MSD 6AL causing tuning problems??

Mr Gadgets · Post by **Mr Gadgets** » Tue Jul 18, 2006 10:49 am

Ok.. got the motor squirted, been trying to tune it for best idle.. 565" BBC, sheet metal intake, 2x 1000cfm throttle bodies, port injection, MSD 6AL box, 3.0 board and MSII.
I configured the fuel and ignition as suggested in the config manual. I have the motor idleing at 650 rpm.. That's good, but it sounds like it is missing, kinda dead response off idle. Running two O2 sensors.. LC-1 WB, connected to MSII and a NB (connected to a gauge) that has been in the other exhaust pipe for a couple of years.. The NB shows major lean compared to what I am used to seeing. The WB flips from full lean to 10.5 to one. I can richen the VE and get it to run good, lean till it slows down and rich till it slows down. The motor is trying to tell me, but I am not sure what???

I pull some plugs and find #3 real wet.. most of the other plugs are damp. New set of plugs, same thing. The motor ran fine ( just couldnt tune it manually) with the other fuel injection system. New dist, wires, plugs, etc.. and it ran good before.

So my though process tells me I should remove ignition control from MSII and put it back the way it was ( dist locked in at 32*), and see if I have a fuel issue or ignition issue..

Question is, using the MDS box, I am not sure how to wire a tach signal to MS?? Can I use the white wire from the MSD box that is a tach signal and just shut off the ignition in the soft ware.. IF things clean up as far as the motor running, then at least I know where my problem is. Or should I mess with the ignition setting to see if that helps??

I know this tuning is an art, but getting a bit frustrated.. With the old system, it would run with black smoke and clean up as it leaned up.. and would run crisp.. I tried all kinds of VE settings and it just sounds like it it running on 6 or 7 cylinders..

Thanks
Dick

krisr · Post by **krisr** » Tue Jul 18, 2006 2:21 pm

Your tach signal (Pin24) should be coming from a distributor or crank trigger. VR or Hall/Points?

The MSD white wire should goto Pin36 and the mag pickup wires on the box just tucked underneath out of the way.

I found it's best to line up the distributor at zero-crossing when the balancer is 10Â°BTDC, that way you have room to play with getting your offset right. Set the trigger offset to 10, use Last Interval predictor with a gain of 0%. Your tach input depends on what Trigger Edge to use. But with a 6AL use Going Low spark edge. Get the motor idling and verify the BIG number in Megatune Trigger Wizard on the balancer. Turn the dizzy or change the offset (smaller number) to sync the BIG number and the balancer. Once you have them in sync, lock your distributor and never touch it again

How big are your injectors? i'd imagine in the 60-70lb/hr range with that big inch motor.

Mr Gadgets · Post by **Mr Gadgets** » Tue Jul 18, 2006 6:46 pm

Krisr,

That is how I have it wired... I was thinking I would like to try it without ignition control. It seems I dont quite understand the zero crossing concept. ???

I set the inital timing for 20* on the dampner.. and the offset is 20*.. they pretty much match.. hard to see the timing mark and I will fix that.

My config is
Trigger Offset = 20*
Skip Pulses = 3.... not sure what this is!
Predictor Algorithm was 1st high rpm, 2nd low... I will change it to Last Interval
predictor gain % was 20 now = 0
Next Pulse tolerance... I have no idea what this is either!
Cranking % = 50
After Start % = 70
Normal Running = 25
Ignition Input capture = Rising Edge
Cranking Trigger = Calculated
Coil Charge Scheme = Standard Coil Charge
Spark output = going low
Max spark duration = 25.5

This is what I have from the info from the MDS 6A ignition control. I suppose I should check that section for any updates.. my copy is 10/28/2005.

Where can I find more in the manual on understanding these settings.. I really do want to use the MSII to control the MSD 6A...

The injectors I am using at present are 65 lbs/hr... Hoping to make 800hp with this set up..

Thanks for your help.. Time is at a premium lately so I try my best to read everything I can.. but just not enough time..

