CSI only runs when cranking…

[Micker747]

I need your help guys. On my ‘75 CSI the engine starts immediately, but shuts off as soon as I stop cranking. On a modern car I would be looking for a crank or cam sensor, how does it work on ours? I suspect that is the culprit.
I took them engine out 10 years ago, I can’t exclude a missing or wrong connection.

 

[bengal taiga]

For "starters," without additional information (and excluding a missing or wrong connection), symptoms suggest bad/improperly wired ignition switch or bad improperly wired ballast resistor. Suspect this issue has been previously discussed in this forum. Perhaps this link may be of assistance regarding the bypassing of the ballast for diagnostic purposes. https://e9coupe.com/forum/threads/perplexing-ignition-problem.37244/ A red coil as depicted in your photo ordinarily requires a ballast resistor. A ballast is not obvious from your photo. It may be that your ballast consists of a thick clear resistance wire rather than a ceramic encased wire. Perhaps the ballast has developed a short.

 

[bill]

For "starters," without additional information (and excluding a missing or wrong connection), symptoms suggest bad/improperly wired ignition switch or bad improperly wired ballast resistor. Suspect this issue has been previously discussed in this forum. Perhaps this link may be of assistance regarding the bypassing of the ballast for diagnostic purposes. https://e9coupe.com/forum/threads/perplexing-ignition-problem.37244/ A red coil as depicted in your photo ordinarily requires a ballast resistor. A ballast is not obvious from your photo. It may be that your ballast consists of a thick clear resistance wire rather than a ceramic encased wire. Perhaps the ballast has developed a short.

On ‘74s and later, the ballast is replaced by a clear resistance wire to the + side of the coil.

 

[sfdon]

A few very simple tests.

1.
Unplug your cold start injector at the top of plenum. Crank…

Does it still start and then die? If not, it doesn’t start at all-you know that only the cold start injector is working and not your fuel injectors.

2.
Run a direct wire from battery positive to coil positive. Crank…

Does it now run? If so- your coil is only getting voltage from the black/red wire at top of starter, only while you are cranking.

 

[Ohmess]

I presume the picture was taken earlier. In the picture you appear to have your fuel hose routed into a Sprite bottle and your dipstick is missing.

 

[merdad]

I need your help guys. On my ‘75 CSI the engine starts immediately, but shuts off as soon as I stop cranking. On a modern car I would be looking for a crank or cam sensor, how does it work on ours? I suspect that is the culprit.
I took them engine out 10 years ago, I can’t exclude a missing or wrong connection.

Is this car in San Diego?