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Tuning adjustments

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Hi guys. I have a twin turbo'd engine controlled with an AEM Infiniti ECU. The car was originally tuned by a tuner back in summer in 110 degrees f weather. I'm not sure if that has anything to do with how it's running now. But the problem I'm having now is that it has a hard time staying running at cold starts. I either have to try starting 3-4 times before it's able to idle, or have have to modulate the gas to keep it from dying.

The 2nd problem is that when the car is off boost under load, or sometimes even at idle, the car hesitates and feels like it's misfiring. I have to downshift and raise the rpm. Once the rpm is up and boost is built, the car smoothens out and feels powerful again.

Please help with adjustments I can make for each problem. The tuner I worked with is 6 hrs away, so I'd like to see if there are adjustments I can make in the meantime to help the car run smoother until I'm able to do another proper dyno tune.

I attached 2 files or each scenario- cold start and no boost idle/under load. Would love to hear some input. Let me know if there's any other info I can provide to help diagnose. Any help is appreciated.

Attached Files

hello this is a very tricky situation because it may not be the tune that is the problem the issue could be totally unrelated like fuel system blocked injectors tight valves etc

i would be most likely check all the mechanical basics first

Regards Ross

Thanks for the input. I'll trace back all the hardware in more detail and report back what I find.

Bingo! Thought I had resolved this problem before. The new injectors have a harness adapter on them. I replaced one during the tuning process due to intermittent fuel cuts and we found that one of the adapters had a bad connection. We replaced it and all seemed well.

But today I rechecked all the harness adapters again and found one not fully connected because of the extra length causing it to hit against some hoses. Pushed it back in fully and voila, the car doesn’t hesitate anymore at low RPM and low boost. Can’t believe I didn’t check those sooner.

The only problem remaining is the cold start. That’s something we didn’t get to dial in since the car was never on the dyno for a cold start condition. The car starts and idles great once warmed up though.

any suggestions for helping keep the car on at first crank?

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