TTP Max / Min rough values?

DeJi · Post by **DeJi** » Mon Jul 13, 2009 9:54 am

I'm going to tweak this table tomorrow to try and remedy my extremely rich idle mixture that doesn't seem to go away no matter how much I tweak K constant (which leans out the rest of the map, but not idle revs..).

Does anyone have a slight idea of what I should set TTP max / min to? I'm running 555cc Nismo injectors (pink) and Z32 AFM in a CA18DET engine.

Should I make it a linear scale, with all the same values, or should the values increase as revs increase?

If I have the same value across the whole TTP min table, and AFR's are fine, I should be fine right? I mean, as long as I adjust the fuelmap to suit. Or can I still have some issues with fuelling if TTP min is way off?

Zuikkis · Post by **Zuikkis** » Mon Jul 13, 2009 7:23 pm

First of all, I think that even the latest Nistune has CA18 TTPMIN/TTPMAX tables reversed..

TTPMAX should be full 255, I see no reason why it you should set in any lower. So in Nistune this is the TTPMIN table.

TTPMIN needs to be setup very carefully, CA18 idle is very difficult with big injectors! First lower the entire table until you get about 14.7 AFR. At this point it's very likely that rpm will start lowering and AFR gets ridicuosly lean, 17-25.. You can try fixing it by increasing the injector latency, but usually you need to increase the left hand values of TTPMIN.. Usually it's good if the first value is at 255, then ramp nicely to lower values.

If you get oscillating idle, monitor how the AFR goes with the oscillation.. If it gets leaner when rpm goes down, you need to increase TTPMIN at low rpm..

DeJi · Post by **DeJi** » Mon Jul 13, 2009 8:53 pm

thank you, that's very helpful

TTP Min is the lowest time the injector will be open for, and TTP max is the maximum time? And maximum should be set to 255 across the table, and the min table should start out where AFR's are good, and gradually ramp to lower values?

This makes the minimum length pulses shorter and shorter as rpm increases.. why? Not criticising anything, just want to know why

DeJi · Post by **DeJi** » Tue Jul 14, 2009 5:52 am

been out for a while and _nothing_ I do can lean out my idle mixture. As soon as I get over 2000rpm or so, the mixture is perfect, but I can't do anything at all about the first 4x4 cells, except richen them even more.
I've tried changing the K-constant from 300, to 400, 500, 600, 700. Made it progressively worse. Okay.. so change to 200, and then 100. Also made it worse? Wtf? Which way should I tweak K-constant to get a leaner mixture?

I also get pops and bangs out the back when engine braking, which I didn't have before, and also when it happens my wideband reads LEAN (leaner than 1:24 or whatever it is). If I have very little throttle, just before it triggers the idle switch, it doesn't pop or bang at all.

Tried tweaking the TTP max and min settings aswell, but same thing there.. I started out setting the whole table to the same value just to see if it would actually do anything at idle. Nothing I did changed a thing for idle revs.

What else could it be? Anyone got an idea? Please? I have a 3hr drive to the tuner tomorrow morning. Luckily the AFR's and EGT's are fine when coasting and even booting it, just not idle revs.

iaredam · Post by **iaredam** » Tue Jul 14, 2009 2:03 pm

Sounds like an Injector Latency issue. ( I don't know if the CA18 ECU has a latency... ) If there is a table for it, try lowering it.

DeJi · Post by **DeJi** » Tue Jul 14, 2009 5:25 pm

Latency has to stay at 1050 or so for idle to remain stabile. If I lower it, it does lean the mixture, but it starts to swing back and forth between 12-18 AFR, sometimes cutting out. Is there another way to cure the swinging AFR problem to compensate for the lower latency?

raddy · Post by **raddy** » Tue Jul 14, 2009 8:52 pm

did you disconecteed narrowband o2 probe before adjusting AFR at idle?

Nissanclubman · Post by **Nissanclubman** » Tue Jul 14, 2009 11:46 pm

Just something I've noticed that could be throwing your adjustments off. Matt perhaps your could confirm this for me.

