iAlex Posted May 7 Report Share Posted May 7 2002 Is300 Na-t. Panicwire harness and G4x Ecu 2jzgte aristo Intake manifold aps+tps Deatschwerks 700cc injectors Bosch VAG-short coils After about 5-6mins when it's trying to idle at target "950," it surges below and above target then it stalls. - I have done a Boost & smoke test - no vacuum leaks - Compression test 170 cyl 1, 175psi across (GTE internals with new rings) Changed and calibrated the tps- the issue remains. Switched alternator and Battery. I will be replacing my 1-year-old Walbro 255 with an AEM E85 fp. I will try a new fpr tomorrow. here is a log of the start-up. Any help is greatly appreciated, Thanks 5.7 start up.llgx Quote Link to comment Share on other sites More sharing options...
koracing Posted May 7 Report Share Posted May 7 It would help if you also posted a copy of your tune, and it would also have a functioning wideband connected to the ECU. That said, based on your log, I would change to closed loop idle control, but I feel most of your problem may be fuel related as the fuel pressure is dropping alarmingly low as it gets warm. Is your fuel pressure sensor accurate - do you have a mechanical gauge to compare it to? Differential pressure is Fuel pressure minus MAP value, and FP oscillating at the end is kind of weird and matches pretty close to the MAP oscillation which seems a little odd. How is your fuel pump wired? Is it using some type of OEM fuel pump control/pwm? 12v relay when triggered by ecu? Quote Link to comment Share on other sites More sharing options...
iAlex Posted May 7 Author Report Share Posted May 7 I will wire a wideband but I don't know how I can connect it to the ECU. Fuel pump is wired how the stock one was. (Spliced new harness and heat shrink) My fpr has a gauge that shows 40/43psi. The fuel pressure sensor is between the fuel rail and fpr (is that a good location?) Start Map.pclx Quote Link to comment Share on other sites More sharing options...
koracing Posted May 7 Report Share Posted May 7 Which Wideband do you have (precise part number and model will help)? Your tune shows that the calibration is set up for an AEM X-Series wideband on Analog input 3 so I'm assuming the harness has a plug for doing this already. Look and see if you can find that plug or the wires with some type of label for Wideband or Lambda input. Post any information you can to get help here if you can't sort this part out. Between the rail and the regulator should be a good location for the fuel pressure sensor. I revised your idle settings for closed loop and changed the base idle target positions based on the log you posted above. Datalog with this tune from a cold start once you have a wideband connected to the ecu and repost that. We should be able to determine if you still have a fuel system issue (please make sure you're not out of fuel). https://www.dropbox.com/scl/fi/c83j9djpi41gpbe3oeuej/iAlex-Start-Map2.pclx?rlkey=ku4a3e3q7klk4n626yajrxup9&dl=0 iAlex 1 Quote Link to comment Share on other sites More sharing options...
iAlex Posted May 10 Author Report Share Posted May 10 Thank you for your quick replies. • New fp and fpr, car still surges the same when it gets warm. fuel pressure was the same (gauge and sensor) • Held the throttle at 3% to bleed the coolant, thermostat did open at 185°. Car still died after I let off gas at 195° • I changed the vvti solenoid. It took longer to surge at idle but it did not stall this time. • Tomorrow arrives the Link Can Lambda With Afr Sensor Here is the latest log after installing vvti solenoid, fp, fpr, and coolant bleed. https://drive.google.com/file/d/1giS0OvPbrbAl5T-FRdsWlRROikAcUULK/view?usp=sharing *Update* Leak down test looks decent.(link below) https://drive.google.com/file/d/15H0MiAwCl8wB5qnzDXj8wgqxE7tYmL31/view?usp=drive_link Quote Link to comment Share on other sites More sharing options...
Adamw Posted May 11 Report Share Posted May 11 No map attached so shooting in the dark a bit, but your log shows your throttle is bouncing backwards and forwards so I would say the main problem is way too much idle actuator integral gain. A typical starting point would be 0.02-0.05 for e-throttle idle so confirm you are around that, if not then try 0.05. Your idle ignition is also a bit more advanced than I would use for E-throttle. Start with idle ign target at 10, min clamp at -5 and max at 30, this will give better torque authority. Quote Link to comment Share on other sites More sharing options...
iAlex Posted May 28 Author Report Share Posted May 28 I finally got the Can-Lambda installed and made the idle changes Adamw recommended. Here is the log of when I started the car and let it run until the thermostat opened. It seemed to idle better but it lean. https://drive.google.com/file/d/1wHt9NZARmb7txsD9vcvNgeyKC2V5YXnu/view?usp=sharing Map https://drive.google.com/file/d/1ql1_YVpt1eoVQiqPSx2DRZiZUkr-jN1M/view?usp=sharing Quote Link to comment Share on other sites More sharing options...
Adamw Posted May 28 Report Share Posted May 28 On 5/11/2024 at 9:15 PM, Adamw said: No map attached so shooting in the dark Attach your map please. iAlex 1 Quote Link to comment Share on other sites More sharing options...
iAlex Posted May 30 Author Report Share Posted May 30 https://drive.google.com/file/d/1ql1_YVpt1eoVQiqPSx2DRZiZUkr-jN1M/view?usp=sharing Quote Link to comment Share on other sites More sharing options...
Adamw Posted May 30 Report Share Posted May 30 That map isnt what was in the ecu when the log was taken so it is not much use, it doesnt even have closed loop idle turned on. The last log showed the same idle position throttle oscillation as the original log, so im 99% sure the integral gain was not set to what I suggested, it is moving about 10 times more than it should. Quote Link to comment Share on other sites More sharing options...
iAlex Posted May 30 Author Report Share Posted May 30 My apologies! I had uploaded the wrong one on google drive. I just ran it again and here it is. Map https://drive.google.com/file/d/1GktO9_uwv-GtNWHRhzqEAyFPQvQ3QPCN/view?usp=sharing log https://drive.google.com/file/d/1bZH5jvkzbSSF_Npx6rLDUOMrXL7a8AP_/view?usp=sharing Quote Link to comment Share on other sites More sharing options...
Adamw Posted May 30 Report Share Posted May 30 So it appears the oscillation or surging that this thread was originally about is gone now by the looks? Is there still an issue? There is an RPM dip towards the end of that log when the fan turns off, this is due to your fan offset being too big. The next steps would be to tune fuel and ignition first before wasting too much time on idle tuning as they will both have a big influence on the final idle settings. For idle control, the APS lockout should be reduced to about 0.5%, the base position table, dashpot, fan, steering and AC offsets will need to be tuned. iAlex 1 Quote Link to comment Share on other sites More sharing options...
iAlex Posted May 30 Author Report Share Posted May 30 Yes, It does not surge or stall, and it sounds better at idle. You are correct about the RPM drop towards the end when fan switched on. I could now schedule a tune. Thank you!!! Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.