megasquirt - post your tables/msq here

[Sergio]

Everyone needs to run their injectors in "simultaneous double fire" - anything else is idle suicide on a V6 with MS1 or 2. Don't just bandaid the problem by running rich - the very first EFI systems back in the day (before sequential) used this and were able to idle at stoich!

Set injector staging to simultaneous and 2 injection events per engine cycle.

Also set a proper injector opening time - note that this should really be labeled injector dead time because it is really t = injector open - injector close. If you have Milly S injectors, put in 0.78ms.

Now you can idle at 16:1 AFR if you so choose.

Verify ignition timing with a light and the engine will like anything between 10-14, with a slight preference to the higher end of the scale.

[poissonn]

why did you say the exact opposite (2 squirts/alternating) in this thread?

http://forums.probetalk.com/showthre...t=simultaneous

[Sergio]

why did you say the exact opposite (2 squirts/alternating) in this thread?

http://forums.probetalk.com/showthre...t=simultaneous

Because that was before I actually completed my MS install (that post is a year old) and wasn't aware of of how MS actually handles fuel timing - which is all undocumented.

[poissonn]

Well then I might try simultaneous...it's just that everywhere on this board I read that it was better with alternating...

[Sergio]

I've done the research, the simulatenous double fire comes from a Ford research paper from the 80's when they were looking at injection methods. It was concluded that if you are not running Sequential then you must run SDF to ensure consistent fuel delivery to all cylinders.

I have oscilloscope traces that prove MS is very flaky when it comes to fuel timing events. It changes the fueling trigger point every time the car is started or it resyncs so when the fuel timing is off for one bank of cylinders they will have misfires. The "fix" was to run rich as needed until the misfires went away.

Switching to SDF was the best improvement to idle quality that could have ever been made. I even passed my sniffer emissions test since the HC and CO was now in spec, idling at 14:7 and without misfires.

[TravisWilliams_GT]

I've got to get the pc hooked back up to the scpgt and check that.......

[poissonn]

Also set a proper injector opening time - note that this should really be labeled injector dead time because it is really t = injector open - injector close. If you have Milly S injectors, put in 0.78ms.

hey Sergio, can I ask how or where you found that 0.78ms opening time for the milly s injectors?

[Sergio]

hey Sergio, can I ask how or where you found that 0.78ms opening time for the milly s injectors?

Here's how it's done:

1) Warm up the car fully.
2) Turn off all EGO, and IAC control
3) Manually set your VE table so you idle around 14 AFR (it's not too important)
4) At this point you should be running Simultaneous/2. Turn off the car and change to Simultaneous/3
5) Restart it and observe the AFR at idle. Adjust your 'injector opening time' until the AFR is the same as in step 3.
6) Keep tweaking it and switching between simultaneous 2 & 3, until the AFR is the same regardless of which one you are running.

[ausloki]

Here's how it's done:

1) Warm up the car fully.
2) Turn off all EGO, and IAC control
3) Manually set your VE table so you idle around 14 AFR (it's not too important)
4) At this point you should be running Simultaneous/2. Turn off the car and change to Simultaneous/3
5) Restart it and observe the AFR at idle. Adjust your 'injector opening time' until the AFR is the same as in step 3.
6) Keep tweaking it and switching between simultaneous 2 & 3, until the AFR is the same regardless of which one you are running.

Is there a similar method for those already running full sequential on MS3, I'm assuming at step 4 you mean you were running alternate.

[H_type]

Hey Mac do you have your old maps for the long tuning you spent via passenger with the milly S injectors?

[poissonn]

Well I tried simultaneous injection today...and it wasn't very successful! I had this lumpy idle! It would go down to 600 rpm then up to 1200 even after tuning the VE map. Any ideas on this? I'd really like to idle at more than 13.2 AFR..

[Sergio]

Well I tried simultaneous injection today...and it wasn't very successful! I had this lumpy idle! It would go down to 600 rpm then up to 1200 even after tuning the VE map. Any ideas on this? I'd really like to idle at more than 13.2 AFR..

Simulatenous/2? Is your IAC cold air path blocked off if you bypassed the coolant lines? Try fixing your timing to 12-14 while you try to dial in the idle.

[poissonn]

Everything is stock idle control wise! I have already have the timing set to 13*...I don't know why it acts like this....

[stoker100]

i found small variations in the A/F ratio around idle seem to make the revs go everywhere, i would manually adjust the bins around idle to ensure your AF's are close. that always seems to work well for me. i would also block your IAC cold air path, let me know if you need help doing this as i have pics somewhere.

[sleepinglh]

Well I tried simultaneous injection today...and it wasn't very successful! I had this lumpy idle! It would go down to 600 rpm then up to 1200 even after tuning the VE map. Any ideas on this? I'd really like to idle at more than 13.2 AFR..

So far this is my 5th day with MS PNP.
I tried SIM 2 fire but it was about 5-10% rougher compared to ALT 2 fire(current setting)
It used to be 10-12degrees of timing in idle area + 6ms of dwell(very bad and ran like crap, came from base map now its set to 3ms, all good)
I have 1litre/min injectors and right now they idle from 750-850rpm when cold and 650-750rpm when warmed up.
base fuel pressure during idle is 25psi
AFR is around 14.5 to 15.4 during idle.
I found that 20degrees of advance @ idle can make a hell of difference to the idle quality, should give it a try.
Also try bringing your timing and VE idle area values closer to the adjacent boxes otherwise it might cause your idle hover between them and thus cause it to go unstable.
Took me 3 days to figure out after reading numerous posts and now the result is a stock like cold start and idle every morning or during heat soaked conditions.
Good luck.