Slow cranking - batteries, battery post wiring and glow plugs good

[afinepoint]

The patient is a 2001 7.3L with about 155k miles.

Since purchased in 04 it has always cranked slowly. It will not start < 40° without help from the block heater. I've changed to synthetic to help but even on a 80° it turns over like 20° outside. Very slow cranking that speeds up after 4-5 seconds. Its like the batteries are near dead. There is a programmer involved but whether no boost or 80hp makes no difference. There is a ground on the GEM so the batteries remain disconnected until needed.

The glow plug resistances are good. HPOP very good. Whether the batteries are 80% or 100 makes no difference. I've cleaned all of the connections at the battery posts. I've not changed the starter.

I searched under "slow cranking" but found nothing.

 

[DaveBen]

Go for it!!! Change the starter!

 

[afinepoint]

Ordered

 

[afinepoint]

Problem solved. I thought the engine was going to jump out and run down the street. Started in < 2 seconds.

And I've been dealing with this for over twenty years. No more holding my breath.

 

[Dave in KY]

If I remember correctly, the 7.3 Power stroke requires from 200 to 250 RPM to start.

 

[DaveBen]

I seem to remember it is 300 rpms before the controller will allow the injectors to work. I am NOT positive on the 300 rpms...

 

[Strikefalcon]

Just curious. I have the same issue along time ago. I choked on the cost of a new starter back then. It cured the problem but only lasted a few years at the most. Now I am dealing with the same issue.

How much ?
Where from?

 

[BruceB]

I fought the same thing for years, going through endless batteries and eventually killing the starter. Again, had to use the block heater overnight even in fall weather.

The problem turned out to be the glow plug relay. It was activating, but the high current contacts inside were shot. About $60 for the part, and easy to change, right on top of the engine. Starts first try every time now, summer or winter.

2001 F250 165K miles

 

[afinepoint]

FWIW changing the starter requires disconnecting the main lead and a small wire on top. You can not see that nut. I gave up feeling for it and removed all mounting bolts which left me holding the starter while removing the nut. That wire is too short to allow resting the starter on something. Be ready with the correct wrench or better have a helper. That starter weighs alot and it feels like it's gaining weight by the second. I thought I could deal with it having an injured shoulder. Bad idea.