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Calling all MS people...


V8 Freak

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Ok.. Brain is hurting... Question for the clever amongst you.... (Diseasel types nothing interesting here so don't worry...)

Timing....

When starting the engine, should the ignition ideally be nearer to TDC or further advanced ? Assuming normal dizzy types would be around 6 BTDC and no less..

In the Omex ECU documents it suggests the setting should be a low advance like 2 degrees.. Feels too near to TDC for me...

and, looking at a cranking correction table I think it may have been set wrong initially. (If my logic is correct..)

Dependent on water temperature, the table adjusts timing for starting. Currently it moves the ignition towards TDC the colder it is. My brain is telling me this is wrong, buy I have been wrong before.... (The setting could perceptively take it past TDC !!!)

Any advice welcone...

Neil

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MS also has functionality to adjust the timing against coolant temperature and intake air temperature…….. I have this setting disabled as I cant really see a lot of point unless it is a race engine that will be subjected to mighty hard use……..

Currently I am using EDIS and not direct driving the coils. I will need to look at the EDIS specification to see what it does during cranking …………once the engine fires and runs, then I know it reads the spark table and this is totally independent of coolant / IAT temperature. If EDIS loses the trigger wheel then it defaults to 10 BTDC, but during cranking I know not :unsure: …………… but I will try to find out…….

If MS is direct driving the coils, then yes, there are different dwell settings between cranking and running, and this must have an effect on the overall timing. My guess is that you have got it correct and the timing is probably closer to TDC (but BTDC) during the cranking……..remember that the more advanced the timing is then the harder it will be to turn the engine over at the point of firing………so it would be best to have the timing nearer to TDC in order to spin it up OK……..

:)

Ian

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I run direct driven coils and currently use 7deg. advance for cranking and it seems happy. I was originally running 10deg in summer (i think it was a default or came in the MSQ i based my settings on) which seemed to be okay but found this was too much in winter causing kickback to stall the starter motor :o

While messing about experimenting with it I did try values as low as 0 but found they took more cranking to make it run.

In the past I tried coolant/IAT related ignition but found it gave too much advance at cold (although the value is adjustable) - making the engine run rougher. Idle valve control is a much better solution.

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So from what I've read tonight, this evenings cold start test should be to set the corrections to zero and crank away with about 7 degrees BTDC.....

Ok.. Will let you know what happens.....

Edit: Changed all cranking corrections to zero. Cranked, started and then died... One more go and similar....

Moved the standard temperature corrections to zero as well (Used fo rthe main maps) and it started and stuggled.... Few blips of the throttle and it settled down.

So I recon we are getting closer. Another try tomorrow with all corrections at zero again and see if minimal tweaks on the correction tables lifts it and holds it...

Neil

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By changing cranking corrections to zero (im not familar with Omex), is this changing the cranking ignition advance only or also the additional fuelling for cold starting? Hows does Omex specify cranking fuelling, as a pulsewidth (milliseconds) or as a percentage of the base fuelling number for different coolant temps?

Would it be worth checking the actual cranking advance with a timing light? disconnecting the injectors to stop it firing up

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Good call Tom...

Looking at the documentation it doesn't explain if this is incremental adjustment or total!!!!

Regardless the temperature corrections are knocked to zero, just need to see if I can prove / find out if the suggested 2 degrees was additional advance or total spark advance !

The fuelling is a pulsewidth calculation and looks to be totally separate from the main maps, hence assuming the timing number was too.

Cranking is defined by parameters.... More than 20RPM, less than 400RPM....

Ok, more reading...

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Can understand that FF.... I'm confused !

In the cranking section...

"Ignition

Whilst cranking, the ignition timing is determined by the Start Ignition option. This is set in degrees and would normally be a low value eg 2 degrees."

Other comments in the same section...

"Start Fuel Pulse Table- This is a single shot of fuel that may be injected into the engine at the start of cranking. The value in the table-selected dependent on temperature is multiplied by Microsec/bit to give the fuel pulse in micro-seconds

Start Fuel Throttle Table – This is the amount of fuel injected in cranking, dependent on throttle position, while the engine is starting. This value is VE (same as main map) so is multiplied by Microsec/bit to give the fuel pulsewidth.

Start Fuel Coolant Table – Extra fuel added to the Crank Fuel due to temperature.

Start Fuel Decay Table – This determines how quickly the additional start fuel decays over time. This is a linear decay in seconds after cranking commences."

