FD LT8s ECU Issue
 

Hello members,

I purchased a FD LT8s ECU from Centeral Florida Turbo about six years ago. Since I have install the ECU, I've had some concerns regarding the wiring of the crank sensors. The wiring of the crank sensors in the manual show it being wired one way; and the Mircotech website shows the wires in the reverse of what the manual states.

I've spoken to John from Microtech and he advise me of a wiring correction; and that I should follow the wiring diagram on the website.

I have now gone threw my 4th engine, corner seals are always running flat. I know flats corner seals are the result of heat due to timing. I run about 32 degree in vacuum, AFRs being 13.4 a 13-8; 13-15 degree advance at 18 psi, AFRs being at 11.2-11.4

I now need of some advise from a Microtech guru. Should I buy a new ECU (9C, 10C, or LT16C) or go with something else. Or what can I do to correct this issue... Please advise!

thanks


Andre

a new microtech won't fix anything, the new "c" series is the same thing in a shiney new package. you will need to diagnose your issue first, have you verified that your leading and trailing is firing in the correct order and timed correctly?

LT8s
 

Please take a look at the diagram... Crank sensor are wired in the reverse.

At this point I don`t know which wiring diagram is the correct.

car wouldn't run if the CAS wasn't wired correctly.


see, Microtech is funny that way. they have used numerous different harnesses over the years and can't even tell which they used and when, so you have varying wiring diagrams with corrections on them. most any other EMS would reprint the schematics, nope, they felt scribbling ink on theirs was "good enuf" when all it really does is makes people feel uneasy about their wiring job.

Funny you should say that. Because I've pinned out the wires according to Microtech instruction
and the car starts and runs which seems to have no issues. However, when I revert to rx7 technical manual it states the opposite and the car starts and runs with no issue as well. (Puzzled now to which wiring is the correct way)

See attachment.

I guess I'll have to check and see which wire supplies the ignition power and then wire the crank sensors according to the technical manual.

there is no ignition power. the sensors are magnetic pulse generators that pulse very small voltage signals to the ECU and the ECU converts them into digital form for trigger inputs. it's been a while since i have wired a microtech but the majority of the issue was between the home and ref signals, not so much the an+ and -.

Spoke with a friend from Speed 1 Rotary and they said they're having the same issue with the old LT8s ECU. Therefore, it seems to be an issue with the ECU's wiring.

Also, if you look on the Microtech EFI website the made a correction to the wiring diagram of the LT10 ECU's crank sensors and ignitor.

Anyone has great success with Megasquirt version 3 on a 13b?

they have corrections for virtually every series of microtech, however i am not sure that the CAS wiring is really your problem with it.

I have used ms1,ms2 and now a microsquirt on rotaries with out a single problem ms3 should be no problem controlling a Wankel engine