Magnum Dual Wheel

[90turbovan]

You may remember my thread about a year ago about this subject under my dad's screenname, djmoyer. The truck has been running for a year now, but it has never run well. No power and kick backs on starting are the major complaints, I started tearing into it this past week to finally figure it out.

Brief overview:

Dodge 5.9 Magnum V8
8 tooth non missing crank wheel (hall)
1 tooth (180 degree) cam wheel (hall)
Rising edge at cam sensor after TDC tooth on crank but before 2nd crank tooth (45 degrees)
Falling edge somewhere, not critical at this point since I'm only using the rising edge of the cam.
Optoisolated 4N25 circuits for both

Toothed wheel mode
Dual wheel mode
8 trigger teeth
Tooth #1 angle is 315 or 45 degrees
Secondary trigger active rising/falling and every rotation of crank
Currently trying active falling and every rotation of cam

I took the front of the engine apart to check cam timing and found that the distributor was in 180 degrees out (how did it run?). Engine cranks and attempts to run, but never catches and idles. No synch loss during cranking or when it actually fires. I have played extensively with fuel and don't think its a cranking pulsewidth issue. Starting fluid doesn't do anything different.

First question is on the setting of Tooth #1 angle. The documentation is confusing as it refers to everything in degrees BTDC when the rotation of the cam/crank diagrams would put the angle as degrees ATDC. Unless it's referring to the actual position of the tooth and not that of the cam event? In either case, since I'm not doing wasted spark, the #1 plug still fires at TDC #1 (from what I can tell...). What is the proper setting of this?

Second question involves the TunerStudio composite logger. I'm getting edges on the crank signal when the cam signal changes (this was in rising/falling mode). The data log shows 9 crank events (should be 8?) for each cam change, so it isn't in the display of the data. Is there actually noise on the crank signal or is the logger not recording something correctly? It's happening on both edges of the cam, is that possible from a noise perspective?

I'll try and get a screenshot of the logger tomorrow morning and maybe check the positions of all the edges. Really wish I had logic analyzer for stuff like this...

[Black99rt]

Why don't you go back to basics and sort fueling while running spark off the factory ECU? You can just grab the coil(-) with a simple trigger. Sorry I can't of help with the ignition stuff.

[jsmcortina]

I think you are seeing a bug in Tunerstudio there that displays the data incorrectly.

Have you set fixed timing and checked it with a timing light? That is a critical step of any ignition install.

James

[90turbovan]

I can't sort out fuel only because MS is the only ECU on this truck ('80 Dodge rollback). I checked that the timing was at 0 several times, it would appear that the distributor was in correctly to begin with? I flipped it around just for fun and it fired up first try. I'm positive that the cam and crank marks were lined up properly and that the distributor was 180 out, but I can't argue with results. I believe my inital problems were cause by the improper setting of Tooth #1 Angle combined with the adjustment of the distributor causing it to run with 45 degrees of base timing. What is the proper setting of this angle? From my understanding, 45 or 315 will work since I'm not running COP or wasted spark, but the documentation is confusing. Is the base timing number from the trigger wizard taken into account? Should I use 40 if my base angle is 5 degrees? The docs are also non existant for idle control, even just a list of descriptions for the settings would be nice (without having to dig through the old posts). Closed loop stepper does work like a dream after everything is sorted out though.

It still has no power, but I'm hoping that's due to a bad map. It does start wonderfully now and doesn't ping on 14 degrees of max timing.

Black99rt,

Would you mind sharing your msq? It'd be nice to have a good map to start with for fuel...

[jsmcortina]

There is only one correct tooth #1 angle BTDC. It is the angle BTDC of tooth #1 when the engine is at TDC.

The two numbers you specify (45 and 315) will result in a 90deg difference in timing, as it happens on a V8 with a distributor that won't actually matter as the cylinders are 90 deg apart.

The trigger wizard should always be set to zero when using a regular toothed wheel.

When checking timing, use the Fixed setting at say 10, 20, 30 degrees and confirm that it stays locked to that advance at different rpms.