The Start Fuel Coolant Table is the only mention of adding to other maps... The others look exclusive but I have no way of verifying.

I wound everying down to zero but the timing number of course.... A lot of cranking before a fire at all this evening.... Me thinks this is not necessarily the way to go...

The wonderful boys at Omex not responded to an email yet !

One more try I recon...

Neil

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"Start Fuel Pulse Table- This is a single shot of fuel that may be injected into the engine at the start of cranking. The value in the table-selected dependent on temperature is multiplied by Microsec/bit to give the fuel pulse in micro-seconds

This looks like the priming pulse at the moment you turn the key. I have mine set independent of CLT and it always fires two 4m/s pulses at 1 second apart. So I guess you could set it to a global 8m/s. If it must be CLT related then how many entries does the table have ? ............. I would set it to fire 10m/s @ 5C and below, then give it linear regression to to about 5m/s @ 70C .................... I have quoted actual injector pulse widths...............

Most, if not all injected engines have this 'priming' feature................when set correctly it allows the engine to start 'on the button' regardless of outside air temperature..............

Start Fuel Throttle Table – This is the amount of fuel injected in cranking, dependent on throttle position, while the engine is starting. This value is VE (same as main map) so is multiplied by Microsec/bit to give the fuel pulsewidth.

This one is more difficult, but I would assume here that it also includes a 'flood clear' option .........i.e. if you apply more then 75% throttle during cranking then the fuel is shut off. Generally with most injected engines you always start the engine with no throttle input and then give it a little throttle as the engine fires. Really I need to know how big the table is ? .......................At zero throttle I would want to see 3m/s total injector time .............

Start Fuel Coolant Table – Extra fuel added to the Crank Fuel due to temperature.

OK ..........It looks to me as though you are supposed to use this in conjuction with the above throttle table.............What size is the table? If we assuming that we already have 3m/s from above then I would add enough to make the TOTAL injector open time to be 10 - 12 m/s @ 4C and below............ about 6 m/s @ 27C and tailing off to 3 m/s at 70C (i.e taking into acount he above, then add zero @70C)

Start Fuel Decay Table – This determines how quickly the additional start fuel decays over time. This is a linear decay in seconds after cranking commences."

Here we really need a better definition of what they really mean. In MS there are 3 distinct starting phases........ engine prime (you seem to have that), actual defined cranking pulses dependent upon CLT (you also seem to have that) and then engine settle time, which is an extra enrichment decay map that kicks in once the engine has 'fired to run. ' So I guess this must be similar............the idea of it is to ensure that the engine keeps running once it has fired........ the colder the CLT, then the more important this setting is.

I have this set to fixed and then deacy ....... fixed for 8 seconds and decay for 3 seconds, giving an 11 second timer. Currenlty mine is set to be alway active, but I have the option to also link it to the Manifold depression. In MS it is taken as a % increase to the values read from the fuel map. This is a 10 site table with fixed CLT values to vary the fuel against................ @ -40C I have 30% fuel increase ................. and @ 71C I have a 2% fuel increase.

Omex (like Emerald) was really developed for race engines, so you will have a lot of settings that are more applicable to that environment (a highly tuned engine is more of a difficult beast when cold starting comes into play) .................... So I guess that you will be able to 'switch off' some features that are not needed, or you may be able to get away with some 'generic' values.

Just to recap the starting procedure will be something like ........... prime .......... cranking prime pulse ..........engine settle decay enrichment.

Cranking is normally defined as rpm below 350................

HTH

:)

Ian

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Thanks for the conversations this evening Ian...

Based on our discussions I set the cranking tables and had a go.... Fired on about the 5th revolution and promptly died.

Tried again and it held for a bit longer.... Third attempt with a little tickle of throttle it held after cranking. At that point we are effectively past the cold start and it runs a dream and ticks over without a fuss...

Tables as promised...

post-1475-1202507859_thumb.jpg

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Neil,

This is what I think your tables should look like .............. i have based theis on setting the Start Fuel thottle table to 1ms with flood clear after 75% throttle. The Start fuel coolant table then adds in the correct % to bring the pulse width up to 10ms at 'kin cold and dropping to 2ms when hot.............

Give it a shot ........... the worst it will do is flood and not start ...............but if i have the correct interpretation of the info, then it may well work.

