Audi RS2

[AVP]

well because that motronic map is done for my car as it is now,with the same excact equipment and it works. i thought that this map i have is giving me about 430 crank hp so having those info on how it is done would give me a good idea of how to try and match it eventually.

I dont have time or access to a dyno atm and if i did i would prefer someone who has more experience in tuning to do the job,but i do have a perfomance box from racelogic and i can do runs here and there and compare them.It will take more time,but at least it will increase my knowledge on tuning this thing..

building a proper ignition timing map needs a dyno for sure,unless you are veeeeery experienced and you can do it on a private road.I may have to check it/ fine tune it in the future.

[gunni]

I see,

you must also know what the other variable factors where present at the time of your motronic map construction
air temps and such as the compensation tables in the motronic will have had an effect on the actual ignition output.

[AVP]

yes i do understand that you are absolutelly right.

my mapping was done in germany in about 15C ambient temps at that time and motronic does use ignition retard based on MAT,but so far i can only add fuel with VEMS. hopefully on a good working 1.1.50 version i can add that to the equations.

good thing is that my IC is efficient,and i only get high MAT only after hours of standstill idle and heatsoak,which quickly goes below 44C which is the threshold seen on motronic to retard.

im playing it safe adding a bit more fuel anyway and slowly giving some back to check the ideal circomstances so far.

today i switched EGO correction off to  tune my VE map better and i actually got the accel.enrichments working!!!!

runs much better now!

small steps of progression....

a few things about cold idle though: though my settings for warm idle with the ISV are very good, it is very bad on cold idle.So today i took the ISV valve off the equation a bit more,so that ignition timing will work more on that area of coolant temps as well. Seems better.

more tests needed though!

[AVP]

Latest idle control setup is:




basically the cold start is the only problem now and with this latest table it seems to respond much better. Hopefully i wont have to tweek it too much after that!

Also managed to fine tune my VE table up to 4000rpm and 150kpa so far which is nice!

[AVP]

tried today for another cold start.

symptoms: Cars requires more secs to start(although i havent touched crank startup settings)

When it firesup, it goes directly to 800rpm,EGTs are very low(about 200-300C= quite rich due to warm up enrichments) and it goes near to stall or stalls after a small accel. on throttle as it comes back to settle on the rpm value.

So although settings for cold start(coolant temps around this time of year are around 24C) are a bit better than before,im wondering if i need to use the IAC more on start up(from 65-to 80 or something) and/or play around with ignition based timing on start up more as well.I dont want to touch the PID settings again as they seem to work beautifully for all other circomstances.

Would it also make a diff. if i reduced the warmup enrichments on that coolant bins as well?

[gunni]

I would begin with opening up the ICV to let in more air.
You´ll have to fiddle with the pwm table to find the right number for each coolant temp.

Same with startup, if it´s harder to start it usually means it needs more fuel to start.

[AVP]

hmm ok then

what ill do is leave warm up enrich. as it is now and play around the ISV pw table as it seems that it needs more tweeking

thanks!!!

[AVP]

played around a bit more today.
i think it is better now,but somehow now when cold revs dont go to the 1100mark,but stay on 800-850rpm and gradually the idle seems more stable...

at that point, the mixture is quite rich,so im thinking of maybe reducing the afterstart enrichment value to test.
it is 99% now.

also if cranking takes longer,does it usually need more PW or less? (high impedence injectors)

[AVP]

when i look at the VAGCOM logs,it seems that motronic is keeping about 8.9 to 9.2Deg of advance in idle,on warm engine and 800rpm. Now would that mean that the ISV is doing more work to keep idle stable there?

im using about 15deg now on warm engine and it is fine...

[rob@vems.co.uk]

I think that the idle of 8-10 degrees would be worth trying, you are attempting to get the VEMS to mirror the same sort of settings as the Motronic so it seems an idea to at least experiment with it.

[AVP]

i think im a bit at a loss here...