In the address file the addresss locations for the tables are

#TTP MAX/MIN
TTP_MAX,&H3F40,8,1,8,1,TTP MAX
TTP_MIN,&H3B00,8,1,8,1,TTP MIN

I think they should be

#TTP MAX/MIN
TTP_MIN,&H3F40,8,1,8,1,TTP MIN
TTP_MAX,&H3F48,8,1,8,1,TTP MAX

If you use the Nistune application and adjust these tables the results just don' t make any sense when compared with all the good information in the thread.

If however you manually adjust the .BIN files at the "I think they should be" address then it all starts making some sense and works the way it should.

Also in the address file it has listed

TP_RECOVERY,&H39A0,16,1,16,1,TP Recovery?

This I think is the second half of the JDM ECU (D003) intake butterfly adjustment table.
The matching pair I think are:

H3990,16,1,16,1,Variable air close
H39A0,16,1,16,1,Variable air Open

This is just what I have found from my own fiddling. I do have the (CA18DET) D003 ECU and have also notice that some pin outs on the ECU don't activate if you use the wrong base Bin file for the ECU even though they may be both CA18DET files.

I'm happy to be corrected on any of the above.

Matt · Post by **Matt** » Wed Jul 15, 2009 2:38 am

i think those tables should probably be put back. I was experimenting with them but the changes got in the latest versions

DeJi · Post by **DeJi** » Wed Jul 15, 2009 6:34 am

raddy wrote:did you disconecteed narrowband o2 probe before adjusting AFR at idle?

I put the temperature to 205, yes.

I just got back from the tuner. I now have a real nice fuel curve everywhere except on idle. Could it be the idle control valve? Cause it feels like the problem doesn't happen unless the TPS idle switch is triggered. I'm gonna try tweaking the idle screw later.

steveb · Post by **steveb** » Wed Jul 15, 2009 7:10 pm

i had something quite similar with mine. have you taken off the idle control valve and taken it all apart and given it a good clean? i had loads of black gunk inside mine, cleaned it out and it idles nice and smooth. what power did you make on the rollers?

DeJi · Post by **DeJi** » Fri Jul 17, 2009 9:29 am

haven't cleaned the valve for a while.. might try that. I did unscrew the idle air screw a turn and a half or so and I think it got a little better. The screw is kinda far unscrewed though so I'm not sure it'll fix everything..

I made 340bhp and 398Nm on the wheels @ 1.6 bar boost

Specs :

GT2871R turbo, XS power manifold and 3" downpipe

Stock cat.converter (!) and frontpipe, 3" catback exhaust (need the cat for MOT, have ordered a 3" race cat)

Port/polished head, blueprinted intake, CPC plenum and KA24E throttlebody

XS Power FMIC and homemade piping. Forge recirc dumpvalve.

Nismo 555cc injectors and Walbro fuelpump, stock FPR and fuelrail

NGK BCPR8ES spark plugs and super spark coils

Forged internals and 1.6mm MHG. Stock (but new) headbolts

Polyurethane engine mounts and stiffer gearbox mount

AP Racing 4puck paddle clutch with Nismo cover

A'pexi AVC-R boostcontroller

19 row oilcooler and Koyo 2" radiator with Volvo electric fan with revotec fancontroller.

steveb · Post by **steveb** » Mon Jul 20, 2009 4:36 am

thats a nice power curve you have there, loads of torque too. i would have thought with that tubby and setup you would have made a little bit more power. do you have much more timing to play with on the map? or was det rearing its ugly head?

steve

DeJi · Post by **DeJi** » Mon Jul 20, 2009 7:12 am

We backed off a few degrees after it started detting, but I think that 391hp at the crank is pretty damn good for a .64 A/R GT2871R @ 1.6 bar. As I said, I was also running with the stock cat.converter at the time

steveb · Post by **steveb** » Mon Jul 20, 2009 7:38 am

did you manage to sort your latency. i run with denso 550's too and have a k of 325 and latency of 850. i do think i have to look at my latency a bit more as i had a sort of stumble as it was coming on boost, then right at the top of my map

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TTP Max / Min rough values?

TTP Max / Min rough values?

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