6.2D starters starts slow, then speeds up

[Catrik]

-Starter always spins really slow for 1-2 secs, then speeds up and engine starts normally. Does it how or cold, glow plugs or not.
-28MT Delco-Remy
-All big cables are newish and tight
-~10-11v at batteries when starting
-Had the starter open some 4 or 6 months ago, everything looked just fine. Did I mess something up putting it together? Its not a daily driver so it doesnt see that many starts.

I really dont know what could cause this...Any ideas? I took the starter off and didnt see anything unusual.

[bd]

Worn armature bushings, worn commutator brushes or uneven commutator, pitted solenoid contacts, weak battery.  How does it run otherwise?

[Catrik]

Batteries are new Bosch 70Ah/630A. I did check the bushing and brushes and they were good, atleast 4-6months ago. Couldn't check the solenoid contacts because it's "non-serviceable" but if it was bad then I guess it would just be always slow starting? I guess I should invest in an clamp amp meter so I could diagnose these kinds of things more easily.

How does the engine run otherwise? Havent had any problems (recently). No bad idle or anything.

Finally found some other forum post with the same problem http://www.dieselplace.com/forum/63-gm-diesel-engines/20-6-2l-diesel-engine/195113-intermitant-slow-crank-but-then-starts.html
Some guys had a loose solenoid wire.. Mine didn't but Im gonna try to wire it directly from battery and see what it does.

[roundhouse]

Make sure ground wires from the block to frame and battery to frame are clean tight and new
And if you decide to replace the starter
Don't buy one.   Have you'rs rebuilt at a local shop

Sent from my iPhone using Tapatalk

[Catrik]

I did some testing and the solenoid works really snappy.
Without load, the starter "kicks" alive but takes a second or two to get full RPM. Might be due jumper cables (not very good connection) or the fact that it revs much higher than with load.

Put starter back in the truck and jumped the solenoid. It seems to run better than before but I think it should be faster.  I dont like "feels" tbh.. I need to invest in an optical tachometer and clamp ammeter to get some actual data 

I noticed my battery terminals dont make a very good contact, going to replace them all.
Tomorrow I will compare jumping the solenoid vs turning the key, if it makes any difference. If not then I will replace the solenoid

Make sure ground wires from the block to frame and battery to frame are clean tight and new
And if you decide to replace the starter
Don't buy one.   Have you'rs rebuilt at a local shop

All wires are new and tight. I made sure ground is good by jumping battery to block when starting, no change at all.
I meant to rebuild the starter 4-6months ago but at that time my problem was just a loose positive cable at starter.

[bd]

If the cables are new then why don't they make good contact with the batteries?  What gauge battery cables did you use?  Are they all copper cables or copper clad aluminum?

Measuring the actual starter draw and performing comprehensive cranking system and voltage drop tests would be the prudent approach.  Frankly, if there isn't an external cause related to battery supply or cabling, I think armature bushings and brush/commutator continuity is the most likely cause.

[roundhouse]

If you have the battery cables that clamp onto the wire at the battery end
Toss em and get some that have the clamp made on


Sent from my iPhone using Tapatalk

[Catrik]

Someone has probably overtightened the battery terminals, they dont seat properly. Cables are big enough industrial welding cable, I dont know what gauge.
Cables have crimped and soldered ring terminals that bolt to the battery terminals.

It's been raining all day so havent done anything yet, hopefully tomorrow. Thanks for the helps so far anyway!

[Catrik]

Well it wasn't the solenoid. I cleaned the contacts but it didnt make any difference. Borrowed another starter which works great.

Then opened up my starter and there was quite a bit gunk in there. And some brushes worn in an angle, maybe they were installed poorly and didnt make a good connection. Commutator is good.

Been trying to find a place to get new parts from for a few days since rockauto wants $150 for the solenoid alone?! Cant find anything from ebay with reasonable shipping to Finland.

[VileZambonie]

Do a voltage drop test from the cable to the terminal and connections as well as along the cable end connection to connection.