1) although vagcom tells me i have 9-10Deg advance on idle, and 800rpm, on the ignition timing map,i have 18.75deg on that cell!

2) it seems that im getting a difference of about 100-120C on EGTs on low revs like 1500 till 3500 until the area of lower lamda values kick in to settle things, and this happens with vaccum till 0.2-0.4bar of boost.

i cannot understand why this is hotter than the original as it makes no sense to have lamda less than 1 on those areas!

I tried(just to satisfy my curiosity really) to make the spark map on those areas less aggressive,and of course it brought the EGTs even higher by a few C.

im going to see my data logs on that area.

As for the idle,it is perfect BUT still sits up to 100C higher than the oem. I refitted the OEM ECU just to check and in a hot engine,it actually sits around 480-520C and on VEMS it varies from 570 to 610C

what is wrong???

Rob, can i send you my msg to see?

[Sprockets]

Ok, first thing.  Never assume always measure   Unless I can observe it, I never trust anything. From the weather to TDC marks, it always holds true.

So, following that piece of advice from my dear old dad, forget what is in any box on a PC screen, what value is the engine actually using? Verify OEM and VEMS with a strobe.

Second, I assume you are using the same EGT and lambda gauge for both the OEM and VEMS? Different gauges can read different values for the same real life temp.  It's all about repeatability rather than accuracy for comparison sakes.  What lambda is the OEM running? should be 1, but as I say, nothing in this life is a given

Also, any chance of a scope on the OEM injector to see the stock PW/injector firing trace?

And lastly, if you say you have a great idle, why worry about the EGT's?  I have tuned many a car without EGT and they have ran hard and good   Sometimes ignorance really is bliss lol

-Gavin

[AVP]

Yes i could go that way and be done with it but i think all factors play their role. Of course the more i complicate things,the more difficult they become to finding a solution.

Let me put it this way. Car was mapped,no hardware has been changed, everything works nicely with OEM ECU.Use an EGT sensor on the turbo hotside and car was mapped according to readings from that, and wideband that was located in the original narrowband wideband at the time.

Changed to VEMS.Added and EGT sensor,but after a misunderstanding with the shop that fitted it they have fitted it away from the turbo,thus reading less than what the original EGT sensor i had fitted on the turbo hotside reads.After lots of data logging and comparison,on lower EGT readings i get a difference of 150C between those two sensors and as the temperatures rise,that gap closes to 120-110C. So eg. when the hotside shows 550C the EGT that feeds VEMS shows 400C. When the hotside reads 800C, VEMS sees 685C and so forth.

IM not keen on having the car working on such high EGT temperatures as i know it is not healthy for the engine.I believe that the map on the motronic has been done to the highest safest level so trying to get VEMS to do what motronic does is something i can use as a reference.

I dont have all maps from the motronic.I dont know how they interconnect to create the final result.So im trying to utilise VEMS maps in to get the live data that would seem to be closer to the motronic.That would be safer possible i think.

after a quick comparison on the logs it seems that possibly a couple of deg.reduction in advance may have caused a small EGT drop.So maybe this is an overly advanced map....more looking into is required.

ALso i realise that my idle is very good,but the fact that the ISV is not working as it should is the reason why i get higher EGTs on idle.So when i start moving,instead of starting at 480C and gradualy EGTs rise as i move along,imagine that this happens from 580C!!! no wonder i drive around on normal city driving and reaching up to 700-750C!!!!. that is highway cruising speed EGTs!!! not simple driving around!

i know im talking about EGTs a lot,but it is something that reflects the combination of spark+fueling,and something that i have a reference between the 2 ECUs

[gunni]

Has your VEMS EGT been configured correctly?

And then again stressing what Sprockets said,
you need to forget assumptions.

Check the live actual timing values before concluding anything.

Rememeber

assumption is the mother of all mistakes.

[AVP]

how does one check the actual timings?

EGT settings were set from Marc