Engine drags on cold start.

[ScottyBoy]

We don't have any Costco stores here.

 

[Bernie]

Dave, what's the voltage at the battery immediately after starting the truck? (You'll need someone to start it while you check the voltage)

I'm betting you'll see a voltage of around 14 to 14.5, dropping down to 13.5 (approx) as the alternator quickly replaces what was drained from the battery while cranking. If that's the case then the alternator is good.

(Oh, and it'll probably drop to 10 or so while cranking, then climb up to 14.5 and then taper off)

12.50 then drops to 10.15 then goes up to 12.50-13.15. This is on hot/warm engine start.

Okay, I was wrong then. Based on those readings right there that alternator is well on its way to becoming toast. Replace it.

 

[Bernie]

We don't have any Costco stores here.

Nope, the closest would be just east of Dallas, in Rockwell

 

[davbell22602]

I have internal fan on the truck now which is 105 amps. Pepboys has a 140 amp external fan for 149.99 made by pb/prostart platinum. Will a external fan work? 100% new not a reman.

 

[Bernie]

It might... It really comes down to the case size/style. You'll know right away if it doesn't though.

 

[davbell22602]

Its look like the same in casing the internal verses casing size plus external fan space.

 

[Bernie]

I went from an internal fan to an external when I upgraded from a 100 to a 140. Slightly larger diameter case but the lugs were shifted slightly so that it kept the proper belt alignment.

IIRC, the 105 is the small case, and the 140 is much larger, so that might be an issue, especially with belt size (might have to go to the next size up), but the main difference will be in the field wire connections. The 140 will probably use the older style CS connector, and you'll need an adapter to connect to it.

In your place I'd probably just go to the shop and ask if you can see one in person, and explain that you want to see if the field connections are the same. Once you compare it with what you have you'll see right away if it will fit or not.

 

[drperry]

If you don't have any additional electronics, and don't plan on adding any more electrical load, you don't need to upgrade the alternator...

 

[thunderstruck]

I'm not saying this is your problem, but do this anyways. Take the battery cables off of the battery and check the surface of the terminals for corrosion. Sometimes corrosion will hide under the rubber surrounding the terminals and cause problems. Make sure you pull apart the two positive battery cables and check between them too.

 

[davbell22602]

Well replaced the alternator with 105 amp. See what that does.