Only starts when you release the key...

[MURZI]

Recently I was invited to help a buddy install an engine in a kubelwagen replica. After installing the engine, and running all new wires to a new ignition switch, the engine will crank and run beautifully...but only after you release the key. You can crank the engine for 30 seconds and it will never pop off, but release the key and she starts at the end.

My thinking is that the battery may be low, and although I have enough voltage to crank the car, the solenoid is robbing the ignition circuit of the power and when you release the key..BOOM the ignition coil gets the voltage it needs.

Just brainstorming here with you buggy freaks 😁. Opinions?

New blue coil
New electronic distributor
New engine 7.5:1 compression
New battery
New UNIVERSAL ignition switch
New battery cables
New wires front to back.

Starter solenoid trigger, fuel pump, and coil all on same leg of ignition switch.

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62 vert
2276
Tim’s welded heads
45 Dells
A1 sidewinder
Fk44 cam

[timcurtis67]

The ignition is probably wired through the accessory position on the key switch. That only gets power when the switch is on and no power when the switch is in the start position.

Check the voltage at the coil while holding the key in the start position. You will see no power.
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67 Desert Fox Spoiler

[MURZI]

Nothing is on the acc position, although I thought about running the fuel pump off of the acc position to allow more current to coil at cranking.

I checked (with a test light) for voltage at the coil while cranking and it was present but light was very dim.

Today we are going to charge the battery throughly and try again.
_________________
62 vert
2276
Tim’s welded heads
45 Dells
A1 sidewinder
Fk44 cam

[slalombuggy]

Bad switch, I've seen this problem in a couple different makes of cars. The contacts inside don't line up when it's in the start position and when you release it they come back enough to connect, the engine is still spinning so it starts.

turn the key to the on position and use a remote switch to crank the starter. That will pinpoint the problem.

brad

[Dale M.]

[MURZI]

He used 16 gauge wire front to back... might be too light of gauge wire.
_________________
62 vert
2276
Tim’s welded heads
45 Dells
A1 sidewinder
Fk44 cam

[Dale M.]

[MURZI]

I’ll run a 12 gauge wire to the coil just to test it out... if it cures the ill that will be a simple fix. Or maybe I’ll just run a wire from the alternator to temporarily test..
_________________
62 vert
2276
Tim’s welded heads
45 Dells
A1 sidewinder
Fk44 cam

[MURZI]

Charged the battery and now works perfect.
_________________
62 vert
2276
Tim’s welded heads
45 Dells
A1 sidewinder
Fk44 cam

[slalombuggy]

16ga is more than enough for the coil and the starter solenoid.

Put a voltage meter on them both while cranking and see what the voltages drop to if you want to know for sure.

brad

[jspbtown]

[MURZI]

I misspoke. The coil and fuel pump are on the same leg...

Anyway with a good charge she runs perfect now. ..just touch the key and she fires...
_________________
62 vert
2276
Tim’s welded heads
45 Dells
A1 sidewinder
Fk44 cam

[finster]

nice looking replica - was it used in film work? they usually like to put the balkankreuz on the sides...
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"we're here on Earth to fart around" kurt vonnegut

nothing lasts, nothing is finished, and nothing is perfect...

[Dale M.]

[MURZI]

Alternator is working perfect. This car went underwater a few times during floods. Basically everything is new. I think the whole issue was that the battery was strong enough to crank this low compression engine but not enough to fire it off. We are doing all this hours away from home so tools for testing were limited.
_________________
62 vert
2276
Tim’s welded heads
45 Dells
A1 sidewinder
Fk44 cam

[jspbtown]