Turning over very slow when hot.

[1983idi]

6.9 Stock IDI. Turns over very very slow when hot. So slow it won't start. It cranks much faster when it's cold and starts no problem. I believe it is the stater. I'm going to pull it and see what it looks like but I am not able to find any replacement armatures that say specifically they fit an 83 6.9. Most I find say they are for 6.9 & 7.3 1994-2000 and most of them also look like they are unbranded garbage. I found decent looking rebuild kits but I have a feeling the armature is going to be the issue. Had problems with air intrusion a few months back and had to do a lot of priming and cranking so the starter probably got overheated.

Thanks for any help guys

 

[Farmer Rock]

Definitely sounds like a bad starter to me. I wouldn't even mess around with cheap units or rebuilding kits. Priming is obviously ******* starters, that is one of the reasons why I personally use E pump. As far as I know, the 6.9 and 7.3 starters are the same. The Mitsubishi and DB starters seem to be the most durable either way.




Rock

 

[IDIBRONCO]

If you still have the original style Delco starter, the best thing that you can do is to buy a different one. I feel that they weren't any good starting in 1983. MANY years later, I can't see them being any better. They were a direct drive and didn't turn the engines over very fast even when new. From what I've seen, they also seem to be poor quality and don't seem to last very long. They are also the only ones that I can remember seeing chew up flywheel ring gear teeth on what seems like a regular basis.

 

[1983idi]

Well I have an update on the starter.

I looked into what style I had and it was not a delco style like @IDIBRONCO had mentioned an 83 would be so its been changed at some point to a mitsubishi. I pulled it apart and found that of the 4 brushes only 2 appear that they could be making any contact so I ordered a new set of brushes. I also checked the armature and it tested ok. One bearing is rough so I found some new bearings at work and changed the. I will update how it goes after getting the brushes installed and maybe post a few pictures if I have time.

It would make sense that it turns over ok cold but not once warm in this scenario. When the starter heats up the expansion may be causing a gap between the brushes and the commutator on the armature and that would cause high resistance & very slow cranking.

I also have a combination of issues here because I have a crappy 1g alternator and it never charges the battery more than 12.7 volts and at low rpm cruise/idle it only give it about 12.2 volts so I bought a 91 Taurus alternator and am working on the swap now. Unfortunately 83 being the first year I have a bit different wiring than all the write up's & videos so trying to figure that all out now. I have a feeling with batteries fully charged and new brushes this truck will crank faster than it ever has for me! Will keep everyone posted

 

[Kevin 007]

Yup. starter. They can fail in different ways, and this is certainly a way that they go.

 

[IDIBRONCO]

With a good rebuild, I feel that those are actually pretty good starters. With a poor one (from a parts store) not so much.