I replaced the starter today, still nothing. I'm thinking solenoid may already be suspect.
Why? It was cranking over with the old starter. Maybe not well, but it was cranking over. Unless you were jumping the solenoid, that shows it was working. Jump your solenoid posts and see what happens.
You should have 4 posts on the solenoid, two large and two small. Large gauge wire from battery to the large input post, other large wire going to starter from the large output post. One of your small posts will be labeled with an
S, that is the start signal wire from your ignition switch. The other small post is marked with an
I, it may or may not be used depending on how your truck is wired. It's been so long since I had my 84 2.8L that I don't recall if it was used, and it was modified anyway.
Here are a few quick test you can perform for the solenoid. You're bypassing the ignition switch and all safeties so make sure it's in park/neutral first. Probably wouldn't hurt to pull the coil wire as well, you aren't trying to start the engine, just crank it over.
First jump across the two large posts, engine should crank. If it does not crank, your solenoid is not the problem at all. Assuming that the battery is good, either your new starter is bad, or you have a bad connection/ground in that circuit.
If it passes that, jump from the input post to the signal post.
- If the engine cranks, you solenoid is good. The problem is in your wiring between the ignition switch and solenoid, the ignition switch itself, or maybe a brake/neutral safety switch.
- If the engine does not crank, but the solenoid clicks, the solenoid probably isn't the problem.
- If it does not crank and does not click, you may have a bad solenoid.
A weak crank condition is unlikely to be cause by the solenoid. Number 1 cause is obviously a weak battery, buy I'd assume you've already take care of that. Possibly by a bad connection at the solenoid, but not likely the solenoid itself. More likely a bad connection at the battery, starter, or block ground. Incorrect timing can also cause hard start problems if it fires too early in the stroke.