X4 issue, possibly dead? Microtech guru's needed
 

I need some help, i have a lt-10s and x4 combo, i've been running it for years. Last weekend i upgraded my alt for what was supposed to be an upgraded fd alt from a rebutible rotary shop. turns out they gave me a rx-8 alt which i didn't realize until i started the car, i had a voltage spike of 19v and the car died.

After checking the car over i realized that inhad no spark, so i ordered a new x4 from atkins. swap it in yesterday and still nothing. I checkek my inputs to the coil with my meter on its min max function while cranking, nothing. i pulled the connectors off of the x4 and checked my inputs and outputs at the x4. again, i had my meter on min max to try and catch the range, i was able to get half battery volts while cranking on my input sides, that should be right since i dont think the meter isn't fast enough to catch the signal so it give me the average. i have nothing coming out on the output side. do you guys agree that i have a crap x4 right out of the box? What else should i be looking at?

Attached is the diagram of the wires i checked.

Thanks in advance,

Izzy

The X4 is an igniter, it does not supply voltage, it supplies a ground. If you have no voltage at your coils you have a fuse fried on the circuit that is supplying the 12v to the coils.

I'm aware of that, thanks. I should specify that I don't have a negative output from the x4. I have 12v+ at the coils, just don't have the negative. And a ground is a voltage, 12v-.

Microtech showing RPM while cranking? Pull the CAS and give it a spin.

I doubt you got a fried X4 out of the box. More likely internal damage on your LT

Chris,

I plugged in a spare cas, same thing. The microtech does show rpm. I even swapped in a know set of spare coils, same thing.

have you had a bad coil at any point?

have you started your car with a wall charger at any point?

if yes to either of these, the problem may be internal in the LT box

not since the initial alternator issue. Last night I simply swapped out the x4, I will check to see if I have a shorted coil tomorrow to see of that's the issue

a shorted coil will fry the X4 box very quickly. i know because this happened to me. just check the resistance across the + and - on all your coils. compare with the rest.

that's what I was going to do, well check and compare with manufacture specs

Checked the coils. They all read .4 ohms, which is what the spec is for that coil.

any other suggestions, or did I smoke the ecu?

have you tried running the Microtech in test mode? i believe that should signal all 4 coils. alternatively you can test the leading coils/plug wires with an inductive timing light when cranking if you haven't done so already. if it doesn't light up, you for sure have an ignition output problem in the ECU or just a bad ground or wiring issue. the chances that you got a bad X4 out of the box are slim to none.

its also important to know that during cranking only the leading coils are fired. so if you're testing the trailing coils, you wont get any signal until its started.

Hello Rotor Head, i have addressed the same issue before but with a haltech, repaired the ignition box and ECU. there is a Mosfet/Igntion IC driver which fails. Have you bypassed the X4 and wired direct to a coil. This will confirm if your ignition semi conductor driver has failed within the ECU. From memory you should see the ECU light also blink on crank this will confirm if an input is received also from the CAS. I would put Mtech in test mode to simulate injectors are firing also to ensure the injector driver are not blown too.

I verifies all of the inputs to the x4 from my lt10-s, I had a good signal from the cas and everything else seemed perfect. So I went ahead and swapped in the x4 from my other car, and no issues. I'm guessing I had a bad x4 out the box