19 mustang misfires

[scoobaru88]

Been trying to trace this problem down for some time. Car in stock form is fine with zero misfires and runs great.
I installed FIC1200 injectors and I was getting misfires across the board, contacted FIC, sent the injectors into them. They cleaned, and flow tested them. Found a bad injector and replaced it.

Received the new injectors and installed them with tune for injectors only (with data supplied from FIC, and FIC verified tune was correct for injectors), and car misfires at idle. only Cyl4 and cyl6 (misfire counts increases fast in Forscan, 300+ in a matter of 10-15seconds). Car idled pretty rough.

Thinking it was injector related, I moved the injectors around, misfire did not follow. Put stock injectors and tune back, car runs fine.
Leak down and compression tests have all been done over the winter - engine itself checks out fine. Spark plugs were new about a month ago (drove car around stock for about 3000miles, and I can put stock injectors back in with zero issues).

What am I missing?

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[HKusp]

Have you tried a KAM reset and a crank re-learn?

 

[HKusp]

Also, for what purpose are you running FIC 1200's? Are you boosted, or planning boost?

 

[scoobaru88]

Also, for what purpose are you running FIC 1200's? Are you boosted, or planning boost?

g3x 100mm pulley. Just went back to stock to figure out this misfire, and started to add parts back slowly - first part being injectors and the misfires came back.

crank relearn and kam both been done with no change.

 

[ice445]

Maybe there's too much pressure loss with those honkin injectors so they aren't all being fed appropriately?

 

[BenjiSayRuh]

g3x 100mm pulley. Just went back to stock to figure out this misfire, and started to add parts back slowly - first part being injectors and the misfires came back.

crank relearn and kam both been done with no change.

any update on this?
I’m going through the same thing

 

[scoobaru88]

any update on this?
I’m going through the same thing

only thing I found was injector orings were some how sucking air. I verified this by going back to stock injectors with supercharger and no more misfires. As soon as I put the injectors back it, had misfires. Did the swap 3-4 times and always had misfires. Not sure if it’s a FIC thing or what, I sent the injectors to them and tested and cleaned them. Still had misfires.

 

[K4fxd]

Did the swap 3-4 times and always had misfires. Not sure if it’s a FIC thing or what, I sent the injectors to them and tested and cleaned them. Still had misfires.

How did you find the o ring problem?

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