Calculated engine load only 60% WOT

[Vasquezz1228]

I have installed LE9 injectors for my 2.2 LAP swapped Miata. I was running siemens 60lb injectors before and one went bad, I installed a set of red top 33lb Saab injectors and tuned the car without a wideband mean while I received the LE9 injectors and wideband. After the install of the LE9 injectors I noticed I had a vacuum leak at the MAP sensor and fixed the issue. I am adjusting the MAF table and I notice that the car is not performing like it was before. the fueling is almost decent but I noticed I am only getting half of the power of the motor. after looking over the data logs I realized I am only getting about 60%-67% engine calculated load on WOT. Previously with the vacuum leak, the car was performing as it should and showing the correct amount of calculated engine load. I did not change anything else but the fix the vacuum leak and pull out fuel since it was leaning out with the leak, i did make changes to the PE table but I don't think that would cause this. I could be wrong. any ideas why this would happen? including logs and the tunes for each log. both logs are with the same injectors except one is with vacuum leak and without.

[ZeroBoostBuick]

Torque Management - Torque Limit vs RPM - Max Torque tables for 1st 2nd 3rd 4th 5th 6th & reverse gears (tables 18205 - 18206 -18207 -18208 - 18209 - 18210 - 18211).

Try changing the values to 500 lb-ft.
Right now you have them almost maxed out at 6,000 lb-ft. Sometimes the ECM will not release all the power when those type of tables are set too high.



Max Torque Limit vs RPM.png

[Vasquezz1228]

I will try this. I have so far changed the intake gaskets, added a new map sensor and cleaned the throttle body. the car responds a little better but still having the same issues. I am thinking it might be the throttle body. Pressing the pedal halfway with the engine off opens the throttle but it does not look like it is completely open. Going from half pedal to full pedal pressed the throttle plate does not move at all. going back to half throttle no change until i let off completely or less than half. Its as if the throttle blade is not moving as far as it should. Currently trying to find an LSJ throttle to test if this is the issue. I will try to install the stock 2.4 throttle body on my day off and test the car again.

Thanks for the advice!

[Vasquezz1228]

Update:

I changed the throttle body to a stock 2.4 throttle body and also made the changes to the torque management tables with no success. the car is still giving me the same issues. i logged the ECM voltage and it is only charging 12.5 volts. I am planning to change the alternator hoping that will be the issue. I have been getting 12.5 volts since I started the car but was running fine before. I will update when that is done hoping to be the final part. I am wanting to add a turbo but it don't want to have issues.

[ZeroBoostBuick]

Seems like you have the 60 lb injectors in the car, but the table is set for 33 lb ?

[Vasquezz1228]

I?m using the LE9 injectors. I believe they are 28lb from the flex fuel hhr file I found. I might try changing the injectors to the Saab 33lb. Maybe I have the wrong flow rate for the injectors

[ZeroBoostBuick]

28 lbs injectors are too small for flexfuel. They must be bigger. Should be at least double that lbs/hr.

What model year HHR are the injectors from ???

[Vasquezz1228]

A 2009 hhr with flex fuel, I couldn’t find one to read the exam so I went with an hhr file from the repository that had flex fuel active.

[Vasquezz1228]

28 lbs injectors are too small for flexfuel. They must be bigger. Should be at least double that lbs/hr.

What model year HHR are the injectors from ???

You were right the injectors are much larger than 28lb. I tried different flow rates and adjustments made to the MAF after changing the IFR table has made the car perform better. I don?t know the actual flow rate of the injectors so getting it to run perfect will be a challenge. I will install the turbo and a new set of 60lb injectors and it should run perfect with the correct data

[cobaltssoverbooster]

tune the maf in and then add 5+ fuel to the whole maf. If you record rich by 5% after the change then the inject flow rate is pretty close. If not, then you need to tweak IFR rates until it lines up. Best you can do in the car.