Your 'one shot' table and decay tables look OK for the moment.

gallery_269_31_15635.jpg

:)

Ian

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Can't set those Ian as the Start Fuel Coolant Table max's out at 480 !! Can't hit the 900 settings you suggested !

I've got the Start Fuel Throttle to give me a base of 1MS and then assuming the coolant % increase is a multiplier and not additional, I've got it set for 300% at 10 degrees to give me 3ms pulses.... See if it is enough !

I have no idea if the coolant correction table for fuel for stable running adds to this cranking area or if it's exclusive. If it adds, then it will build this 3ms up, although presently as soon as the engine is running, that coolant correction number needs to remain small as is runs pants if too much correction is added.

I'll be out to play shortly and will post up how the newest settings work..

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Ok.. The settings I tried this morning were not helping....

Initial fire ok, then dead. But, tickling throttle did bring engine to life and then cold start opportunity was lost.

Thinks..... Still in cranking mode as under 400RPM, so if throttle has an impact, and "Start Fuel Throttle" is straight line so nothing added in cranking area, there must be a relationship with main maps and therefore a potential multiplier I've been missing here...

Oh well, next cold start opportunity tonight.. Engine warm now.

More thinking and head scratching to come....

(Alternative plan.. I do live on a hill, maybe just bump starting is the option !)

:)

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Thinks..... Still in cranking mode as under 400RPM, so if throttle has an impact, and "Start Fuel Throttle" is straight line so nothing added in cranking area, there must be a relationship with main maps and therefore a potential multiplier I've been missing here...

:)

The manual states,

"During cranking, the fuel and ignition are not controlled by the main fuel and igntion maps, but instead by tables and options.

The cranking condition is defined by the engine speed options Min RPM and Start Exit RPM. Min RPM is the engine speed at which the engine is considered to start cranking (typically 50 rpm), and Start Exit RPM is the engine speed above which the engine is considered to be under normal running ie no longer cranking. "

Interestingly the 600 manual is also (if not same) identical to the 710 manual..........................oh, and ignition is spelt wrong several times in the manual

Right now I'm guessing that when it fires and you catch it with the throttle the transition to the main maps must be almost seamless as it detects a burst above the 'start exit RPM',......................

So................. reduce the Start exit RPM to 300 ....................... and then increase the 'one shot' prime pulse to something larger...... about 10 or 12 ms...

I will call you tomorrow Neil.................mid morning ish , if thats OK ................

:)

Ian

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Right...

Cranking maps used tonight.

post-1475-1202763033_thumb.jpg

And the fuel map...

Firstly in Raw format

post-1475-1202763070_thumb.jpg

And Pulse width (This used the Microbit/sec setting of 56 to calculate the pulse width - Tested by changing the 56 setting.)

post-1475-1202763082_thumb.jpg

As you suggested, moved the pulse up a little. Also switched on, held throttle at 10% and cranked. Almost instant start. Fires, revs climbed and held while I held the throttle...

Calling you soon..

Neil

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Neil,

Yes, you WILL need to start yours with some throttle as you have no extra air valve ;) ……… putting your foot on the gas pedal does the same thing, as your main maps don’t come into play until the engine fires and kicks to over 400rpm.

So, I guess the settings now are about correct :i-m_so_happy: , until such time as you fit and idle control valve or the older type EAV …………….

I will ring you later…………..

:)

Ian

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Just called Omex to find out more, maybe get some support, example maps.... They are at lunch !!!!

Can't believe this.... No responses to Emails and they have lunch. (And they close early on Fridays!)

I want a job in their world....

Come on Ian... If Rover can control the stepper, you will be able to advise me how to crack it ! :)

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Yay... Happier now..... I got a response from Omex finally..... Not sure if this helps me much but I'll read it a few dozen more times, I'll even try when I'm mostly awake...

"Hi Neil

Below are a few notes on how to set this up. Note that the cold running must be correct before you can do the cold starting properly.

Cold Engine Running

When cold, engines require different amounts of fuel (and air) to run correctly. The method for setting-up the cold running and idle varies dependent on the load sensing and idle controls used. Note that the cold setup cannot be done until the engine is fully mapped for warm conditions as all of the cold running tables are modifiers on the warm running maps.

The below procedures may need to be followed several times to get the cold running correct, with the running improving by smaller amounts each time until perfect.

Throttle position for load, no idle air bypass motor

Ensure that you have completed the warm idle and warm transient fuel setups before continuing.

