Question: I have a '93 YJ that had a 2.5-cylinder/five-speed manual combo. I swapped in an AMC 401/Turbo 400/Dana 20 with 12 inches of lift, 38.5-inch Boggers, and Dana 60s front and rear with a Detroit and an ARB. After my Holley Truck Avenger carb was stolen off the Jeep, I installed a Holley TBI system and got it up and running without ever really being able to fine-tune it before I had this problem. One morning, I went out to start it and the starter solenoid clicked really fast a couple of times. From then on, the light on the dash cluster that comes on when you first turn your key to the "on" position did not engage, and the starter solenoid no longer clicked. The fuel pump does not receive power, and nothing happens when I try to start it.
After months of ripping apart the electrical system, I found a couple of burnt-out grounds and fixed them. I plugged everything back in and went to start the Jeep. Hurray! The light came on again when I went to start it. The solenoid clicked again, so then, I thought, the battery was a little dead. I tried and started it again, and the light goes out with no power going to the ignition system again. I checked all the ignition and starter fuses, and checked all grounds.
I am running out of ideas and am thinking of just selling it as is, but it is the Jeep that I have always wanted, and anything I buy would be built like this again.
Answer: Problems like this can be really hard to diagnose, especially without seeing the vehicle first-hand. I am sure lots of changes have been made during the course of the various modifications, especially to the wiring. Here is my best shot.
OK, you've checked all the grounds. But have you? There should be a ground between the body and the frame, and between the engine and the frame. This is where people really screw up, not using a large-enough ground wire. I believe that both of these places should have a ground the same size as what you're using for the battery cables, and they must be making a good contact. Be sure there is a good clean connection between the steering column and the dash, as this is the ground for the ignition switch.
But I don't think that is your problem. Usually, when the solenoid just clicks, it's an indicator that the battery is not producing enough current to maintain the contacts within the solenoid. The battery is fully charged, right? The post connections are clean and tight? I have seen just enough corrosion buildup on the posts where low-amp-draw equipment such as the headlights will work, but not enough amps will get to the starter solenoid to make it work. It also could be a bad starter solenoid, but I doubt it.
My guess is that you're not getting a good current flow from the battery to the ignition switch or from the switch to the starter solenoid. A big clue to the problem is the fact that the electric fuel pump is not working. Usually, it gets its power from the power distribution center (mounted to the left of the steering column) or from the fuel-injection control box (computer). A lot depends on how many factory wires were bypassed during the engine and EFI swaps.
So, the first thing to check is whether there is power to the ignition switch. Seems to me the easiest way to find this out is if the signal lights and heater work with the key in the "on" position. Next step would be to check the voltage at the wire that activates the solenoid when the key is turned to and held at the "start" position. There shouldn't be more than about a 0.5-volt drop between the end of this wire and the voltage measured at the battery. If there is no current here, then I would unplug the connector at the steering column and check the voltage there. At the bottom of the plug are three prongs all in a line; the outer left one with the 18-gauge yellow wire labeled "A41" is the one to check.
Still no voltage? Then you have a bad ignition switch. I suggest that you consult a factory service manual on the proper way to replace this switch. OK, so you have voltage here but not at the solenoid. I believe that this wire doesn't go directly to the solenoid but to the power distribution box. In it are a bunch of fuses and relays. Three things that you most likely haven't checked are: the fuel-pump relay (second on top row), automatic-shutdown relay (fifth one, top row) and the starter relay (sixth on top row). There should be a sheet on the inside cover of the box that shows the location of each one. About the only way, and perhaps the best way, to test these would be to replace one at a time with a known good relay. (OK, you could take a bunch of time figuring out which post was ground, feed, trigger, and output, then hook up a bunch of wires and bench-test it.)
I'm not really sure what red light you're referring to that now does not come on. With the original engine and PCM (computer) there is a red lamp that would illuminate when the Powertrain Control Module (PCM) detects an open or shorted circuit, or absence of current flow in an output device such as when the key is first turned on. However, it was only designed to illuminate when the ignition key is turned to the "on" position, and it stays lit for three seconds as a bulb test. Signals that can set the malfunction indicator lamp are low battery voltage input. However, without the original PCM, it should not work unless someone has wired it somehow into the Holley EFI system.
So what it all comes down to is that you spend some time with a test light and volt meter.