Problem starting truck

My husband has been having trouble with his truck starting even after repairs. He has had fuel pump replace, new plugs, head gasket replaced, crank sensor replaced, thermostat replaced. It will run a couple days then won’t start. Heavy rain seems to have an effect. Can you help? We are getting repair poor. The truck has less than 50,000 miles.

When starting problems like that occur the trouble is often with the ignition system high tension wires. Leaks in the insulation are often found and the spark jumps out due to the moisture and finds a path to ground. To see if that may be the cause you can try using a spray bottle with some water in it. Do the test at night time so you can see any sparking that may occur and spray suspected areas with a light mist to see if makes any spark or change in the engine speed occur.

The truck won’t start. Can I still perform this test and what areas should be sprayed?

The truck won’t start. Can I still perform this test and what areas should be sprayed?

Start by changing the sparkplug wires

Check the wires, cap and rotor. Look at the engine when cranking the starter when it is dark outside. You are looking for a white to blue light at the cap or along the wires. When you say it wont start you mean it does not try to start? No bang at all?

The truck turns over freely but does not try to start.

We cranked the engine in the dark. There was no white to blue light at the cap or along the wires. The engine did run on after the ignition was turned off this time.

I should mention that the truck did not start.

If the engine won’t start then check for spark getting to the plugs. If that is ok then check the compression to make sure that is good. Try using some starting fluid to see if that helps it get started.

We need to know the model year, and the engine size, your GMC Sierra 3500.
What other engine problems has the truck had other than the non-starting one? Have there been any trouble codes from the check engine light being on?

Year-1999, engine 305. No other engine problems other than non-starting. Engine light was not on but they ran codes: Crank shaft sensor, temperature sending unit. Both were replaced last week. Head gasket replaced the week before. It is back in the shop today and so far they haven’t found anything. Appreciate your help. It runs typically 1-2 days then turns over but won’t start.

The mechanics think they have solved the problem. A cracked rotor in the distributor.