Starter not engaging intermittently

[redmondjp]

back together and it spins fine.

When you say this, I am assuming that you mean by hand?

After having a starter apart, I always test it on the ground, using a set of jumper cables and a remote starter switch (or garbage screwdriver, same thing ). No use reinstalling a dead starter.

My hunch is that you may have a shorted commutator--the cheaper rebuilders will only clean up used commutators--well, they're supposed to test them too, but . . . they can fail--the insulation can give out, and it can slowly happen over time. Can have a short in the field windings also, and this will consume major battery current when the solenoid is engaged.

Other than that, the problem may be in the solenoid, which is what you probably hear clicking. Once the solenoid engages the drive gear, it's supposed to close a set of high-current contacts and start the motor a spinnin'. To check this, have the starter engaged and check for voltage (use meter or test light) at the terminal on the solenoid that connects to the starter motor itself--if close to battery voltage is present, then solenoid is probably OK and it points to commutator or field winding failure. If no voltage, then high-current contacts inside solenoid are probably to blame.

BUT I can't tell you how many times I've been burned by bad battery terminal connections, where a low current (enough to run headlights) will pass OK but when you go to start, no dice. You've probably been all over this already, but just in case, double-check things again.

I think most of us here have been where you are, at least once. Hang in there, you'll get it figured out. I have learned to quit working on my rig for awhile when I get really mad at it, else I start banging on delicate parts with a heavy object!

[cseger1]

JP,

Thanks for the encouragement, unfortunately I can't go long without that truck. When i said it spins on the bench I meant it works fine when hooked up to the jumper cables. I just went out to see if I could jump it off my project car. I got 13.6v at the battery and only that click. I just don't get how it could work correctly on the bench and again briefly in the truck. Rocking the motor and hammering didn't work either.

[asavage]

Two things come to mind:

a) Hook your voltmeter to the block (ground) and the starter motor terminal (not the starter battery terminal) and watch the meter: zero volts. Then perform your "short across the big terminals on the solenoid" test again, now that you've cleaned out the starter. If nothing happens (no sparks, no motor runs) AND you have approximately battery voltage while doing the test, then --

b) Bad armature. Dead spot. Sorry 'bout that.

Really, once you knock down these issues, they are reliable rigs. But if this truck is your only source of transport, then you may need to reduce your expectations of reliability of 25-yr-old vehicles.

----

I'd like to congratulate you on your mastery of the [gotopost] bbCode tag.

[cseger1]

Really, once you knock down these issues, they are reliable rigs. But if this truck is your only source of transport, then you may need to reduce your expectations of reliability of 25-yr-old vehicles.

HAHa, the truck is the newest vehicle I own. I also have a 63 Buick and a 73 Yamaha motorcycle. Between the three I get around pretty well. Unfortunately I cant carry lots of stuff in the other two, and I carry stuff all the time.

When I changed the battery cables I cleaned all the ground points so I don't think thats a part of the problem. I'll try the hotwire trick with the meter and see what I get.

[cseger1]

Update:

I just tried Al's last recomendation. The battery side terminal reads 12.8 with no load.The voltage between ground and the motor term is o. With the solenoid engaged via short circuit it reads 12.01. do these readings tell you anything?

[redmondjp]

Update:

I just tried Al's last recomendation. The battery side terminal reads 12.8 with no load.The voltage between ground and the motor term is o. With the solenoid engaged via short circuit it reads 12.01. do these readings tell you anything?

Hmmm, well, you're solenoid is working properly, and it's giving voltage to the starter motor . . . but doesn't sound like motor is doing anything with it--I'd agree with Al, I suspect the armature has stopped at a dead spot. If you had a short inside the starter, I'd guess that the voltage at that point would be way less than 12.01.

[philip]

Update:

I just tried Al's last recomendation. The battery side terminal reads 12.8 with no load.The voltage between ground and the motor term is o. With the solenoid engaged via short circuit it reads 12.01. do these readings tell you anything?

The reading suggests that the contacts in the starter cannot carry AMPERAGE suffient to turn the starter but have enough contact for a measly test lamp.

Does the starter spin when a jumper cable is connected to the post on the starter? Yes... faulty solenoid contacts. No ... junk starter.

(poway usd reference page)

Automotive Engine Performance Starter testing on the vehicle Before performing a starter amperage test, be certain that the battery is sufficiently charged (75% or more) and capable of supplying adequate starting current. A starter amperage test should be performed whenever the starter fails to operate normally (is slow in cranking) or as part of a routine electrical system inspection.

General specifications for testing a
starter on the vehicle:
• 4-cylinders = 150 to 185 amps
• 6-cylinders = 160 to 200 amps
• 8-cylinders = 185 to 250 amps

Some service manuals specify normal starter amperage for starter
motors being tested on the vehicle; however, most service manuals only
give the specifications for bench-testing a starter without a load applied.
These specifications are helpful in making certain that a repaired starter
meets exact specifications, but they do not apply to starter testing on the
vehicle.

