Ignition trouble

You'll want to get a multi-meter and check if power is getting through those switches. You might get a helper to turn the key to start and see if you are getting power to the B/Y (Black / Yellow stripe) wire when you have the key in the start position. If you don't, the you probably have a bad ignition switch. If you do, then see if you are getting power out of the other wire in Black / Green strip wire while the clutch is depressed. If not, then the "Starter Inhibit" switch is bad. You can also test it by unplugging it just seeing if you have continuity across it with the plunger depressed... as the clutch pedal would depress it.

If you do have power to the B/G with the key in start and the clutch depressed, then your problem is the starter solenoid or the wiring in-between the solenoid and the starter inhibit switch.

Also, check for the condition of the stopper pads on there. The could be missing and you're not getting full movement on the switch.

Here if a picture of the clutch pedal and both switches. For the record, the one at the top is called the "Clutch Switch" and is used by the ECM. The one at the bottom of the pedal travel is the "Starter Inhibit" or "Starter Interlock" switch. However, it is frequently referred to as the clutch switch or neutral switch, even though it doesn't have anything to do with the neutral or any gear. Anyhow, in this picture, the clutch pedal should have a black rubber stopper pad on it to contact the inhibit switch, just like the at the top for the clutch switch. If it is missing (as it is in this picture), that could be the reason the inhibit switch isn't closing all the way and preventing the starter from engaging.

Hi Scott,
Thanks for your replied. I forgot to mention that my truck is an automatic. So i dont think i would care about clutch switch. I have tested the B/G wire at the starter solenoid and have found 0v when turn key to start position. Tested the starter motor and it spind fine. solenoid is also works good. Im guessing the ignition key is bad but which doesnt make any scences to me. Before i have striped down the engine, everything works like a champ. After put back together, no power at B/G wire? Weired!

Do you know if there's any other connections in between the ignition key and the solenoid? From what im seeing in the schematic, there's no other connections but i could be wrong.

Yes, you should also test the electrical part (not the key/tumbler part) of the ignition switch, they go bad on these trucks like after two decades. One circuit of that switch can work fine, and other parts not work.

An automatic truck would have a safety switch (neutral safety switch) on the transmission to only let the starter run in the park or neutral positions. So you'll want to check that too, in a similar way as to the clutch pedal switch.

Yes, you're going to have to look at the inhibit switch on the transmission. Try putting it in Neutral and see if you can start it there. It's possible that just the "Park" position of the switch is bad. If so, you'll want to replace it, but at least you can start it and use it for a few days until get a new one and get it installed.

Here is the wiring diagram for a hydraulic controlled automatic. You can also see the links for the electronically controlled diagrams too... (these are for a 1991.)






Also, here are the test procedures for the hydraulic....

(These prodecures are from a 92 manual. I think the inhibit switch changed around 91 to 92 for the electronic. I think they went from a single connecter to a dual connecter. So if yours looks different, let me know what year it is and I can get you the correct procedure.)










And here is the electronic....

I have found the problem. The inhibitor switch was moved from Park to Reverse. The shift now stay at Reverse in order to start the engine.

Now, i really need help to timming the piston to have it fires up. I did tried a few cranks and it sounds weired. All i heard was 1 fire every few turns and the smokes comes out on the intake side instead. The intake manifold is hot and exshuast manifold is cool. Looks like i didnt timming right or have i miss something?
I have set the first and last piston to UP position. The 2 center to Down position. The main pulley to 0 degree as marks on the cover. The dizzy is at 10:00pm.

Please help or link me to the right thread. So, i can learn. I will be having fun during the holiday weekend. Thanks for any inputs.