Newly installed, no spark, low voltage while cranking
 

I just swapped a series 4 T2 motor into my 85 gs (was carberated). My friend just finished installing my LTX 8. One problem, the system shows 12 volts at the coils with the key in the on position but once I start cranking the starter, the voltage drops to like 5 volts and of course, we don't get any spark. HELP! My car has been sitting for 2 years and I finally thought I would hear it run tonight :(

My friend thinks maybe the battery were using is not fully charged, or maybe for some reason, the starter is drawing too many volts. This is all he can think of at the moment. I am gonna try slow charging the battery all night.

Any suggestions?

Thanks!

Try adding more groung wires.... https://www.rx7club.com/3rd-generation-specific-1993-2002-16/grounding-101-why-so-many-669814/

my guess is low charge on the battery. Try hooking jumper cables up to it or something.

No, it's not the battery, the battery is good and drops to 10 volts while cranking while the coils drop to 5. Also we hooked jumpers up to a running car and still no luck. I'm thinking something in the wiring is wrong, or I don't know if it's possible for the starter to crank fine but draw to many volts away from the rest of the system. The microtech shows one green light when the key is on, while cranking we have the green light and the orange light goes on an off.

Have you checked your grounds? It sounds like you don't have enough.

I got my car running!!!!!!!!!!!!!! Started it up with just the downpipe.....lol I could see the neighbor across the street jump out of his recliner when I started it haha.

Anyways, the Crank Angle Sensor was wired wrong!

On Microtechefi.com I figured out how to get the Microtech to do a self check so to speak. The Microtech acts as the crank angle sensor and fires off all of the spark plugs and injectors. Well, these all worked so I figured the crank angle senser was either wired wrong or bad.

When we wired it, we connected the red, green and blue wires that come from the Microtech to the red, green and blue wires on the crank angle sensor. Well, after putting the multimeter to them, we figured out that the colors didn't match what the wires actually did. So we repinned them and that took care of it. Thanks for the ideas guys! This car's been sitting in my garage for a couple years due to lack of motivation. After I heard that thing run, I couldn't stop smiling all night

Yep, me too, I was happy for god knows how long. I thought I had a blown engine when I was trying to start it, but it turned out to be old gasoline in the fuel lines.

Once the fresh fuel got in, it roared to life, and idled at 4k rpm lol.

Yeah, I had all new fuel but it was slow to start. The motor had been sitting for about 10 years. (after solving the problem with the cas) we were trying to start it and it just wouldn't start. It would be like pop, pop, pop, like only one rotor was trying to start. After about an hour of messing with it, it started and ran smooth!