L20b Starter disengaging

[Kathos]

Hi all,

I'm a little confused what the problem might be so I'm hoping for some help. I finished my 5speed swap recently and put my automatic starter back on. I'm not going to claim this starter is perfect but I did bench test it and it seemed to operate strong (solenoid and motor).

When I go to start the car, the solenoid engages, the motor spins the flywheel, the engine cranks 1 or 2 times, then the solenoid disengages but the starter motor spins until I turn release the key off crank.
I read on a different forum that if the flywheel taps the back of the starter gear teeth, the bendix is designed to disengage. Does my starter think my engine is starting prior to actually starting? I do pump the gas pedal when cranking if that matters.
I tested my battery while cranking it was around 11-11.5v. My starter solenoid read around 10.5v-10v

[datzenmike]

Power has to travel from the battery all the way to the ignition switch and all the way back to the starter by the chassis harness. This will cause a voltage drop. My 710 was down to 7 volts and the starter acted just like yours. To prove this make a jumper directly from the battery positive to the solenoid and see if it improves the starting. (make sure you are out of gear)

 

If this does the job you can install what is known as a hot start relay. This is a relay connected directly to the battery and uses the weak start signal from the ignition to turn the relay on. This will send power directly from the battery to the solenoid. It fixed my 710.

 

Usually two pums is enough. This sets the choke and squirts raw fuel into the intake. If the choke is working as it should more pumping risks flooding the engine. In colder weather you could try more pumps, but constant pumping while trying to start isn't needed.

[Crashtd420]

2 hours ago, Kathos said:

Hi all,

I'm a little confused what the problem might be so I'm hoping for some help. I finished my 5speed swap recently and put my automatic starter back on. I'm not going to claim this starter is perfect but I did bench test it and it seemed to operate strong (solenoid and motor).

When I go to start the car, the solenoid engages, the motor spins the flywheel, the engine cranks 1 or 2 times, then the solenoid disengages but the starter motor spins until I turn release the key off crank.
I read on a different forum that if the flywheel taps the back of the starter gear teeth, the bendix is designed to disengage. Does my starter think my engine is starting prior to actually starting? I do pump the gas pedal when cranking if that matters.
I tested my battery while cranking it was around 11-11.5v. My starter solenoid read around 10.5v-10v

Your not dropping voltage really low.. I dont think this is a power issue, I think your saying it wrong.... but definitely try Mike's trick to rule it out.... you can also jump the 2 large terminals together and see if it cranks the motor over more time... 

 

The way you describe it It sounds like the bendix is disengaging... not the solenoid....

The solenoid is the the electrical relay on the starter that energizes the starter...  it sounds like your hearing the starter motor spin after the bendix disengages... 

I always thought the bendix was a spring loaded return in the starter... energized it shoots forward and engages the flywheel and then returns when the starter stops spinning.. I dont believe the flywheel kicks it back, it engages till you release the key .... 

 

I think you have a bad or failing starter... 

[Kathos]

Crash, I think you are correct in that my terminology was wrong. And I am going to try the two pump method Mike explained to see if I am simply false starting it. Being that my starter solenoid voltage input is above 10v, I would think that's enough. I have researched the hotstart method and I'm planning on going that route if the input voltage becomes an issue.

From what I read, starters have a mechanical safety mechanism that prevents them from staying engaged when the engine starts spinning the flywheel faster than the starter can. This is to protect the starter.

https://www.howacarworks.com/basics/how-the-starting-system-works

I'll report back after I give Mikes methods a shot

[Crashtd420]

Its definitely worth the try before spending money....

I had a friend with the exact same issue a few month ago and his was a bad starter.... 

That was a good read explains things pretty good.... goodluck

 

[datzenmike]

My 710 sedan did this and because I have 8 or 9 starters I just threw in another... it didn't help and I was all WTF??? If I had bought one I would have been really pissed. Jumping 12v directly to the solenoid gave a crisp starter crank every time. There was a voltage drop along the 15 or so feet (including all the bends and plugs, and the small gauge wire in the harness) from the battery all the way to the ignition and back out to the starter again. I measured the start signal and it was 8v.

[banzai510(hainz)]

I believe with these cars being old and the switches worn most time the starter selinoid needs a good voltage. Remember when the motor is ON it lowers even the key voltage thus maybe making that klicking sound.

I would buy new starters and seem to work only a week later the klicking again. I stuck a cheap Ford Selinoid in there and has been better.

Summit even has hot start relays for 45 with the wires laboled so if be hard to fuck this up. Or wire up a black box tyep light relay is just as EZ also.

 

Do what Mike said and jumper the battery to the selinoid tab and starts HARD I say install a relay

[Kathos]

I tried starting the car with the two pump method and its started right away every time since. I'm not saying the issue is gone, but it's not a problem when the car starts up correctly. Even this morning when it was below freezing.
If it starts giving me issues again, Ill keep a starter rebuild and a hot start relay in my back pocket.

 

Thanks for the help fellas
 

Edited November 8, 2018 by Kathos