My Step-son owns a 1991 Honda CRX Si with the 1.6L EFI Engine. A couple of days ago he was driving with a friend and the car just died, no spuddering, just like the key had been turned off. He and his friend got it off the road and they opened the hood and wiggled a few wires, got back in and it started back up with no problems. Was good for 2 days, then it happened again, same thing, the engine just died. We towed it home after being unsuccessful with the wiggling theory again. It's now in the garage and here is the problem as I see it: The engine turns over fine and will actually run as long as you hold the key in the III position, which of course is engaged by the starter at this time. Letting go of the key as in a normal start procedure, and it will run for about 1 or 2 seconds, then die.
Here's what I've checked:
Main Relay, resoldered all connections and tested it successfully with a 12V battery and a voltage meter.
Checked the wiring to the MAP Sensor, it's good.
Checked ground wires on and near the thermostat, all good, or redone and have good grounds.
Checked every fuse in the car, under the dash and under the hood, all fuses are good. Performed continuity check on the ignition switch, it's good.
Car has plenty of gas. I can hear the fuel pump when the key is put into position II and checked the flow coming out of the fuel filter, it is also good.
Checked distributor cap for cracks, checked the rotor, it looks good.
I seriously thought it was the ignition switch since I noticed that when you put the key in, and turn it to position II, there are NO Lights lit on the dash board? Turn the key to Position III, the starter engages, all the lights come on, but as soon as you let go of the key, the motor dies and there are NO Lights lit?
Checked the ECU, there are and were no codes flashing on it. I did pull the fuse and reset it just in case.
I'm at a loss of where to go now. I sure hope someone else has experienced this similar problem and has the solution, or at least some advice as to where to go next?

Thanks for any help offered.

Bill

Replace the ignition switch and harness:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-2.html#post224652

Even though it tested good using the continuity checks for the ignition switch found in the Haynes Manual and another document that I found online? I was going to bet money on the ignition switch and would have thought that the continuity checks when the key was in Position II were going to fail, but all the checks showed continuity as stated in the documentation? I appreciate the link for the replacement procedure, was a little confused when it mentions "Disconnect 5-P connector from under-dash fuse box and 7-P connector from main wire harness." The continuity checks were done using a 4-P connector from under-dash fuse box and a 5-P connector from main wire harness?
I've read many of your answers to other Honda owners and you no doubt know a whole lot more than I ever will about these cars. Just wanted to make sure of the Ignition Switch and Harness before emplying my wallet.

Thanks again for your advise.

Bill

Your connectors may be different, since these do change from one generation Honda to the next. However, my bet is that the ignition switch is the culprit.

OK, I really appreciate your quick response and am very confident in your suggestion to replace the ignition switch. I will update this question and answer after I've replaced it and let you know if it fixed the problem. If so, I will have a very happy Step-son who gets his car back, and an even happier wife when she gets her car back as well (she was nice enough to let him use her car to go to school and work while his is out of commision)!

Thanks again,

Bill

Great.

Tx GreaseMonkey!! You are the MAN! Replacing the ignition electronics fixed the problem. I have a very Happy Step-son again!

Thanks for all your help!

Bill