[FIXED] Engine won't rev above 4k rpm

[Rwilner]

Hi Matt, Grippo, 24c and others,
My engine won't rev above 4k rpm -- it bounces off 4k as if a software rev limiter was kicking in (it is disabled). The car runs well otherwise and all the sensors are reading as expected including AFR...in fact I ran autotune based on the target AFR table in the attached MSQ and it works beautifully.

The application is a Porsche 914. Some details:
[*] 4 cylinder air cooled 4-stroke engine
[*] COP, wasted spark, batch injection
[*] 36-1 crank-fired trigger wheel

Where should I start looking? VR sensor? Settings (crank pulse tolerance)? Someplace else?

MSQ attached, I could also provide a datalog showing the bounce off of 4k rpm.

thanks in advance for your help!
Rich

[Matt Cramer]

Please post the data log as well. It'll give me more to go on.

[Rwilner]

Thanks matt, I will do tonight.

I have a V2 microsquirt ordered on May of 2008, so I suspect I'm having the diode problem described in this thread:

http://microsquirt.com/viewtopic.php?f= ... 3&p=147261

The gap between my VR sensor and trigger wheel is extremely small -- .01" or so.

[Rwilner]

I swapped the diode for a 1N4148 and the same thing is happening. See attached png...datalog is 4mb, i'll make one under 1mb so i can upload it.

Any help is appreciated

thanks
rich

[Rwilner]

[Rwilner]

I removed C30 from my microsquirt and was able to rev straight to the redline. Not sure if the diode swap or the cap removal did the trick, but either way, I'm leaving it be!!

I don't think this should be an issue with V3 microsquirts.

Rich