VEMS: the unstoppable pulsing idle

[loxxrider]

So you are not using PID for now correct?

If that is the case, then the main thing I think of is not enough fuel on idle. If you don't have enough fuel, the car will pulse like that constantly.

[A80Avant]

yes, please post the config to see what excact settings you have. at the moment my idle is working fine(last time i checked) with the only issue of sometimes causing a minor drop on several occasions, but never stalling. This is something i know that i will solve in due time, as it is partially PID related and also a conjuction of PID and ign. based idle control. These 2 are working in conjuction and always will cooperate, so a delicate balance must be found.


@ PRJ: can you tell me on motronic, from which rpm the fueling becomes rich and what is the timing on that area of the map?

[prj]

It gets richer below 760 RPM and a LOT richer below 600 RPM.
Idle is around 800 RPM at stock. So you can see why that is so.
Timing is around 16 degrees in those areas (before corrections).

[A80Avant]

is it that as it gets richer, it allows the car not to stall?

[prj]

Well, more power is made when it goes richer, so I'd assume so.
Why else would all the I5's I've seen be mapped that way?

[loxxrider]

Mine is much richer in the idle area as well. It just has to be or the car won't run right. Definitely just try giving it more fuel

[A80Avant]

loxi, can you send me your config, or send me the lamda table to see how you have configured it?

as on 1.1.81 i have such a small table to play with i want to dedicate lots of bins on the idle area but i have to compromise.

[loxxrider]

ah yes sorry I didn't know you were referring to me when asking for the config

here is a recent config. I have leaned out the cruising range a LOT recently, but didn't save the map yet. I can post that when I have more time if you need it. Its pretty rich in the cruising range with this map.

Mind you this is for 1100cc injectors and a Holset turbo. It probably won't apply to you much, but maybe you can get something useful out of it.

Why do you have a small table on 1.1.81?

[Billman]

ah yes sorry I didn't know you were referring to me when asking for the config

here is a recent config. I have leaned out the cruising range a LOT recently, but didn't save the map yet. I can post that when I have more time if you need it. Its pretty rich in the cruising range with this map.

Mind you this is for 1100cc injectors and a Holset turbo. It probably won't apply to you much, but maybe you can get something useful out of it.

Why do you have a small table on 1.1.81?

What displacement and what cams? Boost?

[Bram]

Shouldn't this VEMS thread be in another aftermarket Engine Management sub section? Just to get everything a bit organized

[th.b.w.]

I have rampup the ign. at 700 RPM to 16deg. and set at 1100 RPM 9deg.
Than you have ~10-11deg- at 900RPM, when rpm now fall down it ramp automatic up and increase speed.....

look at my configfile in the I5 Maps thread.....

Lambda is at 1.00-1.02 at idle. works fine for me.

Thomas

[loxxrider]

What displacement and what cams? Boost?

2.2l

7a cams

17psi (Holset H1C)

Its tested up to 17 or 18 psi so far. Anything below that is good too of course. Here is the one where I did some cruise tuning. I just went outside and altered it even more because it was too lean for first and second gear where the load is light. I put a lot more fuel in the very low load areas just to help it. Still not quite fine tuned, but I don't have the time for that.

I would turn it up to make more power, but I've got a LOT of ignition table tuning to do before that. I think there is 50hp to be gained at any given boost level on this map just from timing. I need an EGT or a dyno before I really want to tune that though.

[A80Avant]

thanks for that. i mean the lamda table is very small and hence when tuning the lamda to be richer on lower rpm, then it leaves less values for the 900-1100 range which i want it to be lamda=1 in order to pass emmisions and be stable on idle

[loxxrider]

what are the dimensions of the table?

[A80Avant]

lox, you are using 1.1.70 the lamda table is the same as yours. the spark table is 12x12 and lamda is i think 8x8 (IIRC). if i need to use 3 vertical lines for the idle area on lamda, im left with only 5 to tune the rest of the map lamda area that i need for cruise and small adjustments. That is doable so long as i disable EGO after 5000rpm for example,and leave the VE table to take care of the map on vaccum conditions. I now use EGO up until redline and 120kpa