M30 fully sequential

hi to all I’m having some issues with a m30b35 that we are going fully sequential

it has a 60-2 crank 85 degrees btc (stock) and one tooth at cam both Vr sensors I’m getting sync but it seems it’s syncing at wrong cylinder I need a hand choosing the right position for the cam plate

What ECU are you using? Have you tried moving the reference position in 120 deg increments in order to get the reference relative to the #1 cylinder? My first try if it runs non-sequential would be to add/subtract 360 degrees from the reference position.

Hi first off all thanks for your reply

we are using MAXXecu race the reference position it’s one of our problems I do know (or think I know) that the cam position sensor should be mounted 20 to 50 degrees from the crank sensor I do have sync but no start in sequential

br Pedro Faia

When I say move the reference position, I mean in the software. Does it have a method to "check timing" and adjust the reference position to get the timing to align -- that is the value that may need adjusting by 360 deg (or some other increment of 120 deg for your 6 cylinder engine).

With a 60-2 crank trigger and a single sync, the location of the sync input really isn't as critical as most people assume, provided it doesn't coincide with the missing tooth. I generally aim for having the missing tooth occur around 60-90 deg BTDC #1 (which it sounds like you've achieved). Everything else should be dealt with inside of the tuning software with a calibration process for the base ignition timing.

Ive checked timing with stroboscopic light but for instance I have the car working on wasted spark and sequential 360 dregrees without cam sync when I try to go 720 sequential it seems like misfiring I also have to say that we have itb with turbo setup also modified camshafts

br Pedro Faia

Are you using coil on plug? Perhaps your coils aren't wired in the correct order? Some ECUs using firing order not cylinder number and this catches some people.

Andre

When you say that you want the missing tooth (I assume you mean the reference tooth) to be at 60 to 90 degrees BTDC do you mean that the ref tooth should be on the crankshaft at a position 60 to 90 degrees BTDC from the No. 1 crankpin or do you mean that the ref tooth could be anywhere on the crank provided the trigger offset angle is 60 to 90. Can you explain why you prefer this angle.

Leigh, it seems like you might be mixing up some terms. Different manufacturers use different terminology but most tuners will understand "Ref" as the crank trigger (trigger that timing is done from), and Sync is the cam trigger (trigger that synchronises the ECU to the 720deg cycle). Another important feature is the tooth on the crank that the ECU uses as "zero". Many will call this the "index tooth". For most ECU's when using missing tooth patterns the index tooth is usually the first tooth after the gap. This is where the "trigger offset" or trigger angle or CRIP or whatever you call it is measured from.

Most modern ECU's will work with the missing teeth pretty much anywhere but there are still some considerations to keep in mind as best practice (this is where Andre's 60-90BTDC suggestion comes from).

1. The ECU gets less position & speed updates in the missing tooth area so engine position is less accurate, for that reason it is good to have the missing teeth pass the sensor somewhere outside of the normal range of ignition timing - so say more the 50BTDC or 30ATDC.

2. With some engine configurations (high compression, low inertia, 1, 2 or 4 Cyl are the worst) at low speeds the crankshaft slows down a lot as the pistons come up to TDC compression, if the missing tooth area is passing the sensor while the crank is slowing down a lot it can make it more difficult for the ECU to detect the "gap". If you put the missing teeth at about 90BTDC (2 or 4 cyl) the pistons are halfway down the bore so crank acceleration is more predictable. With 6 or more cylinders this effect is not normally an issue.

3. As for the "sync" tooth - again I will generalise as you didnt mention what ecu you are working with, but generally the only golden rule is you dont want it too close to the "index tooth" (first tooth following the gap). Some ecu's have more specific requirements such as it must be be 110-250deg before the index tooth, so you really need to study the manufactures documentation for that.

hi again

lets start over we installed a MAXXecu race in our e36 m30b35 we changed cams lowered compression had dblas itb setup and turbo.

we were trying to go sequential but it always sounded like the firing order was not the correct like if it was firing in the 6th cyl or something...

keep in mind we have the original crank pulley and we have done several other m30 with wasted spark setups in the past so we do know that the timing its arround 85 to 90 degrees btc at crank.

this time we were trying to go fully sequential and bought the cam sensor setup...

we align the cam sensor right before the missing tooth from crank and start the car...

the car fired but always sounded like something wasnt quite right...

so we were back to wasted spark 360 sequential (without cam sync) it sounded better but not quite right yet...

another important data the egt from 1 3 4 cyl are extremely colder than any other 6 cyl arround 500 degrees and 3 and 4 cyl arround 200 (example)

injectors test done and still we have changed it, coils changed spark plugs changed timing checked compression checked...

now if you shut cyl 3 and 4 off its like it had never been there...

i dont know if this is enought to explain whats happening here i can upload a log and base map latter

br Pedro Faia