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Help with sporadic rpm readings after new short block

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Hey guys chasing my tail a bit here so thought I'd ask on here for some ideas for context car was running perfectly previously with the same ecu, loom, sensors and tune. I pulled the motor to put a new shortblock under it. I've been trying to go through the run in process but the ecu is seeing some crazy rpm figures as seen in Screenshot. The trigger signal looks OK to my novice eyes, what else could possibly be causing this? The oil pressure is hitting the upper limit but that wouldn't change the rpm signal the ecu sees would it?

Engines a 2jz, all OE trigger wheel / cas. Kelford cams, 36-2 trigger pickup. G4+ fury.

I'm definitely a novice with this stuff, normally I'd play round until I figure it out but being the first start trying to bed the rings in, it's quite stressful.

Attached Files

Also when the rpm spike happens the software temporarily freezes for a few seconds and reports nothing but rpm limit activated in the event log.

I would look at the integrity of the Crank Position Sensor using an oscilloscope. It would help if you could get a reproducible case (and then what are the conditions - hot/cold, RPM, battery voltage, etc), or does it happen within a few seconds of starting at idle.

With a new engine installation, I'm nearly always suspect a missing ground, or one that is now no good because of paint, anodizing, etc.

As David said, first thing I'd be suspecting would be a ground, or power, issue - don't forget the connections as one may have been compromised, too. It's also not unknown for wiring to be damaged during removal/installation

Solved this one on the Link forum, arming threshold was set too high.


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