Arrange the screen so that you can see the Coolant Fuel Trim table, the Accel Coolant Trim table, and the parameter Spark Idle.

Start the engine from cold anyway possible. The cold running must be completed before the cold starting can be completed.

As the engine warms, watch the parameter Spark idle. At all cold temperatures, adjust the values in the Coolant Fuel Trim table to give the lowest number possible in Spark Idle. When the Coolant Fuel Trim table is set at a particular temperature, blip the throttle and adjust the Accel Coolant Trim table to give the lowest number possible at which the engine still picks-up nicely (or if using wideband lambda, the value that maintains the current lambda reading).

Engine Start Condition

During cranking, the fuel and ignition are not controlled by the main fuel and ignition maps, but instead by tables and options.

The cranking condition is defined by the engine speed options Min RPM and Start Exit RPM. Min RPM is the engine speed at which the engine is considered to start cranking (typically 50 rpm), and Start Exit RPM is the engine speed above which the engine is considered to be under normal running ie no longer cranking.

Ignition

Whilst cranking, the ignition timing is determined by the Start Ignition option. This is set in degrees and would normally be a low value eg 2 degrees.

Fuel

Start Fuel Pulse Table- This is a single shot of fuel that may be injected into the engine at the start of cranking. The value in the table-selected dependent on temperature is multiplied by Microsec/bit to give the fuel pulse in micro-seconds

Start Fuel Throttle Table – This is the amount of fuel injected in cranking, dependent on throttle position, while the engine is starting. This value is VE (same as main map) so is multiplied by Microsec/bit to give the fuel pulsewidth.

Start Fuel Coolant Table – Extra fuel added to the Crank Fuel due to temperature.

Start Fuel Decay Table – This determines how quickly the additional start fuel decays over time. This is a linear decay in seconds after cranking commences.

Setting-up start fuel

It is important to note that the Coolant Fuel Trim table is always active, ever under cranking conditions, and so the cold engine running must be completed before the cold starting can be fully calibrated.

The Start Fuel Throttle table very rarely requires changing from Omex’s standard values. The standard values have 0% fuel at 100% throttle, allowing a flooded engine to be cleared by using full throttle whilst cranking.

In general, an engine that has too much starting fuel will start and then immediately stop again. If there is a very large excess of fuel, the engine may even ‘kick back’ as if it were too far advanced on the ignition. An engine with too little starting fuel will crank for a long time before the engine will start. Both of these situations call for a change to both the Start Fuel Pulse table, and the Start Fuel Coolant table. If the engine starts but will not rev freely for the first few seconds of engine running, then the Start Fuel Decay table usually requires attention.

Best regards

Andy Cornock

Omex Technology"

Ok.. So some I can see is lifted straight from the book of lies.... Some clues in here too.. Will now set up screen so I can play with the settings as suggested... Cold running doesn't last for long with a V8 ! :)

Shame he only mentions settings will need to be adjusted.... Anyone got a chimp or cat willing to run across the keys when I need adjustments ? No idea which way.. Me thinks a phone call is required.

Shame he didn't offer hugs or cuddles though.. Maybe it's because he's shy. Still, good news is they are alive and can write stuff...

Neil

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Cold Engine Running

When cold, engines require different amounts of fuel (and air) to run correctly. The method for setting-up the cold running and idle varies dependent on the load sensing and idle controls used. Note that the cold setup cannot be done until the engine is fully mapped for warm conditions as all of the cold running tables are modifiers on the warm running maps.

The below procedures may need to be followed several times to get the cold running correct, with the running improving by smaller amounts each time until perfect.

Throttle position for load, no idle air bypass motor

Ensure that you have completed the warm idle and warm transient fuel setups before continuing.

Arrange the screen so that you can see the Coolant Fuel Trim table, the Accel Coolant Trim table, and the parameter Spark Idle.

Start the engine from cold anyway possible. The cold running must be completed before the cold starting can be completed.

As the engine warms, watch the parameter Spark idle. At all cold temperatures, adjust the values in the Coolant Fuel Trim table to give the lowest number possible in Spark Idle. When the Coolant Fuel Trim table is set at a particular temperature, blip the throttle and adjust the Accel Coolant Trim table to give the lowest number possible at which the engine still picks-up nicely (or if using wideband lambda, the value that maintains the current lambda reading).

