2JZ Bosch 74mm DBW idle position table

[dan7773]

Hi All,

Need some assistance, basically I fitted a whifbitz Bosch 74mm dbw to my 2JZ, been having a few problems with the setup, for some reason in the TPS callibration it would calibrate ok then when finished would jump to 50%, would only do it on open/closed loop ethrottle, after i replaced all wiring for throttle and pedal, to make sure all ok as the dbw wiring slightly different to how I set up a year ago, checked, double checked all ok. Traced problem to idle base position table, found out that it’s set to 54% for some crazy reason, now I’ve reset to 5% just to get it to idle, just cannot seem to get it right, has anyone got any settings I can try, or tell me where to start. At the moment from -30 to 130 degrees it is set at 5%. It’s a stock non vvti with sard 650 and stock hybrid turbos running a thunder.

thanks ,Dan

[cj]

Did you have a mechanical throttle tuned with reasonable idle before you swapped to the DBW kit? There is no magic number for ethrottle idle and it depends what RPM you want to idle at, and how much ignition advance you have. More ignition = less throttle needed for the same RPM (and vice versa). Assuming roughly stock internals and ~15* timing, you probably want the throttle angle to be about 3-5% once warmed up, and up to 5% higher at 0 Deg.  Before you even worry about fine tuning the idle base table, warm up the engine then zero out the idle table, start with your ethrottle target table: the top "0" row - you want somewhere between 2 and 4 in the columns around idle (500-1500rpm?), and either tapering out to 0 above 2-2.5k, or holding around 2% in that whole top row (depends on how much engine braking you want - zero's = more engine braking). The idea here is that once warmed up, the engine should be close to but just under normal idle rpm with the idle table zero'd out (much like setting idle screw on a mechanical throttle). You can only go in 0.5% increments in the throttle target table. you also want to turn off idle ignition control for now as it will confuse things, and make sure ethrottle idle is set to open loop.

Now go to your idle base table that you zero'd out earlier, and set the value for the warmed up temp (80 deg C ish) to 0.3 or 0.5 or whatever gets you the idle you want when warm. set this same number for every temperature above 80 as well. Now add 0.5 for each 10 deg cooler than 80. so if your 80 deg idle number was 0.2, 70 would be 0.7, 60 would be 1.2 etc. This should put you in the ballpark but probably slightly high while warming up. Now turn it off and leave it overnight to cool. Once really cooled down connect a laptop, make it so you can see the rpm, target rpm, ECT, and the idle base table. Start the engine and wait ~5 seconds for post start enrich to drop off, then look at which temp you are at in the base idle table. wait until you warm up enough to be dead center of a cell then quickly change it up or down until the idle RPM is correct. Wait a minute or so until your temp is dead center of the next cell, then adjust that cell so idle matches what you want. Just sit there watching it warm up and adjusting the cells as you hit them. Once its fully warmed up, you can look at tuning ignition idle to make it a bit more stable. I wouldnt turn on Closed loop ethrottle idle though until the next firmware as there are currently some bugs in it where it will add in 0.4% throttle angle every time you get on the gas pedal at idle and can work its way up to being too high.

You now have a pretty well tuned throttle angle for warm up. extrapolate out from your final values to anything colder than you actually tuned to complete the idle base table. Remember, if you change the ign angle at idle you may have to re-tune this.

[dan7773]

Thanks for the reply,  I’ve had a little play around with the idle, I just set everything at 5% for the min. It starts and idle’s a little bit high but now I’ve got somewhere to start.

thanks again, Dan

[dan7773]

Managed to get it to idle very nicely, went to go for a test drive, all seemed ok, went to change from 1st to 2nd, as soon as I pressed the clutch pedal the revs picked up to 2.5k stayed there for a few seconds then dropped, then from 2nd to 3rd it reved to 3.2k for a few seconds then dropped back down.  Is there anything else I should looking at. The IACV is still fitted to the manifold, but with no power going to it, I thought that would be closed. 

Thanks, Dan

[Adamw]

Log and map will be easier than everybody guessing.

[dan7773]

Sorry I haven't got back to you its been a hectic week, I've attached a copy of the map I'm using, will post a data log of a run in the next few days, when the weather's been a bit better for a decent run. I have also found another problem, it only does it at WOT, think I'm getting a power issue to throttle body as coming up error 73 voltage error. I can sit revving the engine to WOT no problem but when I'm driving and try it goes to limp home mode. Thanks in advance, Dan. 

ETHROTTLESETUP.pclr

[cj]

Code 73 means the power supply voltage for the ethrottle has dropped off. Typically this is because the ECU cuts the relay providing this power, because the ECU error counters on various throttle sensors are too high for too long. Eg if your tps main and sub arent within 1-2% of each other the counter will tick up every second, and when it hits 100 or 255 or whatever, it cuts the throttle. We'd need a log of it driving hard for a while to hopefully see the error counters creeping up and work out which setting is off.

Looking at your map, i'd start with APS calibration. your APS main open voltage is listed as 5v but this is pretty unlikely. usually they would top out at 4.5 ish and leave 5v for error condition only - ie your TPS voltages look normal-ish.

[dan7773]

Been having problems calibrating aps sensor, as it’s a Toyota non linear I’ve set it at 70%, but I’ve gone thru 2 sensors already. When I go to calibrate it’s at 100% allready, so just to get it running I pressed pedal fully even tho it’s allready reading 100% then release. When I go to try again it works ok, it will let me press pedal and works accordingly. I’m using a Toyota sensor from a sc/ls430, I’ve pulled the wiring aprart several times, made new sections up, pins 2/5 are the signal wires, going into analog volt 7/8 respectively. I don’t really want to put my last sensor in if I’m going to kill it. I’m using the 5v input, the last sensor I used it came back saying a voltage error occurred, 300v or something  which is rediculous, so somethings not happy. This is frying my brain as I can’t find what’s wrong, if I have a quite afternoon at work this week will get a data run done and post it.cheers

Supra TB & DBW cables.docx

[cj]

You can manually calibrate these by setting APS main and sub to generic voltage inputs, then start a log, then press the pedal slowly all the way to the floor and then let it off slowly. repeat a couple times, then quickly press it a couple times. Then stop/save the log.

You can now look at the logs to work out the min/max voltage on each line, and the % point where the secondary sensor maxes out as you will see it flatline at a certain point.