[asavage]

I just tried Al's last recomendation. The battery side terminal reads 12.8 with no load.The voltage between ground and the motor term is o.

That's correct. Until . . .

With the solenoid engaged via short circuit it reads 12.01.

This is with the VM on the starter motor terminal? If so, the solenoid is passing current to the starter motor, which is not running. Problem is inside the starter, and unless you find a brush spring missing, or a broken wire, chances are it's the armature that's gone gunnysack.

Upthread, you said:

This is in a truck that has new (rebuilt) starter . . .

Does it still have a warranty?

-----------------------------------

I have a JY SD starter than I've never tested, only cleaned up and put under the bench. I'd be willing to sell it, but you could probably get a cheap rebuilt for what I'd have to get to pry it out of my hands.

The problem with used diesel starters is that they tend to get overused when the GP system or injectors or compression get in poor condition. I'll go drag that one out and hook it up . . . .

. . . yeah, it runs and sounds OK. Well, that's a relief, after both of my spare LD28 starters had bad solenoids.

RockAuto lists five starters for '82 720 w/SD, but I think four of them are wrong: a couple, from the pictures and descriptions are direct drive starters. The fifth is AC Delco 336-1396, and the picture is correct. Click on the part number to see it, it's too much work to figure out how to link their pic here.

RockAuto gets $145 + $29 core for it, which isn't too bad.

NAPA's best starter, the Raylock RAY446011, is $179 + $22 core. They are calling this unit "direct drive" also, even though it's clear from the picture that it's not:

The Raylock starters have a lifetime warrany, plus one free jump start or tow (up to $60 worth, anyway; you pay the difference if the tow is more). You send in the form that comes with the starter, they send you a card you throw in the glovebox, and call their number if you need to use the service.

Never buy a NAPA starter whose part number begins with a "2".

I, personally, would trust and buy the Raylock, if I decided to not let my local rebuilder at it.

[cseger1]

This is with the VM on the starter motor terminal? If so, the solenoid is passing current to the starter motor, which is not running. Problem is inside the starter, and unless you find a brush spring missing, or a broken wire, chances are it's the armature that's gone gunnysack.


Does it still have a warranty?

Yes the Vm reading is from the motor terminal. The warranty is 30 day, the starter is literally 35 days old. For what its worth it was only $79 after the core charge. I am going to try and find the Raylock starter. I like the sound of the lifetime guarantee. Thanks Al.

[ocd]

here is an update on my little sd. after several hours of attention to the electrical connections -cleaning sanding and deox-ing -it still would just click though a seemingly more crisp/concise sounding click. so i grabbed the battery from my volvo and swapped it with the old DieHard and to my surprise/delight/Doh!!! it started up just fine. took the old battery to baxter's and they tested it and the "state of health" index was the lowest to still register but still advised a charge and recheck. and the old battery was not rated for that application -only 640cca.

there have been so many things that i would have liked to have my pickup for -KISS

[philip]

SNIP- I took the old battery to baxter's and they tested it and the "state of health" index was the lowest to still register ...

I know this is real basic stuff but here goes. Battery clamps develop an electrical barrier (black in color) on the surface contacting the battery post. This inhibits large current flows such as the starter draw but is still adequate for lesser loads. Those two part battery cleaning tools (male and female wire brushes) do a good job of removing this stuff but sometimes it's better to just replace the clamp.

Load testing a battery is everything. Volts with low amps ... no good.

[billyg]

I've read everything I can find on the forum about the starters and solenoids and I've tasked myself over the Christmas break to fix it [See user rigs (billyg) to have a look if you're interested]. It's been clicking ever since I got it road worthy again a little over a year ago. My problem is that I can't understand WHICH components could be causing my problem given my method of starting.

My remedy has been to park on a slight incline and, if it clicks, put it in second gear, let it roll enough to turn the engine when i pop the clutch, repeat until it starts. This method hasn't failed (yet) to get me going. My thinking was that the solenoid could be kicking the spur gear into the flywheel but due to having sat for 8 years, it might be so dry that the starter can't push it to 'fully engaged' with the flywheel. This would make sense given my 'starting history' and I had this same scenario once on a Kubota lawn mower. New battery and ground point checked.

It just doesn't consistently act like a pure electrical problem. Rocking the engine wouldn't change the position of the starter motor so it can't be that. I hear a good 'clunk' consistently when i go to 'start' (solenoid kicking the spur gear out). I guess it could be the solenoid contacts and I've just been fooling myself for the past year with the engine rocking??

Opinions/other case studies??