make sure that wires are connected where they belong from the plug (on the CAS side) to the inside of the MS where things eventually terminate.

Ken

J-Rat

iTrader: (2)

We have been using the settings posted in the faq. Believe me, I checked there first!...

If it turns out he is NOT an authorized dealer, can you please inform me of this?

Yeah, I was hoping it wouldn't come to this, but that may be what has to happen next.

Also, can anyone confirm or deny that those variable resistors on the CCA are for gain control?

renns

Voltage trigger and hysteresis. See link below for adjustment instructions:

http://www.megamanual.com/ms2/vradjust.htm

J-Rat

iTrader: (2)

Thank you sir!

muythaibxr

Yep, sorry about that, missed that question before!

Ken

J-Rat

iTrader: (2)

Well,

I am having the ECU brought here to my house because I think the jumper settings/required modifications are not correct. HOWEVER, I am being told that you dont have to knock teeth off of the CAS for the V3. Also, during my research I came across someone that had to solder VRIN to TACH SELECT?

I will post pictures of the board, but I hate to keep posting mundane questions. Is there a place I can look to see if the board is properly modified instead of bothering you all here?

Again, I really appreciate the assistance you all have provided!

I am also seeing that its possible a daughterboard is required that someone here makes. If thats the case, then the "King" may have to take this thing back...

muythaibxr

the FAQ has a list of the modifications, but I'm not sure I listed the jumpers on the board. I'll have to sit down one day soon and update that FAQ to be more inclusive and easier to read.

The VRIN to TACH SELECT needs to be jumpered, as well as TSEL to VROUTINV (or VROUT, it depends on how the VR sensor is wired)... If you want to use the second trigger, you must have a second (usually lm1815-based) VR conditioner, wired the way the FAQ says, with the G sensor wires connected to the second VR conditioner, and the second VR conditioner connected to pin 11 on the MS through a 1K resistor.

If none of this was already done, then that harness and MS was not set up for a stock 13B ignition setup.

If the second VR conditioner does not exist on that board, or on a daughtercard, then it'll probably be easier to knock 2 opposing teeth off the CAS, and treat it as a 12-1 missing tooth wheel, which would mean you would have to turn off the second trigger settings.

I would still like to see an msq with those settings so that I can verify that everything is set right. As I said before, I need to sit down and redo the FAQ to make it easier to figure out what needs to be done, etc... and post new graphics as well. I've been meaning to do this for a while, but just have not had time.

I will also let you know about KingEFI.

Ken

Aaron Cake

iTrader: (1)

This topic may help on the pot adjustments. I find it nearly impossible to stop before the click:

https://www.rx7club.com/forum/showthread.php?t=596050

J-Rat

iTrader: (2)

Well, I had a long and interesting convo with Ken last night, and it appears that the build quality of the ECU in question is a little less then stellar (I figured that out as soon as I opened the case). Not too mention that whomever sold the board to my friend probably has no way to test the functionality of the daughterboard, so that working is up in the air.

I could make a test fixture and test the functionality myself, but why should I? Someone sold a product and should be backing this up.

After all this fun with someone elses Megasquirt, I may just make my own! These things are kind of cool!

renns

You don't have to stop before the click. The click is just an audible method of indicating the end of the adjustment range. These units have a full-span adjustment range of less than 20 turns, so if you can't hear the click, just spin it CCW 20 turns and you'll be at the end of the range.

monkhommey

this was bought from KingEfi? i almost bought one from this guy.. but opted to build one myself. its far easier than i first thought.. i just finished my build and when all the lights came on like they should.. i got giddy like a 12 year old school girl..

i recommend building one yourself then you know a little more about how it actually works. then when your done you can look at it and say wow.. i just build a damn ecu..