James

[90turbovan]

What if my trigger wheel has 5 degrees of advance built into it? From what I gather from the FSM, the Magnums do. I used the trigger wizard to get 0 degrees fixed timing to 0 degrees actual timing. What if the cam trigger happens 15 degrees after the TDC tooth event? The next tooth that it sees is 40 ATDC. I know for a fact if I set it to 0, it fires ~45 degrees off. I can't change the cam trigger to be BTDC since the rotor would be pointing closer to #8 on the cap than #1.

http://www.msextra.com/ms2extra/MS2-Extra_Dual.htm

After reading through the dual wheel documentation again, I see what you mean by just using Tooth #1 Angle and not the trigger wizard. So, I should be using 320 degrees for that angle since the first tooth it sees after the cam trigger is 40 degrees ATDC or 320 BTDC, not tooth #1 from the perspective of the crank. If you would, read through that page and tell me if I'm reading it wrong. If tooth #1 angle is defined as degrees BTDC, one should count backward from the marked tooth or forward from the sensor (backward being opposite engine rotation and forward being in the same direction as engine rotation). That would mean that the description on that page is incorrect?

I will verify that it does track with RPM tomorrow, I only set it up during cranking/idling.

[Black99rt]

No problem. This MSQ is for 65lb injectors, the reqfuel is "correct" so it should scale ok. The original magnum injectors should be 19lbers, but with high 40s/low 50s fuel pressure. The calc would probably work best if you put 21lb/hr in. Also the map is for a twin screw supercharger, but it should get you driving around pretty good once scaled.

Firmware 2.0.1, so AFR is NOT included. EAE is on but not tuned at all.

[jsmcortina]

We aren't asking you to change you engine or trigger arrangement.

The tooth #1 angle is the first crank tooth seen after the cam trigger and is specified as BTDC. In your case that may be 320deg BTDC. That should be fine and the code calculates its wheel table accordingly.

(Some engines have #1 tooth a small angle BTDC, others a small angle ATDC, others in-between - we had to pick one definition.)

We never discuss "base timing" because that is largely irrelevant, when setting the Fixed timing and ensuring your #1 angle is correct we are talking absolute timing. 0 means true TDC. Many engines do not have timing marks from the factory so you have to make them or install timing tape etc. Crossing fingers and hoping the timing is right is never the correct option!

On the documents, if there is ambiguity, please post the words that aren't making sense. Because this angle setting is so important and can be tricky we do need to ensure that the docs make sense to all readers - not just the developers.

The words I'm reading are:
The Trigger Angle/Offset is ignored in Toothed wheel mode, so leave it at zero. The angle used now is the angle that the next tooth (on the main wheel) is seen by the sensor after the 2nd trigger has pulsed. This is entered into Trigger Wheel Settings - Tooth #1 Angle.

James

[90turbovan]

The Trigger Angle/Offset is ignored in Toothed wheel mode, so leave it at zero. The angle used now is the angle that the next tooth (on the main wheel) is seen by the sensor after the 2nd trigger has pulsed. This is entered into Trigger Wheel Settings - Tooth #1 Angle.

That is what I gather is the correct method, now look at the diagrams directly below that text. If you think about the way the crank rotates, the docs are telling you to find the angle BTDC that the "Tooth #1" is when the engine is at TDC, not the angle BTDC that "Tooth #1" is when the cam trigger is active. So, in the example given with a 60 tooth wheel and no missing teeth, the Tooth #1 Angle should be 300 degrees, since the tooth that passes by the crank sensor after the active edge on the cam sensor is 300 degrees BTDC at that point in time. This is where my confusion was coming from.

I wasn't implying that you wanted me to change my trigger arrangment, just trying to give the most information possible about this setup.

I do understand what you mean by base timing being irrelevant, I was just taking out the 5 degrees in the wrong place (trigger wizard, not tooth #1 angle). I was going by how I remembered from last year instead of going through the docs step by step, guess I missed that line.

Thanks for the msq, Black99rt, you've got an interesting VE table...

[jsmcortina]

I think you are on to something there with those diagrams. Will confer and update if required.

James

[Black99rt]

Haha yep, the parts that I haven't hit yet are still really really rich, I was just fleshing it out piece bypiece. The pieces I never hit, just kinda stayed that way.......

[90turbovan]

I've found that 46 degrees for tooth #1 angle gives dead on TDC for every cylinder. Every multiple of 90 added to 46 works except for 316, which is the one that should be correct. Is there anything in the code that would prevent one from using higher values for this setting? I see everything is 16 bit and all degrees *10, so it should be able to handle any conceivable angle well past 720. Just out of curiosity, any reason why adv_offset is added in to the trigger angles if we're not supposed to use it?

[jsmcortina]

At the time that part of the docs were written the trigger angle/offset was totally ignored. After user requests to support it I added the code to allow +/-20 deg adjustment.

James