[Vasquezz1228]

tune the maf in and then add 5+ fuel to the whole maf. If you record rich by 5% after the change then the inject flow rate is pretty close. If not, then you need to tweak IFR rates until it lines up. Best you can do in the car.

I have the MAF pretty spot on. I am only getting about 15lb/h through the MAF now. Better than the 10lb/h I was getting with the IFR at 28lb. I have it at 40.3lb now. I was thinking of trying 36lb and see how it performs. My other thought was to take the injectors to get flow matched. That way I can get the proper flow rate.


When you say 5+ do you mean 5% more fuel and look at the fuel trims?

[cobaltssoverbooster]

I have the MAF pretty spot on. I am only getting about 15lb/h through the MAF now. Better than the 10lb/h I was getting with the IFR at 28lb. I have it at 40.3lb now. I was thinking of trying 36lb and see how it performs. My other thought was to take the injectors to get flow matched. That way I can get the proper flow rate.


When you say 5+ do you mean 5% more fuel and look at the fuel trims?

That's what I'm saying.
If you add 5% and the trims report back -4.5% then you IFR value is high by about 8-10%. On the other side if it reports -5.5% then your IFR value is low by 8-10%.
If you want ot be more accurate you can use 10% instead of 5%. 10% error would be -9 and -11 when using +10% commanded.
I suggest using a histogram filter RPM>1,200 so you exclude all of the idle IFR multiplers. This allows you to leave the short pulse modifiers active and have a better idle while performing testing. It should go without saying that the IFR table is linear. If you make changes based on this test method, make sure you interpolate the data to form a straight line. The IFR multipliers take care of the non-linear flow rate variabes.

[Vasquezz1228]

That's what I'm saying.
If you add 5% and the trims report back -4.5% then you IFR value is high by about 8-10%. On the other side if it reports -5.5% then your IFR value is low by 8-10%.
If you want ot be more accurate you can use 10% instead of 5%. 10% error would be -9 and -11 when using +10% commanded.
I suggest using a histogram filter RPM>1,200 so you exclude all of the idle IFR multiplers. This allows you to leave the short pulse modifiers active and have a better idle while performing testing. It should go without saying that the IFR table is linear. If you make changes based on this test method, make sure you interpolate the data to form a straight line. The IFR multipliers take care of the non-linear flow rate variabes.

I will be trying this today and report back. I am running fuel pressure regulator with vacuum reference and a return line. I have since changed the IFR table to the same value for the table and made changes to the offset values as well. I read a few threads on running a fuel pressure regulator with a return line and how to tune for it. Of course correct me if I am wrong, but I am not running a returnless fuel system like stock ecotec engines do. so my fuel system would be considered a return style system correct?

Thanks for the info.

[cobaltssoverbooster]

Returnless or not, the key is that its a vacuum referenced regulator. It should have a 1:1 reference so its pressure increases by 1 psi for every psi the regulator see's on teh vacuum line. These systems require that the IFR rate be reported as the same value in every cell.

[Vasquezz1228]

Returnless or not, the key is that its a vacuum referenced regulator. It should have a 1:1 reference so its pressure increases by 1 psi for every psi the regulator see's on teh vacuum line. These systems require that the IFR rate be reported as the same value in every cell.

I bumped the IFR table to 52lb and I’m reading more air through the MAF and the car seems quicker. I’m up to about 16.5 lb/hr now. I adjusted the maf with my wide band so the fuel trims are off. I haven’t had a chance to fix them and try what you told me as it has been over 100 degrees out. Way too hot to be driving a Miata with no AC lol. But could the stock flex fuel injectors for a 2.4 really be 52lb? Seems like a lot to me

[cobaltssoverbooster]

44 lbhr oem injectors rated at 43 psi flow roughly 51 lbhr at 60 psi... so depending on the injector calibration pressure vs. the pressure running now, that is possible. I haven''t tested any ecotec injectors beyond 2008 so i don't know what the OEM E85 injector flow rates are. maybe someone else knows?
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