Good evening, so in the past 3 weeks I noticed that when my truck is at operating temperature and I go to crank her over it sound like the starter is very weak or something but if I want a while it cranks over normally. I checked my wiring and checked my ground everything seems to be in tact I even added a ground from the engine to the frame. I thought that was it but it was back it the next day. I have a video so you could see what I mean.

 

What do you have the timing set at? Turn it back a little bit and it should help the problem.

 

Not sure what the timing is set at it had a shop install the DUI distributor but it was fine when they did it and this was last year. Is it common for the timing unset itself?

 

fordboy300, during the last 3 weeks, has the ambient temperature gotten warmer? It might have been cooler, last year, when the distributor was first installed. Do as Franklin2 suggested. Loosen the distributor hold-down bolt and rotate the distributor body clockwise just slightly [your engine is a six cylinder, right?], secure the bolt, and start.

 

Old battery cables can also cause the problem you are getting.
Even though they might appear fine to look at, corrosion & resistance build up internally over time affecting performance (assuming your grounds etc are all good).

 

The DUI looks like a GM HEI. I have had problems with the advance weights getting corroded and sticking, and also if very light advance weight springs were installed, they may not be pulling the weights back to home. Weak springs and corrosion can work together to keep them from coming back to zero, and this would also advance the timing too much and make it crank hard.

You can take the cap off, take the rotor off, and then play with the top of the dist where the weights are and see if it's sticky. A little wd40 works wonders.

 

Worn bushings in the starter will also cause the problem.

 

Check the timing, also check to make sure the vacuum advance isn't sticking in the distributor where it rotates to pull the trigger/sensor to advance/retard the timing. I've had that happen before and damn near pulled my hair out trying to figure out why it would drag the starter down so hard sometimes and sometimes not. Even at a low timing setting. It doesn't have to stick very much at all to cause a pretty big starter drag. A simple emery cloth sanding on the breaker plate where the assembly rotates and some high temp synthetic grease fixed it.

I noticed you said you have a DUI distributor. They sell them in the Duraspark version as well as GM HEI. The problem I specified I had was with a Duraspark distributor but the advance system in the distributor can get dirty/corroded in any mechanical/vacuum advance distributor and cause the same issue.

 

Thank you every one for your replies. I'm sorry I'm just getting to log on. I'm gonna have to take a trip to the shop that installed the dizzy they told me if I had any problems they would look at it for no charge.

 

Take it on a hot day and make sure to get it good and hot so you can show them what the problem is. If it is the timing they should be able to fix it in 5 minutes.

 

Good advice to check the timing, but you're working too hard if troubleshooting this way. Years ago I was taught a good mechanic is a lazy mechanic, and I'd like to think I've proven myself...

To see if too much timing advance is your problem, there's no need to adjust the distributor. Simply disable the ignition and try cranking the engine. Obviously it won't start, but if the cranking speed returns to normal, the timing was as least part of your problem. To disable the ignition, simply pull the center lead from the distributor and ground it.

If the cranking speed is still slow even with the ignition disabled, run a voltage test on the complete starter circuit. Here's a good explanation of how it works. This is a very simple test and can be done in minutes, and will find faults that won't show with regular ohmmeter checks. I swear up and down by the voltage drop test. Even if you don't fully understand why it works, please take my word that it does and give it a go anyway:

Starter Voltage Drop Test Explained in Plain English | AutoTechnician.org