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sEngine feels like on limiter on high load low rpms

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sEngine feels like on limiter on high load low rpms

 
Old 10-07-2018, 06:26 AM
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Default sEngine feels like on limiter on high load low rpms

Hey Guys,

I am struggling with following issue now for more than 2 years, it all started 2 years back when I have had stock ECU in a car.In that time I already had MS in my garage, so I told myself it is about a time to fit it.It happend after autox event, anything above 3kRPM more than light throttle and car did not wanted to speed up, it was making like softcut noise - sometimes you can hear bang from intake (I have randal cowl intake) When you keep your foot down, it will eventually stop after few seconds and car will start to pull perfectly. It never happens after about 4k RPM. It mostly hapens and you can feel it when taking off in a trafic, low RPM first gear, medium load. Then when you start moving from trafic or just start speeding up from cruising around the city in 4-5th gear or whatever gear, but in low rpm and medium - high load.

After fitting it there was no problem, for about half a year. I did few autoX events, spirited driving and so on, no problem...then I went for a weekend on highway with my car - so 85mph, with 4.625 final drive - so approx 4600RPM, sustained for about 1.5hour of drive. on drive back home, after about half of our of same 4600RPM I run off the highway to pick up my hardtop - and in the city it started again. It was so bad that car died a few times on a crossing, even though I reved it quite high to get off - like 4-5k RPM. But when it get a load (you unload the clutch for example) it starts to loose power and makes sound like soft cut limiter. Then I changed spark plug wires and it seemed like solved. Until about month ago, when I was driving all day, on a local tight gocart track. So all day, about 150km (150laps) of hard driving, 2nd and 3rd gear, all the way to redline approx 5times on one lap. On way back home I realized it doing this stupid thing again, after being ok for about a year. It did not went away from that time, I did another trackday on same track yesterday, and it is same, I have a feeling that now it is happening even in higher RPMSs. Few facts. It is not happening when engine is cold - under 80C. It always showed after some spirited driving, with high load, high temp under bonnet, and so...I believe it has to do something with stock coils (stock 94 NA8) but I read elsewhere they mostly die imediatelly, and just stop working.

I attach graph which I did today with MS2e so if you can take a look at it and see something weird please tell me. There is two spots where it happened. 1st 147-148s and then 171-173s, you can see that there is 100percent TPS input and MAP load. Please ignore WB reading, it is disconnected.

Now I will be selling this ECU next week and the engine will go out of the car anyway and will be exchanged with VVT unit with VVT coils, so I hope this problem will be gone, but I still want to know the reason of this behaviour.

Thanks a milion in advance
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File Type: msl
2018-10-07_11.40.00.msl (992.1 KB, 11 views)
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Old 10-07-2018, 06:48 AM
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Cannot open the attached from my mobile, but sounds a lot like a misfire issue. Can you find a known good set of coils to check?
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Old 10-07-2018, 04:06 PM
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indeed it sounds like missfire. I do not really have spare set of coils, I assume NB coils will not fit ? Friend of mine have a few of them as they are known to fail a lot, which seems to be not so big deal with NA ones.
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Old 10-07-2018, 04:11 PM
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definitely misfiring, especially if it's happening with the stock ecu as well. Try some new wires, coils, and plugs. Should go away.
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Old 10-13-2018, 06:26 PM
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update, I just fitted back stock ECU to check how the car drives and so...well other that it idles and feels pretty sweet, it missfires more and I would almost say it happens more even at higher RPMs....Could it be difference Batchfire vs sequential which I used on MS ?
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Old 10-15-2018, 04:07 PM
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no.
try replace ignition parts as said earlier.
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