[63vertSS]

Ok.. so LS1 EFI swap.. has LS1 starter (solenoid on the starter)

here are the highlights...

-Solenoid on starter clicks (once) but wont crank 99% of the time.. 1% of the time it will and cranks strong and fires fast

-Replaced starter, same symptoms

- checked connections and resistance from starter to under the dash by the key (purple wire)

-Key ON =12v

-Voltage at the ignition wire coming off the key switch 12v

-Continuity/resistance good all the way through the purple wire to starter solenoid.

-Jumping the solenoid @ the starter works great

-Purple wire shows only 8.5ish volts coming out of the back of the key switch when cranking.. not sure this is enough to make the solenoid happy, but I do hear it click

What am I missing??

 

[Philip]

8.5 volts is probably not enough for the solenoid to pull the plunger in. Contacts in the neutral safety switch may be bad, could show good for continuity but won't carry the load. Bypass it to test if that is the issue. If so replace it.

 

[63vertSS]

I know it isnt the safest answer, but I dont have the NSS connected at all.. I know I should, and I will, but that isnt in the equation at the moment.

Could this be a problem with the key switch itself? Seems unlikely, but maybe a quick fix to replace it.

Where is the inline resistor wire? I am guessing it is outbound of the key switch vs inbound (makes sense in my head at least). I am not using any of that, but maybe I ran the wrong wire somehow? Purple is what I used because that is what went to the original starter for the I6 and is the only wire that was long enough to reach there.

 

[Mike Goble]

The best and easiest fix is to put a relay in the circuit and power the starter solenoid directly with the relay. It takes far less current to pull in the Bosch relay and it will supply far more current to your starter solenoid.

 

[63vertSS]

I would like to have less complexity if possible.. and I am sure that relay would work, but finding the source of the voltage drop seems important too (something else is wrong, dont want to mask it).

Has anyone seen the key switch being responsible for a voltage drop like this?
Does the wiring plug just pull straight off the back or is it attached somehow (Im at work, so cant check). That would make it easier to diagnose the problem if I can test resistance and voltage from the harness plug and isolate the switch... a switch cant cost that much to replace either.

 

[Mike Goble]

The man who just did a LS1 swap thinks adding a relay is complex?

There are many probable causes of the excess resistance in the solenoid actuation circuit. The wiring, the ignition switch, the NSS switch and any connection along the way. Troubleshooting this circuit could get time consuming and much more costly than the cost of a simple relay.

Adding the Bosch relay will reduce the current through the circuit dramatically and ensure that it operates properly without having to dismantle the ignition switch, NSS or the accompanying wiring.

 

[63vertSS]

Just meant I didnt want any MORE complexity... I will check the connection at the back of the key and clean it.. if that doesnt do it, I will add the relay.

Thanks guys!