I Need HELP!
 

ok i have an 1987 supra, 5 spd, non turbo, 7mge motor. After running for a while the motor has a hic-up, it seems to loose about 200 rpms during the hic-up. Now when driving the car bogs out between 2500-3000 rpms. I put a diagnostics machine on it and it read low ecm voltage but i cant seem to figure out the issue, i cahnged the rotor and the distibutor cap, i changed the coil pack, the temperature sensor nothing seems to work im at a complete standstill can anybody help me please.

Given that the only diagnostic machine every made for the TCCS based system was ONLY available to Toyota dealerships and cost an absolute fortune I'm wondering precisely what you hooked your car up to...

Post numbers... Saying the ECU has low voltage means very little.

Have you checked for diagnostic codes, then? Well, any in memory?

I used a mac machine with the asian imports cartridge and its prety acurate. I mean I was old to check the witing harness for a broken wire. I did and there was none. I was told to check fuses but I don't have the panel cover to see what's fuse is what. I was thinking maybe the ecuj is bad considering my power cable groujnded out one time, and the ground once had a bad connection constantly killing power to the car. Is that a possibility it messed up the ecu.

Never heard of it and there's no way of measuring the voltage to the ECU without pulling the glovebox on the MKIII and simply measuring it at the ECU. The B+ and B1+ lines aren't routed out to the diagnostic box. I'd like to see pictures of what you're using, please.

And no, it's HIGHLY unlikely that you've killed the ECU with an external short to ground... it's a pretty robust beast.

You didn't answer my question either.. do you have any diagnostic codes? (do it the way Toyota does and just use the jumper as detailed in the Toyota Service and Repair Manual; see the FAQ section, there's a thread on how to do it).


EDIT: Wait, do you mean something by MAC Tools? Okay, I've heard of them.... still no idea what the device thinks it's reading though. Have a model number?

Yeah id have to run it again because i forgot the code number but i will also give the way you just mentioned a shot. I know the code came up as low ecm voltage but i dont remember the number.