Rpm oscillations at highway cruising?
What causes this?
- Thread starter Tuppidsay
- Start date
I see you uploaded your log also. You can just copy the BB code from there and paste it into a post and it will embed itself. Like this:
Additional information
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Firmware Interface Engine TMAP_V AvgIgn DWP MethTriggerMode FF MethSafeMode MethAdd MethScale MethPSI VIN E85_Setup VFF_Offset fuel_30 fuel_35 fuel_40 fuel_45 fuel_50 fuel_55 fuel_60 fuel_65 fuel_70
32/15//2 JB4 Android A314 E Series - N54 1.96 3.8 48 0 95 0 69 69 9.8 135X8CN56194 0_2_6_ON 69 50 50 50 50 50 50 50 50 50
BoostSafety PID Gain AutoShiftRed Fuel_OL FUA 1st_limiter 2nd_limiter 3rd_limiter FUD N20_TMAP 6CylMode LastSafety duty_15 duty_20 duty_25 duty_30 duty_35 duty_40 duty_45 duty_50 duty_55 duty_60 duty_65 duty_70
29.0 25 65 60 0 0.0 0.0 0.0 1_2_6_ON 1 4 1 49 49 49 49 49 50 53 57 61 64 65 65
It surges kinda, I've seen and heard from several saying there car is doing this, always when tuned, upgraded turbos. Everything in the log oscillates, even the pedal input and my foot isn't doing it. Also does it on cruise control. It's weird.
All jb4 maps, never tried with jb4 off, worth trying now that I think about it. And every bef I've tried. Granted, it's been the bms bef and then modified bms bef's.
I had this happen too. It would go away then come back a few months over the coarse of two years or so... then last month, I was at a stop light and it did it at idle with the brakes on... then it went away. I suspect there is a vacuum leak somewhere, not in the usual place. When I put it on cruise control, no matter what speed, it would fluctuate also...
Anyways, for my case, over time it developed into 1. excessive backfire and misfiring on wot or hard acceleration no matter in motion or from stop. 2. lurching, hesitation sometimes... then finally 3. the car would hesitate and hiccup from full stop when pressing pedal quickly AFTER it was warmed up.
For my situation, so far I found out that those symptoms were indicative of malfunctioning Purge Valve Solenoid... today I changed it with a new one and the car is so far 100% in all situations. No more hestitation, jerking etc... doesn't matter how warm or hot the engine is. I hope this fixes it permanently and won't come back again.
The purge valve solenoid was the very last thing I replaced after: vanos solenoids, oil non-return valves, crankshaft sensor, both camshaft sensors, high and low pressure fuel sensors, hpfp, lpfp stage 3, new fuel filter/regulator, spark plugs, spark plug wires, battery, new tmap 3.5, new map on manifold, new hoses and clamps, new intake manifold from bmp, new throttle body, oil change.... so you see, it was that purge valve solenoid that was the problem the whole damn time. And the part is not even expensive.
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Definitely something to look at, currently, I've never had any issues anywhere except light throttle cruise. this problem has been there for over 75k miles. Ever since I started tuning the car. I'm on my second engine, still there. Personally I think it's tuning. But I'm open to anything. I will definitely disconnect and plug the Purge valve and see what happens.
