6.2 Diesel Won't Crank

From: Carol Kenyon (Da-Kenyons@webtv.net)
Date: Sun Jul 29 2001 - 08:46:50 PDT


I've been watching the posts on this thread.
Did anyone mention the starter?
These diesel starters take a beating!
That's why the are so heavy and cost so much.
I've seen these starters spit out mounting bolts!
Especially if the extra mounting tab isn't secured...
The starter has THREE bushings, one on each end, and one in the middle
of the shaft.
I have an electric-shop friend who owns (including family) three 6.2
diesel pickups.
It takes him about a half-day to disassemble, turn the commutator, and
round-up parts (bushings and brushes).
If you get to the end of the road and STILL no
crank, I suggest looking at the starter.
If a VAT-40 is available, you could check to see
for extreme starter draw or no draw at all.
Extreme draw (1000A?) would suggest worn
bushings allowing armature to drag on field coils (or internal engine
problems).
No draw suggests bad brushes or no signal to
starter solenoid OR bad solenoid contact disc.
You can approximate the starter draw check IF YOU ARE SURE that the
batteries are wonderful and the cables are fantastic. And YOU ARE SURE
you have no engine binding.
All you do is have someone try to crank while watching if the headlamp
brightness dims considerably, not at all, or just barely.
Cosiderably dims (possibly with a clunk) means
the starter is getting full power but cannot do the work--bad starter,
broken mounting bolts,
engine problms. (remember we said bat and cables ok?)
Doesn't dim at all--Starter not receiving power
from solenoid (bad contact disc) or bad starter
brushes.
Dims barely--either no power to starter at all or
just energizing solenoid--should click.
  If this vehicle were in my shop I would do:
1) Visually check to see if appropriate batteries
are installed.
2) Use Midtronics Battery Conductivity Tester
to check state of charge and real-world CCA or
CA.
3) Since it's diesel, I'd use VAT-40 to check for
battery voltage tapering off under load.
4) If still no crank, I'd momentarily jump bat+
to solenoid terminal--something better happen!
5) If it's obvious that the solenoid is drawing current (I see sparks)
then I MIGHT try jumping
bat+ DIRECTLY to starter motor with jumper
cables to see if it will spin at all...
5) Using heavy-duty jumper cables connected directly to your mounted
starter and a known good or fresh battery can REALLY speed things
up because it removes so much guess-work.
6) The hammer thump on the starter case is something to try here, also.
7) I've see BRAND-NEW 1000A batteries FAIL
both the Midtronics check AND the VAT-40
check. I won't go into brand names.
VAT-40 is Snap-On's Voltage-Ampere-Tester
Around $2000 new. The Midtronics is a little
hand-held tester, around $700 new.
A good shop should have both, maybe several
examples of each! If you aren't sure, remove the batteries for
professional testing.. It only takes a minute of a technician's time to
test.
This battery-cables-alternator-regulator-starter stuff is something I go
through EVERY day!
Good Luck
Don Kenyon ASE Certified Master Automotive
Technician, L-1, CA ENHANCED Smog Check
License

 



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