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Misfiring when cold

Posted: Sun Jul 28, 2019 2:53 am
by D33@+H-Kn1gH+
I have a fully forged turbocharged FN2 and mainly during the warm up phase I'm experiencing misfires if I depress the throttle pedal more than slightly. When the car is warm the issue stops.

As I am using Injector Dynamics ID1700x , I had to lower the target AFR because the car would misfire a lot in the warm up phase and less when it was up to temp. Now as Injector Dynamics advised since my injectors are big I am forced to keep the AFR around 13ish in order to avoid misfires. (Anything above 14.0 AFR causes misfires in general). I must also mention that I am using these injectors on Unleaded 100 gasoline thus the reason for a lower AFR.

I've noticed that the more I step on the throttle pedal the leaner the AFR ( 14.0 - 14.4 ) goes for 1-2 seconds causing the misfires during the warm up. I am also experiencing similar AFR behavior when I step on the throttle pedal and the car is already up to temp but I don't get misfires because the AFR stays below 14.0 . I am using a Honda J37 throttle body and my tuner already altered the throttle flow VS opening for that.

Could this be a throttle tip problem? If yes which table shall I alter "Tip in fuel ECT" or "Tip in fuel throttle compensation" ?

Re: Misfiring when cold

Posted: Mon Jul 29, 2019 9:42 am
by Spunkster
Have you discussed this issue with your tuner?

Re: Misfiring when cold

Posted: Mon Jul 29, 2019 12:05 pm
by D33@+H-Kn1gH+
Spunkster wrote:
Mon Jul 29, 2019 9:42 am
Have you discussed this issue with your tuner?
He said that the fuel injectors are just too big for my engine and Unleaded 100 fuel makes it even worst on these injectors.
It could also be that because they're big it takes more time for them to respond to sudden throttle changes. I honestly don't know..

I am currently breaking in the engine so I'm using a break in map at the moment (3.5 bar static fuel pressure through a regulator, low cam only no vtec, 7000rpm redline)

I really don't wanna spend more money to get the ID1300x if they won't cure the problem. I have also spoken to Injector Dynamics about the ID1300x and they said that I might be a little rich on them too since my engine is a 2.0L but definitely better than ID1700x and the only injectors that are perfect for regular Unleaded fuel are the ID1050x though they're not enough for my build I presume