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misfire possibility @ 1250 rpm?

Old 04-13-18, 08:04 AM
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misfire possibility @ 1250 rpm?

Hello Team,
I have weird issue with my 1983 SA22c RX7 when rev's are brought up to ~ 1300 rpm under load , free revving or even under cruise speeds too ( i used the opt mix fuel and adjusted both positive and negatives values with the same result while maintaining the speed and load), it seems the car sounds like its misfiring around the ~1300 rpm then clears up higher in the rev range.
If I accelerate further or below this rev range issues doesn't seem to be evident. AFR on the wide band sit's around 12.5 to 13.0 afr (free reving @ 1300 rpm). i disconnected the trailing leads to by pass split timing, but same issues foreseen. My next option is to swap leads and plugs to see if this the case, but if such issue was due to leads or plugs, i would suspect this to happen through entire rev range. the car has a Microtech LT10s with IGBT x4
Based on a visual; i believe the standard 550cc injectors are used (~red top)
3inch turbo exhaust, hi-flow series 4 turbo with T4 front cover and wheel
twin Bosch 040 fuel pump, surge tank, plazmaman 2.5 inch inter cooler.
series 5 CAS and 4x bosch coils. I would say mild or standard port 13B series 4(FC) turbo motor. Motor has the knock sensor holes above the trailing plugs.
i adjusted the tune to my best of my abilities with a wide band; runs a little rich.
Please also review the tune file which was taken from the micro tech LT software.I have attached a log to assist the matter. observe the end of the log as i held the accelerator peddle @ 1300 rpm to simulate the problem. Nothing really stands out.

Your thoughts would be much appreciated
many thanks
ABS
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Old 04-21-18, 06:25 AM
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I swapped spark plugs and coils, with the same issue. Anyone have suggestions. Would my timing map in vacuum being too advance?

thanks
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Old 04-28-18, 09:00 AM
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I replaced spark plug leads, same problem has appeared. I looked at adjusting dewl values but seems not help.
looking for other ideas
thanks
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Old 08-26-18, 10:43 AM
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Hey man, first thing you need to do is check your air intake sensor connection. It doesn't seem to be connected or reading. So the ecu is reading that the air outside is 0 degrees and may be compensating in the maps for that
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Old 09-04-18, 08:22 PM
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Originally Posted by BluRR View Post
Hey man, first thing you need to do is check your air intake sensor connection. It doesn't seem to be connected or reading. So the ecu is reading that the air outside is 0 degrees and may be compensating in the maps for that
seconded, all the sensors work together, leave one out and things can get screwy. That being said, mine still has a bit of a sputter at idle but its not bad, in videos you cant even hear it.
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Old 11-03-18, 05:21 PM
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Thanks for the messages team, I haven't got an air temp sensor connected as car doesn't have one. I can do this if need be.
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