Dick

krisr · Post by **krisr** » Tue Jul 18, 2006 10:54 pm

I would use less trigger offset and set your cranking trigger to Trigger Rise. My interpretation of this is that when cranking, an ignition/injection pulse is delivered when each tach signal is detected, 20Â° cranking advance with a hot starter and heaps of compression... we all know what will happen to your starter bendix after a few hundred cranks. Also have you 25.5ms for Max Dwell Duration?

Apart from the trigger offset, I use 10Â° with my MSD Probillet and the cranking trigger our ignition setups are the same. Cranking trigger and ignition map are 2 complete different animals too. FYI I run 30Â° advance at idle to help tame the cam.

Your comment of "kinda dead off idle" says to me your VE isn't tuned. I assume you just got this beast running? The way I tuned my 400 was by using AutoTune at first but I didn't have much luck, then datalogging and parsing the logs through MSTweak. Strongly suggest you familiarise yourself with that program as it's super powerful!!

Did you set your req_fuel constant then generate a VE map - that VE will be pig rich until you take some fat out of it. Below i've attached what my fuelling map looks like so you get a rough idea how my 400 dialed in and I would say your 535 will be similar with those injectors depending on your redline. I shortshift at about 5700 but will turn it to 6500 with no issues.

Goodluck!

davezed · Post by **davezed** » Wed Jul 19, 2006 2:49 am

G'day Dick
At the risk of being yelled at and being called all sorts of things just thought to put my two bobs worth in with respect to MSD 6A. The site does say to connect MS output (pin 36) to the white wire of the MSD and configure Spark output = going low. I don't quite understand why it states going low (sometimes it's confusing where the reference is made to, ie output of the micro controller or the output of the PCB), I would have thought it should be = going high (inverted). The white wire is normally used for "points type triggering" which again unless I'm missing something (having another blonde moment...) surely the spark occurs when the points open (cutting supply to the coil). The MSD has an internal pull-up resistor (to Vbatt), this can be measured without anything connected to the white wire (ie should be about the same as your battery volts). If you connect a spark plug to your MSD coil (via a HT lead) and the spark plug body connected to 0V (the car body), turn the ignition on then touch the white wire to 0V, nothing much should happen, but then remove the white wire from 0V then the MSD will output it's hi voltage (ie you should see an arc across the spark plug). This tells me that you need it to fire on a rising edge (ie = going high (inverted)) not going low. Also if Maximum Spark Duration = 7.0 msec and Maximum Dwell Duration = 8.0msec I have found the output to the MSD almost a perfect square wave over (I think) 1500RPM, in other words very similar to what points would produce (on a V8 at least). Again this is what I have found (and use but I'm not using the VR input to MS), maybe someone will explain where I have gone wrong? Looking at my timing with a strobe it certaining seems good...
As for the "not sure stuff", you would probably best leave it at there default settings (works for my system), you can read up on these in the manual => http://www.megasquirt.info/megatune.htm

Cheers
DaveZZ

Mr Gadgets · Post by **Mr Gadgets** » Wed Jul 19, 2006 4:41 am

Krisr,

I previously had the dist locked at 32* and never had any start problems.. that is with several hundred starts. My thought was to set it to 20* so if I ever had to limp home, it would still have 20* at an idle.

I am still not sure about the zero crossing? Is that the process of matching timing on the dampner to the offset trigger in the trigger wizzard? Or do I need to look at the wheel and pickup in the dist?

I did reset the limit in the ".ini" to allow the Max Dwell duration to 25.5ms. I referenced the info here....

http://www.megamanual.com/ms2/msd6a.htm

under the "MegaTune Settings for the MSD 6A Module" heading. This is the only info I have found on the subject, so I was going by that.

I will change the Cranking Trigger from Calculated to Trigger Rise, that will put everything but the offset the same as yours.. and if yours is working, so should mine!! Thanks!

You are correct, I am just starting the process of tuning, so my VE table is a mess at this point. I did the req fuel and generated a map. But being pig rich should show up on my NB O2 sensor as such, and it shows full lean. If I change the VE at idle, and the motor responds favorably, I dont see any change in either NB gauge or the WB sensors. That leads me to believe that settings for the ignition are not right. Causing miss fires and inaccurate readings on the O2 sensors..