This is the cold running after the engine has started and after the ASE decay timer has expired.................... I though that this was OK on your setup ?. Bear in mind that without an idle control valve \ EAV you wont be able to get a steady idle until the coolant temp is somewhere between 40C to 50C ............ but that soon happen with the V8's

Engine Start Condition

During cranking, the fuel and ignition are not controlled by the main fuel and ignition maps, but instead by tables and options.

The cranking condition is defined by the engine speed options Min RPM and Start Exit RPM. Min RPM is the engine speed at which the engine is considered to start cranking (typically 50 rpm), and Start Exit RPM is the engine speed above which the engine is considered to be under normal running ie no longer cranking.

Ignition

Whilst cranking, the ignition timing is determined by the Start Ignition option. This is set in degrees and would normally be a low value eg 2 degrees.

Fuel

Start Fuel Pulse Table- This is a single shot of fuel that may be injected into the engine at the start of cranking. The value in the table-selected dependent on temperature is multiplied by Microsec/bit to give the fuel pulse in micro-seconds

Start Fuel Throttle Table – This is the amount of fuel injected in cranking, dependent on throttle position, while the engine is starting. This value is VE (same as main map) so is multiplied by Microsec/bit to give the fuel pulsewidth.

Start Fuel Coolant Table – Extra fuel added to the Crank Fuel due to temperature.

Start Fuel Decay Table – This determines how quickly the additional start fuel decays over time. This is a linear decay in seconds after cranking commences.

Again, nothing really new here ...... I guess you already had sussed that one........

Setting-up start fuel

It is important to note that the Coolant Fuel Trim table is always active, ever under cranking conditions, and so the cold engine running must be completed before the cold starting can be fully calibrated.

The Start Fuel Throttle table very rarely requires changing from Omex’s standard values. The standard values have 0% fuel at 100% throttle, allowing a flooded engine to be cleared by using full throttle whilst cranking.

In general, an engine that has too much starting fuel will start and then immediately stop again. If there is a very large excess of fuel, the engine may even ‘kick back’ as if it were too far advanced on the ignition. An engine with too little starting fuel will crank for a long time before the engine will start. Both of these situations call for a change to both the Start Fuel Pulse table, and the Start Fuel Coolant table. If the engine starts but will not rev freely for the first few seconds of engine running, then the Start Fuel Decay table usually requires attention.

Some good info here ................

So the coolant fuel trim is global for both cranking and running ............... fine..........then you should be able to calculate the cranking pulse widths at any given temperature by referencing the tables.

"In general, an engine that has too much starting fuel will start and then immediately stop again." ......... this is true, but yours was not starting, so I doubt very much whether you have too much fuel............. this statement usually is more applicable to the immediate 'after start' fueling ...... i.e. engine cranks and fires, then runs briefly and expires.......

The start fuel decay table is what I originally thought it might be ................. its what in MS is termed as the 'After Start Enrichments'.......... this is extra fueling for a preset period to 'settle' the engine, mine is fixed for 8 seconds and decayed for 3 seconds .............. we need then to set this table correctly. I will post up an ASE table suitable for a V8.......

HTH

:)

Ian

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Ian / Nige,

Sat down last night with all my notes and detail from this thread and built a simple spreadsheet to calculate what settings I thought I ought to have in the Omex ECU for better starting...

post-1475-1203254211_thumb.jpg

The blue lines are fields for input into the ECU.

Orange and Yellow show the crank pulse and initial start pulse respectively that have been calculated.

Uploaded, cranked with the throttle at 10% (This lets in more air but no additional fuel under cranking) and it fired almost immediately.

It became clear it was over-fuelled when running so I'll knock the Start Fuel Decay down. I counted from start to steady running and it was 20 seconds.. So too much fuel after start is suspected.

After a few hours walking the dog / watching my son train at rugby it started again first crank and again still sounded overfuelled (Spluttering) with 10% throttle and settled after 15 seconds.. Again once Fuel Decay runs out. (MS version is ASR)

Questions...

I've based the Total Crank Pulse based on BBC's information and the reast on Fridge's as his engine seems most similar to mine.. 4.6, RP4 cam and nothing too hairy!

What's your views on the Total Crank Pulse numbers in Orange?

(I've based the numbers on the normal running pulses at 800 RPM tickover, but factored in the coolant table which we now know is active in cranking and running..)

Is there a way to add extra air on a simple timer rather than holding the throttle or having anything else linked to the ECU ?

More fun later... Sticking buttterfly on the plenum to sort this afternoon...

Neil

Edited to correct source information used.

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