Irratic running - stable VE gives different lambda?!

[mattias]

Disable "Injector staging" by setting unreasonably high threshold values (as suggested by "F1 for help").

I would move all the functions that you drive with low current drivers to the free ignition outputs instead. I simply don't trust them for anything but a small LED.
It might come back to bite you in the ass when you loose the low current driver chip, which then kills power to the trigger input chip (you're running VR sensor) leaving you stranded by the road side.

What size are the throttle blades?
Something is really odd about your fuel map and the lambda sensor, and it can be hard to get a grip without being there.
First look, I would say it's not near tuned yet.
What sucks too is that the TPS signal in itself sucks as a low load signal.

I would probably recommend something more recent than 1.2.6 as well. There were some sketchy things going on, hopefully less so than what we got in 1.2.23.

[se7ensport]

I am running a second set of injectors, 215cc in the head and 440cc in the TBs. All the low RPM issues that I'm trying to resolve are well before the second set are activated.

So fan and fuel pump are currently on the P259 4 and P259 5, I assume these are the low current drivers you are referring to, I'll move them to an ignition as advised.

Throttle blades are about 40-42mm x 4

I know the tuning is out, but until I can get some repeatable results I don't want to mess with the map any further.

I am questioning my injector deadtimes again:

Option 1 - I have found a set of injector calibration data for the larger set of injectors http://eficomponents.com/specsheets/bluegiant127.pdf

Both sets of injectors are modern Bosch EV6's, the small set are 0280156154 and the larger set 0280156127, I'm curious if Ford have specified very similar/same characteristics.  Do the figures in FNPW_OFFSET directly relate to the simplified deadtime table?

Option 2 - moving back to Traditional using the technique Gunni posted; are the values in the help files now correct ie. Injector Opening Time @ 13.2v = 0, effective rampup = 200 (is the rampup figure in the above table?) and rampup voltage compensation = 4080?


Couldn't agree more that something sketchy is going on! I'll upgrade the firmware and see if it changes anything.

As always, thanks for the constructive input, my motivation is slowly coming back.

[VEMS]

Hello Se7ensport,

I have reviewed the logs you posted and have some initial observations.

1) start by re-adjusting your accel enrich bins (for an Alpa-N car i suggest: dTPS 15, 30, 60 120 Enrichment 2, 4, 7, 10), your current accel enrichment bins make it engage much to early and with way to much fuel, this might cause the bogging effect you describe.

2) also during accel enrich situations EGO switches off (keeping last correction if enabled, but when disabled like in your configuration) reverting to 100% correction -> result, more fuel.

3) avoid any sharp breaks in the ignition table especially around the driving off area 800-1500 rpm 0-15% throttle (in alpha-N this also leads to sharp VE table steps requirement, because actual airflow into engine is dependant on throttle opening and ignition advance (or rather produced engine torque))

4) avoid enabling the before throttle plate injectors (staging set) on such low airspeed, they work properly only when throttle openings are quite high and airspeed is also high. I recommend minimum rpm 2800-3000 rpm and 40% throttle to enable second set.

5) retune the VE table with ego control off, so measured lambda is close to (a bit richer than) desired lambda.

If you follow all hints above, i am sure you will find the engine behaving more predictable. If any problem persists, please make another datalog (.vemslog) and make a sharing report so i can review (link to this can also be posted on the forum).

Best regards, Dave

[se7ensport]

Upgraded firmware and vemstune to latest.

Moved output channels to spare ignitions as advised.

accel enrich bins adjusted (dTPS 15, 30, 60 120 Enrichment 2, 4, 7, 10)

EGO freeze correction enabled.

Started it up to make sure it ran and noticed that the spark angle jumped all over the place, between 10 and 14 on tickover.  Based on the RPM/TPS table it should be 17 degrees, but ignition based idle control is off, so what is causing the variation?


http://vems.hu/vemstune/sharingcenter/reports.php?cmd=view&key=ID2tEj

[se7ensport]

Rolled the firmware back to 1.2.6.

using 1.2.23 and at tickover i get 9.5-13.5, using 1.2.6 and i get 19.5!!!!

log using 1.2.6
http://vems.hu/vemstune/sharingcenter/reports.php?cmd=view&key=3PgRoU

log using 1.2.23
http://vems.hu/vemstune/sharingcenter/reports.php?cmd=view&key=Tq1bb3

what is going on?

