CA18DET + Q45 MAF = Lean out on Boost ( Help )

Alrick · Post by **Alrick** » Sun Mar 01, 2009 11:40 am

Prior to installing the Q45 MAF... the engine was runnin normal.. with a stock S13 CA18DET MAF..

Idle AFR's of 13/14... Full boost AFR at 11..

After installing the Q45 MAF... ( using the mass air regulator feature ) the K - constant was set... at 236..

it starts and idles with no prob and AFR's at 13.3/13.4.. deadly on like fuel map...

the problems is when boosting instead of getting rich, it goes LEAN!.. all the way to 18 and beyond the AEM UEGO can read..

Is the MAF faulty or hooking up the wires wrong may cause lean out on boost ( but still perfect start and idle ).. ?

any help would be usefull.. tnx

Alrick · Post by **Alrick** » Mon Mar 02, 2009 6:25 am

Bump...

No-one had this prob before ? that might know the cause of this ?

Matt · Post by **Matt** » Mon Mar 02, 2009 8:53 pm

you may need to set your maps to 0 and then readjust your K constant so its showing 14.7:1 across the board since the target K constant is a ball park figure to set started

avoid boosting whilst doing this exercise if you can help it

see tuning guide for more details on adjusting your K constant after injector/MAF swapover

iceblade · Post by **iceblade** » Sat Mar 07, 2009 9:31 am

dont know if this will be of any help but i was told that the q45 maf although being bigger doesnt have as much resolution as the z32 maf so might be maxing out maybe

Alrick · Post by **Alrick** » Tue Mar 10, 2009 1:01 am

Tnx for the reply Matt and Iceblade..

@ Iceblade... voltage in nistune doesnt reach 5v on WOT so i dont think its maxing out.. but never know..

@ Matt... I tried what u said.. followed the tuning guide word by word... But.. after putting all cells to 0, I can get the Idle very much dead on 14:7 AFR with the K-value...
but as soon as i try to give trottle it starts leaning out..so i start adding to the cells its using to enrichen it.. but when changing the target cells to AFR u get values of 8.0 AFR or somewhere down there...

this cant be right can it ?
So what i mean is the idle cells have filtered target of 0 and 14.7 AFR.. and all other cells have i.e. 80 filtered value or 8 AFR value...

something wrong or is this right ?

Matt · Post by **Matt** » Tue Mar 10, 2009 1:58 am

post your ROM image up here and i can check for you...

Alrick · Post by **Alrick** » Tue Mar 10, 2009 2:25 am

Here u go...

I just started to tune the cells in the fuelmap.. as u will see they are already in the 8 AFR area and my UEGO wideband still states its a bit lean ( 15 AFR )

Alrick · Post by **Alrick** » Fri Mar 13, 2009 6:14 am

I am about to give up on this...
I tried everything.. it just keeps leaning out no mather what i do..

i see the timing is at -7 at idle.. dunno why.. tried altering the timing with the CAS on the CA18... stays at -7 on nistune.. but engine does work differently..

in anycase.. no help with the leaning out prob with the Q45 maf in place..

before the Q45 it ran very well with the stock maf.. but was maxing out..

So as a last resort i will post the log here that i made ..
stationary trottle to 3000 rpm.. 3 times... in here u will see the leaning out that i mean.. idles at 14 then on trottle it leans out...

Hopefully someone can shed some light on this for me.. cause i'm about to throw that q45 maf out the window...

tnx

Bernardd · Post by **Bernardd** » Fri Mar 13, 2009 9:01 am

Have you tried adjusting your ttpmax?

Matt · Post by **Matt** » Sat Mar 14, 2009 12:20 am

starting with timing

You will notice that timing goes to -7 when the TPS idle indicator on the consult panel is activated. This means that its using different maps to the main timing maps.

It should be using the Idle Gear RPM timing table which is 15 degBDTC. Which version of Nistune are you running at the moment? Looks like idle timing is not reported correctly

As for min/max TTP. Check you have the latest address file from the ROM image pack

Then decrease your minimum TTP to lower values and your maximum TTP to higher values then retry the run. The bin that you have posted and the fact you are getting about 8.29ms maximum injection time (see your log) means its not putting out enough fuel and i think these tables are adjusted wrong and causing the problem

Dwell time with latest address file looks like its come from an older synced BIN file. You will need to use the latest version and make sure this table is not FFs. I'm working on something to update older synced files when address files get improved

Alrick · Post by **Alrick** » Sat Mar 14, 2009 8:45 am

I'm using the latest release 0.9.3.6.1.... Also have the latest ROM pack 2.0

I was using the Adress file in the MISC directory of the ROM pack..
( S13_CA18_256_E_64pt )

I now used the one in the ROM directory...
(S13_CA18_128_E)

This solved the timing issue.. it now stays at 15 on idle...

but leaning out issue still stands...

I tried loading the first BIN map that came with the nistune..
changed the injector sizes with the resize tool .. then set the inj latency
changed maf with the maf tool .. then set the k value to be @ 14.7 AFR on idle..

was still leaning out on trottle.. so I decreased the minimum TTP to lower values and maximum TTP to higher values.. to no avail... leaning out still persists...

Dwell time is still low i see from the log.. so i still dont know what i'm doing wrong here..

I'll post the log again from a run around the block..

Herb-86T · Post by **Herb-86T** » Sat Mar 14, 2009 9:15 am

did you change injectors? try raising K value and lowering latency to get idle back to 14.7?

Legionnaire · Post by **Legionnaire** » Sat Mar 14, 2009 10:47 am

Hopefully someone can shed some light on this for me.. cause i'm about to throw that q45 maf out the window...

let me know what window are you going to throw it out of, i'll stand down there - I'm in need of a bigger MAF

Back on topic here. For some unknown (to me) reason CA18 uses shorter VQ-table than most of other ecus, so just using resize feature or replacing one VQ map with the (part) of another may be not a good idea. Note that your old VQ table starts at 400 region and ends at 59418. After resizing this range stretches slightly and moves right, reaching standard 65535 highest value. IDK if this may be the cause of your problem, but when you decide to do next iteration of your maf struggle, trying from scratch, write down your current K value, load old baseuse map, use "resize injectors" option, then plug in q45 maf and enter just your written K value without changing VQ map. This may or may not solve your leanout, but give this a try. Where on the load scale are you hanging at when you experience leanout?

Cheers, Petros.

Bernardd · Post by **Bernardd** » Sat Mar 14, 2009 2:02 pm

If you set your k value while the car is idling or stationary it will be too low. While you're driving at 2.5-3k increase the k value until the afr's are in line with the fuel map. Then adjust the latency at idle. Lower the ttpmin table to zero to make sure it's not effecting the pw at idle.

Alrick · Post by **Alrick** » Mon Mar 16, 2009 9:30 am

write down your current K value, load old baseuse map, use "resize injectors" option, then plug in q45 maf and enter just your written K value without changing VQ map

Tried this ... This option does not work... as soon as I hit the gas pedal.. engine starts to die..
but thnx for the tip..

If you set your k value while the car is idling or stationary it will be too low. While you're driving at 2.5-3k increase the k value until the afr's are in line with the fuel map. Then adjust the latency at idle. Lower the ttpmin table to zero to make sure it's not effecting the pw at idle.

I spent 2 hours on the side of the road trying to do this... it works better now... K value has been raised ( from 230 to 661 ).... and Injector latency has been lowered ( from 1010 to 720 )... car runs now but a little on the rich side... so still have to fine tune it.. but it doesnt lean out no more...

Oh and i couldnt set the values on the TPMIN to zero... engine just dies..
So i left it like it was...
Tnx for the advice...