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Thread: Part throttle hesitation esp when hitting vvl.

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Posts: 1-10 of 27
2012-01-07 22:21:57
Part throttle hesitation esp when hitting vvl.
Ok so my latest SE-R has had some trouble but for about two months it was really nice.

When I roll onto the throttle it hesitates. Exhaust will pop a bit too. At first it would just do it as VVL comes on at 5k but now it does it all the time at part throttle from ~3.5-6k.

The funny thing is when I get on it fully in the right gear it pulls just fine at wot right through vvl to ~7.5k. But say at like 20mph I hit second it will do it or if I shift down into 3rd @40-50mph it will do it.

I have replaced almost everything under the hood. Its only code is for knock sensor (3,4). Its got VE intake w AEM filter, N1 cams, SSAC, 2,5" catback. Pretty standard. Running the JWT ECU which is not very good imo. Runs rich, some low end loss felt vs my previous VVL B13.

It has had its problems but almost totally worked out. Here the major issue was the wiring harness flopping around (I believe that was it... not 100%)


I'm thinking about just pulling the knock sensor off since that is a new code since the problem started.
2012-01-07 23:28:01
lets not forget when we put my ecu in how it ran but that was before the current issue an during the wiring flopping around issue. With my tune it had that low end power that i was sayin that was missing. so that jwt tune is def not right.

do me a fave an check your settings on your cam switcher bro, remember.. they forget..

i forget the rpm i set it at but you want it on P2 regardless
2012-01-07 23:48:19
I checked the cam switch point a few times and its always at 5k and set on P2. You were probably right that inside the car its slightly warmer so that is not a problem.
2012-01-07 23:52:12
yeah, i've had to reset mine an shirleens lately. only once each but depending on what it goes to depends how the car acts, i've had it come on at like 3k an its a very weird feeling. then i've had it come on at like 1500, almost undriveable.

good to know yours is doing good tho.
2012-01-07 23:54:08
I'm just wondering if a knock sensor can make the car act like this. I've never had one go out before. I know lots of people don't use them at all but since I have this crappy JWT ecu I can't disable it... afaik.
2012-01-07 23:56:15
hmm, we can always try my ecu again, i still use the same tune as i did with the n1's its just a little rich up top..
2012-01-08 00:03:29
Yes you should give me your ECU....

Say did you find those drill/taps?
2012-01-08 00:08:52
yea i found them im just blind haha
2012-01-08 02:20:31
I have never had a knock sensor issue but I would assume it would contribute to the problem, if not the whole problem. Also the knock sensor signal should be undisturbed (no splices, wire extensions, cuts and put back together.).

A knock sensor is designed to detect cetain volume of noises coming from the motor. If its not getting a proper reading (reading knock) it will pull timing causing loss of power and misfires. The problem with these sensors is that they usually can not read properly under WOT and the ECU deems the sensor readings to be false.

Im not saying your motor has knock but the sensor or wiring could be bad and its giving incorrect knock signals at partial throttle when the sensor reading is deemed true by the ECU therefor creating your partial throttle issue.

Also I believe JWT recommends 15* of mechanical timing (adjusted by the dizzy). Make sure your mechanical timing is to spec.
Last edited by D-Unit121 on 2012-01-08 at 02-27-52.
2012-01-08 02:34:28
Replace the sensor, better to eliminate something than to sit there wondering. Hopefully it gets figured out.
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