The motor is in my boat, so I have to hit the water inorder to tune the VE, but dont want to go there until I get a clean idle and the O2 sensors are showing what I think I should see..

I am unable to see the file that you attached, I can never see any files when people mention that they have attached one.. not sure why?? Any ideas on that?

Dave, thank you for the link.. I missed that one.. Now that I read it.. I need to try and digest it..

BIG help!

I think this thread should be in the other Forum.. Ignition Tuning.. I didnt see that one when I posted.. Lance if you want to move this for me.. That would be fine..

krisr · Post by **krisr** » Wed Jul 19, 2006 3:52 pm

You said you have an LC1 connected to MS2. I'd be more inclined to follow that reading over an NB. Zero Crossing is when the reluctor crosses the pickup coil and creates a tach signal. Basically to get zero crossing right (We're talking about magnetic VR pickups) you have to have wired the polarity right. By the sounds, if you're getting rock stable timing at idle and both MT and the balancer are in sync, you're gold.

Now you're fuelling problem. When you said you change the VE table at idle and it responded favourably. Did you add fuel or take fuel out? What is the LC1 telling you in Megatune? Presume you calibrated the AFR table for the Innovate? Can you post a datalog with the motor running & your MSQ.

Mr Gadgets · Post by **Mr Gadgets** » Wed Jul 19, 2006 4:27 pm

Thats the trouble.. the WB that is connected to the MSII goes from 26.xx to 10.5. It flops back and forth.. So I dont trust it.. And yes I did select the Innovate LC1... The NB has been in use for several years, and I know it shows rich when it is running good at an idle. At this point it is reading full lean, all the way to the left.. So something is a miss.. so to speak.
The idled fair at 700rpm. Pretty decent for the big cam I have. I rasied the idle to 1000 and I could adj the VE rich or lean until it would start to drop off.. and the gauges would still read lean.. or the WB flopped back and forth.. Well it mostly reads full lean,, then it will jump to 10.5... no matter if I leaned it or richened it.

I am using an MSD billet dist with the VR sensor.. The timing at idle isnt exactly rock solid, but with the sun shinning on the dampner it is hard to read it.. Have to address that. It was rock solid when the dist was locked at 32* before I made the switch to MS.. That is what makes me think the ignition settings are causing problems.. Going to try and get it out and fired up again tomorrow nite.. With the changes you suggested, I am hoping to see things clear up.. and have the O2's give me decent indications.. I will try to figure out the data logging...

Do you have any idea why I cant see the file you posted with your info??

Thanks so much for you help... I do so appreciate it!!

Dick

ChevelleFan · Post by **ChevelleFan** » Wed Jul 19, 2006 6:26 pm

Mr Gadgets wrote:Thats the trouble.. the WB that is connected to the MSII goes from 26.xx to 10.5. It flops back and forth.. So I dont trust it.. And yes I did select the Innovate LC1...

Dick

I think you need to configure the LC1's controller with Innovate's software, in addition to choosing the Innovate option in Mtcfg.

I don't remember it off the top of my head, but you fire up their software and re-program the output curve on either of the two available outputs. It's pretty simple to do -- you tell it 0v for 10:1 and 5v for 20:1 and that's about it. Look at section 7.6 (page 13) in your Innovate manual.

-Dave

Mr Gadgets · Post by **Mr Gadgets** » Thu Jul 20, 2006 1:56 am

The papers I have for the LC-1 indicate that the second output is configured for 0v-5v and the first output is configed for 0v-1v to connnect to my dash gauge.
I will double check with the software and see what it is setup for.. If I was seeing a decent indication on my NB that has been in use for a long time.. I would have suspected a setup problem with the LC-1... Never hurts to check though. I may be wrong from the factory. I was seeing as high as 26, and that does indicate that it is out of range.
What about C10... saw some discussion about removing it from the input circuit...

Thanks

Dick