Well this early rev limit thing strikes again.

[gixxer750]

Except for this car ran right at one time, vs my last car that did this from the beginning with aem.

I didn't change a single thing on the car, didn't even pop the hood or hook a cable up to the AEM when this started happening.  It just started one day after the car has run 100% fine for over a year with the current tune and mechanical setup.



Pretty cool huh?

[gixxer750]

Oh yes, this is a 1993.5 toyota supra NA-T.  Might as well call it a TT as it is using a FFIM, TT cam and crank sensors....

[PQatPIT]

Sounds like bad cam sensor connection on sensor connector. I bumped into one like this. I also rebuilt engine wiring loom groundings and added a few of my own.

Also, this old Toyota engine wires and connectors have seen better days.

[gixxer750]

Its a new harness, less than 2 years old.

[gixxer750]

bump?  Changed cam sensor, checked crank sensor trigger wheel.  No change.  Tried a new ignitor, no change.

[SB]

Definitely appears to be related to cam/crank signals. Notice that the Timing Errors value increases at about the same time as each 'early rev limit.' Also, Cam-Crank becomes inconsistent around the same areas. Try logging Crank Tooth Period and T2PER (cam tooth period) at the fastest rate possible.

It may be the sensors themselves, the wiring, the connectors (at the sensor or ECU plugs)... difficult to say if it's the crank pickup or cam pickup from that datalog, however. This might sound odd but try changing spark plugs, this is a bit of a long shot but it's not impossible for a ignition misfires to create electrical noise.

[MP Tuning]

I would check to see if the crank trigger wheel is loose and spinning around independantly of the crank, I have seen this before on 2JZ's.

[gixxer750]

Already tried the trigger wheel(which has been welded to the gear already).  Changed ignitors, haven't done cam and crank yet. 

I'll go back through the wiring again this weekend and check for any off the wall resistances or bad connections.  I am 100% sure its not in the tune(which probably isn't the best, since I'm not a pro) because the car ran fine for so long.

I wish there was someone close by I could borrow the cam/crank sensors from...  but since I have the only supra within 100 miles.....

[gixxer750]

problem solved.  Cam sensor wiring chaffed through the heat shrink (where I wired in cam and crank sensors to the stock distributor wiring) and was rubbing each other with a little spot rubbed in the heatshrink on both.


Thanks for the suggestions guys.