5K Redline. No revlimiter in Place. MS3X 4G63

[ae86drftr]

cant rev still.csv

Hi everyone. I have an MS3X with V.3.0 board which I assembled and have tested along on the way. Everything checked out at the time that I assembled it approximately in August. I originally had an issue with my Cam and Crank inputs, however that was repaired through the jumper harness (the jumper harness wasn't connecting the cam and crank inputs). Once I connected the Mega she started RIGHT UP! However, There has been in place a 5000 RPM redline since. I have gone through everything and have tested what feels like everything. If I am forgetting something or need to attach anything else please let me know. I am eagerly searching for a solution.

[billr]

Are you logging fuel pressure? Even if not, post a regular run log.

[ae86drftr]

Im sure I have one in here. Check this one out.

[billr]

I didn't see fuel pressure logged... do you have an FP sensor, what input is it connected to?

[ae86drftr]

No. I do not have a fuel pressure input nor sensor for that matter. The car is a 90 Eagle Talon. I have followed the guide suggested but DIYAUTOTUNE.com and everything kinda works except for this "revlimit" "cutout" This is as close to what I can call it. I really appreciate any and all suggestions and assistance!

[slow_hemi6]

Log shows a significant sync loss when revs get above 5K.

[ae86drftr]

YES!!! There seems to be some sort of limiter or something that prevents me from reving higher than 5K. I dont know what it could be!?

[slow_hemi6]

The the crank or cam sensor signal (However the ecu gets it's tach input/s) is not being read correctly and it is loosing sync. That means it stops firing injectors and sparking till it once again knows engine position. Look up Sync Loss in the manual.
Are you running the latest stable firmware?

[ae86drftr]

I am running latest stable firmware. I know it is sync loss however for some reason I feel the problem is in the components that make up the circuitry. I was searching this and found the pcb layout for the input signals however I was not able to find a diagram for the U7 and U4 IC components. I have my car running on this setup currently. She runs, idles accelerates, and does everything just as intended except past 5K.

[slow_hemi6]

Have you tried using the sync loss logger in the high speed loggers tab? Might help someone on here, provided they know that pattern.

[Matt Cramer]

First, try turning the noise filtering off. I think yours may be too aggressive at high RPM, especially the secondary tach. If that does not fix it, please post a composite log that captures this loss of sync.

[billr]

That run log shows three points where 5K rpm was approached, only one shows sync loss and yeah, it was massive as you tried to push speed past 5K. However, I suspect the sync loss is a symptom of the engine miss-firing, not the cause. Install a (temporary) mechanical fuel-pressure gauge and watch it for obvious FP loss.

[ae86drftr]

Fuel pressure seems a bit far fetched for it to be however I will not negate the idea. I am however temporarily unable to do anything right now due to a failed Harmonic balancer. Once I get another I will be back here to try to figure this inconvenience out. Thanks EVERYONE so far for the assistance!!!

[ae86drftr]

Also one last bit of information. I have ALL noise filters completely turned off. It seems to make no difference with or without noise filtering. I think on one of them I had a value of 45 with still no change. I have tried countless settings tweaks. I too agree with billr that I feel this is a symptom and not a cause. But of what!?

[Matt Cramer]

The MSQ you posted had noise filtering enabled on both the primary and secondary tach, with the secondary tach noise filter time period set to 417 microseconds. If this is in fact the MSQ you are running, this could prove to be too aggressive for a 4G63.

[ae86drftr]

Thanks for the input Matt. I just now figured it out, I THINK!? I hooked up my MS3X to a good friend of mines JimStimX and was able to figure out the Hysteresis adjustments were not adjusted correctly. I must have read it incorrectly. So far right now I have near full rpm and basically require actual tuning. So time for a fill up and tune! Thanks to everyone up until now and quite possibly into the future.