[mattias]

(looking at your 1.2.23 datalog)

900 rpm is the lowest RPM bin in your ignition table. Below 900 rpm the ignition advance will interpolate between what you got in that table, 15 degrees, and your cranking rpm which is 25 degrees.

You also have to adjust the new table in 1.2.23 which is the CLT/TPS ignition adjust table. You have -32 degrees in that table, better start off with 0.
Please read the notes before using : http://www.vems.hu/wiki/index.php?page=GenBoard%2FUnderDevelopment%2FFirmwareChanges

[se7ensport]

A default of zero would have been good.

I can't find this table to adjust, which section is it in?... I am using 1.5.24 (2014-01-08) vemstune, downloaded the latest nightly 2014-02-06 but it still opens as 2014-01-08. 

[mattias]

It's in the "Tuning" menu like all the other common tables.
I agree, a good default would've been nice.

[se7ensport]

I'm sure I'm not going mad

scaling is massively out:
http://locostbuilders.co.uk/upload/tmp_DSC_0564-59091739.JPG

[mattias]

I'm sure you also "updated the ini files manually" as it is suggested on the firmware changes wiki page?
It's in the Preferences menu.

1.2.23 reads specifically :
     as always, VemsTune must be newer than firmware, use the most recent, and don't forget to run iniupdate

[se7ensport]

Cheers Mattias, "user error" on my part.

[VEMS]

Hi Guys,

Safe default values are provided in default_config_1.2.23, but unfortunately due to the way the CLT/MAP Ign adjust table is mapped in memory on firmware upgrade they are not applied default.

I have therefore applied new config criteria (will be fetched through ini update together with the latest ini's) to warn user specifically if if any bad configuration of CLT/MAP Ign adjust table is detected. Of course without the latest ini's VemsTune does not provide warning, thats why we always ask to update ini's first.

Best regards, Dave

[se7ensport]

Thanks all for the suggestions and for getting the new config running.

I am still getting the same symptoms that caused me to open this thread initially. 

I have now captured them in two short log files at tickover, I literally turned the engine off after running for a couple of minutes and restarted it, this caused the lambda to go from 0.65 and off the scale to 0.87.

What is changing within vems for this to happen?

initial start up:

http://vems.hu/vemstune/sharingcenter/reports.php?cmd=view&key=bZjegt

restart:

http://vems.hu/vemstune/sharingcenter/reports.php?cmd=view&key=BC5iQC


James on another thread is reporting similar issues, although no log provided: http://www.vemssupport.com/forum/index.php/topic,2220.0.html

[Sprocket]

I'm wondering if this might have something to do with the way in which VEMS can run sequential injection without a secondary trigger. A potential problem with that is you will never be sure whether you are injecting on the intake stroke (fuel almost going straight into the cylinder) or the combustion stroke (fuel sitting in the port for nearly half engine cycle), thus a particular engine set up could potentially run differently?......................

the angle at which the injector injects fuel in the port could also potentially cause differences in this sync free sequential system. Are your injectors positioned as the OEM had intended?.... I'm not saying it is a problem, just suggesting other  possabilities. I can at least say I experienced a similar but less noticible effect on my engine without cam sync, but it was not so noticable to be concerned about at the time.

Do you have the facility to run a secondary trigger on this engine?

[se7ensport]

Hi Sprocket

The first stage injectors are OEM and in OEM location.

Fitting a secondary trigger is possible, but a real pain as I need a very specific cam cover that will also hold COP.

I agree with you that the the timing of injection will impact burn efficiency, but this seems to be something else as it is such an extreme difference.

Is there a simple way to rule this out??? would doubling the number of squirts per cycle so that it fires half the fuel on a closed valve and half on an open valve do it, if this is the issue the behaviour should become consistent and irrelevant of cam position in start up.